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.

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