Saturday, April 26, 2008

A Home Made Iron Lung for the Hospital for Sick Children

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.

Sunday, April 20, 2008

Are the Ventilator Numbers Real?

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.

Saturday, April 12, 2008

Why There is a Need for the Pandemic Ventilator

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.

Friday, April 4, 2008

WWSEF Science Fair Results

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

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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