Pandemic Ventilator Project

End of the Project

2011-05-22T17:28:00.000-07:00

If you landed on this page first, you may want to look at my list of all blogs in the following link. You can follow the project from beginning to end or just view the best parts. http://panvent.blogspot.com/2007/02/pandemic-ventilator-project-list-of-all.html

The H1N1 pandemic scare has now passed into history. It was (thankfully) very mild, and the need for extra ventilators was minimal. Most governments and health care providers have reasonably sensible pandimic plans now in place. Some companies have produced very affordable and reasonably capable ventilators that are being stockpiled in case another pandemic occurs. I guess the H5N1 still is a threat, but most authorities and news media are not interested in pandemic talk anymore. Hopefully that never mutates into a human contagion.

I don't think there is really that much more that I can contribute. I will leave the site open for comments and weed out the spam from time to time. Occasionally I still hear from people that want to talk about the project and the social ramifications of doing something like this

I would like to thank everyone who worked on the project, commented, given me ideas or valuable criticism and support. I have a lot of ideas on many topics. I hope to start work on a device I designed that can improve the life and health of home dialysis patients. I work in home dialysis and have spoken to a lot of people about what they want and I know of a way to provide this flexibility at a low cost. This time I want to use the traditional approach of patent and IP protection. I hope to start another blog sometime where I discuss some of the other ideas for inventions that I have.

In any case I am doing well, and my son (who built a prototype for me) is also doing very well. I think the process of working on this project has been a very good experience for us both.

Bye for now,
Dreamer

ECMO Dialysis H1N1 and MacGyver

2009-10-01T18:10:00.000-07:00

Many people have called what I am doing a “MacGyver” approach to supplying ventilators for a possible shortage during a pandemic. In case you are not aware, MacGyver was a character on a TV show. The clever solutions MacGyver implemented to seemingly intractable problems, often in life-or-death situations required him to improvise complex devices. He used knowledge of science and engineering along with a little innovation to build these devices out of whatever materials he had at hand, to free or save the lives of the people he needed to help. Now that I think about it, I don’t think the comparison is too far out.

Last month I was pondering some articles I had read about the treatment of ARDS (Acute Resoiratory Distress Syndrome) in the H1N1 (swine flu) pandemic. These articles said that some of the people that were getting very sick from H1N1 could not be adequately treated using ordinary ventilators. They required the use of HFOV (High Frequency Oscillatory Ventilators) or ECMO (Extra Corporeal Membrane Oxygenation). I researched HFOV and found a published design that I thought could be modified so that people could build these units as emergency pandemic ventilators. http://panvent.blogspot.com/2009/09/high-frequency-oscillatory-ventilator.html
I have more detailed information in my previous post. I also have designs for a more basic ventilator as well.
http://panvent.blogspot.com/2007/03/preliminary-layout-for-open-source.html

When I first heard about ECMO, I thought that surely ECMO must be beyond the scope of the Pandemic Ventilator Project. It is a complex process requiring complicated equipment. I did a little research on it on my break at work. (I work as a dialysis technologist.) As I read about the requirements for equipment to do ECMO, an odd thought occurred to me. Everything that the paper in front of me said I needed to do ECMO was on this machine that was right beside me. That machine is a hemodialysis machine. I did some more searching on hemodialysis and ECMO and found that dialysis is often used in conjunction with ECMO by either using 2 sets of equipment, or just by adding a dialyser to the ECMO circuit, but I could find nothing about actually doing ECMO on a dialysis machine.

I thought, “Now this is an original idea!” I quickly put my thoughts together and posted it as a possible help for pandemic flu sufferers. I contemplated it again later and thought that it may even have some advantages over conventional ECMO in that citrate anticoagulation could be used. I asked for comments on the blog which were mixed, but nobody said they had done it, were considering it, or had even heard of it being done.
http://panvent.blogspot.com/2009/09/using-dialysis-machine-to-do-ecmo.html

Today I did a little more research. This time it was for CRRT (Continuous Renal replacement Therapy) and ECMO. I found something truly amazing. Someone had already thought of this more than 2 years ago and used it to save the life of a child. (Goodbye original idea.) Here is another of those heroes I love, like the people that built ventilators to save the lives of children during the polio epidemic. http://panvent.blogspot.com/2008/01/everything-old-is-new-again.html

This person is Dr Abhay Divekar of the Winnipeg Children’s Hospital Health Sciences Centre. He used his idea of doing ECMO on a dialysis machine to save the life of Keith Porcher. The spokesman for the hospital told a news conference “We felt the baby had no other option, that if this experimental procedure wasn't going to be tried, the baby was going to die."

Dr. Divekar, (a true MacGyver, someone should present you with a gold Swiss Army knife) you are a hero in my eyes, and I would love to talk to you some time. I have plans to post a hall of fame page in the future describing every one I could find that built ventilators in an emergency to save someone’s life (most from the polio years). You will definitely be on that page.

So now doing ECMO on a dialysis machine seems much closer to a viable option for emergency use in a pandemic. I even found something about using citrate with ECMO. Vanderbilt University is doing a study on citrate use in babies on ECMO.

CBC radio ran an interview they did with me about the Pandemic Ventilator Project on the Oct 3 episode of White Coat, Black Art. you can get the podcast version here:
http://podcast.cbc.ca/mp3/whitecoat_20091003_21062.mp3

The part about the Pandemic Ventilator Project is at the end.

Here are the links.

JAMA article shows that most patients with severe H1N1 that are treated with ECMO survive
http://jama.ama-assn.org/cgi/content/full/2009.1535

Winnipeg surgeon "MacGyvers" artificial lung
Dialysis machine transformed into heart/lung bypass, saves newborn http://www.nationalreviewofmedicine.com/issue/2007/03_15/4_advances_medicine1_5.html

Rescue ECMO
ECMO used on CRRT machine in Winnipeg
http://www.hsc.mb.ca/press_release22.doc

Experimental artificial lung saves baby
http://www.cbc.ca/health/story/2007/02/16/lung-baby-porcher.html?ref=rss

Study Using Citrate to Replace Heparin in Babies Requiring Extracorporeal Membrane Oxygenation (ECMO), Vanderbilt University
http://clinicaltrials.gov/ct2/show/NCT00968565

MacGuyver at IMDB
http://www.imdb.com/title/tt0088559/

A High Frequency Oscillatory Ventilator Design For Use in Pandemics

2009-09-26T18:20:00.000-07:00

This is a continuation of some of the ideas I expressed in a previous post on HFOV design. You can see it here: http://panvent.blogspot.com/2009/08/crisis-is-near-now.html

Some of the news items I have been reading say that there will be a particular shortage of high frequency oscillatory ventilators. Many ICU units do not have any or may only have one. This type of ventilator is required to care for patients with the most damaged lungs. Here is a little more information on a design for an HFOV. This is very preliminary. It surely needs more work. Someone would have to to build and test a prototype to determine if it is feasable.

What is HFOV?

An HFOV (High Frequency Oscillatory Ventilator) is an advanced ventilator design that is sometimes used in ARDS (Acute Respiratory Distress Syndrome) patients when a conventional ventilator will no longer provide adequate ventilation. Using a HFOV is considered a “lung sparing” technique.

When using conventional ventilators, the ventilation levels can be increased by increasing the percentage of oxygen fed to the ventilator, increasing the stroke volume, or increasing the rate or frequency. Other measures to improve ventilation can be increased PEEP (Positive Expiratory End Pressure) levels, reversed I/E (Inspiration/Expiration) ratios, methods to increase the average airway pressure, or even PLV (Partial Liquid Ventilation) has been tried, where a perflourocarbon solution (perfluorooctyl bromide) is put into the lungs to reduce lung damage without reducing oxygen transfer. ECMO (Extra Corporeal Membrane Oxygenation) is another method that can prevent damage to lungs by the use of high pressures and oxygen levels in conventional ventilation.

The HFOV can maintain a fairly high mean airway pressure, resulting in better ventilation without causing as much lung damage. With the high rates required for HFOV, each breath is less than the dead space in the lungs. There are various mechanisms that explain how it works (http://priory.com/cmol/hfov.htm), but it does work quite effectively. The breathing mechanism is similar to a dog panting at a high rate.

How HFOV Works

To make a HFOV work, you need to have a system that maintains a set average airway pressure and then have another device that oscillates this column of air at a desired rate, amplitude and I/E ratio. That’s the fundamentals of what it does.

Now to optimize this design you need to have a gas management system that controls the oxygen level, temperature, humidity and inlet pressure and flows to the HFOV device. We do not have to worry about designing these parts. They are all standardized respiratory equipment that is also used on conventional ventilators.

Other design considerations are that the air flow goes through the tubing in such a way as to optimize gas exchange, and we will also need other alarms to warn us of low or high pressures, improper rates and loss of supply gas. We may also want additional alarm systems that warn us of equipment failure modes. The tubing should be relatively non-compliant and the system should have minimal dead space.

Fig 1. HFOV design from IEEE Transactions on Biomedical Engineering
this link.

This design would be based mostly on the diagram in Fig 1. The controls and operator interface could be modeled to be similar to the 3100B from Sensormedics. The 3100B is the most commonly used HFOV for adults. Many RTs are already trained in its operation. By making the controls and alarms similar to the 3100B, it could be more easily deployed in a pandemic situation.

This is how the device in Fig 1 works:

A filtered, humidified air/oxygen mixture is fed into the feed tube near the ET (Endo Tracheal) tube. The flow rate is monitored and controlled by the mass flow meter
It travels down the tube towards the oscillator unit and exits via the servo controlled restriction valve.
The pressure sensor is that thing on the tube between the inlet and outlet ports. The electronics control system will receive this pressure signal and adjust the servo controlled restriction valve so that the average airway pressure is equal to the desired set point.
The pneumotach is not really required for operation. They have to do measurements for their study. Vacuum is not really required either, as average airway pressures will always be positive.
The oscillator is that plunger looking thing on the right hand side. It looks and works like a speaker in the 3100B but is really a special purpose built device. They call it the driver.
The plunger moves in and out at the desired rate, wave shape and amplitude as determined by the driver circuitry and the operator settings.
Now, you can see, that column of air is going to push and pull air in and out of the ET, which goes into the lungs. When the air comes out of the ET, the fresh bias flow gas will flush it away and out toward the servo controlled restriction valve. Fresh bias air is pushed into the lungs when the plunger moves toward the ET tube.
The oscillations of the plunger will change the instantaneous pressure in the tube positive and negative with respect to the average pressure.
The position feedback device improves the performance of the oscillator circuit and can also be used as a part of a safety system

Parts And Controls

I will group parts into 3 general categories.

Oscillator driver and driver circuit.
Sensor, actuator and associated circuitry.
Control and display system.

Oscillator Driver and Driver Circuit

For the oscillator driver we would want to use a big, high power subwoofer type speaker. It should be tough and able to handle high duty cycles and long periods of operation. It should have a metal cone to make it inflexible. We might have to glue a metal plate to the cone to make it more rigid. In order to reduce the dead space, we could make a mold of the front of the cone surface in resin or silicone with an air access hole drilled in the center to mate with the speaker cone assembly.

I am not certain how well a speaker will work though. There must be technical reasons why the designers of the 3100 use that design. Speakers, even subwoofers have a certain compliance and harmonic resonance built into them that is at a higher frequency than the rates we would need to use. It may require a large speaker using only a small portion of it's maximum designed excursion in order to minimize the effects on the output airflow pattern caused by the damping effects of the speaker cone suspension.

I am not sure if a position sensor is absolutely required, but something can be attached to the back of the cone if it is. Cooling may also be required. We could use lots of air and fans, or perhaps an active system using peltier devices.

The drive circuit would be a high output audio amplifier. I think it is best to use one designed for automotive use. These are generally more rugged, modular and can easily run on a 12 volt battery for electrical backup purposes.

Sensor, Actuator and Associated Circuitry

The sensor and circuitry would be similar to the one my son Jeff used in his ventilator design (Norman). It would convert the pressure pulse to a digital value encoded and sent on an RS232 port. We may wish it use more than one pressure sensor in order to provide redundancy for safety reasons. The pressure controller and alarm board would be a servo controlled valve and driver circuitry that operates by RS232. It could also house the audio alarm. This alarm would also engage and cause the valve to open if communications were lost. These circuits would have to be hand built unless there is a commercially available alternative.

Control and Display System

The control and display system would be a computer. It would probably be a PC and probably a laptop. A laptop has its own integral battery backup system. A program such as Labview can be run to show a display that looks similar to the control interface from the 3100B.

The instantaneous pressure readings received from the sensors could be integrated over time for display. The minimum and maximum pressures would be the peak recurring pressure extremes integrated over a short time interval. The average pressure would be integrated over a longer time period.

Operating parameters could be entered by selecting the appropriate box on the screen and entering the parameter via the keyboard. Alarms could also be displayed and color coded.

The computer would also output an audio signal to the speaker amplifier. This wave shape is normally a square wave pulse produced by a pulse circuit with variable duty cycle, frequency and amplitude in the 3100B. In our machine, we would have full control of the waveform via software. We could add pre-emphasis and custom wave shaping to the output to compensate for physical design shortcomings in the speaker and driver circuit or shortcomings in the housing and tube.
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Here are some resources if you want to learn more about HFOV.

Guidlines for the use of HFOV
http://priory.com/cmol/hfov.htm

HFOV guidelines from Stanford Hospital and Clinics
http://scalpel.stanford.edu/ICU/HFOV%20Guidelines.pdf

The use of HFOV in surgical patients.
http://www.surgicalcriticalcare.net/Guidelines/High%20frequency%20ventilation.pdf

Slide show of HFOV in the adult patient.
http://intranet.unchealthcare.org/hospitaldepartments/respiratorycare/practice-education-and-research/inservices-presentations/HFOV%20in%20the%20Adult%20Patient.pdf?searchterm=suction

University of Virginia experience with HFOV.
http://www.healthsystem.virginia.edu/internet/respiratory/Research/Retired/HFOVposter.pdf

ARDS and HFOV from Express Healthcare.
http://www.expresshealthcare.in/criticare2009/criticarefrontiers200912.shtml

Ventilation article from Answers.com.
http://www.answers.com/topic/mechanical-ventilation

Wickipedia Article about HFOV (please improve this)
http://en.wikipedia.org/wiki/High_frequency_ventilation

Spec sheet for the 3100B
http://www.viasyshealthcare.com/prod_serv/downloads/062_3100B_Spec_Sheet.pdf

Picture of a 3100 HFOV
http://commons.wikimedia.org/wiki/File:HFOV_3100A.jpg

Competency exam for 3100B operators.
http://www.viasyshc.com/smc/Reference/Critical_Care/Exams/3100BExam.pdf

Video showing operation of the 3100B
http://www.youtube.com/watch?v=jLroOPoPlig

Video showing initial operator calibration of the tubing set for the 3100B
http://www.youtube.com/watch?v=O2TaDyzxQAY

HFOV design is Coming Soon

2009-09-24T09:11:00.000-07:00

If you are looking for my ideas on using a dialysis machine to do ECMO treatments you should visit my previous post here: http://panvent.blogspot.com/2009/09/using-dialysis-machine-to-do-ecmo.html

A lot of people have been looking at my ECMO post, and I have now had somefeedback on it. I am in the process of making contacts with local people to see if they will look at my idea and discuss its merits and drawbacks. I am not sure what the best strategy is to pursue this, through the Pandemic Ventilator Project or by other means.

Another idea I am working on is to produce a design for an HFOV (High Frequency Oscillatory Ventilator) using readily available components. See here: http://panvent.blogspot.com/2009/08/crisis-is-near-now.html .
I visited an ICU and saw one in operation. I talked to an RT about how it works and how they manage the device (thanks, Sue). I have also obtained some technical details and specifications for existing designs. I have a few days free this weekend and I hope to work on this idea a little more. Hopefully I can have some more info on the blog for Sunday night.

Here I reprint an excellent article I read on Propublica.org. The original is available at:
http://www.propublica.org/article/flu-nightmare-officials-ponder-disconnecting-ventilators-from-some-pat-923
This article is one of the most comprehensive, balanced and well written pieces I have read so far on the subject of ventilator shortages in the H1N1 pandemic. I hope that it is widely read by the public, as well as planning and “deciding” individuals.

Flu Nightmare: In Severe Pandemic, Officials Ponder Disconnecting Ventilators From Some Patients
by Sheri Fink, ProPublica, September 23, 2009 6:15 pm EDT

With scant public input, state and federal officials are pushing ahead with plans that -- during a severe flu outbreak -- would deny use of scarce ventilators by some patients to assure they would be available for patients judged to benefit the most from them.

The plans have been drawn up to give doctors specific guidelines for extreme circumstances, and they include procedures under which patients who weren’t improving would be removed from life support with or without permission of their families.

The plans are designed to go into effect if the U.S. were struck by a severe flu pandemic comparable to the 1918 outbreak that killed an estimated 50 million people worldwide. State and federal health officials have concluded that such a pandemic would sicken far more people needing ventilators than could be treated by the available supplies.

Many of the draft guidelines, including those drawn up by the Veterans Health Administration, are based in part on a draft plan New York officials posted on a state web site two years ago and subsequently published in an academic journal. The New York protocol, which is still being finalized, also calls for hospitals to withhold ventilators from patients with serious chronic conditions such as kidney failure, cancers that have spread and have a poor prognosis, or "severe, irreversible neurological" conditions that are likely to be deadly.

New York officials are studying possible legal grounds under which the governor could suspend a state law that bars doctors from removing patients from life support without the express consent of the patient or his or her authorized health agent.

State and federal officials involved with drafting the plans say they have been disquieted by this summer’s uproar over whether Medicare should pay for end-of-life consultations with families. They acknowledged that the measures under discussion go far beyond anything the public understands about how hospitals might handle a severe pandemic.

By every indication, state and federal officials expect to weather this year’s flu season without having to ration ventilators. That assumes that the H1N1 virus will not mutate into a more serious killer, the vaccines against it and the other seasonal flus will continue to prove effective, and any dramatic surges in the number of patients in need of ventilators will occur in different parts of the U.S. at different times.

In recent months, New York officials have met three times with physicians, respiratory therapists and administrators to rehearse how their plan might play out in hospitals in a severe epidemic. In one of those “tabletop exercises,” participants suggested that the names of triage officers charged with making life and death choices among patients at each hospital should be kept secret. The secrecy would be needed, participants said in interviews, to avoid pressure and blame from colleagues caring for patients who were selected to be taken off life support.

When they posted their plan on the web in coordination with a video conference in 2007, New York officials promised to solicit public input. Since then, they have consulted with medical and legal professionals and other experts, but few members of the general public, and the plan has remained unchanged. They declined to make the comments they have gathered immediately available for review, and those comments are not published on the Health Department's Web site [1].

In the initial proposal, officials called public review “an important component in fulfilling the ethical obligation to promote transparency and just guidelines.”

The academic publication of the plan envisaged the use of focus groups to solicit comment from “a range of community members, including parents, older adults, people with disabilities, and communities of color.” Those have not been held.

Beth Roxland, the current executive director of the New York State Task Force on Life and the Law, said the ethicists included in the state's planning process focused largely on vulnerable populations. "Even if we didn’t have direct input from vulnerable populations," she said, "their interests have been well accounted for." Roxland said that public comment solicited when the ventilator plan was posted on the Health Department Web site was "sparse."

Dr. Guthrie Birkhead, Deputy Commissioner of the Office of Public Health for New York State said he wondered whether it was possible to get the public to accept the plans. "In the absence of an extreme emergency, I don’t know. How do you even engage them to explain it to them?"

Even so, other states, hospital systems and the Veterans Health Administration—which has 153 medical centers across all states -- have drafted protocols that are based in part on New York’s plan. The inclusion and exclusion criteria for access to ventilators, however, are different. For example, under the current drafts, a patient on dialysis would be considered for a ventilator in a VA hospital in New York during a severe pandemic, but not in another New York hospital that followed the State’s plan, which excludes dialysis patients. The VA’s exclusion criteria are looser because the patient population it is charged with serving is typically older and sicker than in other acute care hospitals. Different states, reflecting different values, have also established different criteria for who gets access to lifesaving resources.

The Institute of Medicine, an independent national advisory body, is expected to release a report on Thursday morning, at the request of the U.S. Department of Health and Human Services, that will recommend broad guidelines to help guide planners crafting altered standards of care in emergencies. At an open meeting held to inform the report on Sept. 1, participants described successful public exercises related to allocating scarce resources in Utah and in a Centers for Disease Control and Prevention study conducted in Seattle.

Questions about how hospitals would handle massive demand for life support equipment arose when New York state health department officials ran exercises based on a scenarios involving H5N1 avian influenza.

“They kept running out of ventilators,” said Dr. Tia Powell, director of the Montefiore-Einstein Center for Bioethics and former executive director of the New York State Task Force on Life and the Law, which was asked to address the problem. “They immediately recognized this is the worst thing we’ve ever imagined. What on earth are we going to do?”

Officials calculated that 18,000 additional New Yorkers would require ventilators in the peak week of a flu outbreak as deadly as the 1918 pandemic. Only a thousand machines would be available, the officials estimated. The state’s acute care hospitals in 2005 had about 6000 ventilators, 85% of which were normally in use. A moderately severe pandemic would have resulted in a shortfall of 1256 ventilators, health officials found.

In 2006, New York planners convened a group of experts in disaster medicine, bioethics and public policy to come up with a response. After months of discussion, the group produced the system for allocating ventilators. They first recommended a number of ways that hospitals could stretch supply, for example by cancelling all elective surgeries during a severe pandemic. The state has also since purchased and stockpiled 1700 Pulmonetic Systems LTV 1200 ventilators (Cardinal Health Inc., NYSE) -- enough to deal with a moderate pandemic but not one of 1918 scale.

Officials realized those two measures alone would not be enough to meet demand in a worst-case scenario. Ventilators were costly, required highly trained operators, and used oxygen, which could be limited in a disaster.

The group then drew up plans for rationing of ventilators. The goal, participants said, was to save as many lives as possible while adhering to an ethical framework. This represented a departure from the usual medical standard of care, which focuses on doing everything possible to save each individual life. Setting out guidelines in advance of a crisis was a way to avoid putting exhausted, stressed front line health professionals in the position of having to come up with criteria for making excruciating life and death decisions in the midst of a crisis, as many New Orleans health professionals had to do after Hurricane Katrina [2].

The group based its plans, in part, on a 2006 protocol developed by health officials in Ontario, Canada which relied on quantitative assessments of organ function to decide which patients would have preference for an intensive care unit bed. The tool, known as the Sequential Organ Failure Assessment (SOFA) score, is not designed to predict survival, and not validated for use in children, but the experts adopted it in light of the lack of an appropriate alternative triage system.

This summer, New York officials brought the state’s plan to groups from several New York hospitals for the tabletop exercises. They met behind closed doors to assess how hospitals might implement the proposed measures if the H1N1 pandemic turned unexpectedly severe this fall. In the fictional scenario, paramedics were ordered not to place breathing tubes into patients until physicians “can assess whether they meet the criteria to be placed on a ventilator.’’

Problems were immediately apparent. Dr. Kenneth Prager, a professor of medicine and director of clinical ethics at Columbia University Medical Center, was concerned about the lack of awareness of the plan among the larger public and the majority of the medical community. Societal input “is totally absent,” he said and called for more outreach to the public. “Maybe society will say, 'We don’t agree with your plan. You may think it’s ethically OK; we don’t.'"

The protocol, he said, would also place a great burden on clinicians charged with selecting which patients would be removed from life support. Physicians were concerned doctors involved in the legitimate and painful selection processes might be inappropriately construed as "death squads." “We facetiously dubbed them the ‘death squad’ or the ‘guys in the back room’,” Prager said. He envisioned family members breaking down and screaming when they found out their loved ones would be disconnected from ventilators. “It really is a nightmare.”

Even so, he felt that the plan – and its effort to save the greatest number of patients – was ethically appropriate. “If we don’t use triage, people will die who would have otherwise been saved,” he said, because a number of ventilators are “being used to prolong the dying process of patients with virtually no chance of surviving.”

Doctors at the exercises feared that they would be sued by angry patients if they followed the draft guidelines. “There’s absolutely no legal backing for physicians,” said Lauren Ferrante, a medical resident at Columbia University Medical Center. “Who’s to say we’re not going to get sued for malpractice?”

New York State law forbids doctors from removing living patients from ventilators or other life support except in cases where the patient has clearly stated such wishes, for example in a living will, or through his or her legal health care agent. Other sources of liability could come from federal and state anti-discrimination laws or claims of denial of due process.

New York officials said they were currently working out legal options for implementing the plans, such as gubernatorial emergency declarations or emergency legislation.

“You can take something today that’s not necessarily active and overnight flip the switch and make it into something that has those teeth in it,” said Dr. Powell, who served on the committee that drafted the plan.

Dr. Powell cautioned that it is critically important to maintain flexibility in the guidelines. Any rationing measures taken in a disaster must be calibrated to need and severity.

Guidelines can also promote investment in new technology, such as cheaper, easier to use ventilators, that would make rationing less likely. Already at least one company, St. Louis-based Allied Healthcare Products, is marketing a line of ventilators [3] specifically for use in disasters.

Some states, including Louisiana and Indiana, have adopted laws that immunize health professionals against civil lawsuits for their work in disasters. Other states, including Colorado, have drawn up a series of relevant executive orders that could be applied to address these issues.

