Many patients with the respiratory disease COVID-19 need mechanical ventilation to give them a chance at recovering. Modern respiratory ventilators are complex machines and difficult to produce and serve one patient. What is required is a simple mechanical ventilator that is robust and reliable and serves many patients. Frankly, looking at pictures of modern respiratory ventilators I shudder at the thought that the exhaled air from the patient is vented into the ward; it should be extracted, sterilized and vented to the outside to reduce contamination.

I am an electrical engineer by training and not a medical professional; however I can imagine the minimum functional requirements of a mechanical ventilator for multiple patients as requiring the following:

  1. Adjustable breathing rate for each patient.
  2. Adjustable ventilation pressure regulator for each patient.
  3. Common or individual oxygen enrichment.
  4. Dual common over pressurized air supply manifold. This allows for the periodic sterilization. (Pointed out by Jeff in the fist comment below.)
  5. Common under pressurized extraction manifold which is vented out of the room, preferable through a sterilization system.
  6. The system needs to be battery backed and a certain amount of dual redundancy for the common parts should be provided.

My sketching skills are limited, but the basic idea should be conveyed. The manifolds could be constructed from standard PVC piping, and be shipped in standard lengths which then can be extended at  the to-be-erected make-shift hospitals.

I am sure that I have missed something; hence I invite you to pass this on to someone with more knowledge, or leave comment below or in the forum. Better still would be if a research/manufacturing group could take up this idea and challenge.

Wishing you all good health,

    • Jeff on Portfolio12 wrote:

      This gets to be quite a bit more complicated. The devil is literally in the details. Not only do you have to worry about sterilizing air going out but also coming in. You don’t want to have mold, bacteria, fungus, etc going into peoples lungs that could be forming in the lines. I’m not sure PVC is appropriate for that. There are certain materials that you have to use for medical applications and in the medical device industry they are well known. The functional requirements are a good start, but they would need to be further expanded upon. From an electrical standpoint you have to design a robust circuit in combination with software that has to be verified and validated. You need to verify that the system will not only perform but won’t fail to work or kill your patient when the software or hardware reaches fault conditions. You are going to have to perform some level of environmental qualification testing to ensure you electronics, fittings, tubing maintain functionality, sealing, and structural integrity. Then you need to make sure your design can actually be manufactured without defects, within a reasonable timeframe, and for a cheap enough cost. Of course there’s FDA approval.

      This is not everything, but you can begin to see why medical equipment development and production is so pricey and wrought with risk.

      Maybe other countries might be more relaxed about what I mentioned above. Obviously FDA approval doesn’t matter in that case, but you still need a reliable, safe, easy to manufacture design.

      FYI, I don’t personally work in medical devices, but my wife does as a quality engineer. I am an Electrical engineer but design test equipment in a different industry.

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