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'Pandemic ventilator' could offer solution in potential 'worst case' scenario

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Re: 'Pandemic ventilator' could offer solution in potential 'worst case' scenario

#51

Post by dschuler »

totalZero wrote: post #45
thornjm wrote: post #35

Earlier quoted context omitted.

Med student here - so I know some of the theory only. The most relevant "law" is Fick's Law of Diffusion ( https://d2jmvrsizmvf4x.cloudfront.net/CTU792sKR2evT2ezizQp_f... ). Doctors can increase diffusion by increasing the partial pressure of oxygen. In a diffuse infection a patient begins to lose both lung area (due to shunting) and the thickness of the diffusion barrier increases (due to inflammation). To help over…

It's too bad we can't put sick people in an airplane, put oxygen masks on them, shut the door, and pressurize the cabin. Like a hospital, but at the airport.

Very creative idea, I wouldn’t have thought of that.

So standard pressure at sea level is 29.92inHg, a 737 MAX can sustain 39k ft altitude indefinitely I suppose, where the exterior air pressure would be 7.66inHg. The cabin is normally pressurized to the equivalent of 8k ft, giving 26.63inHg. The fuselage could withstand a pressure differential of 26.63inHg - 7.66inHg = 18.97inHg (at least, possibly more).

That’s 63% higher than regular pressure at sea level. Not bad.

If you gave each patient a full economy row, that’s about 60 patients per plane, so 48k patients across 800 grounded 737 MAXs.

Re: 'Pandemic ventilator' could offer solution in potential 'worst case' scenario

#52

Post by asdfman123 »

JohnBooty wrote: post #38

From the article: "We're talking about a device that we want to have available in the worst case conditions and strangely enough, COVID-19 is not the worst case envisioned," he said. Made me think. Perhaps in 3, or 5, or 20 years.... Maybe we'll be thankful that COVID-19 was sort of a "training wheels" pandemic... something that helped to prepare us for the even worse pandemics that are sure to follow. Deaths due to…

Well, it's so bad because it's generally so mild. More severe illnesses were able to be contained because they made people very ill before they got infectious.

No one goes to work with a mild case of Ebola.

Re: 'Pandemic ventilator' could offer solution in potential 'worst case' scenario

#53

Post by l_davis »

DoreenMichele wrote: post #7
iqster wrote: post #3

Earlier quoted context omitted.

The key insight that made me want to post this is we should actively try to move to an older ventilator design (does bulk of the work, not optimized but easier and simpler). I have encountered this in my life as a software engineer. MFC (Microsoft Foundation Classes) in the mid 90s was hard to grok .. you had this huge book by Jeff Prosise to absorb. I cracked it when I chanced upon a manual for MFC 1.0. It was super…

There are people in the world who live with very serious lung issues who do home management daily in order to survive. Non-mechanical lung clearance methods are a part of their daily routine. I've left some comments here on the possibility of doing lung clearance in the absence of sufficient numbers of ventilators: https://news.ycombinator.com/item?id=22640905 I don't really care to argue it with anyone. Please go fi…

I just saw an interview with an Italian physician where he briefly mentioned therapies for the lung before things got to the stage where ventilators were needed: https://youtu.be/3dmIzW3icRs

It was a brief reference without enough details to be sure that he was referring to clearance methods similar to our the same as what you reference, but it sounds as if this may be part of therapy already. So well in line with what you have described.

Re: 'Pandemic ventilator' could offer solution in potential 'worst case' scenario

#54

Post by baxtr »

war1025 wrote: post #41
pmoleri wrote: post #33

Earlier quoted context omitted.

Interesting, so a little improvement there may lead to less ICU beds and sorter overall time at the hospital. Wonder if that's possible.

My understanding is that's the hope for Chloroquine and the other drugs being rolled out en-masse this week. They have shown enough promise by various limited trials that we are rolling them out nation-wide to see if they actually do help reduce the severity of the virus. If they do, then less hospitalization, and less ICU / ventilator needs. If Chloroquine doesn't end up working, basically we need to find something…

At this stage it is totally unclear if Chloroquine will work. Unfortunately. Because, all the work published so far has not been produced through double-blind studies in randomized trials.

Re: 'Pandemic ventilator' could offer solution in potential 'worst case' scenario

#55

Post by enchiridion »

totalZero wrote: post #45
thornjm wrote: post #35

Earlier quoted context omitted.

Med student here - so I know some of the theory only. The most relevant "law" is Fick's Law of Diffusion ( https://d2jmvrsizmvf4x.cloudfront.net/CTU792sKR2evT2ezizQp_f... ). Doctors can increase diffusion by increasing the partial pressure of oxygen. In a diffuse infection a patient begins to lose both lung area (due to shunting) and the thickness of the diffusion barrier increases (due to inflammation). To help over…

It's too bad we can't put sick people in an airplane, put oxygen masks on them, shut the door, and pressurize the cabin. Like a hospital, but at the airport.

This is a really off the wall idea that might actually work. Can anybody get this idea some lift? Definitely a way for Boeing to get some desperately needed good PR.