Dr. Carl Schultz, a professor of emergency medicine at the University of California at Irvine and co-editor of the forthcoming textbook, Koenig and Schultz’s Disaster Medicine (Cambridge University Press), is one of the few open critics of the establishment of altered standards of care for disasters. He says the idea “has both monetary and regulatory attractiveness” to governments and companies because it relieves them of having to strive to provide better care. “The problem with lowering the standard of care is where do you stop? How low do you go? If you don’t want to put any more resources in disaster response, you keep lowering the standard.”
Federal officials disagree. “Our goal is always to provide the highest standard of care under the circumstances,” said RADM Ann Knebel , deputy director of preparedness and planning at the Office of the Assistant Secretary for Preparedness and Response, Department of Health and Human Services. “If you don’t plan, then you are less likely to be able to reuse, reallocate and maximize the resources at your disposal, because you have people who’ve never thought about how they’d respond to those circumstances.”

Using a Dialysis Machine to do ECMO

2009-09-08T19:05:00.000-07:00

(There is more on ECMO on my Oct 1, 2009 Posting)

http://panvent.blogspot.com/2009/10/ecmo-dialysis-h1n1-and-macgyver.html

Many of the recent case reports indicate that sophisticated machines are required to treat the patients infected by the current novel H1N1 strain of influenza. Basic ventilators such as the existing Pandemic Ventilator Project designs may not be adequate for these H1N1 patients that develop ARDS. Pandemic Ventilator Project type units, however could possibly be utilized on other existing patients to free up more sophisticated equipment for patients requiring advanced therapies. I have also found a design for high frequency oscillatory ventilator that I posted (here).

Another technology that almost certainly will be in shortage during the pandemic is access to ECMO (Extra Corporeal Membrane Oxygenation) machines. ECMO machines oxygenate the blood directly using a gas permeable membrane. These machines can keep people with severely damaged lungs alive long enough for their bodies to repair their damaged lung tissues. There is very little of this equipment around. Many centers do not have any ECMO machines, or have only one.

Consider this:
An ECMO machine pumps blood from the patient, adds an anticoagulant, runs it past a gas exchange membrane to remove CO2 and add O2, regulates the blood temperature with a heat exchanger, removes air bubbles via drip chambers, checks incoming and return pressures, and has safety systems to ensure air is not infused, or pressure limits are not exceeded.

A dialysis machine pumps blood from the patient, adds an anticoagulant, runs it past a dialyzing membrane to stabilize electrolytes and remove toxins and fluid, regulates the blood temperature by controlling dialysate temperature, removes air bubbles via drip chambers, checks incoming and return pressures, and has safety systems to ensure air is not infused, or that pressure limits are not exceeded.

Hemodialysis System

They are pretty similar eh?

Note that terminology for blood access is opposite in ECMO vs hemodialysis.

In ECMO, the port where the blood is drawn into the pump is termed the Venous line and the port where the blood is returned to the body is termed the Arterial line.
In Hemodialysis, the port where the blood is drawn into the pump is termed the Arterial line and the port where the blood is returned to the body is termed the Venous line.
In CRRT, (a form of hemodialysis) the port where the blood is drawn into the pump is termed the access line, and the port where the blood is returned to the body is termed the Return line.

The Hemodialysis picture is from METU BIOMAT, and the ECMO picture is from Medscape. (Note there is an error in the Medscape ECMO drawing, both pressure ports are named "Post-Membrane Pressure Monitor". The lower one should be named "Pre-Membrane Pressure Monitor) Note also that fluids and heparin are normally infused post pump in hemodialysis, as this method is usually considered a safer method. Air removal, and monitoring safety systems are also not in the ECMO picture. Both VV-ECMO and Hemodialysis can use a Jugular Venous Dual Lumen Catheter for access.

VA-ECMO vs. VV-ECMO
There are two types of ECMO. VA-ECMO or Venous-Arterial ECMO, has a more complicated method of attaching to the patients circulation system. VA-ECMO operation is similar to the use of a heart-lung bypass machine in that it replaces the function of both the heart and lungs of a patient. VV-ECMO or Venous-Venous ECMO, has a less complicated method of blood system access. It is done using high flow central line catheters similar to the ones used for dialysis. It replaces only the lung function of the patient.

Some patients with H1N1 are getting lung damage and progressing to ARDS. They may require ECMO because their lungs are so damaged that they can no longer provide enough gas exchange to maintain other body functions. A ventilator may not be adequate in these situations. The heart is not usually compromised. These patients could benefit from VV-ECMO if a machine was available. As stated earlier, available ECMO machines would probably be in very short supply during the pandemic.

You can see that the equipment for ECMO is very similar to the equipment required to perform dialysis. In fact CRRT or SCUF are sometimes done in order to control electrolyte and fluid volume levels by adding a dialyser to an ECMO machine without needing any additional equipment.

It seems to me that one could do VV-ECMO treatments using a dialysis machine with a diffusion membrane oxygenator attached in line on the blood tubing set. Some extra gas and oxygen regulators and controls may also be required. If a standard hemodialysis machine is used, it can be run at a low dialysis flow rate (available on machines such as the Fresenius 2008K) to run in a SLED (Sustained Low Efficiency Dialysis) mode continuously. I would like to hear comments from people that have worked with ECMO equipment to hear if they think this is at all feasible.

This Just in (Sept 15, 2009)

Article in New York Times about ECMO use in H1N1 pandemic and potential shortage of ECMO machines.
http://www.nytimes.com/2009/09/16/health/research/16flu.html

Lancet article about the efficacy of ECMO for severe influenza treatment.
http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(09)61069-2/fulltext

Bloomberg article on using ECMO for near death swine flu cases.
http://www.bloomberg.com/apps/news?pid=20601080&sid=a3B182GF_auk

Belfast Telegraph article about ECMO
http://www.belfasttelegraph.co.uk/news/health/article14493762.ece;jsessionid=80D2A25F7E4033BF410D32971134D6DA?postingType=posting&mode=thanks&postingId=14493924

Update, Sept 18 2009

I have been thinking about this doing ECMO using a dialysis machine for a few days now. So far I have not had any comments either for or against on this blog.

I have done some further research into the equipment required for ECMO and some of the problems with ECMO therapies. It appears that maintaining systemic coagulation using heparin is sometimes a problem. Patients may not properly respond to the heparin therapy, they may have allergies, or there may be bleeding problems associated with systemic coagulation. These are problems that are also very common in hemodialysis and CRRT therapies. One solution to this problem is to use regional citrate anticoagulation. Citrate is infused into the blood circuit at the blood access port to initiate anticoagulation and calcium is infused at the blood return port to cancel the effect of the infused citrate.

This can be more complex than straightforward heparin infusion because the infusion of these chemicals also alters the calcium, pH, fluid volume and sodium levels of the patient. In CRRT and SLED therapies these parameters are monitored and controlled by adjusting the sodium and bicarbonate levels of the dialyzing and infusion fluids. Patient fluid volumes are also easily controlled by the dialysis machine.

Regional citrate anticoagulation has been shown to significantly extend the filter (dialyser) life compared to heparin coagulation by reducing clotting. It is sometimes used when the patient has HIT (Heparin Induced Thrombocytopenia). Regional citrate anticoagulation can also reduce other complications that would occur when using systemic anticoagulation protocols.

During a pandemic, it may be difficult to obtain enough membrane oxygenators to do ECMO. It is reasonable to assume that regional citrate anticoagulation could also extent the serviceable life of the membrane oxygenator by reducing clotting in the device. It will be important to make the best use of whatever supplies one has on hand. If it is indeed possible to use a dialysis machine to do ECMO, and also employ regional citrate anticoagulation with it, this could be a good way to save more lives with the possibly limited supplies available.

Here is a link to a PubMed abstract of an ASAIO journal article about using regional citrate anticoagulation with ECMO.
http://www.ncbi.nlm.nih.gov/pubmed/16883129?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum

Some More Info if this Intrigues You...

JAMA article shows that most patients with severe H1N1 that are treated with ECMO survive http://jama.ama-assn.org/cgi/content/full/2009.1535

Some general Info on ECMO systems and complications
http://www.anzcp.org/CCP/Clinical%20applications/ecmo.htm

Here is a link to a Patent for an ECMO system
http://www.google.com/patents/about?id=QoIcAAAAEBAJ&dq=ECMO

CDC info on the use of ECMO and CRRT on novel A H1N1 patients.
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm58d0710a1.htm

Response to the first comment by Anonymous (see below)

Thank you for your comments. I have been waiting to get some feedback on this issue. Just to clarify, ELSO is Extracorporeal Life Support Organization centered at the University of Michigan.

Now you have question about the origin, purpose and legitimacy of the Pandemic Ventilator Project. It was started on Feb 22, 2007 to promote alternative methods of supplying additional ventilators during a pandemic. In order to reduce the death toll of people either ill from a pandemic or those who would be denied life support so that the ventilator they are using could be used to save a pandemic victim (due to triage protocols). Now when you question legitimacy, I am not quite sure what you are after. I am not trying to defraud or manipulate anyone, and my motives for the project are entirely humanitarian. It is not a commercial venture; in fact I have spent a fair bit of my own time and money on it. All of my work and postings are available for you to view and see for yourself. Now if by legitimacy, you mean authority, I really have none. The opinions I express are my own. It is up to the reader to determine if my arguments are rational and my sources of information are valid.

Now when you warn against an untrained person just setting up ECMO on a dialysis machine when no prior testing or feasibility studies have been done you are absolutely correct. When I proposed this idea, it was for people that are qualified to do ECMO treatments to try to find innovative alternative ways to provide this potentially life saving treatment even if there were a shortage of existing ECMO equipment during a pandemic. I was hoping that knowledgeable people could look at the idea and see if they could make it work safely rather than dismiss it out of hand. Perhaps a someone could find a solution to this problem with the pumps that you mentioned.

Now when you assuredly state that there will be NO shortage of ECMO systems in the US, I do not think you can say that for sure. When we have Dr. Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota (CIDRAP) http://www.cidrap.umn.edu/ worried about a shortage of ECMO machines http://legal-ledger.com/item.cfm?recID=12283 , http://www.startribune.com/lifestyle/health/59253022.html?elr=KArksD:aDyaEP:kD:aUbP:P:Q_V_MPQLa7PYDUiD3aPc:_Yyc:aUHDYaGEP7eyckcUr, and with Dr Dr. Giles Peek of Glenfield Hospital in Leicester, England talking about how few the number of ECMO machines are available in Britain. http://latimesblogs.latimes.com/booster_shots/2009/09/bypassing-lungs-helps-swine-flu-pneumonia-victims.html The World Health Organization is also warning developed countries "to anticipate this increased demand on intensive care units, which could be overwhelmed by a sudden surge in the number of severe cases." http://news.eirna.com/209051/h1n109-who-issues-warning-on-second-wave-of-pandemic

There is agood chance that the current H1N1 pandemic will remain mild and within the ability of our current infrastructure and surge capacity to manage, But I do not believe anyone can definitely say that this will be the case.

What you say about legal liabilities is unfortunately sadly true. The heroic measures undertaken by individuals during the polio epidemic to build their own ventilators to save the lives of children could never happen in today’s legal liability climate. The only hope for that is if legislatures provide legal liability exemptions to the individuals that decide who gets which machine and treatment in a pandemic. Under today’s legal climate it is more prudent for a physician let his patient die by denying access to a potentially life saving treatment than to risk a lawsuit by using an uncertified device.

I must say in defence of any nephrology professionals that read this, hemodialysis is also a type of life supporting treatment that is done extracorporeally. Most of the complications that can occur in VV-ECMO can also occur in hemodialysis. Hemodialysis is routinely done in a safe mode by trained individuals. There were over 300,000 patients safely dialyzed for more than 150 million hours of treatment in more than 4000 centers in the US last year alone.

Clarence Graansma

Are the H1N1 Death Numbers Low?

2009-09-07T12:48:00.000-07:00

The Number of Deaths Due to H1N1 Compared to the Number of Deaths Due to Seasonal Flu.

I keep hearing about how the numbers of deaths from H1N1 are really quite low worldwide. In one respect, this is true, and I hope that it stays that way. Here is a CBC article from Sept 4 2009.

If you read discussion forums or the comments section on some news websites, many people use the currently low death ratio to argue that the H1N1 pandemic declared by WHO is a non-event, and that we are spending way too much time and energy on it. There are even conspiracy theories regarding vaccination programs.

So here are some raw numbers:
About 36,000 deaths per year on average due to seasonal flu in the USA alone.
2,837 worldwide from H1N1 flu since the pandemic began.

From these numbers, it seems like the H1N1 pandemic is very small compared to the seasonal flu epidemics. These numbers are deceiving though. First of all you have to look at how the numbers are counted. The H1N1 fatalities are all confirmed, reported H1N1 cases. The 36,000 annual US death number for seasonal flu is based on a statistical method. If only confirmed, reported seasonal flu deaths were counted, the seasonal flu number would be about 2,000. That is not to say that the 36,000 figure is incorrect, it is just that very few death certificates actually list flu as the cause of death. They usually list a complicating factor such as pneumonia or heart failure.

Another thing to consider is that deaths from seasonal flu are more common among the elderly and persons with chronic conditions that compromise their immune systems. The H1N1 virus as well, is more likely to cause death if the infected person also has some other compromising medical condition, but it is not age specific in favoring the elderly. In fact it has more of a bias to causing severe disease in younger persons.

Another thing to consider is that as the time of year that flu typically increases in the northern hemisphere approaches; the incidence of all types of flu is expected to rise dramatically.

Here is an article from Slate magazine about this

Here is an article from JAMA that you can download

And, one more thing...

The Pandemic Ventilator Project has been referenced in a book by Tom Atlee. This book has contributions by many people that are very knowledgeable in the field of sharing intelligence to improve the world.

It is called Collective Intelligence: Creating a Prosperous World at Peace

It is available at Amazon in hardcover here.

It is appropriately published under Creative Commons, same as this blog.

If you want to see it in PDF format you can get it here.

This is the section that has the Pandemic Ventilator Project Reference in it (page 457). It is written by Mark Tovey.

The Crisis is Near Now

2009-08-31T18:41:00.000-07:00

A High Frequency Oscillatory Ventilator Design

Some of the news items I have been reading say that there will be a particular shortage of high frequency oscillatory ventilators. Many ICU units do not have any or may only have one. This type of ventilator is required to care for patients with the most damaged lungs.

I found a design for such a device in the IEEE transactions on Biomedical Engineering publication. Here is the drawing.

The link to the PDF is located at this link.
The PDF essentially gives instructions on how to build this ventilator.

This device is much more complex than the basic ventilators I have built, but it seems that it would possible to build such a ventilator from common valves, sensors and control systems substituting for some of the components that are listed. The diaphragm actuator for example could be a large bass (subwoofer) type speaker.

It would be great if someone could build one of these unists and get back to me about how feasible it is and how well it works in testing.

Next week an idea for using ECMO.
Don't know what ECMO is?
Have a look.
http://panvent.blogspot.com/2009/09/using-dialysis-machine-to-do-ecmo.html

Now My Rant
Many of the recent reports that I have read indicate that there is a high likelihood that the current H1N1 pandemic will result in very busy ICU units and shortages of ventilators this fall in Canada. Doctors that work in ICU units that have had to treat H1N1 patients with Acute Respiratory Distress Syndrome (ARDS) say that the patients may have to be on a ventilator for a longer time period than they have seen with patients that got lung function complications in normal seasonal flu.

Here is a link to one such news item from CP.
Intensive care units likely to be main battlegrounds in the war against H1N1
There have been many stories like it originating from hospitals in Canada, the US, India, Australia, UK, Brazil, etc.

When I first proposed the Pandemic Ventilator Project two years ago as a means to alleviate some of the needs for ventilators in a pandemic, I expected it might be used for the H5N1 Avian flu. It seemed like a good insurance plan for a pandemic that, if we were lucky, might not even happen. Things have changed a lot since then. Now it is H1N1, people have actualy died from it, and this pandemic might return stronger this fall and winter, killing even more people. The risk of ventilator shortages has gone from a remote possibility to more likely. A lot has changed in the last six months.

Unfortunately, something that has not changed is the development status of the Pandemic Ventilator Project. As I have said several times before, the project has largely reached the limits of what I can do on my own to develop it. I need people with more ideas, more technical knowledge, more clinical expertise and better management and organizational skills than I possess on my own to carry the project further than I have. It would be a shame if we reach the stage where we really could use a ventilator from he pandemic ventilator project, but no one worked on it beforehand to get it ready in time.

Canada to Buy Ventilators for the H1N1 Flu

2009-07-04T18:43:00.000-07:00

I saw an article in the Globe and Mail Today. I posted a comment on the article. Here is my comment:

The potential shortage of ventilators has been an issue with ethicists and planners for a while now. Most feared for the pandemic was the H5N1 Avian flu. Some officials thought that stockpiling ventilators would be a waste of resources because the expected H5N1 pandemic would be so severe that there would not be enough hospital staff or supplies to run them anyway.

With the comparatively mild H1N1 strain, some feel that existing resources will be adequate. The truth of the matter is that predicting the severity of a future pandemic is nearly impossible. It could be anywhere in between these extremes, and can change rapidly during the course of a pandemic as well. Many experts are concerned that with the very high numbers of infections happening with the H1N1 strain, that even a moderate increase in the severity of illness could cause widespread shortages of ventilators.

The Canadian and Ontario governments have not done very much up to this point of addressing the potential of a very deadly ventilator shortage. Governments in the US that have done the most to provide a creditable emergency supply have mostly focused on buying low cost, lower tech ventilators that can be operated by individuals with moderate training levels. The optimal number to purchase is between one and two times the current number of ventilators being used in ICU units.

I have a discussion of some of these issues in my blog at panvent.blogspot.com Pay special attention to an article I wrote more than 2 years ago comparing the government and Canadian Red Cross's inadequate response to the issue of AIDS contamination in the blood supply. http://panvent.blogspot.com/2007/02/trusting-in-pandemic-plans.html

I will be gone fishing for the next 2 weeks.

Possible Swine Flu Pandemic Brewing

2009-04-26T13:08:00.000-07:00

It has been a while since I have posted. I have had other priorities and this project has been left on the back burner. The events of this week seem to have made the Pandemic Ventilator Project a priority once again.

For the sake of those that are visiting this blog for the first time I will summarize the goals of the Pandemic Ventilator project. I will then discuss the work that has been done to date. I will then relate the project to the current swine flu outbreak that could possibly become a worldwide pandemic requiring many ventilators, possibly more than are currently available.

In February of 2007, I became aware of concerns by the World Health Organization that a worldwide influenza pandemic was imminent. One of the problems that will almost certainly be encountered if there is even a moderately severe pandemic is a shortage of ventilators. I had the idea that using modern industrial control devices such as PLCs (Programmable Logic Controllers), readily available solenoid valves and other readily available components, a functioning emergency use ventilator could be constructed. I came up with an initial design that I published on this blog and invited others to improve on the design or come up with better, different designs.

The project has had some success but is not complete. So far three different prototypes have been built by two other persons, and myself but there has been limited testing done. There have also been projects started by students at Michigan Tech University and two different groups in India that have used some of the ideas presented here develop different ventilators for use in pandemics or third world situations. If you follow through the blog postings from the first one, you can see the development of the project. In addition to working on my ventilator design, I have also written postings that encourage greater participation by government agencies in increasing the stockpiles of ventilators set aside for pandemic use. There are also several postings defending the use of non-commercially made ventilators in emergency situations. These postings mainly chronicle the brave individuals that built home made ventilators during the last polio epidemic. There are also reviews of other publications and videos.

It is difficult to predict if this outbreak will develop into a worldwide pandemic that is bad enough to cause a severe shortage of ventilators. Two factors cause it to be hard to predict. One, it is difficult to get good information because government authorities want to control panic and reduce economic disruption, and two, the nature of outbreaks themselves is unpredictable.

So what do we know? First the people that are dying are not the typical elderly and very young. They are mainly healthy young and middle aged adults. The death rate seems fairly high, perhaps as great as 10%. Death rates early on in a pandemic however are very difficult to pin down, as we really do not know how many people were infected but in fact had very mild symptoms and were not counted. The virus is spreading to many geographical locations quickly. The WHO has already stated that it’s first line defense against pandemic outbreaks, which is containment, is no longer possible. The reason that there are no major travel restrictions imposed by governments is not that they think the threat is too minor, but that it is past the point where travel restrictions will help. What is still unknown is how severe it will eventually be, and how readily it will spread.

In the region that I live in, there are about 50 ventilator equipped ICU stations. The population served is about 500,000. If we had an pandemic that struck 10 percent of the population in each wave, and the virus was severe enough that 1 percent of those infected in each wave required a ventilator, then the number of ventilators required would be 500. Let us hope and pray that this pandemic is a very, very mild one.

Here is a link to a BBC News Link on Mexico Flu Experiences

Video: Avian Flu: Innovation in Healthcare

2008-09-12T18:00:00.000-07:00

11 Sept 12
I have found a few good videos on pandemic planning and ventilators and will be posting these for much of the summer. If you are new to this blog, take a look at the right side of the page to see links to previous articles and the archives.

Avian Flu: Innovation in Healthcare
7:19
IBM
IBM collaborated with the Scripps Research Institute and several worldwide government and nonprofit health organizations to help work on developing a vaccine for avian flu by developing tools to assist in predicting the mutations the virus might take and develop vaccines targeted towards those mutations.
The last statement made in the video is very powerful.

Video: On Avian Flu

2008-09-05T18:00:00.000-07:00

I have found a few good videos on pandemic planning and ventilators and will be posting these for much of the summer. If you are new to this blog, take a look at the right side of the page to see links to previous articles and the archives.

On Avian Flu, Part 1: Is a Pandemic Coming?
8:44
Urgelt
March 21, 2007
Expert virologists estimated that there is a 15% chance of an avian flu pandemic erupting in the next several years, and that the mortality of such a pandemic could be very high.
http://www.youtube.com/watch?v=qcTotoQNUFY

On Avian Flu, Part 2: Vaccines
5:30
Urgelt
March 23, 2007
The flu vaccine industry will probably take many years to provide full protection against any human transmissible strains that may emerge.
http://www.youtube.com/watch?v=gbDift3llvI

On Avian Flu, Part 3: Protective Measures
9:31
Urgelt
March 25, 2007
Some suggestions for protecting yourself against the threat of an avian flu pandemic.
http://www.youtube.com/watch?v=Y-ovLJu6kss

Video: California Pandemic Influenza Preparedness Summit

2008-08-29T18:00:00.000-07:00

I have found a few good videos on pandemic planning and ventilators and will be posting these for much of the summer. If you are new to this blog, take a look at the right side of the page to see links to previous articles and the archives.

California Pandemic Influenza Preparedness Summit Part 1
University of California Television
March 30, 2006
58:24
This program introduces the need for proactive Pandemic Influenza Preparedness, and highlights the state and federal governments' activities to help protect Californians. The program calls upon citizens to become active partners in the control of a flu pandemic or other infectious disease outbreak. Speakers include Sandra Shewry, Director of CA DHS, Kim Belshe, CA Secretary of HHS, L.A. County Supervisor Zev Yaroslavsky, U.S. Secretary of Health and Human Services, Michael Leavitt and CA Governor Arnold Schwarzenegger..

California Pandemic Influenza Preparedness Summit Part 2
University of California Television
March 30, 2006
59:24
This program outlines some specific strategies that federal, state and local health agencies to prepare for pandemic flu. The speakers in this program include: Jeanne Santoli, Deputy Director of CDC's Immunization Services Division, Chet Lunner, Acting Director State and Local Government Coordination Department of Homeland Security, Mark Horton, CA State Public Health Officer, Jonathan Fielding, Director L.A. County Department of Health Services.

California Pandemic Influenza Preparedness Summit Part 3
University of California Television
March 30, 2006
53:01
This program highlights some steps toward pandemic preparedness in the arenas of Business, Education and Healthcare. The speakers include: Kas Kasravi, Consultant for Applied Innovation at Electronic Data Systems, Kimberly Uyeda, Director of Student Health Services of L.A. Unified School District and Benjamin Chu, President of Southern California Region, Kaiser Permanente.

Video: Davos 07: Pandemics

2008-08-22T18:00:00.000-07:00

I have found a few good videos on pandemic planning and ventilators and will be posting these for much of the summer. If you are new to this blog, take a look at the right side of the page to see links to previous articles and the archives.

Davos07: Pandemics (1/2) monitoring risk
22:42
Pandemics: Monitoring a Risk in Hibernation. After a period of heightened concern, the fear of a new global influenza pandemic has receded from media attention. Yet the risk remains basically unchanged and beyond influenza.

Davos07: Pandemics (2/2) monitoring risk
15:44
Pandemics: Monitoring a Risk in Hibernation. Conclusion of the discussion on the threat of a pandemic at the World Economic Forum in Davos

Video: Emerging Infections: How Epidemics Arise

2008-08-15T18:00:00.000-07:00

7 August 15
I have found a few good videos on pandemic planning and ventilators and will be posting these for much of the summer. If you are new to this blog, take a look at the right side of the page to see links to previous articles and the archives.

Emerging Infections: How Epidemics Arise
Research Channel and Howard Hughes Medical Institute
1999 Holiday Lectures on Science
Confronting the Microbe Menace Series
57:54
Tackling the complex causes of epidemics, Dr. Donald Ganem explains how mutations in genes and changes in the environment and human social behavior can give rise to new infectious diseases. He cites the influenza virus as an example of genetic changes that have led to epidemics and pandemics. He also shows the impact of weather on a 1993 outbreak of Hanta virus, describes the effect of human migration on the spread of smallpox, and examines what happened when the myxoma virus was introduced in Australia in the 1950s to control the rabbit population.

