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 development looks very promising for 'sub-intensive' cases -- adapting decathlon masks to provide positive air pressure (to help reinflate lungs) without intubation or leaking contaminated exhaust: https://www.isinnova.it/easy-covid19-eng/. Some emerging theories of pathology suggest that lung function can be increased by reinflating collapsed alveoli with constant pressure:
https://emcrit.org/pulmcrit/cpap-covid/
Incidentally, that's exactly why medical systems to not stockpile ventilators. Under reasonable condition, the number of ventilators closely mirrors the expected number of Hail Mary procedures done at a given time and some spare units.
The links I added in my edit suggests that using non-invasive, constant positive air pressure (C-PAP) with a closed mask could help certain patients from needing intubation and ICU as early (or at all). If this turns out to be the case, this might reduce the overload on the hospital system. They might be attempting it in Italy. Hopefully, it works.
And the survival rate is only 3% to 20% for COVID-19 specifically, based on data from Wuhan, following patients for a month. Long-term mortality will be even less.
Plus you need nurses and doctors to intubate the patient and setup and monitor the actual ventilator. The machine itself is a small part of the equation.
I think the focus on ventilators is somewhat misleading. If you need mechanical ventilation, you're a goner anyway, and your bed and healthcare staff could be better used on someone else. The 'lack' of a machine is just a very visible component.
If this is true, the death toll of Covid-19 is going to be a lot worse than currently indicated, is that right?
The complications of ventilators and whatever lasting damage is caused by the disease itself; will be killing a significant portion of the recovered population, will it not?
Most mortality estimates and forecasts include only deaths directly attributable to the virus. There are many indirect deaths that will be caused by it. Long term lung damage is one of the ways this will happen, probably among the most delayed. Many more deaths will happen because hospitals that are operating at capacity won't have the resources to prevent other deaths that they normally stop, or will have to stop non-critical treatments in ways that will reduce patients' life expectancies. I live in Madrid and know a neurologist that has stopped any intervention that can't be delayed.
Actually Italy counts everyone who dies who has COVID19 as a COVID19 death. This does not include future death by long term after effects but it includes more then what e.g. was included in China, which is part of why the death rate is so much higher in Italy (the other part is in average people are much older in Italy then China).
Also put that in context with the fact that Italy reported that the majority of death is with people which have preexisting conditions/other illnesses.
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 that does, because that is the only feasible way to get us out of this mess. We have shuttered the economy because the healthcare system can't handle so many people needing hospitalization. The only scalable way around that is to find a treatment that significantly lowers the need for hospitalization.
" The only scalable way around that is to find a treatment that significantly lowers the need for hospitalization."
This isn't quite true.
Taiwan, Singapore and S. Korea have not 'shut-down' their economy, and they have tamed the problem.
Massive and widespread testing, assertive isolation and tracking of individuals who test positive can work on some level.
Combined with some other things like maybe keeping 'big gatherings' or 'social gatherings down', requiring people to wear masks on trains, busses, airplanes - we may be able to reasonably suppress Corona without a medical discovery.
Published literature suggests that surgical masks reduce the amount of escaped virus by 3x. If we can make enough masks, we need everyone to start wearing them. They should be handing them out at grocery stores!
Hydroxychloroquine is what's actually mentioned in at least some of the stories. It is supposed to be much less hepatotoxic. Though the point that neither may work stands.
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.
I bet you could find five or more recent peer reviewed studies on it working quite well.
You realize most science isn’t double blind, right? I’ll grant you thats it a gold standard for long term drug use but saying “totally unclear it will work” is absurd.
And we still do useful work relying on simple correlations, r values, peer review. We have all that now supporting some of these drugs. In a crisis and last resort that seems like plenty.
They find hundreds of relevant-sounding papers, registered trials, and guidelines, but almost no data beyond one in vitro study to back it up. That one study is promising--and it'll be great to see what the trials show--but the road from "works in a dish" to "drugs for all" is a long, bumpy one at the best of times.
We need to do this right so that if it works, we know that it works, and if it doesn't, we can make informed decisions to do something else.
>You realize most science isn’t double blind, right?
That's nice, but most science isn't reproducible at scale. We need to do a drug trial for SARS-CoV-2 because we need to 1)establish efficacy and 2) establish safety for this drug in this disease. There are a significant amount of adverse drug effects in individual infectious diseases. Jarisch–Herxheimer reaction when treating syphilis, epstein-Barr mononucleosis and penicillin; Reye syndrome with Aspirin and influenza. The list is long here. We want the most vetted research possible because even if the chance of death is less than half a percent, half a percent of what seems like is going to be over a million is going to be in the tens of thousands here.
