Modifying Hospital Ventilators to Work with Multiple Patients

One of the key shortages in areas overwhelmed by COVID-19 patients (like Italy) is ventilators in hospitals. COVID-19 is a respiratory illness and respirators are essential in treating patients with acute symptoms. In the US and other countries, experts are warning of ventilator shortages and manufacturers say it will be difficult to ramp up production quickly enough to meet demand. So healthcare providers are looking for other solutions.

One potential solution is modifying ventilators to work for more than one person at a time. Based on feasibility research published in 2006, the simple technique uses inexpensive parts that hospitals already have on hand to modify machines to work with 4 patients at a time (with important caveats). One of the authors of that research paper, Dr. Charlene Babcock, explains how to hack the ventilators in this video:

Some notes from the video:

• The initial study used test lungs (not actual humans)
• You need to make sure the lung size and resistance of all four patients hooked up to a single ventilator are the same. No mixing adults and kids, for instance.
• Make sure the ventilator tubes leading to and from the patients are all the same length.
• This technique has been used successfully in the field, during the aftermath of the 2017 Las Vegas shooting.
• They did not investigate cross-contamination effects, so you have to make sure all the patients connected to one machine are COVID-19 patients in order to mitigate the risk.

In closing, Babcock says:

Now here’s my disclaimer. This is off-label use of the ventilator. The ventilator is made for one person and I’m using it here in a simulation of four patients. I always hope that you would never need to use it in this way, but you can never predict what’s going to happen in a disaster. And if it was me and I had four patients and they all needed intubation and I only had one ventilator, I would simply have a shared discussion meeting with all four families and say “I could pick one to live or we could try to have all four live”. But this is clearly off-label and likely would only be used in dire circumstance, which we may see with COVID-19.

Other people are working on designing and deploying open source ventilators and ventilators made from parts of other machines. All this reminds me of that scene in Apollo 13 where NASA engineers design a modified CO2 scrubber using only parts available on the spacecraft. A similar “failure is not an option” spirit might be called for in this case as well.

• Charlene Babcock
• Covid-19
• medicine
• science
• video