Video: Avian Flu

2008-08-08T18:00:00.000-07:00

I have found a few good videos on pandemic planning and ventilators and will be posting these for much of the summer. If you are new to this blog, take a look at the right side of the page to see links to previous articles and the archives.

Avian Flu (1): The H5N1 virus
Vetstoria.com
6:49
A veterinarian explains what the H5N1 avian flu virus is all about.

Avian Flu (2): Threat of a pandemic
Vetstoria.com
7:53
A veterinarian explains how the H5N1 avian flu virus may become very contagious and deadly to people.

Video: Protecting the Healthcare Workforce in Pandemic Influenza

2008-08-01T18:00:00.000-07:00

I have found a few good videos on pandemic planning and ventilators and will be posting these for much of the summer. If you are new to this blog, take a look at the right side of the page to see links to previous articles and the archives.

Protecting the Healthcare Workforce in Pandemic Influenza; “Just in Case Curriculum
California Department of Public Health Emergency Preparedness and The center for Infectious Disease Preparedness US Berkley School of Public Health
59:31
How healthcare workers can take care of themselves and their families in a pandemic situation.

Video: Influenza Pandemics: Past and Future

2008-07-25T18:00:00.000-07:00

I have found a few good videos on pandemic planning and ventilators and will be posting these for much of the summer. If you are new to this blog, take a look at the right side of the page to see links to previous articles and the archives.

Influenza Pandemics: Past and Future
Research Channel and The Office of Research and Graduate Studies; University of Michigan Medical School
Third Annual Biomedical Research Symposium; Global Infectious Disease
45:14
Oct 17, 2006

Discussion of the Influenxa Virus, past pandemics including 1918 and how what we have learned can be applied to future pandemics.

Video: Interview of John M Barry author of The Great Influenza

2008-07-18T18:00:00.000-07:00

I have found a few good videos on pandemic planning and ventilators and will be posting these for much of the summer. If you are new to this blog, take a look at the right side of the page to see links to previous articles and the archives.

Interview of John M Barry author of The Great Influenza
KEXL
54:50
February 9, 2005
Interview with John M. Barry author of "The Great Influenza: The Epic Story of the Deadliest Plague in History".

Video: Standing in the Safety Zone

2008-07-11T18:00:00.000-07:00

I have found a few good videos on pandemic planning and ventilators and will be posting these for much of the summer. If you are new to this blog, take a look at the right side of the page to see links to previous articles and the archives.

Video Link Here - http://www.youtube.com/watch?v=pNP9KwFMU6Y

Standing in the Safety Zone
Centers for Medicare and Medicaid Services
25:23
Remembering the 1918 Spanish Flu epidemic and how lessons can be applied to modern flu pandemics
The 1918 pandemic from the perspective of African Americans in Baltimore.

Video: Larry Brilliant: TED Prize wish: Help stop the next pandemic

2008-07-06T12:44:00.000-07:00

I have found a few good videos on pandemic planning and ventilators and will be posting these for much of the summer. If you are new to this blog, take a look at the right side of the page to see links to previous articles and the archives.

Video link Here - http://www.ted.com/index.php/talks/view/id/58

Larry Brilliant: TED Prize wish: Help stop the next pandemic
26:02
Larry Brilliant
Feb 2006
Accepting the 2006 TED Prize, Dr. Larry Brilliant talks about how smallpox was eradicated from the planet, and calls for a new global system that can identify and contain pandemics before they spread.

Hospitals "Full-Up": The 1918 Influenza Pandemic

2008-06-27T18:00:00.000-07:00

It is summertime, and I will be away a lot and not have o much time to write new blog posts. If you are new to this blog, take a look at the right side of the page to see links to previous articles and the archives. I have found a few good videos on pandemic planning and ventilators and will be posting these for much of the summer

From: UPMC Biosecurity
8:23
Overviews the 1918 pandemic and questions whether hospitals have the capacity to deal with a pandemic today.

Pandemic Ventilator at Queens Park

2008-06-22T09:25:00.000-07:00

Jeff presented his Pandemic Ventilator at Queens Park on June 10. Queens park is the seat of government for Ontario. SciTech Ontario arranged this presentation. SciTech Ontario is the organization that promotes and arranges sponsorship of Science Fairs and participants in Ontario. Several MPPs came to see the display.

Jeff with the Pandemic Ventilator

Showing the Ventilator to the public.

Jeff won the sponsors choice prize.

Being interviewed for judging

Another interested judge

Jeff with MPP John Milloy

Jeff was also featured in a newspaper article this week with his Pandemic Ventilator.

Here is a link to the article.

Staff Priority for Ventilators? ... Yes?

2008-06-04T08:21:00.000-07:00

Today’s posting addresses the issue of providing preferential access to ventilators for health care workers in a pandemic. This is a somewhat touchy subject from an ethical point of view. Any opinions expressed here are strictly my own, but I will try to provide a rational basis for any opinions that I do express. If you disagree with my opinion, (or agree) you can leave a comment below and we can discuss it. If you think this is an important discussion, please post a link to this post ( http://panvent.blogspot.com/2008/06/staff-priority-for-ventilators-yes.html ) in other discussion forums. I should declare that I am a health care worker myself, and that could be a considered a conflict of interest in this discussion. Nevertheless, I hope you hear me out.

The May 2008 article in Chest journal DEFINITIVE CARE FOR THE CRITICALLY ILL DURING A DISASTER
(available at http://www.chestjournal.org/content/vol133/5_suppl/)
and ALLOCATION OF VENTILATORS IN A PUBLIC HEALTH DISASTER published in Disaster Medicine and Public Health Preparedness Vol 2/No1, recommends that health care workers do not receive any preferential treatment in a pandemic. Many other planning documents recommend the same. I have a great deal of respect for these documents and the people that wrote them. The authors of these documents are trying to make plans that will save as many lives as possible during a pandemic using the limited resources that they expect will be available to the health care system. They try as much as possible to stay within traditional ethical guidelines, but insist that the principle of doing the greatest good for the greatest number of people is the primary principle and this should override values based on the traditional ways of delivering health care.

The principal rationales for not providing health care workers with preferential access to ventilators are these:

Fundamental ethical principles demand that there is no discrimination in access except for survivability criteria. Discrimination based on age and health status is acceptable because this allows the triage team to identify which individuals are more likely to have an increase in survivability by having access to the limited supply of health care.
It is unlikely that a health care worker that is given preferential ventilator access during a pandemic will recover in sufficient time to be able to come back to work and help others before the pandemic is over.
The triage protocols demand that certain persons be given authority to decide who gets access to medical treatments in limited supply. The public must trust that these persons will make decisions based on the pre-established rules and sound ethical principles. If the public believes that the decision makers are giving preferential access to people that they personally know, it may undermine this trust.

Discussion of Point #1
I believe that the principle of non-discrimination except for areas where it improves overall survivability is very valid and should be pursued. Where the argument for not favoring health care workers may fail is that it considers the availability of healthcare in a pandemic to be a zero sum game; that whatever is available at the beginning of a pandemic is all that will be available. They state this explicitly when they say that whatever is used to help health care workers will not be available to help the general public. This is may not be entirely true, as I will outline in point 2.

Discussion of Point #2
Now it may be so that once stricken, the health care worker as an individual may not be able to contribute a positive benefit to the pandemic care effort, but it is wrong to look at health care workers strictly as individuals. Health care is a team effort. The work that must be done by health care workers during a pandemic is not the routine of the non-pandemic. Society will demand that health care workers place themselves (and possibly their families through indirect exposure) at greater personal risk than the general public, and will demand that they work under more severe and hazardous working conditions and longer hours than they normally do.

It is essential that health care workers are motivated to not only work under these conditions, but to provide the most and best quality work they can. Staffing level is one of the key issues identified as a major limiting factor in being able to provide the maximum care to save as many people as possible in a pandemic. One way to get staff to work more would be to impose stringent laws and use force to draft anyone able to provide health care to work whether they want to or not. This would not be good way to get maximum efficiency from all workers and most plans do not recommend it. The workers must be motivated to provide the very high level of performance expected from them during a pandemic.

The health care worker component of a pandemic shortage is not a zero sum game. Some conditions will encourage healthcare workers to go to greater lengths to provide the most that they possibly can, and other conditions will cause them to retreat from working into a place of self preservation. It is not as straightforward either as being that worse conditions cause more people to retreat. Many people will work very hard in poor working conditions and even in situations of great risk if they feel their cause is just. Military organizations understand this, and place a great value on maintaining morale, group cohesion and supplying a valid reason for soldiers to contribute their maximum effort.

The US military is known as being one of the finest fighting organizations in the world. They do not rely only on just having the best equipment, but also focus on getting the maximum that they can from their people. One of the ways they do this is by saving every captured or injured soldier that they can. The principle is best stated in the Ranger Creed of “No Man Left Behind”. (See http://www.yaleherald.com/article.php?Article=532 for a discussion of this.) Each soldier is willing to risk his life to save his fellow soldier, even in the face of extreme odds, because he knows that the other would do the same for him. This cohesion and dedication then translates into a high degree of effectiveness for the many other things a soldier is asked to do.

Now look at two scenarios, handled in different ways and what could be the possible outcomes. Both scenarios start the same way. A pandemic strikes; workers are worried for their safety, but feel a sense of duty and commitment to work. Most show up for work, but are not sure about volunteering for extra work. Some are distrustful that their employers are doing everything they can to protect them and stay away from work. They talk about this a lot at breaks. One of the nurses gets sick and needs a ventilator. The other staff believes she got sick from caring for a pandemic patient.

In the first scenario the nurse is refused a ventilator so that it can be given to another person. The other staff worries that they too may get sick and believe that not enough will be done for them. More staff now stays home from work. The hospital can now care for less patients than they could before due to staff shortage.

In the second scenario the nurse is put on a ventilator. Other workers volunteer extra hours to make sure she is well looked after. Some workers that initially stayed home now also come to work. They have greater trust that they will be looked after if they get sick and also wish to be available if any more of their coworkers get sick and need help. The hospital can now care for more patients than they could before.

It is interesting that the second scenario works even if the nurse does not survive. It is the fact that they were able to try to save her that is important.

Discussion of Point #3
The public may accept that health care workers will go to great lengths to care for their own. We accept this from other groups that put themselves in danger in order to protect us. Two examples are police and firefighters. When they go to great lengths to save one of their own, or in the case of police to obtain justice for the death of one of their own, the public does not complain that they are now providing a lower level of service to the rest of us. We accept this, and even demand it. When it was found out by the public that many injured Iraqi war veterans were poorly treated the public demanded that conditions improve. The same happened for many police and firefighters injured in 9/11. The public respects the risks that people place themselves in for the public good and demand that they receive the best care possible when they are hurt in the line of duty.

Conclusion
I would like to believe that I would do everything I can to help in a pandemic crisis regardless of risk to myself, and I think most people feel this way. I just can’t be sure that everyone will actually act so magnanimously when a crisis actually occurs. A lot can be learned from studying staff reactions during the SARS crisis in Toronto when some people felt that the hospitals involved did not provide adequate information and protection to staff working with SARS patients. I understand that the critical care system is a public trust and that the health care workers cannot arbitrarily use these resources preferentially for themselves. The triage plans that have been published take a much more pragmatic approach to the allocation of scarce resources such as ventilators in a crisis such as a pandemic. These plans are willing to forgo systems that are currently used such as first come, first served, in favor of allocation systems that will save the most people possible. Perhaps they should study how staff will actually behave in a pandemic system, and adjust the plans accordingly if it could in fact save more total lives.

Clarence Graansma

P.S.
Maybe this is the place for the Pandemic Ventilator. Maybe if healthcare workers volunteer extra hours to look after their own in a pandemic and even build their own ventilators…

Building a Pandemic Ventilator

2008-05-31T06:23:00.000-07:00

On Thursday May 29, Jeff and I gave a presentation about the Pandemic Ventilator Project to some of my friends and colleagues at work. The presentation went smoothly and was well received. We received encouragement from the attendees to continue working on the project. We had the presentation videotaped so that more people could see it. Thank you Manuel for your help and ideas in videotaping this presentation.

The presentation is about 35 minutes in length overall and is divided into 4 sections below as YouTube videos. The title of the presentation was "Building a Pandemic Ventilator”. It is an overview of what we are tying to achieve with the Pandemic Ventilator Project.

Building a Pandemic Ventilator Part 1
9:08
Presented at Grand River Hospital May 29 2008.
The purpose and origins of the Pandemic Ventilator Project and the history of home made ventilators.

Building a Pandemic Ventilator Part 2
6:42
Presented at Grand River Hospital May 29 2008.
A description of how the Pandemic Ventilator actually works.

Building a Pandemic Ventilator Part 3
9:16
Presented at Grand River Hospital May 29 2008.
Some pandemic planning ideas and the future of the Pandemic Ventilator Project.

Building a Pandemic Ventilator Part 4
9:52
Some discussion, questions and a demonstration of Jeff’s Pandemic Ventilator.

Dr. Eric Toner Blog post

2008-05-24T20:00:00.000-07:00

Here is an interesting interview with Dr. Eric Toner about pandemic planning with regards to H5N1. Dr. Toner is with the Center for Biosecurity at the University of Pittsburgh Medical Center. I have referenced articles from this group before. There is a lot of useful information available at the UPMC Biosecurity site, and it is frequently updated.

Dr. Toner talks about how severe a pandemic arising from the H5N1 virus could be, and compares this worst case scenario to the projections commonly used by the CDC flusurge software. In case you are interested in alternative projection models to flusurge, check out the panalysis spreadsheet.

Here is the PDF of the Toner interview

If you would prefer to listen to the audio version the links are here:
Part 1 “What is Avian Flu?” (4:23)
Part 2 “The difference in Death Rate Assumptions” (2:50)
Part 3 “Why we need Hospital Interventions” (6:03)
Part 4 “Why Not Enough is Being Done” (8:40)

You can also go to the Health Business and Policy website directly for the HTML version

Health and Business Policy has more pandemic related interviews available here.

Be aware, most of the information on the Health and Business Policy site seems to be older, from about mid 2006.

Pandemic Ventilator at the Canada Wide Science Fair

2008-05-18T19:05:00.000-07:00

I mentioned earlier that my son Jeff had built his own pandemic ventilator and entered it in a science fair. At the regional science fair he won; Award of Merit, Gold Medal in Senior Engineering, the University of Ontario Institute of Technology Innovation Award, a Conestoga College Entrance Scholarship, a University of Guelph Entrance Scholarship, a University of Waterloo Entrance Scholarship and a Wilfrid Laurier University Entrance Scholarship.

He also got the opportunity to enter in the Canada Wide Science Fair and compete against the top entries from all of Canada. At the Canada Wide Science Fair he won an Honourable Mention in Engineering and the Engineers Without Borders prize. The Engineers Without Borders prize is awarded to a humanitarian engineering project that can improve the lives of people in developing nations. Jeff will also be invited to the next Engineers without Borders Canada national conference.

Here is a link to the WWSEF awards page.

Here is his project report.

Here is a picture of the ventilator in its case as it was presented at the Canada Wide Science Fair

Here is the compressor

Here is the PLC

This pandemic ventilator design has its own air source so it does not rely on hospital high-pressure air sources. This allows it to be able to be used in settings outside of the standard hospital ICU. It has a link to a PC via LabView software. It has a pressure transducer to measure airway pressures. There are alarms for airway overpressure, line occlusion and loss of air from the compressor. The PC keeps track of minute volume, total volume, respiratory rate, PLC connection status and alarm status. It also shows a real time pressure waveform. The PC could be located outside of an isolated patients room in order to reduce the number of times staff have to enter the isolated room. An external monitor such as this can reduce risk of staff exposure and also reduce personal protective equipment usage.

The video shows the ventilator operating with a lung simulator. The patient overpressure, line occlusion and loss of compressed air alarms are demonstrated.

The Cost of Efficiency

2008-05-12T18:43:00.000-07:00

Modern hospitals have become much more efficient than they were in 1957 or 1968 when we had our last pandemics. Today, hospitals are run more like a business than they ever were. Even non profit hospitals and hospitals in countries with socialized medicine or single payer systems have had to run more efficiently. This is not entirely a bad thing. Hospitals have had to become more efficient as the ongoing improvements in health care technology became more readily available. Many more high tech health options are possible today, and they are generally more expensive. We treat heart disease, cancer, trauma, premature birth and organ failure much more aggressively than we did 40 or 50 years ago. We can also routinely save or extend more lives than we did back then. Efficiency is how we afford it.

To make hospitals more efficient we utilize space, supplies and staffing as much as we can. We do not have empty rooms. If too many rooms are unused we close wings and convert them to outpatient departments or offices or close some hospitals. We do not let equipment sit idle, we buy just what we need and rent some extra to get us over the peaks. We use just in time supply systems to reduce excess inventory and waste. We hire fewer full time staff and use temporary staff or pay a bit of overtime here and there to handle the peaks. The average length of a hospital stay has been dramatically reduced.

We no longer have any excess capacity left. We designed it that way. Any hospitals that resisted this change in the past were closed and branded inefficient. This efficiency has a cost though. Our efficient health care systems could no longer handle a pandemic even of the type seen in 1968. Pandemics require far more resources than the ordinary ebb and tide of daily business. Too much efficiency can be deadly.

Quick Review of “Definitive Care for the Critically Ill During a Disaster”

2008-05-09T20:08:00.000-07:00

This week the report from the “Task Force for Mass Critical Care Summit, January 26–27, 2007” was published in CHEST. The series is titled “Definitive Care for the Critically Ill During a Disaster”. It consists of five separate articles subtitled:

Summary of Suggestions From the Task Force for Mass Critical Care Summit
Current Capabilities and Limitations
A Framework for Optimizing Critical Care Surge Capacity
Medical Resources for Surge Capacity
A Framework for Allocation of Scarce Resources in Mass Critical Care

I quickly read through all these papers this week. I will review each of them in more detail in upcoming postings. You can get all five of the published articles for free at this location. Thank you CHEST for supplying these articles for free. If you are involved in pandemic planning, I urge you to download these papers and read them. They offer many suggestions and solid frameworks for planning your response to a mass critical care incident.

The publishing of these papers has generated a few news reports this week. Most of the newspaper articles were sensational, focusing mainly on the list of classes of people that would be excluded from care. Here are a couple of news links. AP, Globe and Mail.

When you read these news articles you would think that the summit meeting was all about denying care. When you read the actual papers you will see that the summit was really about providing the best care possible under various worsening and even the nearly hopeless conditions that could possibly occur. The sensational articles referred to the list of recommendations of who would be refused care in the most severe crisis. This list was merely a suggestion, and the authors state in the papers that there must be an ethical discussion of these issues by non medical professional people to determine whether society will accept these criteria.

The papers do not focus only on pandemic planning, but stress that plans must be flexible enough to account for many different types of mass casualty incidents. The included charts list nearly every type of incident and the appropriate responses. Still the main focus is on pandemic preparedness. Short of a nuclear war, a severe pandemic is probably the incident that would most stress the existing critical care infrastructure.

Some of the papers I have read before these on pandemic planning were very complex and tedious to follow. Many other papers focus on the numerous problems, give many “what if “ scenarios and concentrate a lot on how little we know. These papers focus more on how to get to a solution rather than moaning about the hopelessness of it all. The planning goals are focussed on three main areas; stuff, staff, and space. Essentially they say you have to have enough of each. If you are well prepared in two areas and short in the third, you are still limited by that area. They focus less on trying to predict the severity of any incident and more on how hospitals can maximize their ability to respond.

Stuff is things like ventilators, medications, PPE and other medical supplies. Staff is the number of staff that are not affected by the event plus the number of addition personnel that can be trained and used as well as how much you can increase the number of patients existing staff can care for. Space is the suitable areas that can be used to provide complex critical care.

In a nutshell, they recommend that facilities aim to increase by a factor of 3, the amount of critical care (including ventilators) they can provide, and also stockpile enough supplies to last about 10 days, with perhaps some additional buffer, and to ensure they can maximize their staffing and space to make this possible. I think these are very good recommendations. They are very similar to the recommendations I posted on the BMG website last year. I also suggested that facilities try to increase their ability to manage ventilated patients by up to a factor of 3 in one of my posts last year.

They warn that manual ventilation will not work. They are very skeptical that sharing ventilators among several patients will work with real patients that have ARDS. They provide an extensive list of requirements that facilities should look for when purchasing ventilators for surge capacity, but acknowledge that is unlikely that anyone will actually buy that many ventilators ahead of time. They also provide a much shorter list of the minimum requirements for a ventilator in suggestion 3.2:

(1) be able to oxygenate and ventilate most pediatric and adult patients with either significant airflow obstruction or ARDS
(2) be able to function with low-flow oxygen and without high-pressure medical gas
(3) accurately deliver a prescribed minute ventilation when patients are not breathing spontaneously
(4) have sufficient alarms to alert the operator to apnea, circuit disconnect, low gas source, low battery, and high peak airway pressures

The pandemic ventilator should be able to meet those short list minimum requirements.

P.S.
My son Jeff is taking his own pandemic ventilator design “Norman” to the Canada Wide Science Fair in Ottawa this week. I will have a more detailed report on “Norman” next week. I think you will be impressed with the work Jeff has done. I am.

How Many Ventilators Does New York Really Have?

2008-05-02T17:37:00.000-07:00

A couple of weeks ago, I posted a piece on how hard it is to get good numbers on the quantity of ventilators available. I checked through some documents from the New York State Workgroup on Ventilator Allocation in an Influenza Pandemic. Last year they published some preliminary information and asked for public input on setting up guidelines for ventilator use in a pandemic or similar emergency. I sent in some information to them about the Pandemic Ventilator Project and some of my ideas about how to expand the availability of ventilators and clinical capacity in a crisis, but they never asked me for more details. They recently published some guidelines based on that exercise in Disaster Medicine and Public Health Preparedness. I will have to see about getting a copy of that article and reviewing it.

Anyway, I found two documents by the same workgroup stating the number of ventilators in New York. Unfortunately they quote two different numbers. One is 60% higher than the other. Here are the details:

First we have:
Allocation of Ventilators in an Influenza Pandemic: Planning Document
NYS Workgroup on Ventilator Allocation in an Influenza Pandemic
NYS DOH/ NYS Task Force on Life & the Law
Feb 13, 2007 (listed access date)
Available here:

On page 9, it states:

the population of New York State is approximately 19 million,
there are currently 3,981 adult and pediatric ICU beds staffed,
15% of the admitted patients with pandemic influenza will require intensive care,
7.5% of the admitted patients with pandemic influenza will require ventilators,
there are currently 6,100 ventilators in acute care settings in New York State,
at any given time, 85% of the ventilators in acute care settings are in use, and
70% of deaths related to pandemic influenza are projected to occur in a hospital.

And then we have:
New York State Workgroup on Ventilator Allocation in an Influenza Pandemic
New York State Department of Health/ New York State Task Force on Life & the Law
March 15, 2007
Available here:

On page 1, it states:

a) Community Demographics
New York State has an estimated population of 19,254,630, which represent 6.5% of the total United States population. Approximately 13% of New Yorkers are age 65 or older; an estimated 18%of the state population over the age of 5 is disabled.

b) State & Local Public Health Infrastructure
NYSDOH is empowered to issue voluntary, non-binding guidelines for health care workers and facilities; NYSDOH is also empowered to issue binding regulations for hospitals that would app to standards of care during a pandemic.

c) Health Care Delivery System
There are more than 650 nursing homes in New York State housing 120,000 beds. Of the 240 hospitals in the state, 44 are classified as trauma centers, and 13 are classified as critical access hospitals (CAH) in rural areas. There are 3,981 adult and pediatric staffed intensive care unit beds throughout the state. There are currently 3,861 mechanical ventilators in acute care settings in New York State; at any given time, 85% of these ventilators are in use.

So here we have 2 documents. Both are produced by the same workgroup on ventilator allocation. Both of these documents list Gus Birkhead and Tia Powell as contributors. One of the documents says that New York State has 6,100 ventilators in acute care settings, and the other document says that they have 3,861 ventilators in acute care settings. Both of them say that they have 3,981 ICU beds.

It is hard to know what numbers to believe. As I said before, how can you know how many ventilators you have to stockpile if you are not even sure how many you have now? How can you know how far you can extend your resources and clinical skills capacity if you are not even sure how many ventilators those workers are supporting now? A definitive census is needed with plans that list actual (validated) numbers of ventilators that exist, how many will be added for surge capacity and how far it is possible to stretch clinical support capacity.

Maybe in their latest article, Powell and Birkhead can tell us which numbers are the real ones.

A Home Made Iron Lung for the Hospital for Sick Children

2008-04-26T18:01:00.000-07:00

I had some previous postings on home made iron or “wooden” lungs from the 1950s and 1940s. Here is a story of some home made ventilators built by the Hospital for Sick Children in Toronto Ontario to deal with the 1937 polio epidemic. It amazes me how the very same ethical dilemmas regarding shortages of ventilators we may face in an influenza pandemic were forced on these people in the 1930s.

From a Time Magazine article Sept 13 1937:

Toronto during the past fortnight was also the scene of some mechanical ingenuity. Hospital for Sick Children had only one mechanical respirator, and needed at least one more. The only professional manufacturers of this life-saving device are: Warren E. Collins, Inc. of Boston, which makes respirators designed by Professor Philip Drinker of Harvard's School of Public Health; and J. H. Emerson Co. of Cambridge, Mass., owned by John Haven Emerson, inventive son and namesake of New York City's onetime commissioner of health. The two companies long quarreled over patent infringements. Meanwhile, since 1929 only 250 Drinker respirators have been manufactured (price: $1,350 to $2,450), and since 1931 only 30 Emerson respirators (price: $1,000 to $1,600). Neither firm keeps many respirators in stock.