"Peer reviewed" is a better assurance of the accuracy of the observation. It can't do anything about the fact that evidence for current treatment attempts is purely based on observations that could be the result of hope and the placebo effect.
Furthermore, there is a difference between observations of aggregate numbers, like the number of people on ventilators and their survival rate, and small numbers of uncontrolled drug interventions where there are obvious ways for the data to be deceiving. Not all observed data has the same reliability.
My understanding is that it's part of the official Chinese treatment regimen. That seems like good enough authority to me given they've been through the worst of it so far.
No, building a ventilator is like building an engine because you need to go to the store - you're missing so much of the solution to the problem. I've also posted before [1] on why they are a terrible idea to waste time on "designing".
That said, ventilators I believe are already a solved problem for COVID. We have tens of thousands in the strategic stockpile, and production capacity is being ramped up hopefully to meet demand. This is exactly how these stockpiles were intended to work.
I don't these stockpiles exist. At least the order by the German government seems only to be fulfilled by new production [2] and other governments might have to queue due to few manufacturers [3]. I don't know if in market forces and IP worked to our good here. I think current design challenges could at least channel random good ideas wrt ventilator designs. [1]
It absolutely isnt a solved problems, most countries affected by the pandemic do not manufacture the ventilators and have like a 10x shortage compared to what's needed to incubate everyone who will be sick. (Obviously depending on how bad it gets).
The struggle to ramp up production is a desperate one, and this is one case where IP is killing people - there are several consortia in the UK that are ready to manufacture, but need a certified design they could build.
> potential needs is in the millions and the current ventilator count is 100,000
There are only 96,596 ICU hospital beds in the United States according to the AHA. As I said, ventilators are already solved to the point that something else is the bottleneck.
People are hearing about Italy running out of ventilators and choosing which patients to save. Since we don't want that scenario we are looking to have enough ventilators.
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, couldn't they be churned out by the thousand in a short space of time (ie. days)? My understanding is that the tooling is comparable to that used to produce a kitchen cabinet. They can even be manually operated in the absence of a motor or control system.
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 overcome this you want to increase pressure and oxygen concentration.
An iron lung helps ease the work of breathing by reducing thoracic pressure and thus creates a larger pressure gradient for inspiration. However, it does not cause an absolute partial pressure of oxygen change compared to the atmosphere.
Unfortunately, to bind haemoglobin in physiological lung conditions we need partial pressure of oxygen around 100mmHg. My guess is that an iron lung does not help increase the partial pressure of oxygen so it will do little but ease the work of breathing (which is better than nothing!).
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.
I don't know much about it, but I think it's usually provided by pressurized bleed air from the engines.
There are cabin pressurization test carts for use on the ground, as well as start carts to provide bleed air for starting engines, and bleed air in turn can supply cabin pressurization in flight, although this probably requires some rigging on the ground.
Interestingly, they switched to electric compressors for the 787 [0] because those no longer provide bleed air from/to each engine to simplify the plumbing.
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.
Theoretically, yes. The Environmental Control Systems on all our commercial airplanes positively charge the airflow at a nominal Delta P of 9.8 psi and have HEPA filtration down to 10µm, but at $100M+ per 737 MAX, delivery customers highly frowning upon such a practice and not being able to deliver them as a "New" airplanes after contamination, highly unlikely.
The A380 fleet is starting to retire prematurely only after 10 short years of service due to lack of profitability and demand due to COVID-19. Those huge retired Behemoths could serve very well as a quarantine base in remote locations.
Hello! I'm just a medical student myself, but here's my take on this:
Your lungs operate on the principle of differential pressure. During normal breathing, hen the pressure inside your lungs becomes less than that of the surrounding atmosphere, air rushes in to normalize and fill it until they are again equal pressures. Gradually increasing or decreasing the pressure of the atmosphere around you (as on a plane or while diving) does not change the physical difficulty of breathing. It may slightly alter the diffusion coefficients of gasses passing through the membranes in your lungs, but this effect is mild at the pressures you could attain in an aircraft hull (and toxic at higher pressures! [0]).
For this reason, you'll notice in images of people in iron lungs, their heads are outside of the device. This allows those who cannot create negative pressure (due to damaged or paralyzed diaphragms or ribcage muscles) to follow a different path. The pressure outside of their chest becomes lower than that experienced in their lungs, forcing an expansion; in order to breath out, the pressure in the chamber is increased. In an aircraft hull a person's lungs/trachea/mouth would be exposed to the same pressure as their chests.
This of course does bring up the very valid question: What happened to all of the iron lungs after the decline of Polio?
