Monday, February 26, 2007

Trusting in the Pandemic Plans

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.

Sunday, February 25, 2007

Using Existing Infrastructure as a source of Ventilator Parts

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

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

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.

Thursday, February 22, 2007

Pandemic Ventilator Contingency Planning

Pandemic Ventilator Contingency Planning
A Proposal for an Open Source Reference Design
Prepared by Clarence Graansma Feb 22, 2007


The number of ventilators required to save the lives of people stricken with respiratory failure in a pandemic is far greater than the number of ventilators available. Many people will die needlessly unless something is done. 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. We need an organization to develop a design for an automated ventilator that will be adequate and can be built from parts that will be available in sufficient quantities during a pandemic. This organization will design, and test a freely available open source ventilator design, that individuals and healthcare organizations can build themselves in a pandemic crisis.


In a Pandemic (H5N1 Flu?) many people will develop Acute Respiratory Distress Syndrome (ARDS) and require mechanical ventilation for a period of several days.

Current ventilator capacity in Canada and USA is about 75% to 95% utilized with existing cases (COPD, elderly, accident victims, trauma, post surgical, cardiac, etc)

Ventilators are expensive to buy and maintain. Budget strapped hospitals are not buying additional ventilator units in order to cope with the surge demand expected in a pandemic situation. Central governments feel that their money is better spent on vaccine development, stockpiling antiviral drugs and planning. Only a small number of extra ventilators will be stockpiled, about 10% in the US and nothing in Canada. Even if the central governments were committed to purchasing large numbers of ventilators, in a crisis the companies that produce them may not be able to ramp up production capacity to supply the demand in time. (This happened to some extent with Tamiflu) This is also a very politically risky position for any government to take in that the timing and severity of the next pandemic are unknown. If they purchase say 50% excess capacity, that may still be not enough and they will be criticized, on the other hand if a pandemic does not arrive for many years, the purchased equipment may not be usable if it has not been serviced.

The expected surge demand is unknown. Right now, in the US there are 105,000 ventilators, and even during a regular flu season, about 100,000 are in use. In a worst-case human pandemic, according to the national preparedness plan issued by President Bush in November 2005, the country would need as many as 742,500. To some experts, the ventilator shortage is the most glaring example of the country's lack of readiness for a Pandemic. (New York Times, March 12, 2006) The number of people that will die because of the ventilator shortage that would have otherwise survived the pandemic may be significantly greater than both the 911 and Katrina disasters.

The main response to this expected surge demand from top-level agencies and governments is to institute a triage system that will maximize the number of lives saved. There are many unresolved ethical issues such as can treatment be withdrawn once started and do we also factor in quality of life and predicted life expectancy. Legislative changes will be required to protect institutions and caregivers from existing legal liability, as well as granting greater powers to institutions to compel people in a crisis and to control persons who are prevented from obtaining help for their loved ones.

The net result of the triage proposals is that many persons will be unable to obtain a ventilator and will die. A significant percentage of these people would have survived if a ventilator were available. The triage proposals will attempt to mitigate the damage as much as possible. It is expected that a very large percentage of the victims will not be elderly.

Some institutions and organizations are stockpiling manual ventilators (bag type) and disposable mechanical ventilators meant for short-term transport as a solution. These devices can be purchased for less than 100 dollars each. It is hoped that these could be used on people that are refused the use of a standard full function ventilator. There is much criticism of these programs by some experts. The experts contend that the people afflicted with ARDS may require ventilation for over a week. This will be physically impossible and very unsafe over an extended time with a manual bag type ventilator. Even when basic transport ventilators are used, they require an expert to continuously monitor them, or significant patient injury or death may result. There are not enough expert trained personnel (Respiratory Therapists RTs) available to provide this level of monitoring. Also, some of the RTs will be themselves sick or unavailable, and they will already be at full capacity with the existing ventilators.

During a pandemic event there will almost certainly be a black market in ventilators, and the price of available units may be very high. There may also be theft of ventilators from hospitals and persons on chronic ventilation in order to supply this market.

Ventilators are expensive for the following reasons:

Liability issues. The companies that make these devices are often sued and require considerable insurance or financial reserves to accommodate these (in many cases unavoidable) contingencies.

Engineering and design. Engineers and product design people and consultants can be expensive to support. The equipment may have to be frequently redesigned to accommodate obsolescence and technological changes.

Testing and product support costs. Equipment must be proven safe and certified by the FDA.
The company must also be certain that their customers are adequately trained and aware of any safety issues identified with their product.

Marketing costs. It is expensive and time consuming to market to bureaucratic institutions such as hospitals. There is also significant pressure to add features to the product to differentiate it from the competitor’s product or to replicate the functions available from competitors. Some of these features are expensive to implement relative to their actual usability but are still required to remain competitive.

Financing costs. Medical device manufacturing is considered to be a risky market sector by the financial community. In order to induce individuals and institutions to invest in these companies, a higher profit is expected in order to compensate for the additional risk.