Faced with these conditions, Superintendent Joseph Henry Winteringham Bower of Toronto's Hospital for Children, a civil engineer by training, fortnight ago determined to build a duplicate of a Drinker respirator. All that was required was an airtight container out of which air could be intermittently pumped to inflate the patient's lungs, Superintendent Bower summoned his chief engineer, Harry Balmforth, and his carpenter William Hall. With pine boards, three hinges from a trunk, some metal rings, a rubber sheet, an air hose and a vacuum pump, they did the job. The work took only seven hours The cost was negligible because they used any old thing available. Before this "wooden lung was long in use. Denver set up a wail for a respirator. Two little girls there were taking turns dying without aid of the city's only respirator. Toronto heeded the plea, sent the wooden device. In spite of its use, one of the Denver children died.

Last week Messrs. Bower, Balmforth and Hall, with money provided by the Ontario government, were busily building six steel replicas of their wooden respirators. Final cost for each respirator will be less than $500.

Here is another account, from “The Middle-class Plague: Epidemic Polio and the Canadian State, 1936-37” by Christopher J. Rutty.

The Toronto press focused considerable attention on the need for more life-saving iron lungs as the 1937 epidemic worsened through August. The emergency was leaving "little tots struggling for breath" in hospitals. HSC’s single Drinker machine was used for a small number of mild chest paralysis cases, but on 21 August, a young girl in critical condition was placed in the lung, which happened to be open, but it was clear that she would have to remain in it for a long time. She would then have to be "weaned" off the iron lung when evidence of recovery was clear and periods outside the iron lung could then be progressively lengthened. This situation greatly concerned HSC’s Superintendent, Joseph H.W. Bower. The City of Toronto had ordered one commercial machine for Riverdale Isolation Hospital. London and Hamilton had also ordered lungs. Yet it would be several days at least before Riverdale’s lung arrived, and it would be ten days to two weeks before another one would be available. With this news, Bower knew he would have to build respirators at the hospital for any bulbar cases that might develop.

Meanwhile a four-year-old boy had been admitted with chest paralysis on the morning of 26 August. As the Drinker machine was in use, an experimental respirator for premature infants was modified and coupled with a quickly-built wooden box in which the little boy was placed and stabilized. This "emergency-made ‘lumber lung’" "saved" the child’s life. The boy’s mother then turned to the newspapers to plead for the "wealthy to buy iron lungs," each of which was worth some $2,000. The prominent place of this appeal in the Toronto press reflected the unusual vulnerability to polio among the well-to-do, whose wealth could not protect them from this disease. Two more commercial "lungs" were eventually bought, largely through an "Anonymous Donor." Meanwhile, at HSC, efforts were concentrated on building more lungs. By noon of 27 August, plans were complete and enough parts were ordered and delivered by the next evening to start assembling the first iron lung. Two days later this first lung was complete and placed on HSC’s Infectious Floor; within fifteen minutes a patient was placed in it. By 31 August, four "homemade" iron lungs had been assembled in the hospital’s basement.

Hospital for Sick Children Iron Lung

The iron lung symbolized the disease and its worst possible effects while at the same time it provided the medical community with a specific and hopeful technological tool against them. Still, the limited supply and success of iron lungs, especially during the crisis of an epidemic, frequently raised the difficult ethical dilemma of having to decide who to treat and for how long. Nevertheless, the iron lung also gave the provincial government another opportunity to demonstrate that it was doing everything possible against the worst effects of this disease.

Incidentally, the Hospital for Sick Children (Sick Kids) is a national treasure, I know several people who work there and have had one of my own children treated there as well. They still provide first rate care.

In Australia they also built their own ventilators when they could not purchase enough of the Drinker commercial models in 1937.

Australian made "wooden" Iron Lung

Some Royal Navy men made a ventilator to save the life of a young army officer afflicted with polio in 1944.

Are the Ventilator Numbers Real?

2008-04-20T18:43:00.000-07:00

Last week I wrote about why there is a need for a pandemic ventilator and used facts, numbers and statistics from various sources to support my statements. Whenever I write an article, I generally compose it, then go back to a list of articles and websites I have saved to validate what I have written. Most of the information is easy to validate, but I always find it difficult to come up with verifiable numbers. Often I see the same number used in many reports and assume that it must be correct. It may be though, that everyone is just referencing the same inaccurate source.

The numbers for US ventilators and usage I used last week are ones that I have commonly seen used in other places. I got a good comment on the article that suggested that the actual number of ventilators may be lower, and that usage rates may also be a bit lower as well. I have had some concern with the inability to obtain good solid numbers.

When I reviewed the Ontario Health Plan for an Influenza Pandemic, I noted that the per capita numbers of ventilators for Ontario was significantly lower than the US numbers. Ontario has a comprehensive socialized medical system that treats everyone needing care, and I have never heard of anyone being refused the use of a ventilator in Ontario that required one. I checked the pandemic plans for the region where I live and also the hospital I work at, and the number of ventilators is pretty close to what you would expect from the numbers in the OHPIP report based on population. The utilization rates though are usually pretty high, and it is not uncommon for a hospital to borrow vents from other hospitals if they run short.

The 105,000 number for the number of ventilators in the US for the US population size is 4 times as many as the ratio in Ontario. It is hard to believe that it should be so different. Even the 70,000 number quoted by the comment last week seems high by this criteria.

I think that every pandemic plan should explicitly state how many ventilators they have, and what the utilization rates are. They should also have a good idea of how much they believe that they can extend the capacity of their staff to handle additional ventilated patients if the additional ventilators were made available. Proper planning requires that they know the present status, calculate how much they can extend their capabilities, and compensate as much as possible for any shortfalls in staff or equipment. I have seen very few plans that give figures for all these variables. If they do not have good numbers to base the plans on they are really just guessing.

Why There is a Need for the Pandemic Ventilator

2008-04-12T18:04:00.001-07:00

The World Health Organization, (WHO) is concerned that the H5N1 strain currently circulating in birds, may mutate so that it may readily infect and spread in humans. The current WHO pandemic status is level 3, which is a pandemic alert.

Pandemics vary widely in severity. Some mild pandemics do not cause much more illness than the normal seasonal flu strains and can be handled by the existing medical care system with minimal problems. The flu pandemics of 1957-58 and 1968-69 were like this. Other pandemics were very severe and caused many deaths. The 1918 pandemic was very severe and caused more deaths than World War One did. It is estimated by some, that the 1918 Spanish Flu pandemic may have killed between 50 and 100 million people.

Pandemics occur because a virus mutates to a new form that the current living population has not been exposed to before. It has been 40 years since the last pandemic, and today most people in the world have never been exposed to a pandemic influenza strain. Many experts say it is not just a matter of “if” another pandemic occurs, but “when”. Because of the high lethality of the current H5N1 strain in birds and the humans it has infected, many health experts are concerned that if a pandemic arises from this strain, it may cause very serious illness in the people it affects and may cause many deaths.

Many of the deaths caused by pandemic (and seasonal) influenza are due to reduced lung function caused either directly by the influenza virus or by opportunistic pneumonia infections that result from additional secretions in the lungs and the flu’s effects on the persons immune response. The lung injury condition that results is called ARDS (Acute Respiratory Distress Syndrome). For seasonal influenza, most deaths are in the very old or very young. Pandemic influenza causes many deaths in young adults. Medical treatment, including the use of a ventilator is the only way to save these young lives if they are afflicted with ARDS from pandemic influenza.

The WHO, the CDC, HHS and many other national and international health organizations take the threat of another pandemic in the future very seriously. They are actively monitoring the spread of H5N1 and doing every thing they able to minimize the chance that it will infect human populations. There is also research ongoing into developing vaccines for any emerging pandemic influenza, and also stockpiling of antiviral medications that can be used to control and limit the spread of the virus if it starts spreading from human to human. Many governments also have plans to control people’s individual freedoms, alter standards of care, and impose tight controls on freedom of movement of the population in the event of a pandemic so as to reduce the number of deaths.

There are not enough ventilators available right now to treat the number of people that will develop ARDS in a moderate or severe pandemic. Many people will die from pandemic flu that could have been saved if they had access to medical treatment with a ventilator. In the US, there are about 105,000 ventilators in hospitals. Of that number, only about 20,000 or less are available and not being used at any given time. There are also a number of ventilators in strategic stockpiles and there may be other ventilators that can be diverted from anesthesia machines. No one has done a strict inventory of availability, but these numbers suggest that there could be 30,000 to 40,000 ventilators made available from this existing stock for use in a pandemic. It is very difficult to know exactly how many ventilators will be required ahead of time. This depends on how many people get the pandemic influenza and also how severe the resulting illness is. Estimates for the number of people needing a ventilator for a moderate pandemic range from 100,000 to 200,000. Estimates for a severe pandemic range upwards of 700,000. Most pandemic plans acknowledge that a shortfall will occur, and will use triage protocols to ration the available ventilators.

Triage means that someone will determine who gets the opportunity to survive by getting one of the few available ventilators. Everyone needing a ventilator, whether he or she has pandemic flu or another condition will be assessed using a Sequential Organ Failure Assessment (SOFA) score. People who are very sick and are judged to have a lower chance of survival will be refused a ventilator. As the need increases, this threshold will be lowered. Many people who could have survived will then be refused a ventilator as well. Most triage plans do not discriminate based on age, so many of the deaths will be young people. It will not be possible to purchase enough commercially made ventilators during a pandemic to alleviate this crisis once it begins.

The Pandemic Ventilator is a design for a ventilator that can be constructed from readily available materials even after a pandemic begins. The design will try to have as many alarms and required features as is feasible. The idea of the public building homemade ventilators in the face of a shortfall to augment existing supplies is not without precedent. Home built ventilators were used to save lives in the 1940s and 1950s during the polio epidemic. Popular Mechanics even published plans for one in 1952. (See my other posting on this.) Using modern computerized control systems, we can build much more capable devices than they did.

WWSEF Science Fair Results

2008-04-04T13:55:00.000-07:00

Below is the pandemic ventilator prototype "Norman". Norman was built by one of our developers in his automation and robotics class.

This prototype is named “Norman” after Norman Burn. Norman Burn was the Chief Technician at the Department of Anesthesia at Newcastle. Norman Burn built many of the very first positive pressure ventilators. Some of his “home made” ventilators were used during the polio epidemic in Britain in 1947. (link here)

This developer is a high school student and has contributed to the Pandemic Ventilator Project right from the beginning. He has added many insights to the design of the project and did all the PLC programming for "Max" as well as his current prototype. He entered "Norman" in the Waterloo Wellington Science and Engineering Fair.

The Pandemic Ventilator at the Science Fair

He won 3 awards at this Science Fair:

Silver Medal in the Senior Engineering Division

The University of Ontario Institute of Technology Innovation Award for demonstrating the most innovative development, adaptation or use of technology in a science project.

An Award of Merit

In addition to the awards, his project has been accepted to participate in the National Canada Wide Science Fair to be held in Ottawa Canada from May 10 to May 18th 2008.

We congratulate him on his hard work and dedication.

Receiving the Silver Medal Award
for Senior Engineering

Receiving the University of Ontario Institute of Technology
Innovation Award for Demonstrating the Most Innovative Development,
Adaptation or Use of Technology in a Science Project

Receiving the Award of Merit

-------------------------------------------------------------------------------------
Correction

It seems there was an error made at the awards ceremony. Instead of the silver medal he was awarded, he was supposed to have received a gold medal and several university and college scholarships. So, we congratulate Jeff on his gold medal award. Here is a link to the official site.

Here are the awards he was supposed to have received:

Award of Merit,
Gold Medal, Senior Engineering,
University of Ontario Institute of Technology Innovation Award,
Conestoga College Entrance Scholarship,
University of Guelph Entrance Scholarship,
University of Waterloo Entrance Scholarship.
Wilfrid Laurier University Entrance Scholarship.

His project is also entered in the Canada-Wide Science Fair

Another Video of Pandemic Ventilator Norman

2008-03-30T16:11:00.000-07:00

Here is a picture with the Plexiglas cover installed, ready for the science fair. The jug of water that was used for a weight is now replaced with a can filled with 4.5 Kg of metal. This makes for a more compact weight. The computer monitor is used to display LabView which is running on a P3 computer under the table.

Norman Pandemic Ventilator Ready for the Science Fair

Last week I showed some pictures of “Norman”, and a video of the ventilator running.
(link here)

This week I have another video that shows the functioning ventilator with alarms enabled and also outputting a pressure wave to Labview on the computer. When you see the video, it again shows it running with a pressure of about 22 cm of water and a stroke volume of about 400 cc. The black bag that is inflating and deflating is a lung simulator, and the gauge that is turning is a spirometer. The patient line occluded and the loss of air pressure alarms are demonstrated by occluding the patient line and then the compressor line. The pressure signal from the pressure transducer is displayed on the computer monitor.

Norman has now run for many hours with no failure of the bag. This prototype shows that the pandemic ventilator design can meet the pressure and volume requirements for a ventilator and can also be equipped with safety alarms, remote monitoring and control.

Norman Running on Video

2008-03-21T16:38:00.000-07:00

In the blog so far I have written about and shown two prototype pandemic ventilators that we are working on. They are “Vinnie” (link here), and “Max” (link here). Today I will present the third prototype. This prototype will be named “Norman” after Norman Burn. Norman Burn was the Chief Technician at the Department of Anesthesia at Newcastle. Norman Burn built many of the very first positive pressure ventilators. Some of his “home made” ventilators were used during the polio epidemic in Britain in 1947. (link here)

A high school student at Forest Heights Collegiate in Kitchener Ontario is building “Norman”. It will be entered in the Waterloo Wellington Science and Engineering Fair to be held on April 1 2008.

Picture Here

Norman Pandemic Ventilator

Rockwell Allen Bradley Micrologix 1500

Ventilator Compressor

Jug of Water on the Bellows Plate

“Norman” is built from readily available components that can easily be obtained or re-purposed from other uses during a pandemic. It was constructed using the original design (link here) and is similar to “Max”, but with a few changes and improvements.

The bellows is a vertical slider instead of a hinged bellows. The slider is constructed from Bosch struts (link here) and plastic panels. It is an innovative design that does not jam, yet is easily constructed and forgiving of slightly out of tolerance assembly.
It uses an integral compressor so that it does not need to rely on pressurized air being available, but only electricity.
It has a pressure transducer instead of a manometer. A restrictor valve has been added in the “to patient” line, so that the inspiration time can be adjusted.
The bellows bag is a 2-liter PVC peritoneal dialysis bag. This is a very strong bag and has run many hours with no breakdown or apparent wear.
The PLC is an Allen Bradley Micrologix 1500.

Here is a video of Norman running.

You can see that there is a jug of water on the bellows plate. Adjusting the amount of water in the jug on the bellows plate controls the maximum pressure generated by the bellows. The Checkmate pressure gauge behind the ventilator shows the maximum pressure is about 22 cm water. The Boeringer spirometer is recording a tidal volume of about 400 cc and a minute volume of about 7 liters.

Dr John Hick Interviewed by the Star Tribune

2008-03-15T19:15:00.000-07:00

"But when we get hit hard with a bad outbreak, people are going to be saying, 'Why didn't you prepare for this?' And there won't be any good answers."
Dr. John Hick

You may have noticed that media coverage of the shortage of ventilators that will happen in the next pandemic has reduced somewhat recently. The coverage peaked about 2 years ago and has been slowly dropping in frequency. This week there were two stories, one in the Wall Street Journal (link here) and also a very interesting article in the Star Tribune of Minneapolis St Paul Minnesota. Warren Wolf of the Star Tribune interviewed Dr. John Hick of Hennepin County Medical Center about the recent shortage of ventilators in Minnesota hospital intensive care units. (link here)

Dr. John Hick is very prominent in the pandemic flu planning literature. He is the medical director for an emergency-preparedness compact of Minnesota hospitals. He has been involved with many planning committees and has authored several articles dealing with the expected scarcity of key medical supplies including ventilators in a pandemic. He is also frequently referenced in other major articles on this subject. He is clearly one of the leading thinkers on this issue. He is one of the authors in a document I recently reviewed entitled Mass Medical Care with Scarce Resources: A Community Planning Guide. (link here)

Dr. Hick, as you can expect, is usually somewhat more restrained in his comments in his major written articles. In fact, I have even criticized him previously for not pushing hard enough, or looking at enough options. In this interview however, he is a little more open. I was very impressed with his comments and will be re-quoting several of them here.

The Star Tribune article is about a recent shortage of ventilators in Minnesota hospital intensive care units that had many hospitals renting extra ventilators and had several hospitals directing patients with respiratory problems elsewhere for care. Dr Hick was asked about the “crisis” and said he did not think it was a real crisis but that it was a little too close for comfort.

He then linked the temporary shortage of ventilators they experienced to the real problem he perceives. "Even if we hit a temporary local crisis, we can deal with that. What worries me -- what keeps me awake sometimes -- is what will we do when we get a regional or national pandemic? That's going to happen. It's just a question of when and how bad.”

He then says the shortage will cause unnecessary deaths. "The truth is, in a major crisis like a pandemic we may be forced to triage patients because we just won't have the hardware, and some will die.” He said a major disaster or flu outbreak could "tip us over the balance and people would die for lack of ventilators."

The article then says; Hick has urged state officials to stockpile ventilators, "but in a year when we're cutting health care spending, buying ventilators at $50,000 each in case of emergency is kind of a hard sell.”

Hick concludes with, “This is a scary situation and it ought to make people nervous, We got through last week and we can do it again -- we probably will. But when we get hit hard with a bad outbreak, people are going to be saying, 'Why didn't you prepare for this?' And there won't be any good answers."

Thank you Dr. Hick. For telling it like it is.

Review of - Positive-Pressure Ventilation Equipment for Mass Casualty Respiratory Failure

2008-03-08T17:22:00.000-08:00

Today I will review the document “Positive-Pressure Ventilation Equipment for Mass Casualty Respiratory Failure”. This is available for free as html or PDF at
http://www.upmc-biosecurity.org/website/resources/publications/2006_orig-articles/2006-06-15-positivepressureventilationformasscasualtyrespfailure.html
The authors are: Lewis Rubinson, Richard D. Branson, Nicki Pesik, and Daniel Talmor

This document discusses the need for additional ventilators for a mass casualty event including an influenza pandemic. They discuss the need to stockpile additional ventilators for such an emergency. They also acknowledge that it would be very expensive to stockpile and maintain enough full-featured ventilators to be adequately prepared for such an event, so they discuss how positive pressure ventilators (PPVs) with fewer alarms and capabilities could also be used to supplement the existing stocks in time of emergency.

In my opinion, this is a very well researched and prepared article. Many of the issues documented in this article have in fact shaped the aims of the Pandemic Ventilator Project as well. It deals at length with the advantages and disadvantages of various types of ventilators for use in mass casualty respiratory failure. The emergency ventilators we are designing at the Pandemic Ventilator Project are not meant to compete with or replace regular commercial ventilators, but are meant as a backup in case authorities do not stockpile adequate numbers ahead of time.

The use of improvised ventilator equipment during the polio epidemic in Copenhagen in 1952 is discussed. They had only 4 devices available, but had to ventilate as many as 70 persons at a time. They designed and built a number of devices that were manually operated by medical students and saved many lives that would otherwise have been lost. This is a great example that innovative ideas, methods and pragmatic thinking can be used in times of crisis to save lives.

(For additional information on the use of alternative ventilators in the Polio epidemic, see my previous post http://panvent.blogspot.com/2008/01/everything-old-is-new-again.html )

They then discuss how the use of PPVs requires highly trained and skilled health professionals, and that even in normal times, the number of skilled professionals and equipment is sometimes in short supply. In addition to increasing the physical supply of PPVs, there will also have to be plans in place to be able to extend the capabilities of the health care professionals. There is a discussion of different ways to stretch the existing supply of ventilators. There are details of various disaster scenarios and how they will affect the need for PVPs.

They give a good overview of the logistics of ventilator stockpiling and airway management. Endotracheal intubation is preferred. There is a chart that details the various types of alternative Ventilators and their characteristics. The text provides a detailed analysis of the advantages and disadvantages of each type.

They then reiterate the expected shortage:
“Even with significant state and regional investments in PPV caches, there will likely be a shortage of available PPV equipment during a severe influenza pandemic. Standardized approaches to prioritize allocation of scarce resources such as ventilators must be considered for such events.”

They close with this ominous statement:
“Even though not enough PPVs could be stockpiled to ensure that each patient with ARF has a ventilator during a severe influenza pandemic, the additional capacity afforded by reasonably sized caches can help a significant number of patients survive. This additional PPV equipment must be purchased within the context of a rigorously developed strategy to provide a coordinated medical response to catastrophes. Without such equipment, many patients may die despite having survivable clinical conditions.”

The Pandemic Ventilator Project exists to supply a design for a ventilator that can be built from readily available components to fill that last shortfall. I wonder what the writers of this document think of the Pandemic Ventilator Project? I wonder if they are even aware of it? This document was written nine months before the Pandemic Ventilator Project was started. They cite the use of jury-rigged ventilators constructed during the polio epidemic in Copenhagen as an example of how lives can be saved by using alternative ventilators, but then they recommend that only FDA approved devices be used. In fairness, I do not see how any planner working under the existing liability framework can recommend anything other than an FDA approved device. It is only when an actual crisis arrives, when they are faced with triaging the available ventilators to do the greatest good for the greatest number of people that real alternative solutions can be considered.

Review of Ontario Health Plan for an Influenza Pandemic

2008-02-29T19:25:00.000-08:00

I have reviewed other pandemic planning documents that deal with the shortage of ventilators before and today I will discuss one that has some particular importance for me. It is produced by the Ontario Ministry of Health and Long Term Care (MOHLTC), and is entitled “Ontario Health Plan for an Influenza Pandemic” (OHPIP). It is dated July 5, 2007 and is the fourth edition. This document is available at
http://www.health.gov.on.ca/english/providers/program/emu/pan_flu/pan_flu_plan.html
Ontario has planned extensively and early for a possible flu pandemic. This is most likely because of its direct involvement in the SARS and the fear that it would become a pandemic.

This plan is important to me of course because I live in Ontario Canada. Previous OHPIPs issued by MOHLTC have been referenced by other planning organizations. Ontario has been early to recognize the need for a triage plan to deal with the expected crisis for health care in a pandemic, and particularly the shortage of ventilators and trained health care staff that will arise. As in other review posts I have done, I will concentrate mainly on the ventilator issue using excerpts with my attached comments.

The list of contributors to the document is very long and diverse including hospitals, community groups, and businesses as well as academia.

It first has a quote by John M. Barry:
“Every expert on influenza agrees that the ability of the influenza virus to reassort genes means that another pandemic not only can happen. It almost certainly will happen … influenza is among the most contagious of all diseases … the influenza virus can spread from person to person before any symptoms develop. If a new influenza virus does emerge, given modern travel patterns it will likely spread even more rapidly than it did in 1918.”

The document begins by discussing the need for pandemic planning and why there is a particular concern for an influenza pandemic now. It then discusses the role of the WHO and other governing and regulatory groups in pandemic planning. There is a discussion of the ethical framework required for the plan. It references “Stand on Guard for Thee”. Legislation that is required to implement the alteration of rights and government control required to implement the plan is also discussed. The planning goals are then explained. The plan uses the Meltzer model from the CDC, uses the FluAid 2.0 software, and assumes a pandemic of mild to moderate severity.

They do not mention central purchase of ventilators.
“The MOHLTC will provide centralized purchase and distribution of certain personal protective equipment, vaccines/antiviral drugs and other clinical supplies.”

Section 4 has a very good list of links to Ontario and world organizations and other information documents. I will post a copy of the links at the bottom of this post. There is also a very detailed section on credentialing including checklists. There are also general plans on how to increase the availability of staff levels. There is much more very good general planning information, but I will skip now to the portions relevant to ventilator shortages.

Here is a hospital capacity table.
This is also a “most likely “ scenario. I am not sure why there are no numbers for ventilators for weeks 9 and 10 in the scenario. Click on the image to see a clear copy.

Tables such as these are deceiving. At first glance it looks as if we will only have a real ventilator shortfall in weeks 4, 5 and 6, but this excludes the normal utilization of the ventilators in hospitals. They assume 1096 ventilators in Ontario. Now if we assume a normal inter-pandemic utilization rate of 80%, then we really only have 219 ventilators available from our existing pool.

The ventilator shortfall becomes this:

---------------Zero Extra Vents------------500 Extra Ventilators
Week 1 ------------58
Week 2 -----------368
Week 3 -----------683----------------------------183
Week 4 -----------972----------------------------472
Week 5 ----------1070---------------------------570
Week 6 ----------1035---------------------------535
Week 7 -----------777
Week 8 ----------469
Total ----------5374----------------------------1760

These are the numbers of ventilator triage decisions that will have to be made each week during this calculated scenario. Now remember, there is a very good chance that the real numbers could be much worse. If the number of supported ventilators could be doubled, then no ventilator triage decisions would have to be made. If the number of supported ventilators could be increased by 500 (50%), then the total number of ventilator triage decisions could be reduced from 5374 to 1760.

Here is a method they suggest to increase the ability to care for ventilated patients. In this example it doubles the capacity.

