A High Frequency Oscillatory Ventilator Design For Use in Pandemics

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

Using a Dialysis Machine to do ECMO

(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

Canada to Buy Ventilators for the H1N1 Flu

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

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

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

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

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..

Video: Davos 07: Pandemics

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

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

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

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

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

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

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

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.

Pandemic Ventilator at Queens Park

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?

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:

1. 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.
2. 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.
3. 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…

Another Video of Pandemic Ventilator Norman

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.