Re: 'Pandemic ventilator' could offer solution in potential 'worst case' scenario

#56

Post by DoreenMichele »

l_davis wrote: post #53
DoreenMichele wrote: post #7

Earlier quoted context omitted.

There are people in the world who live with very serious lung issues who do home management daily in order to survive. Non-mechanical lung clearance methods are a part of their daily routine. I've left some comments here on the possibility of doing lung clearance in the absence of sufficient numbers of ventilators: https://news.ycombinator.com/item?id=22640905 I don't really care to argue it with anyone. Please go fi…

I just saw an interview with an Italian physician where he briefly mentioned therapies for the lung before things got to the stage where ventilators were needed: https://youtu.be/3dmIzW3icRs It was a brief reference without enough details to be sure that he was referring to clearance methods similar to our the same as what you reference, but it sounds as if this may be part of therapy already. So well in line with wh…

Thank you for that. I've watched it. It's nice to hear that the Italian doctors are concerned about the issue and trying to stave off use of ventilators.

The interviewer suggested this is a different policy from what is happening in the UK/English-speaking world where they/we are basically begging for more ventilator capacity.

Re: 'Pandemic ventilator' could offer solution in potential 'worst case' scenario

#57

Post by ars »

thornjm wrote: post #35
femto wrote: post #28

What about a "Both Respirator"? [1] In the 1930s polio epidemic there was a shortage of "iron lung" respirators, which were expensive to produce. Edward Both invented a plywood version, which was cheap and easy to produce. A re-purposed car factory then churned them out by the thousand. Is a negative pressure ventilator relevant for COVID-19 treatment? (Any knowledgeable medicos here who can offer a critique?) If so,…

Med student here - so I know some of the theory only. The most relevant "law" is Fick's Law of Diffusion ( https://d2jmvrsizmvf4x.cloudfront.net/CTU792sKR2evT2ezizQp_f... ). Doctors can increase diffusion by increasing the partial pressure of oxygen. In a diffuse infection a patient begins to lose both lung area (due to shunting) and the thickness of the diffusion barrier increases (due to inflammation). To help over…

Could we build a huge hyperbaric building and place all the patients in there?

Would that accomplish the same goal as a ventilator?

Re: 'Pandemic ventilator' could offer solution in potential 'worst case' scenario

#58

Post by DoreenMichele »

totalZero wrote: post #45
thornjm wrote: post #35

Earlier quoted context omitted.

Med student here - so I know some of the theory only. The most relevant "law" is Fick's Law of Diffusion ( https://d2jmvrsizmvf4x.cloudfront.net/CTU792sKR2evT2ezizQp_f... ). Doctors can increase diffusion by increasing the partial pressure of oxygen. In a diffuse infection a patient begins to lose both lung area (due to shunting) and the thickness of the diffusion barrier increases (due to inflammation). To help over…

It's too bad we can't put sick people in an airplane, put oxygen masks on them, shut the door, and pressurize the cabin. Like a hospital, but at the airport.

I imagine oxygen masks in airplanes aren't as sterile as needed.

Planes are horribly cramped and if you filled every seat you would be violating social distancing while filling them with sick people.

I can think of a few other criticisms, but those are probably the most defensible concerns.

Re: 'Pandemic ventilator' could offer solution in potential 'worst case' scenario

#59

Post by bamboozled »

tcbawo wrote: post #30

If you read enough news and Twitter, you will find some really heartbreaking descriptions of the folks on ventilators. For most, this is a Hail Mary attempt with only 50% survival rate. Many will have significant lung damage if they survive. We need more ventilators to be sure. But we desperately need to find ways to halt the progression of runaway lung inflammation that leads to needing a ventilator. Edit: this deve…

I was going to say the same, there seems to be thread after thread about ventilators, but are they a golden ticket to good health ?

Re: 'Pandemic ventilator' could offer solution in potential 'worst case' scenario

#60

Post by enchiridion »

notatoad wrote: post #27
swalsh wrote: post #26

I've been wondering, it seems like people have been setting up systems where multiple patients are connected to a single ventilator (with individual regulators?) If that works, maybe it might be more efficient to solve the supply problem, not by building a million cheap individual ventilitors, but rather a few thousand mega ventilators designed for multiple people.

Putting multiple people on one ventilator requires matching lung capacities, it seems like you can get away with 2-4 people on a ventilator if you really need to and have enough selection of patients to pick matching ones, but more than that wouldn't be feasible. (I'm not a doctor and my only source of knowledge on this is other hacker news comments)

I think that algorithms/ML people will have something to offer here. This essentially changes triage into a hard optimization problem.

IANAD, but it's not just a problem of matching people in the current pool. You also have to plan for incoming patients. Having the parameters of the ventilator not perfectly match the patient likely affects the probability of survival in a smooth way (with in some bounds).

So now the problem becomes minimizing the total death by maximizing the average likelihood of survival. You have to take the patient ventilator parameters into account (tidal volume, lung-compliance, weaning, etc) , as well as information about the distribution of those likely to be sick at the same time (which will change over time based on behavior).

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