Scaling Back Elective Services
Scaling back elective services and surgeries can free up hospital areas, such as surgical intensive care units, endoscopic units, step-down units and post anaesthetic care units [PACU], that are well equipped to provide critical care for influenza and non-influenza patients. How much critical care capacity can be increased will depend largely on the availability of ventilators, and personnel skilled in managing critically ill patients. Scaling back elective and non-urgent services can also provide additional personnel who may have skills transferable to critical care – particularly when a team care model is used (figure 17.2). In this model, health care providers who lack experience in a specific area can be supervised by those with the relevant experience. Instead of individual health care providers caring for one or two patients, a team that has a complete skill set and relevant experience collectively cares for a group of patients. For example, a team of 2 ICU nurses supervising 3 stepdown nurses working with a respiratory therapist and a physician could care for 8 to 10 patients instead of the usual complement of 4 ICU nurses caring for 5 ventilated patients (i.e., 1:1 or 1:2 ratio). The care team model has proven effective in past emergencies(5;6).

Here is the Protocol for prioritization of Patients

The final component of the triage protocol is the prioritization of patients for potential admission to the ICU and ventilation. For ease of use, the common blue-red-yellow-green colour scheme was used.

• Blue patients are those who fall in to the expectant category and should not receive critical care. Depending on their condition and medical issues the patient may either continue to have curative medical care on a ward or palliative care.

• Red patients are highest priority for ICU admission and a ventilator if required. The aim is to find the balance between those who are sick enough to require the resource and will do poorly if they don’t receive it, but are not so sick that they are unlikely to recover even if they do receive intensive care. Patients with a single organ failure, particularly those with respiratory failure due to influenza and who otherwise have a very low SOFA score are included in the red category -- if they have no exclusion criteria. The goal is to optimize the effectiveness of the triage protocol so that every patient who receives critical care will survive.

• Yellow patients are very sick and may or may not benefit from critical care. They should receive care if the resources are available but not at the expense of denying care to someone in the red category who is more likely to recover. At the re-assessment points, patients who are improving are given high priority (red) for continued care, while those who are not showing signs of improvement or worsening are prioritized as yellow.

• Green patients should be considered for transfer out of the ICU.

So what is my overall impression for the plan for my province?

I have worked in the Ontario health care system for about 20 years, and in my experience I have found that there is a strong commitment to caring for the patients we are entrusted to. This document addresses that commitment many times, even when it acknowledges that there are limits to what can be done. On first glance the plan looks very thorough, and is detailed in many areas. It does however have one glaring shortfall. It recognizes that there will be many possibly avoidable deaths because there will not actually be enough ventilators. It has plans to increase the physical space available, antiviral medications, legal issues, and even the staffing plans that could support more ventilators, but there is no plan to actually increase the stockpile of ventilators to a number that could have a significant impact.

The estimated number of ventilators seems low. It is stated as 1096 and is stated as the number of ventilator supported beds. The typical numbers used by US planning authorities is 105,000. The population of Ontario is about 12 million and the population of the US is about 300 million. This is a 25:1 ratio. (The US seems to have 4200 ventilators per 12 million population. This may include patients on chronic ventilators.) It seems that the issue of the number of ventilators available for use should be looked into more closely and this discrepancy accounted for.

The number of available anesthetic gas machines that could be used as ventilators should be accounted for as well. The plan does not go into how the number of available ventilators can be expanded or what the requirements for any acquired surge capacity ventilators should be.

I am sure that the MOHLTC does not want to make the types of planning errors in the face of an impending flu pandemic that the Canadian Red Cross made in the 1980’s in the face of the impending AIDS pandemic, where they could have done several things to save lives but they did not. The CBC archives has a retrospective on this at http://archives.cbc.ca/IDD-1-70-737/disasters_tragedies/tainted_blood/

If you are a pandemic planner, or you work for the MOHLTC, you may wish to listen to these clips, and while you listen, think of how you would respond to people who have lost loved ones in a pandemic due to a ventilator shortage, asking about whether you ever considered getting an additional supply of ventilators ahead of time.

(See my earlier post ~ Trusting in the Pandemic Plans)

I will end with another quote from John Barry that was used in the document:

To have any chance in alleviating the devastation of the [1918 influenza] epidemic
required organization, coordination, implementation. It required leadership and it
required that institutions follow that leadership.

The Great Influenza, John M. Barry

Links from Chapter 4

General Information Resources for the Public

Ontario Ministry of Health and Long-Term Care Pandemic Planning information web site
http://www.health.gov.on.ca/pandemic

Telehealth Ontario
A free, confidential telephone service you can call to get health advice or general health information from a Registered Nurse. 1-866-797-0000

Ontario Ministry of Health INFOline INFOline would direct callers to the appropriate information source for health information.
1-800-268-1154 (Toll-free in Ontario only)
in Toronto, call 416-314-5518, TTY 1-800-387-5559

Government of Canada Information on the Preparedness and Response to a Flu Pandemic One-stop access to information from Government of Canada departments and agencies on pandemic, avian and seasonal influenza.
http://www.pandemicinfluenza.gc.ca

Government of Canada pandemic influenza information hotline
For answers to specific questions or comments about avian, seasonal, or pandemic flu.
1-800-454-8302

Public Safety Canada Web Site for Pandemic Preparedness
A compilation of pandemic preparedness plans from several organizations and levels of government (federal, provincial and municipal plans are linked from this site when available). http://www.safecanada.ca/pandemic/index_e.asp

U.S. Government Avian and Pandemic Flu Information Managed by the U.S Department of Health and Human Services.
http://www.pandemicflu.gov

World Health Organization Web site for pandemic influenza Planning, technical and surveillance
information for pandemic influenza.
http://www.who.int/csr/disease/influenza/pandemic/en/

What you should know about a flu pandemic
A public information brochure by the Ontario Ministry of Health and Long Term Care, which is available in 24 languages.
http://www.health.gov.on.ca/pandemic

An American Sign Language Video Visually presents the contents of the public information brochure.
http://www.health.gov.on.ca/pandemic

Fact Sheets

Ten fact sheets including “What You Should Know About a Flu Pandemic,” are available in printable formats in 24 languages.
http://www.health.gov.on.ca/english/public/program/emu/pan_flu/pan_flu_materials.html#fs

Centers for Disease Control and Prevention Information on Community disease control and prevention.
http://www/hhs/gov/pandemicflu/plan/pdf/S08.pdf

Canadian Pandemic Influenza Plan
http://www.phacaspc.gc.ca/cpip-pclcpi/

World Health Organization
http://www.who.int/csr/resources/publications/influenza/GIP_2005_5Eweb.pdf

Health and Human Services, USA.
Pandemic Influenza Plan.
http://www.hhs.gov/pandemicflu/plan/

Resources for Health Care Providers
Ontario Ministry of Health and Long-Term Care Pandemic Influenza
Information for Health Care Professionals. Information includes provincial emergency status, the Ontario Health Plan for an Influenza Pandemic, fact sheets about treatment and patient care, and links to other health Web sites.
http://www.health.gov.on.ca/pandemic

MOHLTC Healthcare Providers Hotline
For answers to health care providers’ questions. 1-866-212-2272

Ontario Ministry of Labour (Occupational Health and Safety)
Information on Occupational Heath and Safety regulations and protocols in Ontario.
http://www.labour.gov.on.ca/english/hs/index.html

Government of Canada Pandemic Influenza Information for Health Care Professionals
Provides information kits, technical information and Epidemiological Surveillance reports.
http://www.influenza.gc.ca/hpi_e.html

Public Safety Canada Website for Pandemic Preparedness
A compilation of pandemic preparedness plans from several organizations and levels of government (federal, provincial and municipal plans are linked from this site when available).
http://www.safecanada.ca/pandemic/index_e.asp

World Health Organization Website for Pandemic Influenza
Planning, technical and surveillance information for pandemic influenza.
http://www.who.int/csr/disease/influenza/pandemic/en/

Pandemic Information compiled by The Public Health Agency of Canada (PHAC).
http://www.phacaspc.gc.ca/fluwatch/

The MOHLTC’s Emergency Management Unit Health Care Provider Hotline
Includes information for health care providers, employers and first responders.
Toll-free phone 1-866-212-2272; email emergencymanagement@moh.gov.on.ca
http://www.health.gov.on.ca/english/providers/program/emu/emu_mn.html

Important Health Notices (IHN)
Issued by the MOHLTC in response to abnormal events that require ministry direction. The information is intended primarily for use by health care workers and facilities/organizations providing health care, including pharmacies, hospitals, long-term care facilities, community-based health care service providers, and pre-hospital emergency services. IHNs are distributed by email, daily at midnight, and are posted to MOHLTC web site. www.health.gov.on.ca/english/providers/program/emu/ihn.html

Fact Sheets for Health Care Professionals

Fact sheets for matters regarding protection, treatment, and patient care.
http://www.health.gov.on.ca/english/public/program/emu/pan_flu/pan_flu_materials.html#fs

Centers for Disease Control
and Prevention Information on Community disease control and prevention.
http://www/hhs/gov/pandemicflu/plan/pdf/S08.pdf

Canadian Pandemic Influenza Plan
http://www.phacaspc.gc.ca/cpip-pclcpi/

World Health Organization
http://www.who.int/csr/resources/publications/influenza/GIP_2005_5Eweb.pdf

Health and Human Services, USA.
Pandemic Influenza Plan
http://www.hhs.gov/pandemicflu/plan/

The Role of Health Leaders in Planning for an Influenza Pandemic
a Publication by the Canadian College of Health Service Executives
http://www.cchse.org/PandemicEnglish.pdf

Context and Assumptions

“Fluwatch”
Maintained by the Public Health Agencyof Canada (PHAC).
Includes archives and up-to-date information on influenza in Canada.
http://www.phacaspc.gc.ca/fluwatch/05-06/def05-06_e.html

The Meltzer Model.
Martin I. Meltzer M.I, Cox N.J, and Keiji Fukuda.
The Economic Impact of Pandemic Influenza in the United States: Priorities for Intervention. Centers for Disease Control and Prevention, Atlanta, Georgia, USA.
http://www.cdc.gov/ncidod/eid/vol5no5/meltzer.htm

FluAid 2.0 software
Developed by the U.S. Centers for Disease Control and Prevention
http://www2a.cdc.gov/od/fluaid/

FluSurge program
Developed by the U.S Centers for Disease Control and Prevention
http://www.cdc.gov/flu/flusurge.htm

FluWorkLoss software
developed by the U.S. Centres for Disease Control
estimates the potential number of days lost from work due to an influenza pandemic.
http://www.cdc.gov/flu/tools/fluworkloss/

The Role of Bioethics in an Influenza Pandemic.
Gibson J et al (2005). Ethics in a Pandemic Influenza Crisis. Framework for Decision Making. Joint Centre for Bioethics, University of Toronto. WHO Global Pandemic Alert Phases
http://www.who.int/csr/disease/avian_influenza/phase/en/

Legislation

The Ontario Health System ImprovementsAct (2007)
http://www.ontla.on.ca/web/bills/bills_detail.do?locale=en&BillID=519

The Ontario Health Protection and Promotion Act (2006).
http://www.elaws.gov.on.ca/DBLaws/Regs/English/030166_e.htm

The Ontario Crown Employees Collective Bargaining Act (1993)
Provides information on the duties of “essential employees”
http://www.elaws.gov.on.ca/DBLaws/Statutes/English/93c38_e.htm

The Ontario Emergency Management Act
http://www.elaws.gov.on.ca/DBLaws/Statutes/English/90e09_e.htm

The Ontario Regulated Health Professions Act (RHPA).
http://www.elaws.gov.on.ca/DBLaws/Statutes/English/91r18_e.htm

The Ontario Occupational Health and Safety Act
http://www.elaws.gov.on.ca/DBLaws/Statutes/English/90o01_e.htm

The Ontario Workplace Safety and Insurance Act
http://www.elaws.gov.on.ca/DBLaws/Statutes/English/97w16_e.htm

Surveillance

Public Health Agency of Canada
FluWatch surveillance system provides a national picture of influenza activity.
http://www.phacaspc.gc.ca/fluwatch/index.html

The Canadian Network for Public Health Intelligence
Contains various internet-based applications and resources designed to provide a secure way for public health authorities to share information and manage resources in an outbreak situation.
https://www.cnphircrsp.ca/cnphi/index.jsp?src=CPHLN

Ontario Influenza Bulletin
Includes regularly updated information on influenza in Ontario
http://www.health.gov.on.ca/english/providers/program/pubhealth/flu/flu_05/flubul_mn.html

Infection Control

Preventing Respiratory Illnesses, Protecting Patients and Staff
Document created by the MOHLTC which includes the FRI Case Finding Protocol
(Note: these guidelines have been developed for non-outbreak conditions; however, because influenza is primarily droplet and contact spread, the principlesof infection control in the guidelines can be applied more broadly.
http://www.health.gov.on.ca/english/providers/program/infectious/diseases/ic_fri.html)

Infection Prevention
A reference booklet for health care workers produced by Engender Health.
http://www.engenderhealth.org/res/offc/safety/ip-ref/pdf/ip-ref-eng.pdf

College of Physicians and Surgeons of Ontario – Infection Control in the Physician’s Office.
http://www.cpso.on.ca/Publications/infectioncontrolv2.pdf

Ontario Ministry of Labour (Occupational Health and Safety)
Information about occupational Heath and Safety regulations and protocols in Ontario as well as a reference about people’s rights as employees.
http://www.labour.gov.on.ca/english/hs/index.html

Infection Control Toolkit Strategies for Pandemics and Disasters.
Can be ordered through the Community and Hospital Infection Control Association (CHICA - Canada). Phone 204-897-5990 or 866-999-7111; email chicacda@mb.sympatico.ca
Canadian Pandemic Influenza Plan Annex F

Infection Control and Occupational Health Guidelines during an Influenza Pandemic in Traditional and Non-Traditional Health Care Settings.
http://www.phacaspc.gc.ca/cpip-pclcpi/pdf-cpip-03/cpip-appendix-f.pdf

Routine Practices and Additional Precautions for Preventing the Transmission of Infection in Health Care.
http://www.phacaspc.gc.ca/publicat/ccdrrmtc/99vol25/25s4/index.html

Handwashing Techniques
http://www.health.gov.on.ca/english/public/pub/pubhealth/pdf/handwash_tech.pdf)

Canada Communicable Disease Report Prevention and Control of Occupational Infections in Health Care.
http://www.phacaspc.gc.ca/publicat/ccdrrmtc/02pdf/28s1e.pdf

Canadian Tuberculosis Standards 5th ed.
Produced by the Canadian Lung Association in 2000
http://www.phacaspc.gc.ca/publicat/ctsncla00/pdf/cts00.pdf)

Ontario Best Practice Manual
Contains information on proper cleaning, disinfection, and sterilization.
http://www.health.gov.on.ca/english/providers/program/infectious/diseases/ic_cds.html

Infection Control Guidelines on Handwashing (Health Canada).
http://www.phacaspc.gc.ca/publicat/ccdrrmtc/98pdf/cdr24s8e.pdf

Engineering Controls. CSA Standard CAN/CZA-Z317.2-01
Special requirements for heating, ventilation, and air conditioning (HVAC) systems in health care acilities. Toronto: Canadian Standards Association, 2001.

Occupational Health and Safety

Ontario Ministry of Labour (Occupational Health and Safety)
Information about occupational Health and Safety regulations and protocols in Ontario as well as a reference about people’s rights as employees.
http://www.labour.gov.on.ca/english/hs/index.html

The Occupational Health and Safety Act
Regulation: Health Care and Residential Facilities
http://www.elaws.gov.on.ca/DBLaws/Regs/English/930067_e.htm

The Workplace Safety and Insurance Act
http://www.elaws.gov.on.ca/DBLaws/Statutes/English/97w16_e.htm

Ontario Safety Association for Community and Healthcare (OSACH)
Pandemic Planning Resources
http://www.osach.ca/new/SaftInfo/PanPlan.shtml

For a complete listing of products and services available from all of Ontario's designated Safe Workplace Associations, see:
http://www.preventiondynamics.com/

Canada’s National Centre for Occupational Health and Safety Pandemic Planning Portal
http://www.ccohs.ca/pandemic/

United States Department of Health and Human Services Health and Safety Information
http://www.pandemicflu.gov/health/index.html

Occupational Health and Safety Association (OSHA) Guidance on Preparing Workplaces for an Influenza Pandemic
http://www.osha.gov/Publications/OSHA3327pandemic.pdf

Potential Training Resources for Volunteers
St. John Ambulance Brigade. Brigade Training System (1997).
http://www.sja.ca/english/health_safety_training/index.asp

St. John Ambulance Brigade. Handbook on the Administration of Oxygen (1993)
ISBN 0-919434-77-0.

Yes, You Can Prevent Disease Transmission (1998).
The Canadian Red Cross Society

Immunizations / Vaccines

The Canadian Immunization Guide, 6th Edition
A comprehensive guide produced by Health Canada
http://www.phacaspc.gc.ca/publicat/ciggci/pdf/cdn_immuniz_guide-2002-6.pdf

Vaccine Storage and Handling Guidelines
A set of guidelines produced by Ontario Ministry of Health to ensure that vaccines are stored and transported at ideal temperature in the appropriate containers
http://www.health.gov.on.ca/english/providers/program/pubhealth/flu/flu_03/implementation_package/vac_store_hand.pdf

California Department of Health Services Immunization Branch
Information on Comforting Restraining for Immunization
http://www.dhs.ca.gov/ps/dcdc/izgroup/news.htm

WHO Directions for the Vaccination ofChildren
http://www.who.int/child-adolescenthealth/publications/referral_care/

Further Information on Safe Vaccine Administration, and Healthcare Worker Safety http://www.who.int/vaccinesdocuments
http://www.safety.ed.ac.uk/resources/Bio/Guidance/General/Preventing_injuries.shtm
http://www.seiu.ca

Laboratory Services and Safety

The Laboratory Annex, Canadian Pandemic Influenza Plan
Contains additional information on avian influenza infection in
http://www.phac-aspc.gc.ca/cpippclcpi/

Transportation of Dangerous Goods Regulations
Detailed information on infectious substance (specimen) packaging and transport
World Organization for Animal Health (Office International des Epizooties)
All novel H5 and H7 influenza strains discovered in a laboratory should also be reported here because of possible “crossspecies” transmission and infection.
http://www.oie.int/eng/oie/en_oie.htm

Public Health Agency of Canada Containment Levels
Updated information is available from the Office of Laboratory Security of the PHAC
(Phone) 613-957-1779, or (fax) 613-941-0596
http://www.phac-aspc.gc.ca/olsbsl/index.html

One Year Anniversary

2008-02-24T16:42:00.000-08:00

Today is just over a year since I started the Pandemic Ventilator Project. To commemorate, I have added a new logo pVp to the blog (on the right) and will also use a smaller version as my avatar on discussion boards. Vinnie is nearing completion of the first prototype stage. Not all the features and alarms are yet in place but it is far enough along that it can be seen that this is a very feasible approach.

I have decided to give the other prototype ventilator a name as well. I will call it Max in honor of Maxwell K. Reynolds. He is the man who built those ventilators in Marquette Michigan to help save children from dying in the Polio epidemic when a commercial iron lung was not available.

In many ways I am quite happy with the progress so far. The basic principles of the design have been validated, and it also appears we can build a more advanced version with improved control and alarm capabilities. On the other hand, I expected that the project would have involved more people by now than we currently have. There are really only 3 active developers and a small number of contributors that provide advice, direction and promotion help as well.

The basic development work done so far has been done with no funding. We have purchased all components and equipment on our own. We are reaching the point that if we want to scale up the project to do more testing and be able to increase the number of available units we will have to seek some form of funding source. Everyone working on the project now is either in a full time job or education. The development work is done in our spare time. We really need the help of a professional in respiratory therapy. I have a background in biomedical technology, but I have to learn all the clinical requirements of ventilator therapy as we go along.

I have learned a lot in the last year. I thought my idea of building home made ventilators for use in a pandemic was original, but I have since learned that the same approach was used to save lives in the polio epidemic in the first half of the last century. I thought my weighted bellows idea was original but have come across many designs for older ventilators that also successfully used that principle such as the Blease Manley Ventilator. I thought the idea of building a low maintenance, low cost ventilator that can be serviced by local people in third world countries was novel, but there is a successful precedent for that as well. http://www.glostavent.com/

One idea I hold that I wish were shared by more people is that the use of home built ventilators from a proven design using readily available highly reliable industrial control system components and other common materials is a valid approach to supplying ventilators in a WHO phase 6 pandemic alert. I believe that this is one more way of maximizing the number of lives that could be saved, but not necessarily a complete solution to the ventilator shortage. I have no idea of how I can impress this idea on the people that make the triage plans and allocation decisions for pandemic planning. I have produced this blog, contacted them directly and have made numerous posts in other prominent avian flu pandemic discussion forums. I find it hard to believe they have not heard of this proposal. I have not heard from any high level planner about this. Not even criticism.

Test of the Pandemic Ventilator with Manometer

2008-02-16T15:50:00.000-08:00

It has been a while since I did much development work on the ventilator I am building. This is one of three pandemic ventilators currently being developed. A much more functional unit that requires some special order components (Vinnie) is also being built, and someone is building another unit with capabilities somewhere between my unit and Vinnie.

Now if you have seen my last demonstration, (link here) you will see I used another bellows unit as my test lung then. I had no idea of what weight to place on the bellows, so I guessed and put some wrenches on them. Since then I have acquired a proper test lung. It is a Puritan-Bennett 0612. I have also mounted the ventilator on an old chair stand to make it easier to work on and move around with the heavy weights.

Once we started using a real test lung, we found out that the wrench on the bellows lid would not do for weight. One pound per square inch is about 27 inches of water. The Ziplock bag I was using was about 100 square inches so it would need 100 pounds on the bellows. I don’t think the poor bag would stand that very long. I needed a replacement that was tough and readily available. I settled on a 2 liter peritoneal dialysis bag. I tested this by standing on it, so I knew it would withstand at least 200 pounds without bursting. I then tried a destructive test by jumping on it. It still did not burst. Case closed. The uninflated surface area of this bag is about 50 square inches. I put about 30 pounds of weight on the bellows .

The manometer is constructed almost exactly to the original plan. I decided to go with a small diameter tube to keep the total compliance of the system low. The internal diameter of this tubing is 0.17 inches (3/16 nominal), this is about 44mm, and adds about 3 c.c.s of compliance at 20 inches of pressure. This is a negligible amount for a 500cc tidal volume (0.6%). This size of tubing (3/16ths) is about as small as you can go with water. If you go with a smaller tubing diameter you can end up with sections of air between water sections that are difficult to purge. This small diameter will not let me use my floating magnet trick for a sensor. I added food grade coloring to make it easier to see the level.

You can see it runs fairly well. As near as I can calculate, it is running a tidal volume of about 500 cc. I checked this by inflating the test lung to this size and placing it in water and comparing it to the pre inflated displacement. The rate is about 18 breaths per minute. This works out to a minute volume of about 9 liters. Not bad. I think I am getting close to a truly useful device for use in a pandemic.

If we wanted to change these parameters we could:

widen the bellows settings to increase the tidal volume or
narrow the bellows settings to decrease the tidal volume
increase the weight on the bellows to reduce the inspiration time or
decrease the weight on the bellows to increase the inspiration time
increase the cycle time of the PLC to increase the expiration time or
reduce the cycle time of the PLC to reduce the expiration time

Things I learned:

The peritoneal dialysis bag will work OK. I am a lot less worried about reliability with this bag.
The bellows should be built more sturdy.
The manometer principle is valid for peak inspiratory pressure.
I will have to think about the best way to handle the manometer level sensing. In order to sense the level accurately, I will need sensors for fluid in tubing or use conductive sensors.
I will have to improve the sensing position adjusters. i may use mechanical switches instead of magnetic switches.
I may try adding the maximum weight on the bellows for a safe maximum pressure and adjust the inspiration time with a manually operated valve that lets me control the flow rate out of the bellows.
I need better regulation of the input air pressure.
Once I get all the bugs worked out I will rebuild it to a more useful form factor.
I will have to do a calibration of the system using other pressure sensing equipment, then I can mark the levels on the manometer.

Review of - Mass Medical Care with Scarce Resources: A Community Planning Guide

2008-02-15T13:46:00.000-08:00

Today I will review another US government planning document. This is from the US Department of health and Human Services (HSS) and the Agency for Healthcare Research and Quality (AHRQ). This one is titled Mass Medical Care with Scarce Resources: A Community Planning Guide, and is available for free at http://www.ahrq.gov/research/mce/ in html and PDF formats. Again, I will be exerpting the ventilator specific sections and making a few comments. The original document is a 181 page pdf file.

This is document has very broad coverage of not only the avian flu threat and pandemics in general but also other mass casualty events. It is a government document and so tends to avoid much discussion of extreme events and generally assumes a pandemic of similar intensity to the 1918 Spanish Influenza as a worst case position. It discusses the ethical decisions that need to be made in the face of difficult choices and provides good background info and principles but generally steers away from making definitive suggestions on what ethical choices to make.

It presents a case study of a Pandemic Flu outbreak and addresses the expected ventilator shortage. They recommend that a triage system be established to decide which patients will get to use the limited supply of ventilators. They also suggest that hospitals may be using manual resuscitation bags to provide ventilation in response to a pandemic influenza. There are also comments about the need to prevent infection of staff by patients on ventilators by using intubation and by having ventilators with an adequate alarm system so that staff do not have to constantly attend patients.