EDIT: Oh I realize I didn't fully discuss the possibility of using a plane as a hyperbaric chamber [1]. The constraints around this concept also rule it somewhere outside of what I would consider feasible. Aircraft typically use bottled oxygen (I believe the 737M does) or a chemical generator, neither of which can produce continuous oxygen or fill the entire plane with it to high levels [2]. If you were able to outfit patients with individual tanks (which would also have to accommodate for increased pressure), the gains seem mild at best compared to 100% O2 in a hospital setting. Fick's Law for the membranes in your lungs is roughly
Rate of diffusion = (Area * Solubility of gas * concentration gradient) / (membrane thickness * sqrt(molecular weight of solute))
The factor that increasing pressure would modify is the solubility of the gas, which according to Henry's Law [4] is
directly proportional to pressure. At absolute best (100% O2 on the plane at 2atm), you could expect to get 2x improvement in blood oxygen saturation. Unfortunately I don't believe the breathing issues that are being described can be overcome by this strategy. It's an incredibly creative concept though!
The aircraft could fly empty to arrive at airports near outbreak areas, then be used as a hospital after it arrives and the pilot disembarks. Once the hospitals in the area gain some ability to control the outbreak, remaining patients can be sent to local hospitals, the aircraft can be decontaminated and left to sit for some period of time, and the aircraft can move to the next region.
If it were truly necessary, you could also set up an airtight septum to separate the contaminated part of the aircraft from the front part that includes the cockpit. There is an aft door (as well as emergency exits) that can be used to access the rear of the aircraft.
We public know what the issues was. Apart from MCAS risk, I think the planes would be mostly safe for these one-off missions.
It just has to fly handful times, from Boeing park lots to a depot in a desert and back from frontline after months/years. They are supposed to be clean before deployment, and can be cleaned by medical professionals before reflying. Or maybe cracks would develop and can't be manned after anyway, either way not much there is in terms of infection risks.
Covid19 is not the only germs they will be carrying. The people who are the sickest are the ones that most need oxygen supplementation. Reports suggest that most of the people dying from it already have other serious medical conditions.
This is exactly how antibiotic resistant infections get bred. You would be creating a melting pot of horribleness and cross-contamination and god-knows-what would come spewing out of it.
I've been wondering whether CPR breaths could be used in extremis. It'd be pretty hellish, but I could imagine doing this for 24-36 hours if it was the only option to save my wife, for example.
There's both partial pressure (O2 concentration and overall atmospheric pressure) and repiratory function. Forced-air respirators (most current models) and iron lungs (operating with partial vacuum) both address this mechanism.
At a certain point, external oxygenation (heart-lung machine) may be more appropriate. But hyperbaric chamber, elevated supplemental oxygen, and repiratory assistance might be an approach.
> While the standard for a conventional ventilator uses a mask or nose tubes and follows current guidelines, the pandemic ventilator is at a standard from the 1970s and requires a patient be intubated, the medical word used to describe putting a tube through someone's mouth and into their airway.
Do intubated patients need more attention from nurses/doctors? It certainly sounds harder then putting on the mask.
Yes. You need usually an ED physician or CCU physician. We get taught how to do it in medical school, but that doesn't mean we're proficient. You need an ICU nurse level of skill to monitor the vent and it's an intense process. There are some drugs you can give to attenuate oral and esophageal secretions. Usually there's a significant amount of suctioning involved.
How it compares to managing a mask day to day? I honestly don't know, that's something an ICU nurse/respiratory therapist would know.
Yes. Without proper cleaning, it is a highway for infection. You also need to maintain a balance of blood oxygen and carbon dioxide. Many of these people require supplemental oxygen. So, you have to control respiration rate and oxygen mix. This would be a very bad to try yourself.
One of the other big issues hitting during this crisis beyond simple availability of ventilation machines is the number of nurses and doctors available to monitor and care for patients when they have to go to the ICU. Ideally the machine would be both cheap and easy to produce and require less qualified monitoring.
If we get way more machines but those machines require a lot of intensive monitoring we could wind up with plenty of machines but not making any progress on the fatality rate.
IANAD, but my understanding is that minimal sedation leads to better outcomes, so patients may be partially awake some of the time, varying the dose of propofol and fentanyl. During these low-sedation times they may do breathing trials to try to wean off the ventilator. (They called this "sedation vacation" in the ICU I visited.) Not sure if this is how COVID victims will be treated, though.
"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 COVID-19 will be staggering, but it's somewhat mild as far as possible pandemic scenarios go. Imagine if it had mortality rates comparable to ebola, TB, etc.
When this blows over, the world should be better prepared for the next one, with better procedures.... emergency stockpiles of ventilators, masks, etc.
(Or at least we will be... until we go ten years without a pandemic... and all those stockpiles get liquidated in order to help some politician to balance a budget or whatever...)