Inherent technological risk. Companies can be locked out of a market that they have invested a lot into, if a competitor comes up with a significant improvement in design or manufacturing ability and the competitor is able to protect this advantage with patents or trade secrets

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 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. Any disposable devices that it uses that are common to existing devices should be able to be reprocessed and reused so as not to impede the continued use of the existing devices in hospitals.

The source of the components during the pandemic may very well be from existing PLCs, valves, sensors and computers taken from our industries and businesses. I believe that is much more sensible and humane to Triage our infrastructure than to condemn our children and loved ones to a painful and agonizing death.

Considering the constraints from politics, markets and financial systems in place, I believe that the best way to engineer and distribute such a reference design would 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.

We need to start the Pandemic Ventilator Project now.

Basic Design (Draft)

The ventilator must be able to be built from commonly available components sourced from the industrial and instrumentation marketplace. Perhaps even air brake components could be utilized.

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 possibly on a linux platform.


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.

Community of Developers

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.

Legal Issues

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.


Initially viral marketing techniques could be used such as email campaigns. It may be helpful to establish a website and try to get a high ranking on sites such as Digg.

It may be helpful to post on pandemic and flu related discussion boards and Blogs.

At some point the mainstream media may notice the project and promote it.


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.

Pandemic Ventilator Project List of All Posts

Pandemic Ventilator Contingency Planning
Ethics of using non-regulated devices
Using Manual Ventilators in a Pandemic Crisis
Using Existing Infrastructure as a source of Ventilator Parts
Trusting in the Pandemic Plans
A Proposal for an Open Source Design to Assemble Ventilators to Meet Pandemic Surge Demand A reworking of my original proposal
The Cost of Providing a Ventilator Safety Net for a Pandemic (And the Cost of Not)
Being Aware of the Shortage
Preliminary Layout for Open Source Pandemic Ventilator Design PDV1 070319
Planning the Prototype Build for the Pandemic Ventilator
Bellows With Bag Fully Inflated
Bag Loaded Into Bellows Unit
Back of Bellows Unit With Curved Edge
The Bellows Unit is Constructed
Putting The Parts Together
Video of the Ventilator Running
New Bellows Design and Magnetic Sensors
Valves Picture
Control Box and Lung Simulator
Figure 4 Manometer Over Pressure
Figure 3 Manometer Maximum Pressure
Figure 2 Manometer Minimum Pressure
Figure 1 Manometer Zero Pressure
Manometer Operation Details
On Hiatus for the Summer
Does Open Source Hardware Development Work?
Assembly Instructions
Link to Commentary on Ventilator Shortage
Progress Report Vinnie
The Ventilator is a Lifeboat
Some Short Pandemic Info Videos from Youtube
Larry Brilliant on Bird Flu
Everything Old is New Again Workshop Built Ventilators
A Personal Account of Home Made Ventilator Saving a Life
Review of Online Book - Ethical and Legal Considerations in Mitigating Pandemic Disease: Workshop Summary
Review of - Mass Medical Care with Scarce Resources: A Community Planning Guide
Test of the Pandemic Ventilator with Manometer
One Year Anniversary
Review of Ontario Health Plan for an Influenza Pandemic
Review of - Positive-Pressure Ventilation Equipment for Mass Casualty Respiratory Failure
Dr John Hick Interviewed by the Star Tribune
Norman Running on Video
Another Video of Pandemic Ventilator Norman
WWSEF Science Fair Results
Why There is a Need for the Pandemic Ventilator
Are the Ventilator Numbers Real?
A Home Made Iron Lung for the Hospital for Sick Children
How Many Ventilators Does New York Really Have?
Quick Review of “Definitive Care for the Critically Ill During a Disaster”
The Cost of Efficiency
Pandemic Ventilator at the Canada Wide Science Fair
Dr. Eric Toner Blog post
Building a Pandemic Ventilator
Staff Priority for Ventilators? ... Yes?
Pandemic Ventilator at Queens Park
Hospitals "Full-Up": The 1918 Influenza Pandemic
Video: Larry Brilliant: TED Prize wish: Help stop the next pandemic
Video: Standing in the Safety Zone
Video: Interview of John M Barry author of The Great Influenza
Video: Influenza Pandemics: Past and Future
Video: Protecting the Healthcare Workforce in Pandemic Influenza
Video: Avian Flu
Video: Emerging Infections: How Epidemics Arise
Video: Davos 07: Pandemics
Video: California Pandemic Influenza Preparedness Summit
Video: On Avian Flu
Video: Avian Flu: Innovation in Healthcare
Possible Swine Flu Pandemic Brewing
Canada to Buy Ventilators for the H1N1 Flu
The Crisis is Near Now A High Frequency Oscillatory Ventilator Design
Are the H1N1 Death Numbers Low?
Using a Dialysis Machine to do ECMO
HFOV design is Coming Soon
A High Frequency Oscillatory Ventilator Design For Use in Pandemics
ECMO Dialysis H1N1 and MacGyver