This document, like the one I reviewed last week has a lot devoted to the process of deciding which patients will receive the ventilator therapy and which ones will not and how to be sure this process is very ethical. All of the planning documents I have read so far are similar in this regard. They write about how we will have to have altered standards of care. These altered standards include: waivers of certain legal liabilities for decisions that care providers must make, licensing requirements for caregivers, using drugs such as antivirals and vaccines in different dosage levels than recommended by the FDA in order to stretch supplies, and using physical facilities that would not normally meet the standards required for hospitals.

No one sees the fact that we could alter the standards required for ventilators so that we could double or triple the supply of ventilators available in a short period of time. The plans set forth by the Pandemic Ventilator Project will allow this to happen. I have written letters to many of the authors of government planning documents and told them of our plan and invited their feedback or support. I even sent a letter to one of the authors of this document; John L. Hick, M.D in March of 2007. I have never received any reply from them.
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Here are the excerpts related to ventilators:

EMS in an MCE: Expected Shortages and Needs
In the case of an MCE, many health care resources at the local and regional levels will be overwhelmed or eliminated. Those EMS response agencies that are able to remain operational likely will encounter a demand for services that will outstrip the supply and available resources. EMS systems will confront:

Personnel shortages.
Breakdowns in supply chains.
Lack of coordination and information sharing among diverse EMS providers, public safety, hospitals, trauma center, and public health.
Breakdown of logistic support for operational sustainability, including such things as fuel shortages; inadequate availability of transport vehicles; and shortages in supplies, equipment, and pharmaceuticals.
Overloading of hospital emergency departments and associated services such as intensive care capabilities; specialty services such as burn care or decontamination units; and specialized equipment such as ventilators, PPE, or negative pressure rooms.
Breakdowns in local “burden sharing” strategies (mutual aid agreements) due to overwhelming demand and lack of surge capacity.
The need to implement modified treatment protocols to meet the extraordinary conditions of the MCE that may be limited to reasonable life-sustaining activities where appropriate.

Hospital and Acute Care in the Context of a Catastrophic MCE
The overall goal of hospital and acute care response in an MCE is to meet the reasonable care needs of as many patients as possible while also meeting at least minimal obligations for comfort to each patient.63 In the case of a catastrophic MCE, however, hospitals will not have access to many needed resources (e.g., manual resuscitation bags to provide ventilation in response to a pandemic influenza, supply of antitoxin in the case of mass botulism poisoning). Thus, difficult decisions will have to be made regarding the allocation of available resources.

Inadequate Supplies.
Lack of sufficient supplies, particularly of specialized equipment such as personal protective equipment, ventilators, and negative pressure rooms, will be a challenge for most hospitals.

Ideally, hospitals should be able to follow guidance and decision support tools to make resource allocation decisions (e.g., who should receive mechanical ventilation) that are sanctioned and approved at the Federal level and are distributed by the State. Even with the support of these tools or policies, however, it is the hospital that will have to take on the role of implementing them.

Interstate regional coordination is another means of managing allocation of scarce resources. Interstate agreements and cooperation help promote sharing of assets across State lines. These types of agreements also help ensure consistency of response (e.g., National Capital Region) where inconsistencies between State plans could prove problematic. This level of interstate cooperation is difficult to achieve but is one of the most important ways to maximize resource allocation. The development of national-level clinical decision tools to address commonly limited resources (e.g., dialysis, mechanical ventilation) would be very valuable in helping to facilitate greater interstate cooperation.

Using expert panels or planning groups
At this time, no current predictive model is sufficient to serve as a decision framework for determining the allocation of critical care resources (e.g., ventilators, intensive care therapies). One valuable strategy for examining the allocation of scarce resources, however, is to convene a balanced expert panel that can bring in multiple viewpoints and establish decision making guidelines. The panel must be inclusive of relevant stakeholders who reflect the jurisdictional area and its demographics, in addition to recognizing border issues with adjoining States. The composition, functions, and operational role of these groups must be carefully considered.

Convening An Expert Panel To Address The Allocation Of Scarce Resources: The Example Of New York State
In March 2006, the New York State Task Force on Life and the Law (TFLL), in partnership with the State’s Department of Health, convened a workgroup to consider clinical and ethical challenges in the allocation of mechanical ventilators in a public health crisis. The group includes experts in the areas of law, medicine, policymaking, and ethics. Its goal is to develop clinical and ethical guidance for local health care systems that will promote the just allocation of ventilators in an influenza pandemic. The panel considered a range of policy options necessary to support such an allocation system, including the development of recommendations for laws or regulations in areas including liability and appropriate standards of care. Further information on the TFLL is available at www.health.state.ny.us/nysdoh/taskfce/index.

Expansion of critical care capacity by placing select ventilated patients on monitored or step-down beds; using pulse oximetry (with high/low rate alarms) in lieu of cardiac monitors; or relying on ventilator alarms (which should alert for disconnect, high pressure, and apnea) for ventilated patients, with spot oximetry checks

Clinical Adaptations represent the allocation of scarce resources or services based on the ethical principles outlined in Chapter 2.
Examples of clinical adaptations include the following:

Triage of patients to home care, acute care sites, or other offsite locals who would otherwise be treated as inpatients
Assignment of limited resources (e.g., ventilators, radiographs, laboratory testing) to those most expected to benefit

The hospital should be able to follow State guidance regarding clinical triage decisions. If no guidance exists, it will be incumbent on the hospital to have a plan or strategy for bringing together the appropriate personnel who can make the best decisions possible and reevaluate the situation during each planning cycle (e.g., each shift a day). When there is little advance evidence to guide allocation decisions (for example, not knowing how different age groups with pandemic influenza respond to mechanical ventilation), good clinical judgment by experienced clinicians will be the final common denominator to justify resource allocation decisions. The decision making process, based on ethical judgments that include maximizing good consequences across the many while meeting at least minimal duties and obligations to all, should be shared openly with staff members, patients, and the public and should be as consistent as possible across facilities.

One of the key decision points in the delivery of out-of-hospital care at an ACS is the ability to provide oxygen and respiratory therapy, particularly the ability to provide mechanical ventilation. The logistics and expense of sustaining oxygen delivery systems in an ACS setting, however, is extremely complex and prohibitively expensive. The exception to this may be the use of nursing homes and long-term care facilities in the role of alternative care facilities, given their existing medical gas supply.

The Challenge of Supplemental Oxygen
The use of an ACS for patients who require supplemental oxygen is highly problematic from a logistical point of view. Options to supply supplemental oxygen run from a home fill unit (10L/min maximum, less than $1,000) to deployable oxygen generation or liquid oxygen storage and distribution system (multiple patients, high technology, upwards of $480,000). Given the variables of cost, general availability, ease of use and sustainability, the most promising options for supplying supplemental oxygen would be either a bank of 10L/min home fill units or a rack of eight interconnected “H” oxygen cylinders, each supplying 7,000 liters of oxygen for a cost of approximately $13,000. Even this rack setup is severely limited, however, as the eight “H” cylinders could supply only 50 patients at 2 liters of oxygen per minute for 8 hours. This would necessitate three refills per 24-hour period and would require the rapid installation of a rudimentary gas distribution system. Support for ventilated patients would increase the rate of oxygen consumption significantly, further complicating this issue, and most likely would not be possible.

Locations ordinarily used to care for persons with eventually fatal chronic illnesses (e.g., nursing facilities, home health agencies) need to be ready to handle more severe complications. Plans should address the prospect of not transferring patients needing ventilator support if they are too sick to survive but prepared to provide appropriate palliative care services.

Potential shortages of ventilators could be particularly problematic. In the case of such a pandemic, hospitals may not have an adequate supply of reserve ventilators required to treat patients suffering from acute respiratory failure.

Key AARC Ventilator Capacity Recommendations

Increase human resources to assist respiratory therapists and physicians and have easy-to-use ventilators available in the event the respiratory therapists on the hospital staffs cannot handle the volume and noncritical care professionals must be enlisted.
Extend ventilator capacity for any mass casualty response, expanding the Strategic National Stockpiling Program by 5,000 to 10,000 ventilators. Additional ancillary supplies for ventilator use also should be stockpiled.
Develop a distribution plan for ventilators at both the local and national levels.
Intubation (placing a breathing tube down the windpipe) is recommended for patients suffering acute respiratory failure during a pandemic flu, because ventilation by mask may increase the risk for infection to staff and other patients.
Prepare for a power outage: each medical center should identify emergency power sources for electricity and compressed gas.

Assess surge capacity (beds, ventilators, etc.) to meet expected increased needs during a pandemic

Conduct Just-in-time-training for staff members, including influenza transmission, general information, infection control information, ventilator management, and hospital plans. Training is to be conducted via e-mail, informational posters, and shift briefings.

Open a joint information center (JIC) with the hospital association acting as liaison with all hospitals in the region. The regional coordinating hospital provides updates and solicits baseline availability of ventilators and patient beds.

Respiratory therapy manages ventilators only; other respiratory care services are to be provided by nurses. Floor nurses are to receive training in basic ventilator monitoring, with floor units supervised by a roving ICU nurse to monitor ventilated patients.

Select operating room and procedure room space to be used for additional ventilated patient care.

Set up a triage team (may consist of one critical care and one infectious disease physician, among others) to review conflicting resource needs (e.g., two patients needing a single ventilator) on a case-by-case basis.

Identify a Bed Czar to monitor the bed and “hard” resource statuses (e.g., ventilators), make assignments based on availability, and implement triage team recommendations.
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There is a mention of where to obtain the Sphere Handbook for Humanitarian Response in the original document. The listed website is incorrect. Here is the correct one:
http://www.sphereproject.org/component/option,com_docman/task,cat_view/gid,17/Itemid,26/lang,English

Review of Online Book - Ethical and Legal Considerations in Mitigating Pandemic Disease: Workshop Summary

2008-02-10T16:31:00.000-08:00

Today I am presenting sections from the online book:

Ethical and Legal Considerations in Mitigating Pandemic Disease: Workshop Summary
Stanley M. Lemon, Margaret A. Hamburg, P. Frederick Sparling, Eileen R. Choffnes, and Alison Mack, 2007

I will concentrate primarily on the issues that affect ventilator shortages. This is only a small part of the book. The pdf file runs 250 pages.

This book is available complete for free as a pdf file at:
http://www.nap.edu/catalog/11917.html

Available from The National Academies Press at http://www.nap.edu

This book presents a fairly complete and balanced view of the ethical issues to date regarding pandemics.

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The book begins with a quote from Goethe:
“Knowing is not enough, we must apply;
Willing is not enough, we must do.”

The following excerpts are from the workshop discussion:

Addressing Shortages: Medical Care
While it is widely acknowledged that an infectious disease pandemic is likely to overwhelm the U.S. medical system, the federal government has given scant attention - and even less money - to redressing this situation. “There is a great gaping gap here,” said speaker D.A. Henderson, who criticized government planners for focusing on what he believed to be “fringe things,” such as stockpiling and delivering countermeasures of questionable efficacy, rather than concentrating its efforts on “a problem which we know we are going to have.” He attributed the lack of progress toward addressing this critical and predictable need to poor communication between public health officials and hospital administrators, as well as between HHS and CDC.

Although individual hospitals are attempting to prepare themselves for pandemic influenza by conducting surge capacity trials, Henderson observed that few facilities are prepared to handle a worst-case scenario in which patients could exceed capacity by 30 to 40 percent. He predicted that under those conditions hospitals would begin to turn away patients, including some who desperately need care. In order to accommodate them, Henderson recommended the creation of alternate regional sites staffed by volunteer caregivers. He also noted that plans for medical care during a pandemic need to address such issues as liability, the credentialing of volunteers, nonpaying patients or patients without adequate health insurance, the cancellation of elective surgical procedures, and pandemic associated losses in hospital revenue.

Workshop participants considered a variety of gaps that exist in pandemic preparations at the hospital level. According to one estimate, if an influenza pandemic occurred today, demand for ventilators would exceed supply by nearly 200 percent (Bartlett, 2006)

Addressing Shortages: Global Supply Chains
Another far-reaching concern regarding the U.S. pandemic influenza strategy is its failure to recognize America’s dependence on and interdependence with fast-moving global markets. Forum member Michael Osterholm observed, for example, that the vast majority of medicines in the U.S. are manufactured abroad or made from precursor materials that are manufactured abroad. Furthermore, critical supplies such as oxygen are delivered just in time to hospitals and other end-users and are therefore dependent upon fuel, which is also largely foreign in origin.

Duty to Care
Health-care workers on the front lines in infectious disease outbreaks (e.g., smallpox, Ebola, and SARS) have consistently fulfilled their duty to care for patients even when it has cost them their lives (see Heymann, page 33). Ruderman and colleagues report, however, that during the SARS crisis in Canada, “serious concerns arose . . . about the extent to which health-care providers would tolerate risk of infection,” leading to the anticipation of a potential crisis during a pandemic (Ruderman et al., 2006).

Ethical Guidelines for Clinicians
An influenza pandemic is likely to produce extraordinary shortages in medical care. Hospital resources—both human and material—may be stretched beyond their limits. In order to manage the many ethical dilemmas inherent in this situation, physicians and hospital administrators will need specific guidelines,
Lo said (see Lo and White, page 192). His observations were echoed by several workshop participants, some of whom spoke from a personal perspective, as they themselves will be called to play certain roles in a pandemic. Among the challenges that pandemic influenza will present to clinicians, one of the likeliest and most daunting will be a grave shortage of mechanical ventilators. Such a shortage, Lo observed, will require physicians to choose which patients will receive the life-saving use of a ventilator and which will die without respiratory therapy. There will be no time to weigh alternatives in a pandemic, Lo argued, so it will be important to develop clear criteria ahead of time for when to triage patients, along with guidelines and procedures for addressing problems that will arise as the triage system is implemented, such as handling disagreements with family members and managing patients in respiratory failure who do not receive mechanical ventilation.

Lo urged pandemic planners to anticipate the ethical and legal dilemmas that doctors and other health-care providers will face in a “worst-case” ventilator shortage and to create, with input from the public and specialists in various disciplines, guidelines and procedures for dealing with shortages of ventilators another medical supplies. While suggesting that rules for triage should maximize the number of lives saved, Lo also pointed out that physicians must rely on limited evidence to predict a patient’s prognosis. Triage rules, he said, should be administered by an external authority, not the physicians dealing with the patients, and they should be implemented by physicians and other health-care workers in such a way that their fairness cannot be doubted. Fairness in allocating scare resources will be necessary to secure public trust in the process, Lo observed, but it will not be sufficient. Triage policies and priorities must also reflect popular will, he said. Moreover, the policies must be communicated clearly and in a way that people will understand. And they must be presented in a way that leads society to accept the idea that, during an infectious disease emergency, some patients will die who might otherwise have been saved under normal circumstances. Lo also stressed the importance of providing the public with ready access to the data, reasoning, and deliberative processes that support such triage guidelines. Unfortunately, Hearne observed, some states have not only failed to engage the public in pandemic planning, but they have actively excluded them from the process and have kept their plans secret, even from hospital workers and other health-care providers.

Civic Engagement
Since the nation’s experience with the aftermath of Hurricane Katrina, many Americans have come to be extremely cynical about government efforts meant to protect them from disaster, Hearne observed. As a result, she said, broad changes in public health law will be needed to prevent a potentially disastrous breakdown in public health authority during a pandemic.

Ethics in the Midst of Uncertainty
While recognizing the ideal of public participation in pandemic planning, workshop participants nonetheless agreed that public health professionals must expect most people to be entirely unprepared when the next pandemic strikes.

-----------------------------------------------------------------------------------------------

The following excerpts dealing with ventilators are from the included paper:

INTENSIVE CARE UNIT TRIAGE DURING AN INFLUENZA
PANDEMIC: THE NEED FOR SPECIFIC CLINICAL GUIDELINES
Bernard Lo, M.D.
University of California, San Francisco
Douglas B. White, M.D.
University of California, San Francisco

During a severe influenza pandemic, a dire shortage of breathing machines— mechanical ventilators—is projected. According to one estimate, a pandemic will require 198 percent of the current supply of ventilators (Bartlett, 2006). If this happens, many people in respiratory failure who need mechanical ventilation in order to survive will not receive it. This grave shortage of ventilators will raise unprecedented allocation dilemmas that ought to be addressed before a pandemic strikes.

Ventilators should be considered a scarce resource to be allocated according to public health guidelines rather than by the decisions of individual physicians and patients.

Guidelines for allocating scarce medical resources during a pandemic will require several levels of specificity. At the broadest level, state public health laws express a general societal agreement that during a public health emergency the decisions of individual physicians and patients will be constrained by public health policies (Gostin, 2000). At the next level of specificity—the level of clinical care decisions—hospitals and physicians need criteria for triaging various patients who need mechanical ventilators when the demand greatly exceeds supply during a pandemic. To minimize overall loss of life during a pandemic, priority should be given to patients who require mechanical ventilation but who are highly likely to survive after only a few days on the ventilator. Finally, at the most specific level, frontline physicians need guidance in implementing these triage priorities in specific clinical cases.

Ventilator Shortages During a Pandemic
Suppose for the sake of a dramatic example that an ICU in the midst of a pandemic has only one available bed and ventilator. In the emergency department are several patients in respiratory failure, all of whom will die without mechanical ventilation. It is not feasible, given staff shortages, to keep these patients alive by manually squeezing a bag to drive air into the lungs. One patient is a 30-year-old whose only medical problem is respiratory failure, presumably from influenza. Another patient has not only respiratory failure from influenza but also hypotension and renal failure. The presence of these additional problems means that the second patient has a worse prognosis than the first (Graf and Janssens, 2005). Additionally, there are two other patients in the emergency department with respiratory failure who also will die without mechanical ventilation. One is a 22-year-old with an acute asthma attack who has no clinical evidence of influenza. Another is a 58-year-old who requires emergency coronary bypass surgery for continued myocardial ischemia despite optimal medical management.

These latter two patients are expected to survive if they receive just a few days of mechanical ventilation. Thus the shortage of ventilators will affect not only patients with influenza but also those who have respiratory failure from other causes.

Ethical Guidelines for Triage of Mechanical Ventilators During a Pandemic
A scarcity of ventilators during a pandemic will require an allocation policy based on different ethical guidelines than those governing usual clinical care. The term triage is commonly applied to the process of sorting, classifying, and assigning priority to patients when available medical resources are not sufficient to provide care to all who need it

The first ethical guideline for ventilator use during a pandemic is that increasing the number of lives saved may take priority over patient autonomy. Public health officials, working in concert with clinical experts and public representatives, should set guidelines for prioritizing patients who need mechanical ventilation.
Individual physicians and patients must then make decisions that are consistent with these guidelines.

The second guideline is that patients with a high likelihood of surviving after a few days of mechanical ventilation should receive the highest priority. Characterizing this group will be difficult, however, because data are incomplete and uncertain.

The third guideline is that during a public health emergency fairness and perceptions of fairness are crucial.

The fourth guideline is that transparency is essential during a public health emergency. The public needs to know how ventilators will be allocated in order to trust that the allocation is fair. Triage priorities and policies should be explicit. The public should have ready access to the triage guidelines, the data and the reasoning underlying them, and the process by which they were derived.

Applying Triage Principles to Specific Cases
Even if there is wide agreement on the triage principle of minimizing loss of life during a pandemic, hospitals and health-care workers will still face many difficult decisions when making triage decisions in specific cases. Before a pandemic occurs, it will be important to identify these dilemmas, analyze them, and reach some agreement on how to resolve them.

During Triage, Should Patients Already on Ventilators Be Reassessed?
We have framed the problem of allocating ventilators as “the last bed in the ICU.” In reality, the situation is more complex because patients already in the ICU on ventilators may have a worse prognosis than new patients with respiratory failure. Suppose, for example, that one of the ICU patients is a 38-year-old man with influenza who has developed multi-organ failure and whose condition has worsened during five days of intensive care. His prognosis now is worse than that of a new patient who presents with respiratory failure as her only medical problem, with no other organ failure. Or suppose that there is also a 68-year-old patient with chronic emphysema and respiratory failure who is gradually improving but who is likely to require several weeks of ventilator support as his lungs slowly improve. Keeping such current ICU patients on ventilators leaves fewer ventilators available to other patients in respiratory failure, who will die without them and who are likely to survive after receiving ventilation for only a few days. Therefore, allowing patients already in the ICU to remain on ventilators without regard to new patients with respiratory failure is likely to decrease the total number of lives saved. On the other hand, removing patients from ventilators who are not improving after several days would violate the usual ethical guideline that a physician should act in the best interests of patients and be faithful to them.

What Other Considerations Should Be Taken into Account During Triage?
We have identified a high likelihood of survival and a short-term need for mechanical ventilation as two criteria for giving high priority to patients with respiratory failure during a pandemic. If there is still a shortage of ventilators after these criteria have been applied, a number of other criteria might be considered. Such criteria might include the likely duration of life and the likely quality of life in a patient after treatment or the existence of personal behaviors that may have led to the respiratory failure, such as smoking or non-adherence with asthma medications. Judgments about quality of life and personal behaviors are more subjective that a strict medical prognosis and inevitably involve value judgments over which reasonable people may disagree. Because incorporating these considerations into triage decisions would heighten concerns about unfairness, they are best avoided during a public health emergency.

How Will Disagreements by Family Members Be Managed?
Civilians have no experience with triage, unlike military personnel who are familiar with the approach. Faced with the death of a relative which might be averted with mechanical ventilation, families might strongly object to foregoing the use of the ventilator. In light of this, several issues likely to face frontline physicians should be addressed before a pandemic strikes. Would it be feasible, for example, to create timely appeals mechanisms for decisions regarding ventilator use? During public health emergencies, governments have the police powers to enforce public health measures; will there be police in hospitals to enforce triage decisions about ventilators? And how can the risk of violence be minimized?

A Personal Account of Home Made Ventilator Saving a Life

2008-02-06T18:59:00.000-08:00

My post from last week about homemade ventilators used during the polio epidemics in the 1940s and early 1950s (Everything Old is New Again) generated some response. I received a personal account of a ventilator being quickly made for a child during a polio outbreak in Marquette Michigan. This is an account I got from Joan and Don Miller in Marquette, who generously let me reprint it here.

THE IRON LUNG IN MARQUETTE

These are some recollections of mine regarding the iron lung that I saved from my grandfather Max Reynolds belongings. It appears that the story I remember takes place in the late 1930's here in Marquette during the polio epidemic. I will start out with a bit of background on the gentleman and then relate the story of this device.

Grandfather Max came to Marquette as a civil engineer with an explosives company. He married into the Peter White family, one of the founding fathers of Marquette. As time went along Grandfather got very involved with what then was St. Lukes Hospital- now Marquette General Hospital, The Michigan Crippled Children's Clinic, and Bay Cliffs Health Camp. He also pursued two of his most cherished hobbies- boating and photography. The boating interest lead to the building of the Lake Superior Yacht Yard along with it the shop where many things were created and built.

Maxwell K. Reynolds became a director and chairman of the board at the hospital, then a small nonprofit hospital. So he was very interested in the day to day operations of the hospital. When the polio sickness arrived, he got started creating and building the Iron Lungs. I'm not really sure where he picked up the ideas, but he was a very inventive and creative person. So he guided his staff in making a number of these devices. Some of the lungs he made were built out of old oil drums, boxes, or about anything else he could find.

One day the hospital called with an urgent request for a lung. Apparently, they had a patient that required help quickly, and could he help. Max said he would provide a device. He went quickly to the old railway station and found an old refrigerator box- made of plywood in those days. He got that to the Shop and the crew started putting together the unit I still have. A door was made on one side, secured with window sash locks. The neck hole was secured with a rubber knelling pad with hole to fit the youngsters neck. Next, a source of vacuum, so grandmas vacuum cleaner was connected to the box. The air was let into the box with a simple plug valve that would be operated by an attendant to control the child's breathing. Later they tried a phonograph as an actuator, but that required some extra time to perfect. So the story goes, from the first call to the time the unit was delivered was 4 hours!

I guess there are not too many people around now that can assist with this accounting. This is as I recall, and I must add that grand pa Max died when I was about 8 years old. He had many talents and tried to get me started on some of them. I only wish that we had a bit more time, since he was quite a guy!

Recalled by Peter W. Frazier, grandson to Maxwell K. Reynolds, Marquette, Michigan

There is a similar account in the Marquette Monthly of Sep 2006, Back Then.

Link here:
The Wooden Lung, Fighting polio with boxes and vacuum cleaners. by Becky Kratz

Everything Old is New Again

2008-01-27T17:33:00.000-08:00

Workshop Built Ventilators

I return to something I mentioned in an earlier post about homemade (wooden) iron lungs described in a 1950s Popular Mechanics article. the link under the picture will take you to a site that posts the original complete assembly plans.

Intended only for emergency use until a commercial respirator could be obtained, this “wooden lung” was designed by engineers and built by a volunteer group under the supervision of Dr. Gerald M. Cline, Dr. Homer O. Dolley, and Sister Celine of the medical staff of St. Joseph’s Hospital, Bloomington, Illinois. On completion, the unit was put into immediate use in emergency treatment of eight-year-old Rudy Landheer, a victim of polio in the epidemic of 1949. The original unit did emergency service for 12 hours until a conventional iron lung could be obtained.

I will also talk about some of the earliest positive pressure ventilators built in Great Britain and home made iron lungs used in the United States.

The British ventilators were built in Newcastle for anesthesia and also the polio epidemic in the late 1940s and 1950s. These ventilators were built by the inventive Newcastle professor of Anesthesia Edgar Pask, his chief technician Norman Burn and his staff of highly able technicians using war surplus parts.