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.
A mild-onset-long-latency-ultimately-debilitating disease with high transmissibility might be a worst case. It could spread widely, evade detection, and not trigger immediate concern.
HIV/AIDS, several hepatitis variants, and tuberculosis approach thiS, as might syphilis in earlier times.
Kyle Harper's The Fate of Rome explores the notion that new diseases don't simply emerge, but co-evolve with their host populations and environments. The implications are disturbing.
I think Climate change, population growth, travel, antimicrobial resistance are all good candidates in increasing the risk of this happening more often.
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 simple and down to the essentials. All the fancy stuff they added from 1.0 to 5.0 was icing and made things complex.
I think people who are actually working on ventilators should seriously consider going for a simpler design .. it might be this or might be something else. The person in this article also said he is happy to give the design away.
I think if the Malaria Med+Antibiotics treatment from the French study don't work (we'll know in about a week I think), we need to move to a war footing and start producing ventilators. My back of the envelope math has scared the crap out of me (best case 500K Canadians dead, worse case 3 million).
I really hope someone who can make a difference sees this.
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:
I don't really care to argue it with anyone. Please go find somewhere else to vent your spleen about how stressful this is. My recommendation is and has always been: If you have no other option and you are going to die because of it, you can try this.
That's it. That's my entire point. All the accusations that I'm up to something nefarious and dangerous are completely unfounded.
Take care. Try to not stress too much. Thank you for trying to be part of the solution.
And here I thought I was an idiot for wondering if just having people sleep in a position to help fluid drain from their lungs would help. I guess I wasn't so far off.
More prosaically, I think I've reduced durations of basic colds by deliberately coughing early on. Needs more experiments, but as you said side effects are minimal, so you may as well try. I'm starting to think this is a family of life hacks that should be much more widely known.
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.
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.
Thank you for bringing these techniques, verified by actual use, to our attention. I can well believe that, in a world where good first options are the norm, fallbacks may not be widely known. Even if they are insufficient in the worst cases, thay are still worth consideration.
Best wishes to you and your family in these trying times.
You persist in attacking a straw man in direct reply to a post that explicitly disclaims it. Quit pattern matching on "non-doctor comments on medical issue" and look at what she's actually saying.
> I think if the Malaria Med+Antibiotics treatment from the French study don't work (we'll know in about a week I think), we need to move to a war footing and start producing ventilators. My back of the envelope math has scared the crap out of me (best case 500K Canadians dead, worse case 3 million).
We should assume they won't work. War footing time is now.
It is going to be bad. People are still out and about touching everything then touching their face. I saw one lady today leave Walmart then upon getting to her car put all the groceries in the back then grabs a bag of chips and pops them open and starts eating them just moments after handling her shopping cart. Are people not seeing the videos of the people dying or on ventilators struggling for oxygen? Mean while the number of people around here being infected is slowly getting larger and larger each day. I have been telling people wash your hands before you do anything. They say social distancing, but that is the dumbest thing if you ask me because people seem to think that means if I am out and about and I stay 3 feet away from other people I will not get sick. What it really means is when you are out and about you need to not be in contact with other people or objects that other people may come in contact with. If you do come in contact with an object another person may have come in contact with, you may be exposed to the virus. Any time you touch an object others may have touched wash your hands. Social Distancing= Distancing from People and Any Objects they may have Touched. The other huge thing is do not touch your face, if you must it should only be after you thoroughly washed your hands. I am a home care aide and look after hundreds of elderly. This is getting crazy and feels as if we are just about to blow up in numbers. I wish people would take this more seriously. Vancouver Island is starting to take off. Good luck every body
There's also another model MCV200, 10 "in stock," $5,091.71 each.
Anyone got $95 grand lying around?
Edit: btw, in 2006/2008, the AARC recommended to the White House and/or HHS to buy 10k additional ventilators for the SNS, but the govt failed to do so. Now, the US, is for lack of better adjectives, royally-proper fucked.
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).
okay so how long does it take to certify that and how different is it going to be compared to just have General Motors produce under license on existing designs
We don't have anything that kills the virus but doesn't kill living tissue as well. Pouring alcohol over your hands is fine because skin evolved to protect you from a harsh environment. Pouring alcohol over mucous membranes is a very bad idea.
Edit: this development looks very promising for 'sub-intensive' cases -- adapting decathlon masks to provide positive air pressure (to help reinflate lungs) without intubation or leaking contaminated exhaust: https://www.isinnova.it/easy-covid19-eng/. Some emerging theories of pathology suggest that lung function can be increased by reinflating collapsed alveoli with constant pressure: https://emcrit.org/pulmcrit/cpap-covid/