This is the Newcastle ventilator. (Known as a respirator at the time.) Just as we named our ventilator “Vinnie”, they named the ventilator they designed and built. They named theirs “Mother”.

"Mother"

The electric motor was controlled by mercury switches. A spinning disc allowed speed variation, and a camshaft moved four small bellows up and down to provide the ventilation.

After the success of their first ventilator design they wanted to design another that could be easily and cheaply and quickly constructed by any able technician. They were building these ventilators to save lives in the polio epidemic. There simply were not enough “iron lungs” available in Britain to deal with this epidemic. There were about 1000, but many of these were already in use. There were 1000 cases of polio in 1946 in England and Wales, but this increased to 9000 by 1947. The use of a ventilator could reduce the death rate of those polio victims that were afflicted with respiratory paralysis from 90% to 30%.

One version of a cheap and easy to build ventilator was the Bang ventilator of 1953. This design was shared with others and similar units were built elsewhere.

The Newcastle "Bang" ventilator

The “Bang “ ventilator design worked well, but it required frequent adjustment and maintenance. The mercury switches it used were important for anesthesia, but were not required for polio patients. They could also be difficult to obtain.

They then built two prototype "polio ventilators" out of materials that were readily available in any workshop. The “blow” side of a domestic vacuum cleaner powered these ventilators. Up to 10 ventilators could be powered from one Hoover.

Two Polio Ventilators

These ventilators were made of plywood and perspex. The one on the left, used a magnet to operate its main valve. Inflation pressure was varied by adding weights onto the hinged flap on top much as we do with our design. There were no electronic controls and alarms. Cycling was controlled by regulating the leak out of the plastic bag under the flap. When the bag emptied, the magnet lowered and opened the main valve, allowing inspiration until the bag had filled enough to again lift the magnet from the valve, which would then shut until the bag was empty again

The device on the right used the "flick over" rocker from a light switch as a main switch which opened and closed a piece of tubing to allow gas flow. Inflation pressure was varied by altering tension in springs rather than by using weights, while controlled gas leak was still used to control cycling.

Both these devices split the inlet air, from the vacuum cleaner, to both the patient and the control bag. The expansion of the bag triggered the main valve that stopped the flow of air and allowed expiration.

The inspiratory and expiratory phases of the wooden polio ventilator

Above is a more functional diagram of one of the “Polio” ventilators. These devices seem incredibly crude by today’s standards. Even with the most basic of control systems and electrical valves, a far more sophisticated and reliable system can be constructed today. The people that designed and built these early ventilators were very inventive, brave and capable. They saw the need for ventilators during the polio epidemic and did whatever was required, in order to supply them. Although these units seem crude, they, and others like them saved many lives that would have been lost.

These early ventilators were followed by many more, for both adults and infants. "Home made" ventilators of all shapes and sizes were used for another thirty years at the Royal Victoria Infirmary.

In America, the polio epidemic also caused a large demand for ventilators. There was more demand than could be supplied by the existing stock of "iron lung" negative pressure ventilators.

An Iron Lung ward filled with polio patients. 1953

Rancho Los Amigos Hospital, Downey California

During the height of the polio epidemic years, the iron lung became such a crucial part of treatment that Philip Drinker and Edgar L. Roy offered instructions for building a makeshift emergency ventilator for cases of life-threatening paralysis. Although this emergency version of an iron lung was only intended for use until a board-approved version arrived, it was functional enough to save lives.

Image of an emergency ventilator, from the article by Drinker and Roy.

In contrast to the original, professionally crafted iron lung of 1929, Drinker and Roy employed common household and conveniently available hardware store materials in their emergency respirator. The materials included a car inner tube for a rubber collar, a common vacuum pump to provide pressure, a six-inch square piece of double-thick glass, a piece of sole leather to serve as the valve, a glass U-tube with colored water to show pressure, and several pieces of spruce wood. Drinker and Roy provided detailed construction plans and clearly indicated that it was an emergency respirator that could only accommodate small children and was not meant to replace the standard-size iron lung. Nonetheless, they fully supported its use in emergency situations

Assembly diagram

You can see these and more at :

The Brian Welsh Memorial Museum of Anaesthesia

University of Virginia Historical Collections at the Claude Moore Health Sciences Library

Here is a personal account of a homemade ventilator quickly built and used to save the life of a child

Larry Brilliant on Bird Flu

2008-01-17T17:34:00.000-08:00

Here is a video on Bird Flu from Larry Brilliant.
It is about 55 minutes long.

Larry Brilliant is an M.D., M.P.H. board-certified in preventive medicine and public health, and a former associate professor of Epidemiology and International Health Planning at the University of Michigan. After studying religion in a Himalayan monastery, he joined WHO in 1973 as a medical officer and helped manage the WHO smallpox eradication program in South Asia. He was a staff member of the WHO Global Commission to Certify Smallpox Eradicated and served as the last WHO medical officer to visit Iran in search of hidden smallpox.
More Info on Larry
What more can I add, the name says it all.

Larry has a very balanced look at the whole issue of bird flu and pandemics. He says that Pandemics are a low probability high impact issue. The probability is low in any given year but over a longer term approaches certainty. He has a very interesting take on people who are worried about catastrophe and people who want to ignore the issue. He calls them "Chicken Little" and "Ostriches" (both birds).

Here is another article he has written.

Some Short Pandemic Info Videos from Youtube

2008-01-07T17:43:00.000-08:00

Any Community That Fails to Prepare

U.S. Secretary of Health and Human Services Michael Leavitt comments on the need for all communities to prepare for pandemic in this excerpt from his interview with Charlie Rose that aired on Feb. 14, 2007.

How Does a Pandemic Start?

Dr. Gregory Poland, founder and head of The Vaccine Research Group at the Mayo Clinic discusses how pandemics start and why H5N1 is on track to spark the next pandemic in this excerpt from the BBC Horizon show "Five Things You Need to Know About Pandemic."

Pandemics Happen

U.S. Secretary of Health and Human Services Michael Leavitt addresses the fact that pandemics have happened throughout history in this excerpt from his interview with Charlie Rose that aired on Feb. 14, 2007.

Pandemic Is Hard to Talk About
U.S. Secretary of Health and Human Services Michael Leavitt explains why pandemic is a difficult topic of discussion in this excerpt from his interview with Charlie Rose that aired on Feb. 14, 2007.

Pandemic Preparation Is Good for Any Emergency

U.S. Secretary of Health and Human Services Michael Leavitt explains that preparations for pandemic will serve communities well in the event of other types of emergencies in this excerpt from his interview with Charlie Rose that aired on Feb. 14, 2007.

Preparation Saves Lives

U.S. Secretary of Health and Human Services Michael Leavitt comments on the the fact that pandemics are unlike any other disaster known to humankind in this excerpt from his interview with Charlie Rose that aired on Feb. 14, 2007.

Two Key Pandemic Differences

U.S. Secretary of Health and Human Services Michael Leavitt discusses the two key differences between pandemic and other natural disasters in this excerpt from his interview with Charlie Rose that aired on Feb. 14, 2007.

Why Kids Are at Most Risk During Pandemic

Dr. Gregory Poland, founder and head of The Vaccine Research Group at the Mayo Clinic discusses why children are at the most risk of infection and death during a pandemic in this excerpt from the BBC Horizon show "Five Things You Need to Know About Pandemic."

The Ventilator is a Lifeboat

2008-01-06T19:41:00.001-08:00

The Pandemic Ventilator Project is an effort to try to supply enough ventilators to fill the needs in a pandemic. The original prototype, which you can see elsewhere on this blog is a very basic unit that can be constructed of commonly available materials. It is not a sophisticated design, but with more refinement may be able to provide a very basic level of support.

Lately we have been working on a second prototype. This one we call Vinnie. If you look at my original proposal I had hoped that we might eventually have a more capable unit to offer as well. It looks as if Vinnie may be that more capable unit. We have gone over what we believe is possible to achieve with Vinnie and compared it to the AARC guidelines for mass casualty care, and we hope we can meet these specifications.

The original unit is designed to be built with commonly available components that are expected to be available even with the economic and transportation disruptions that may occur in a pandemic. In order to achieve a design that could encompass the AARC guidelines however, we needed to have more design flexibility. Many of the components in Vinnie are still commonly available components, but some key control components are not commonly available and may have to be custom made. We have made every effort to keep these custom components at as low a cost as possible. Due to this change, it would be required to stockpile some components ahead of time to ensure availability.

Now about the lifeboat story and how it relates. In the early days of seagoing vessels, it was known that travel by ship was a dangerous activity that passengers did not always survive. There was often little that could be done to save the passengers if a ship sank even if they had enough lifeboats, because no one knew the ship had sank and so no one would go to rescue. Some ships had enough lifeboats and others did not. There was little regulation or enforcement. Many ships did not carry enough lifeboats because the owners thought they were ineffective, or the ship was so rugged it could not sink, or they were just too expensive to stockpile.

This changed after the Titanic sinking. After the Titanic sinking, ships were required to have adequate lifeboats and radio communication ability. The regulation changes were not made because no major sinking and loss of life had ever occurred before, but it was because it was then realized that technology had improved so much that it was possible to save a lot more lives than previously.

The Spanish flu of 1918 killed an estimated 50 million worldwide. There was not a whole lot that 1918 technology could do to save the victims. By mid century medical technology had improved considerably. The Asian flu of 1957 and the Hong Kong Flu of 1968 were mild compared to the 1918 pandemic so the loss of life was also much lower. Now with the H5N1 virus, we face the possibility of a severe pandemic similar to the 1918 one. This time however, there is much that modern medical technology can do to save lives. Knowledgeable tracking systems, quarantines and vaccine deployment may reduce the impact considerably. We also have a far greater capability to treat those that are infected.

One of the tools required to treat the infected is a ventilator. Unfortunately, many people say we do not need to have a very large stockpile of ventilators because they believe they would be ineffective, or the vaccines will be so good we will not need them, or they are just too expensive too stockpile.

Having a stockpile of ventilators is like having a lifeboat. Technology has changed. We can save the lives if we want to.

AARC Standard for Mass Casualty Ventilators
Lifeboat Standards

Progress Report

2007-12-27T20:16:00.000-08:00

There has been a lot of interest in the ventilator recently. It has been linked to by Makezine,
http://blog.makezine.com/archive/2007/12/pandemic_ventilator_proje.html
and I also put the assembly instructions on Instructables.com
http://www.instructables.com/id/The-Pandemic-Ventilator/
It is also listed in several compilations of open source hardware project lists.
(Unfortunately, someone removed the Wikipedia article.)

This has resulted in a number of people showing interest in the project.
Several weeks ago, I was contacted by someone interested in helping out the project. I sent him some background information and also some information on how to construct a prototype and asked him if he could build another unit, perhaps make incremental improvements where he could. Here are some pictures of his efforts. I am very pleased with this work. The new prototype also has a name. He calls it “Vinnie”. Talking about pandemic all the time can get a little dreary.

As you can see, the workmanship on Vinnie is much improved over the first prototype. The sensor pole is made in such a way that the sensors can be accurately placed and adjusted. The wiring is laid out better , and the part of the bellows that accepts the bag is more refined. Beyond these structural improvements, Vinnie will have a far more capable control system.

To make Vinnie available to as many different situations as possible, it is envisioned that control of the ventilator may be accomplished by any one of several different controllers. These include a PLC (as used on the first prototype), directly via a PC using the parallel printer port, or by using a low cost microcontroller.

When the PC Parallel Port solution is employed a low cost printed circuit board is required. A PC’s parallel port can be controlled via software running on Microsoft Windows or even using DOS. A simple printed circuit that provides an interface to a PC parallel port was designed and built. Pictures are included herein. The parallel port was not designed for this kind of application and hence there are some limitations. DOS may sound retro, but it is more reliable than Windows.

A dedicated microcontroller provides a more capable solution. The new prototype is being tested with a microcontroller development board from Futurlec. This board only costs about $40USD and provides the following advantages:

1. Can operate stand-alone without a PC (but PC may be required to set operating parameters)

2. Can monitor/control more signals - greater control is possible

3. Has an 8 channel analog-to-digital converter – can monitor pressure, temperature, and volume

4. Can communicate to a PC for data logging and for graphical display of data– improves medical care

5. Can detect fault conditions - improved safety

6. A single PC can talk to many of these microcontroller boards

7. The monitoring PC can display graphs of key data, especially pressure

The Futurlec board (model: ATMega Control Board) is very capable, but it is envisioned that we will design a similar board that will correct deficiencies and will feature a few improvements that will make it much easier for you to build your own personal Vinnie. The design and layout of this new controller is not scheduled to begin until Vinnie has been thoroughly tested using the Futurlec board.

This will allow a far more powerful interface and make the operation of the ventilator much easier. There can also be graphing and storage of the operation status of the ventilator so that the clinical condition of the patient can be better monitored.

Vinnie’s creator is also helping me with the documentation of the project. So the number of people involved in the Pandemic Ventilator Project is slowly increasing. I am getting collaboration on design ideas, and I have people helping with promoting visibility of the project in discussion boards and posting to other sites. If you think that you are interested in participating in the project, leave a note or send me an email. Especially it would be great to have someone participating that has experience in running an open source development project.

Here is an updated design schematic.

Overall Layout

Link to Commentary on Ventilator Shortage

2007-11-16T10:55:00.000-08:00

Here is a link to a very good commentary on the potential of shortage of ventilators in an Avian Flu Pandemic.

http://pandemicethics.org/What_ethical_problems.html

Assembly Instructions

2007-11-09T08:39:00.000-08:00

Here are some details of how the Pandemic Ventilator is constructed.

It basically consists of the bellows unit, which is made of wood, valves and piping, a PLC controller, some wires and switches and a power supply unit.
The whole unit is mounted on a piece of ½ inch thick that is plywood 18 inches by 21 inches.

To get started you will need the valves. You may be able to find some used ones somewhere. New valves are expensive, over $100 each. The inlet valve can be ¼” normally open valve, the other two should be a minimum ½” diameter, one normally open (NO) and the other normally closed (NC). They must be of a direct acting solenoid type.

Direct acting solenoid types are required to operate with air. Pilot operated types will only operate with liquids. Pressure ratings do not matter for the 1/2'' valves, but the 1/4' valve should have at least a 50 psi rating. If you can only get either NO or NC 1/2" valves you can still make it work by adjusting the PLC output. The inlet 1/4' valve must be a NC valve or you will end up blowing up a lot of bags in the testing phase.

The valves are connected with pipe and mounted in such a way that the “T” to the Bellows lines up with the center of the bellows unit.
I used threaded pipe fittings. I used:

Two ½” NPT “T”s,  One ¼” airline fitting (to connect to an air supply)
Four ¼” pipe nipples (short pipe sections threaded at both ends)
Three ¼” to ½” adapters
Two ½” pipe nipples
One ½” plug

The bellows unit has a hinged section of ¼ inch plywood that is 10 ½ inches by 12 ½ inches.
There is a 1 and a 1/2” by 1 and a 1/2” by 9” sensor pole attached beside the bellows that is used to position the magnetic switches. It should be angled at the bottom so that the top leans back about 1and ½ inches from the bottom.
The bellows hinge is constructed of 4 pieces of 1 and a 1/2” by 7” 5/8” plywood pieces and one 1 and a 1/2” by 1 and a 1/2” by 17 inch piece of wood, two 3” hinges and a 2” by 12 and a ½” reinforcement.
The bellows is made by screwing down the bottom 2 plywood pieces to the backing board.
Arrange the other 2 plywood pieces directly over the first two, cover with the 17 inch piece of wood and and clamp together.
Drill holes centered 2 and ¾” in from each end to accept ¼” carriage bolts inserted from the bottom.
Unclamp and remove the top 17” piece of wood.
Insert carriage bolts from the bottom to line up the middle layer plywood pieces and clamp again.
Screw hinges to middle layer plywood. Ensure the screws do not protrude through the plywood to the bottom layer.
Screw the other side of the hinges to the bellows lid between the lid and the reinforcing strip.
The bag is clamped between the two plywood sections during operation using the nuts and washers on the carriage bolts.
The magnet is attached to the end of the bellows near the sensor pole, and the sensors are attached to the sensor pole.

To make the bag for the bellows, I used a large size Ziplock freezer bag.

Cut off the ziplock part.
Inert ½” plastic tubing into the center and use Tuck tape to seal and reinforce the edges.
The tubing should stick out of the bag far enough to be able to be slipped over the end of the ¼” nipple section of piping.
The taped seam of the bellows bag should be in on the bottom plywood section.
Install the hinged cover and then the top 17” section.
Clamp together with the 4” long ¼” carriage bolts, two nuts and 2 washers.

The valves, sensors, switches and power supplies are wired to the PLC unit.
Wiring diagram and program will be posted later.

Closeup of a Valve

Bags

Back of hinge and bellows feed

Bellows bolted together

Does Open Source Hardware Development Work?

2007-06-11T18:20:00.000-07:00

The Pandemic Ventilator Project was started on this blog on February 22, 2007. I initially had envisioned an open-source, public participation, Web 2.0 sort of project. I put out my design, asked for feedback, and hoped for others to join in the development. You can look here for my initial post.
http://panvent.blogspot.com/2007/02/pandemic-ventilator-contingency.html#links

I did not expect that I could start a blog, and immediately have people flock to my site. I knew I would have to promote the site somewhat and tell people what I was doing. I signed up on several flu pandemic discussion forums, and told people what I was doing. I also put a sitemeter tool on the blog so that I could do some traffic analysis to get some feedback on what worked. I went to the Google website and studied what was required to get a higher ranking on a Google search, and followed the recommendations.

So, you may ask, “How is it going?” Well, the results are mixed. I certainly got some constructive feedback from people I met on the various forums, and I had some people help me by placing additional posts. I had some people email me with suggestions. I have had very little negative reaction. Most of the negative reactions were from people who believe the project is a waste of time and resources, because the pandemic will be so severe that having additional ventilators will not help. I hope they are not right about that. I have had about 500 visitors so far. The visits come now from all over the world. Many are from government or educational ISPs.

As long as I promote the blog on other sites, I get visitors. As soon as I stop promoting, the traffic slows. There was only one large unexpected surge, when someone posted this blog on Reddit. http://reddit.com/search?q=ventilator If you think this blog should get more notice, then go to the Reddit site, log in and click on the up arrow.

So far, there have been no offers from others to join in the development. I am doing it all myself with my son helping. I have had quite a bit of help from people I know personally in the “non-wired” world. I have been loaned and given supplies and development tools to use on the project, and much encouragement. So far, I give Web 2.0 a 2 out of 5 for effectiveness, personal networking gets a 4 out of 5.

Here are some interesting links to other pandemic ventilator sites:

A do-it-yourself ventilator design from the 1940’s, originally in Popular mechanics magazine, more recently in Makezine.
http://www.makezine.com/blog/archive/2006/01/diy_wodden_lung.html

A blog that was asking for someone to do a DIY ventilator last year already.
http://www.liveatthewitchtrials.blogspot.com/

Project Extreme, an education program that gives out free DVDs to get more people cross trained in operating alternative ventilators during a pandemic.
http://www.ahrq.gov/prep/projxtreme/

A conference that will be dealing with the problem of ventilator shortage during a pandemic.
http://www.aarc.org/education/meetings/summer_forum_07/mechanical_vent.html

A report from the Center for Biosecurity about Ventilator Allocation.
http://www.upmc-cbn.org/report_archive/2007/05_May_2007/cbnreport_05032007.html

And another article on ventilator requirements in a pandemic.
http://www.upmc-biosecurity.org/website/resources/publications/2006_orig-articles/2006-06-15-positivepressureventilationformasscasualtyrespfailure.html

My letter to the British medical Journal
http://www.bmj.com/cgi/eletters/315/7102/254/a#162772

On Hiatus for the Summer

2007-06-03T12:51:00.000-07:00

Summer has arrived, and I have many other things that are keeping me busy now. I will probably get back to active development in September. (Unless there is a major development in the transition of avian flu to humans.) I will be still be posting on ventilator and pandemic issues from time to time. Anyway, I am happy with what is working so far with the project and it looks like the plan will be feasible. In the fall, I hope to finish the manometer portion and will try to get someone to port the PLC program to an Allen-Bradley/Rockwell platform, as that is a more commonly available type of PLC.

Manometer Operation Details

2007-04-15T12:52:00.000-07:00

I have been away for the last 10 days and so have not been posting. Now that the control system is built and the software is running. I will be working on getting the pressure monitoring installed.

The system so far accomplishes about as much as if you had an automated ambu-bag running. It could provide repeated breaths of a controllable volume, and a fairly consistent rate but there is no pressure monitoring or fail-safe should something go wrong. What we want to have is to be able to determine if an overpressure situation arises and so be able to stop the ventilator to prevent lung injury. We should also have some sort of backup failsafe that does not depend on the PLC or exhale valve functioning properly, in case the source of the problem is in fact one of these components. We should also have some sort of visual indication of the pressure at any time in order to aid the clinician that is monitoring the device.

The design for this is very basic. It is a manometer with a float, magnet and sensors. The floating magnet and sensors provide a signal to the PLC if the positive over pressure or lower pressure limits are exceeded. The lower pressure sensor can also be used to operate the ventilator in a demand mode or to implement PEEP. A third or fourth sensor could also be added later to provide redundant alarm points for tubing disconnect or blockage.

In the following diagrams you can see the function of the manometer.

In Figure 1, the manometer is at its neutral state and both sides are at the same level.

In Figure 2, the manometer is under negative pressure and the lower sensor is activated.

In Figure 3, the manometer is under a positive pressure and the maximum sensor is activated.

In Figure 4, the manometer has gone past the positive control point and it is acting as a safety overpressure. The air will leak past the bottom of the U portion of the curve and bubble up through the top.

Figure 1 Manometer Zero Pressure

Figure 2 Manometer Minimum Pressure

Figure 3 Manometer Maximum Pressure

Figure 4 Manometer Over Pressure

Figure 1 Manometer Zero Pressure

2007-04-15T12:51:00.000-07:00

Figure 2 Manometer Minimum Pressure

2007-04-15T12:50:00.000-07:00

Figure 3 Manometer Maximum Pressure

2007-04-15T12:49:00.000-07:00

Figure 4 Manometer Over Pressure

2007-04-15T12:45:00.000-07:00

Control Box and Lung Simulator

2007-04-01T16:13:00.000-07:00

Here is a picture of the control box and the PLC unit for the Pandemic Ventilator. In the back you can see the original bellows I built. I am using it as a lung simulator to test the operation of the system. You can see the ventilator in operation in the following video.

Valves Picture

2007-04-01T16:09:00.000-07:00

Here is a picture of the valves. The valve on the left is the exhale valve, the center one is the inhale valve and the one on the right is the bellows fill valve. The manometer is not yet constructed. You can see the clamp for the bellows unit at the bottom of the picture.

New Bellows Design and Magnetic Sensors

2007-04-01T16:04:00.000-07:00

Here is the new bellows design. It is open at the ends and sides to prevent wear on the bag. I also taped the seams of the bag for extra strength. It is clamped into place, and the clamp provides strain relief for the tape seal along the open end of the bag. The upright section on the left has the two magnetic sensors duct taped to it.

Video of the Ventilator Running

2007-04-01T15:34:00.000-07:00

Here is a video of the Pandemic Ventilator on its first test run. This is just the control system, we have no alarms in place yet. The new style bellows is on the main board with the valves, control box and the PLC. The original bellows unit I built a week before is being used as the patient lung simulator. The wrenches on the bellows and the simulator provide weight to empty the bellows and simulator.

Putting The Parts Together

2007-03-31T11:38:00.000-07:00

I have gotten many of the parts I need to build a prototype for the Pandemic Ventilator. I have two 120V Asco ½” solenoid valves for the inhalation and exhalation valves, and a 120V Burkert ¼” solenoid valve for the bellows fill valve. These valves must be direct acting and not the pilot operated type. They are rated for air as well as water. I got all the pipe fittings needed to connect the valves and other equipment. The magnetic switches are the type usually used for security systems. The PLC unit is a Direct Logic 06 DO-06DR from Automation Direct. I recycled an old control box from another project and I can rewire the switches and lights and buzzer to fit this project.

I tested the bellows unit I made last week to see how long the bag would last. In order to accelerate failure so as to find the weak points I cycled it manually under much higher pressure than it would normally be subjected to. It seems the weak areas are around the tube that is taped in, the taped end, and the edges that rub on the side of the bellows unit. I made some improvements in a second unit by clamping the taped end, allowing more space around the tube for flexing, and removing the sides and end of the bellows unit. It does not need the sides or end to contain the bag once the taped end is clamped into place. The clamp provides physical support to the taped end. I can use the bellows I made before as a lung simulator when I test the control system of the unit.

The plumbing work is done. It just needs the electrical connections made. I hope to be able to test the software for the control unit soon.

The Bellows Unit is Constructed

2007-03-24T16:58:00.000-07:00

I made the bellows unit today. I made it out of scrap wood, a zip-lock bag, some tubing and Tuck Tape. It is not difficult to construct and worked exactly as I envisioned it first try. I tried it out with a can of bolts on the lid for a weight as well. It worked very well and the flow rate is very good from the half-inch tubing. Following are some pictures of the unit. I am actually surprised at how few problems I had getting it to work as I envisioned it. I hope the manometer goes as well. I am going to have to start looking for some solenoid valves and switches now.

Back of Bellows Unit With Curved Edge

2007-03-24T16:52:00.000-07:00

Bag Loaded Into Bellows Unit

2007-03-24T16:51:00.000-07:00

Bellows With Bag Fully Inflated

2007-03-24T16:49:00.000-07:00

Planning the Prototype Build for the Pandemic Ventilator

2007-03-23T18:10:00.000-07:00

Now that I have a basic design laid out, I will move on to building a prototype. To aid in planning development I will break the design down into functional sub-units.

I will start on the most complex component to physically build. That is the bellows unit. I will have to do some trial and error to determine the best physical shape. I intend to not have the bag fully inflate and deflate on each cycle so that there will be less fatigue on the plastic. I will have to see about how best to contain the edges of the bag so that it does not get pinched in the moving portion of the bellows.

The manometer is fairly straightforward. The main concerns are getting the optimal tubing lengths and vertical positioning. Possibly I may have to adjust the diameter and length of the tubing at some points of it so that the water is not sucked into the patient circuit.

The rest of the airflow circuit is easy to build. I will use switches to control the valves to bench test the circuit without a PLC unit initially. I will cycle the valves manually with the switches.

Next is to add the PLC and magnetic sensors and get the unit to cycle automatically. Once the system is functioning at a basic level, the alarm software can be added to the PLC and tested. I have only rudimentary PLC programming skills myself, but I know several people that can help me on this.

Next will be the PC control/monitor integration. I have not really thought this far ahead yet. I have a pretty good idea of what I want it to do, but am not sure of the best approach to achieve it. I will take pictures and video of each step and post them. Hopefully by the time I am able to demonstrate a basic system functioning, I will have a programmer interested in doing the PC portion of it.

Preliminary Layout for Open Source Pandemic Ventilator Design PDV1 070319

2007-03-20T18:47:00.000-07:00

For some reason this picture came out blurry when I uploaded it. You can get a clearer version if you copy it or double click on the image. CC creative commons licence at bottom of page.

Description of Preliminary Layout for Open Source Pandemic Ventilator Design PDV1 070319

The design consists of a pressure regulator, 3 valves, a bellows unit, a manometer pressure sensor unit, some switches and alarms, a PLC and a PC.

This design is optimized to be able to be built with readily available components. Other than the tubing that connects to the patient, (which would be sterilized and reused) none of the components are specifically “medical parts”. It is expected that supplies of components specifically designed for medical devices will be in very short supply in a pandemic situation, and would not be available. Later on I will try a version using a commercial pressure sensor instead of the manometer system described. This will allow greater control flexibility of the device. The design philosophy is such that the physical components can be constructed fairly easily. All the parts are commodity items and easily available (you could steal em from factories if you had to) even if all production and supply ceases in the pandemic. The software design for the PLC and PC will be more complex, but will be freely available as open source including source code.

The Pandemic Ventilator is designed to meet AARC guidelines for Acquisition of Ventilators to Meet Demands for Pandemic Flu for alarms and for ease of use. I have not yet added humidification, oxygen concentration control or PEEP to this design but these additions will probably not affect the final design too much. In concept it is a system that essentially takes something similar to an ambu-bag manual ventilator and adds enough automation and safety control systems to bring it up to the AARC acquisition guidelines.

Description of Components (see drawing)

A bellows unit is constructed from plywood or sheet plastic using a standard door hinge at one end. More exact plans for the bellows will be published once I build the first prototype.

A plastic bag (possibly a drainage bag) is placed in the lower portion of the cylinder, with the opening of the bag connected to the system tubing with Tuck tape. The bag supplies the sealing properties for the bellows, and may have to be changed on a regular basis if it wears out.

The bellows will have a magnet attached at the top to activate the position sensors.

MS1 and MS2 are magnetically activated sensors (either Hall effect or magnetic switch) that sense when the piston has reached the top and bottom of its travel. MS2 is a fixed sensor, and MS1 can be adjusted to allow for adjustments in volume per cycle.

A weight is placed on the top of the bellows in order to allow the bag to deflate and push air into the patient’s lungs during the inspiration phase. The amount of weight on the bellows divided by the area in contact with the bag determines the maximum pressure that can be developed.

V1(NC), V2(NC), and V3(NO) are ¾” or ½” solenoid valves (or similar).

The manometer is a U shaped tube filled with water. It’s height in relation to the measuring point and the length of vertical tubing are adjusted in order to be able to measure the limit maximum and minimum pressures expected. A magnet is inserted into some foam in order to make it float at the water surface. The water level limits (which indicates the pressure limits) is monitored by magnetic sensors clipped to the outside of the tubing. The pressures can also be marked on the tubing so that the operator can have a visual indication of the maximum pressure achieved. I will publish more exact specifications as to the height and length of the tubing once I build and test the prototype.

An outlet filter is connected to the exhalation line in order to prevent infection of staff with flu virus.

Interconnections are with standard plastic pipe and flex hosing with gear clamps.

The PLC should have a minimum of 7 inputs and 5 outputs. The PLC should also have a communications port (RS232) in order to communicate with the PC. Software to operate various popular brands of PLC will be developed and made freely available. Various controls and alarms are connected directly to the PLC.

Description of PLC Control Algorithm (see drawing)
(Starting from the pressurized air source)

The pressure regulator reduces the supply pressure to a reasonable working pressure

The PLC opens V1 and closes V2. V3 is open to let the patient exhale.

Air enters the bellows and raises the piston. The PLC will sense MS2 opening and begin a timer. If the allowable window of time interval between MS2 opening and MS1 closing is not achieved, a malfunction alarm is generated, stopping the cycle.

When the magnet reaches MS1, V1 closes.

When the low pressure limit of the manometer is triggered or enough time has elapsed since the last cycle based on the selected inhalation to exhalation ratio or set time, V2 opens and V3 closes to inflate the patient’s lungs. The pressure limit points on the manometer are monitored by the PLC. If the pressure rises too high, an overpressure alarm is generated and V2 is closed and V3 is opened to protect the patient from overpressure.

The piston begins to drop and MS1 is opened. The PLC starts a timer. If the time interval between MS1 opening and MS2 closing is too short a line disconnection alarm is generated. If the time interval is too long, an obstruction alarm is generated. When the piston drops and MS2 is closed again, V1 opens, V2 closes and V3 opens to allow the patient to exhale again.

The PLC also monitors the cycle rate over time and generates an alarm if the selected control parameters are exceeded.

The PLC generates audible and visual alarms as required. Audible alarms can be set to sound different for different alarm conditions. The Stop, Mute and Reset/Resume keys allow for control of the ventilator.

Description of PC function (see drawing)

The PC is connected to the PLC via an RS232 connection. This connection transfers status data from the PLC to the PC and also allows the PC to input set points and controls. The PLC does not absolutely require the PC to maintain operation, but will generate an audible alarm if the communication is interrupted.

The PC will have visual interface software that mimics popular existing ventilators in appearance and operation. Non supported operations will be crossed out on the interface. This allows for easier retraining and higher comfort levels among operators of the equipment. The supported equipment type is selected when the software is installed.

The relevant operating and alarm parameters are entered into the PC and they are transferred to the PLC registers.

The PC can also perform diagnostics on the operation of the PLC in order to enhance total safety. The PC can also generate it’s own visual and audible alarms.

The UPS generates an alarm at power failure and supplies backup power as well. If the PC is a laptop with a battery, it will also be able to supply power failure alarms.

Still to be done
Oxygen, Humidification, PEEP design
Build and test a prototype with PLC only.
Add PC control functionality

I could use some help, so far it’s me, my son, and some friends at work (in dialysis) developing this.

Please be patient if I do not have all the terminology right, and comment or email tell me if I am making some drastic mistakes or you have some insight that would let me make this thing much better. I knew almost nothing about ventilators three weeks ago

Being Aware of the Shortage

2007-03-18T18:49:00.000-07:00

The need for more ventilators for pandemic planning is quite obvious, but, given the fact that most large organizations respond to events rather than proactively plan, and they are always worried about appearances. Letters to public media to investigate will probably have more effect than individual letters to hospitals, as media sources are far more difficult to ignore.

The questions to ask of your hospital or local planning organization are:
1. Are you aware of the need to plan for a pandemic?
2. Do you have plans in place to deal with the expected surge?
3. Do you think the existing plans will be sufficient or do you need more support in place?

I hope to have a preliminary design posted soon.
If you think this is an important issue, please send this website address to your friends and click on the Digg button.

Thanks,

The Cost of Providing a Ventilator Safety Net for a Pandemic (And the Cost of Not)

2007-03-14T19:23:00.001-07:00

The Cost of Providing a Ventilator Safety Net for a Pandemic
(And the Cost of Not)

Today I am talking strictly money. This does not men I do not appreciate the extreme suffering that many avoidable deaths will have on the fabric of our (caring?) western civilization. I just want to put the numbers in focus.

Donald McNeil (mcneil@nytimes.com) of the New York Times, in his column of March 12, 2006, "Hospitals Short on Ventilators if Bird Flu Hits" says that it would cost the US 18 billion dollars to buy enough ventilators to prepare the US against a pandemic similar to the 1918 Spanish Flu. I think this number is way too high. Numbers like this scare the government so much that they buy almost no ventilators at all. They give up.

$18,000,000,000 dollars will buy 600,000 ventilators at $30,000 dollars each. Since there are only about 100,000 ventilators currently in the US, the existing physicians, respiratory therapists and RN staff would have to be able to expand their workload by a factor of 6. This, also in the face of many of their own number being sick. I think a more reasonable number would be that they could expand their capacity by a factor of 3.

McNeil obviously bases his estimate on the figure quoted by the US government that 750,000 would require ventilators in a pandemic. The 750,000 would not all show up at the hospital the same day. Pandemics can take as long as 12 to 18 months from start to finish. They can come in several waves, so that each ventilator can be used to treat several patients sequentially. 200,000 ventilators is a more reasonable maximum. The ventilators need not be the most expensive fully featured units either. If you could get 200,000 ventilators for $5,000 each, the cost would be only 1 billion. That’s less than a penny a day for each US resident over the next year.

Now a very high proportion of the deaths will occur in younger people. These are the people that are supposed to be paying for the huge national debt and social security obligations of the older people. How many trillions of dollars in lost future tax revenue does this represent.

In the US, they are planning on 5,000 to 10,000 spare ventilators, depending on whose numbers you believe. In Canada there are no plans to stockpile additional ventilators. Thank You Mr. Harper.

2007-03-12T18:40:00.000-07:00

Below is a reworking of my original proposal. I added some references and some calculations of the number ventilators required in a pandemic.
See Preliminary Layout for Open Source Pandemic Ventilator Design PDV1 070319

I am also having an ongoing discussion of this topic at
http://forums.starnewsonline.com/eve/forums/a/tpc/f/8841089365/m/8301010606
If you want to hear what others think or submit your own ideas, go over and have a look.

A Proposal for an Open Source Design to Assemble Ventilators to Meet Pandemic Surge Demand

2007-03-11T17:52:00.000-07:00

Clarence Graansma

Abstract:
In a predicted pandemic influenza outbreak, it is expected that there will be a severe shortage of ventilators. Ventilators are expensive to buy and maintain, so government organizations are stockpiling only a minimal reserve. Manual type ventilators will not be adequate for many cases. The solution to this problem may an open source design for an automated ventilator that will be adequate for the perceived need, and can be built from parts that will be available in sufficient quantities during a pandemic. A community of developers must design, and test a ventilator, and make the design freely available for individuals and healthcare organizations to build their own units in a pandemic crisis.

Background:
It is expected that in a pandemic influenza outbreak the number of people requiring a ventilator will be much greater than the number of ventilators that are available in hospitals. There are approximately 105,000 mechanical ventilators and 60,000 intensive care unit (ICU) beds in the United States. This is only 1 ventilator for every 2600 people and 1 ICU bed for every 4500 individuals. In an avian flu pandemic, it is estimated that 30% of individuals will become symptomatic and up to 50% will require ventilatory support. Using more conservative estimates, data from the H1N1 pandemic flu of 1918 suggested that 2% of people required ventilatory support. If the same is true for H5N1 (although less than what is currently estimated), a city of 1 million people will have 300,000 affected individuals and 6000 of whom will require a ventilator .

Based on these numbers, a city of 1 million people would have 385 ventilators in its hospitals. Since 80% to 100% of the stock of existing ventilators is typically already being used in the ICU units , this leaves at most only 77 ventilators available at any given time. Triage methods will be used to remove some of the people already on ventilators in order to give to people requiring ventilatory support due to the pandemic. Now it is possible that the impact of the pandemic may be considerably less than the 1918 event due to the use of vaccines and anti-viral medications. Let us assume again a very good response to medications, and we reduce the number of people requiring ventilatory support by 50%. The expected patient load would now be 3000. Pandemics do not always strike all at once, but may come in several waves such as the 1918 pandemic . The same ventilator could be used sequentially 2 or 3 times in each wave to treat pandemic victims in perhaps 3 subsequent waves. This means that each ventilator could now be used to treat 6 to 9 people. Assume we made up to 200 ventilators available via triage by removing existing chronic and elderly patients from ventilatory support and then used each of these ventilators to save 8 people from the pandemic. This would save 1600 of our 3000 patients.

It is obvious that even strict triage and with conservative assumptions of severity, we will be short of ventilators. Even if we had an unlimited supply of ventilators, we will not save everyone. Many will die even with a ventilator and good critical care. If the availability of ventilators were not the issue, the limiting factor then would be how far we can extend our critical care support system. Physicians, intensive care nurses and respiratory therapists will also be affected by the pandemic and their ability to respond may be reduced. There are also issues of availability of other supplies. A reasonable assumption of the limits of support extension would be between a factor of 2 to maybe 3. This means our city of 1 million would need to have available between 385 to 770 additional ventilators. Now these ventilators need not have every possible alarm and treatment option, but they must have enough automation so that nurses and respiratory therapists (RTs) can run them without constant intervention.

Some hospitals and organizations are stockpiling manual ventilators for such an emergency. These are either bag type manually operated ventilators, or pressure driven transport type ventilators with no alarm systems . These have the advantage of low cost, disposability and no maintenance. These devices require extensive supervision by qualified personnel, however and will not be adequate in this situation. They may be useful if appropriate automation and alarm systems could be fitted. To buy enough full function ventilators to fulfill the need is too expensive for hospitals to consider. Even if the government were to pay for enough ventilators to supply the entire country, there would not be enough centralized manufacturing capability to supply the product when it is needed. Neyman and Irvin have published an innovative method to put up to 4 patients on a single ventilator. This system requires further testing and would not have very good monitoring ability.

Proposed solution:
From the previous sections it is obvious that what is required is a reference design for a low cost, relatively reliable ventilator that can be produced in a large quantity in a relatively short time from commonly available materials that are not in short supply. The device will not require every feature and ability of existing full function ventilators, but must have the features required to properly care for Acute Respiratory Distress Syndrome (ARDS) in a pandemic situation. The device should be automated as much as possible as to enable the existing RTs to care for a large number of patients. Also the design of controls and alarms should be intuitive so that other persons can be trained to help support the devices in use. The components used to build these devices must be components that will be available during a pandemic.

The best way to engineer and distribute such a reference design would probably be based on an open source model. Existing projects to emulate and gain organizational insight could be the "One Laptop per Child" project or the various open source software projects such as the Mozilla Foundation or various Linux branches. The non-profit Architecture for Humanity (http://www.architectureforhumanity.org/) is doing a similar thing for designs for housing to rebuild communities in the wake of natural disasters. We need to start a Pandemic Ventilator Project now.

The ventilator must be able to be built from commonly available components sourced from the industrial and instrumentation marketplace. The component specification should be standardized as much as possible. For example a good specification would be "12V solenoid actuated air valve with a minimum flow rate of 3 liters per minute" rather than "ACME solenoid valve AS3506T." This will allow substitution if required.

A centralized listing would be have to be established and maintained of possible components that will satisfy the requirements and known supply sources. The design should incorporate "fail-safe" design techniques as much as possible. In order to use "off the shelf" components, the design will have to rely on an electronic control system to enhance safety and usability instead of using innovative pneumatic component designs. It will probably be either PLC based or some type of dedicated PC control.

Testing criteria and minimum performance specifications will have to be developed.
It is expected that alpha, beta and release candidate versions will be released and then tested. There may be version upgrades based on testing results. It may be beneficial to fork the project at some point in order utilize differing design philosophies or to produce devices tailored to certain requirements, such as simplicity of operation, desired features or ease of assembly.

A community of developers will need to be established. It is doubtful that existing ventilator manufacturers will participate on a formal level due to competitive and legal obstacles, however it is expected that they may allow some of their engineering staff to participate on their own as a humanitarian gesture. It would be expected that professional groups may encourage their members to support the project. It would be very helpful to obtain the support of university engineering labs. It is expected that the bulk of support would be individuals from the medical, instrumentation and information technology communities.

A legal framework will have to be established to protect contributors to the project from legal liability of any misuse of the reference design or any lawsuits from failure of a device. Something like the GPL will have to be used to control derivative use of the reference design. As it is unlikely that the design will be submitted for FDA approval, there would have to be legislation enacted by governments in a crises to permit use of any devices produced. Perhaps some draft documentation to guide the government agencies at the time of a crisis could be produced ahead of time. Humanitarian groups may wish to use the designs for third world relief projects.

A foundation may have to be established to support the project. A core group will have to be established to control and maintain the direction of the project. Training, servicing and operation guidelines and materials must also be produced and maintained. A website for feedback, communication and software distribution will be required. Perhaps Sourceforge could be used.

Mar 11 2007
www.panvent.blogspot.com

References

1 Disaster Medicine: Understanding the Threat and Minimizing the Effects
Christopher J. Lettieri, MD
Medscape Emergency Medicine. 2006;1(1) ©2006 Medscape
Posted 05/31/2006
http://www.medscape.com/viewarticle/532446

2 CMAJ • November 21, 2006 • 175(11) | 1377
DOI:10.1503/cmaj.060911
Christian, Michael D. et al

3 Mass Critical Care with Scarce Resources: A Community Planning Guide AHRQ Publication No. 07-0001 Marc Roberts PHD et al

4 Taubenberger JK, Morens DM. 1918 influenza: the mother of all pandemics. Emerg Infect Dis [serial on the Internet]. 2006 Jan [date cited]. Available from http://www.cdc.gov/ncidod/EID/vol12no01/05-0979.htm

5 BIOSECURITY AND BIOTERRORISM: BIODEFENSE STRATEGY, PRACTICE, AND SCIENCE
Volume 4, Number 4, 2006
The Prospect of Using Alternative Medical Care
Facilities in an Influenza Pandemic
LAM, CLARENCE et al

6 A Single Ventilator for Multiple Simulated Patients to Meet Disaster Surge
Greg Neyman, MD, Charlene Babcock Irvin, MD
ACADEMIC EMERGENCY MEDICINE 2006; 13:1246–1249

Trusting in the Pandemic Plans

2007-02-26T18:58:00.000-08:00

In 1984 the Canadian Red Cross publicly informed hemophiliacs that the blood products it distributed were safe, even though not all sources of blood were tested. Spokesmen for the Red Cross also referred to the need to look at the cost benefit ratio in treating hemophiliacs. It was later found that more than 800 of Canada’s 2500 hemophiliacs had contracted AIDS from using the untested blood. About 95% of them contracted Hepatitis C. Even two years after it was known that untested and untreated blood was dangerous to use, the Canadian Red Cross was still distributing its older untested stocks.

This incident was a blot on the integrity of public health care organizations in Canada. Many people asked afterwards, “How could this happen?”, “They knew the dangers”. The answer of course was that they placed fiscal accountability and efficiency above the needs of the people that placed their trust in them. The Canadian Red Cross was not the only group that fell short of their responsibility. This same pattern was repeated by other organizations in other countries of the world as well.

We all tend to place a great deal of trust in organizations such as the Red Cross. Such groups we trust are the FDA, the CDC, HHS. In Canada we have The Ontario ministry of Health and Long Term Care, Health Canada and The Public Health Agency of Canada. These groups have developed plans to deal with a pandemic. They all acknowledge that there will be a severe shortage of ventilators. The plans they have to increase the availability of ventilators fall far short of even their own predictions. Again they know the dangers, but are not doing enough to solve the problem. They have to be fiscally accountable and efficient you know. That old cost benefit ratio.

They have a plan to deal with it though, it involves rationing. They will pick who lives and dies. You can find lots of these plans on the web. Just Google Pandemic Ventilator Plan Ration. Now Ontario, Canada where I live, has 1,096 ventilator support beds in ICUs in the province. The total demand for ventilators in a pandemic could easily be twice this amount. There are also 1,400 chronic ventilator patients on other ventilators. The published triage plans are not very specific on whether it will involve taking ventilators away from sicker chronic patients to give to the pandemic patients. I hope we can trust them.

Using Existing Infrastructure as a source of Ventilator Parts

2007-02-25T12:28:00.000-08:00

Let me deal with one possible objection to the feasibility of the plan I laid out, that says it would be impossible to obtain enough parts in a crisis situation to build the large number of ventilators required all across the country.

It is assumed in many planning proposals and scenarios that during a pandemic event that there will be considerable disruption to our transportation and manufacturing infrastructure. The movement of products will be curtailed in order to prevent the spread of infection from one location to another. Non essential manufacturing will be hampered due to regulations restricting the gathering of large numbers of people, again to reduce transmission of the virus.

This will make it difficult to obtain parts from a centralized source to build a large number of ventilators, and since the manufacturing capability is shut down, additional parts can not be produced. There is a rather elegant solution to this problem. Instead of seeing the shutdown plants as yet another obstacle, you view it as an opportunity in that you can actually use the shutdown manufacturing plants as the source of the components to build the ventilators.

Using Manual Ventilators in a Pandemic Crisis

2007-02-25T12:25:00.000-08:00

Some of the current plans for dealing with the expected shortage of available ventilators in a pandemic crisis depend on stockpiling manual ventilators (ambu-bags). They would arrange for teams of friends and family members operate the ambu-bags during the crisis. There is some disagreement as to whether this is a viable option. Some experts dismiss this as being totally unworkable in a mass casualty situation as there are three basic problems with this plan:

1. The physical effort of squeezing a bag continuously is too exhausting for a person to manage very long.
2. Infection control issues related to having many volunteers man the bags in an ICU full of contagious flu victims. The number of deaths due to additional infections generated by such a plan could actually be greater than the number of people saved with the manual ventilators.
3. Lack of monitoring combined with minimally trained volunteers will probably result in a very high morbidity and mortality for the patients.

Now of course it is possible for a team of trained experts to keep someone alive on a manual ventilator for an extended time. In 1955, as a result of a polio epidemic, the demand for negative pressure ventilators exceeded the availability of negative pressure ventilators. There was such a shortage in Sweden that medical students, working in shifts, manually ventilated patients to keep them alive. Now a polio epidemic may sound bad, but the number of patients requiring mechanical ventilation in a flu pandemic will probably be many times higher.

Now instead of throwing our hands in the air in a panic and crying doom, suppose we looked for a way to solve these three problems. Number 1 is easy to solve. Just take an electric motor with some gear reduction and a cam arrangement, to make a pair of mechanical hands to squeeze the bag. The operator can now just turn a control knob to speed up or slow down the rate, or press a button for each cycle if you wanted to have some sort of assist mode going. If you solve problem #1, you also solve problem #2 because you do not need that large group of volunteers.

Solving problem #3 is a little harder. You would need a pressure sensor and an electronic controller to analyze the pressure conditions in the ventilator circuit to determine when alarms such a low rate, high pressure and disconnection occur and sound an alarm. A rudimentary but functional device could be constructed from any standard instrumentation pressure sensor and basic industrial programmable logic controller. If someone worked out a good program ahead of time, that was well tested, this could be freely shared to run thousands of devices across the country.

Incidentally, if you were fortunate enough to have stockpiled a quantity of pressure driven transport ventilators ahead of time, you do not get problems #1 and #2. The same monitoring system could be used to enhance safety of these devices for unattended operation.

Ethics of using non-regulated devices

2007-02-25T10:31:00.000-08:00

Most administrators and physicians will be concerned about using a non-regulated device. It is not intended that such devices ever be used except when there is no alternative. The ventilator design I am proposing will of course be tested by the design team and possibly validated by some other party, but it does not seem feasible to get FDA approval. The FDA could not approve even a perfect design in which the prototypes tested flawlessly because the FDA also requires that there be very tight control of the manufacturing and assembly process.

If you get right down to it, a ventilator consists only of a few components; some valves, sensors, possibly a blower or regulator and a sophisticated control system. The valves, sensors etc would be of industrial instrumentation grade. This grade of component is extremely reliable and these components can run continuously for years in a harsh industrial environment with minimal failure. The project would identify suitable components, build and test prototypes ahead of time. All the tests for over-inflation, low rate, disconnection etc would be performed and documented by the development group.

Much of the value and the safety of a ventilator resides in the sophistication and reliability of the control and user interface software. This software would be developed in an open source format so that the source code is available for anyone to inspect and improve on. It has been shown that open source software can be as reliable or even more reliable than closed source software in this regard. I believe that such a device design approaching the reliability and safety of regulated devices could be produced, providing that the project team consisted of the right group of people.

Now if we looked at this reliability issue from a real world, worst case point of view, and a device was produced that killed say 10% of the patients that used it due to equipment failure. The FDA would view this as a horrible device and of course would never approve its use. Now suppose this (poorly designed) device was the only one available and you had to choose to use it or allow say a friend or relative to die without the ventilator, (100% chance of death as opposed to 10%) the choice is now quite clear.