
'Pandemic ventilator' could offer solution in potential 'worst case' scenario - iqster
https://www.cbc.ca/news/canada/london/pandemic-ventilator-coronvirus-hospitals-1.5493830
======
tcbawo
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/](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/](https://emcrit.org/pulmcrit/cpap-
covid/)

~~~
notyourday
> For most, this is a Hail Mary attempt with only 50% survival rate.

Non Hail-Mary Ventilators have only a 30% survival rate at 1 year mark:

[https://www.ncbi.nlm.nih.gov/pubmed/8404197](https://www.ncbi.nlm.nih.gov/pubmed/8404197)

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.

~~~
tcbawo
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.

------
femto
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, 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.

[1]
[https://en.wikipedia.org/wiki/Both_respirator](https://en.wikipedia.org/wiki/Both_respirator)

~~~
thornjm
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...](https://d2jmvrsizmvf4x.cloudfront.net/CTU792sKR2evT2ezizQp_ficks-1498D1741D90BC0C7D21.jpg)).
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 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!).

~~~
totalZero
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.

~~~
dschuler
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.

~~~
dorfsmay
What create the air pressure in an airplane? Is it external air speed? Or
compression from the engines?

If the latter, how does it work on airplanes with needless engines?

~~~
dschuler
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.

[0] [https://aerosavvy.com/aircraft-
pressurization/](https://aerosavvy.com/aircraft-pressurization/)

------
theamk
This seems pretty important:

> 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.

~~~
aardvark291
Do intubated patients have to be sedated/anesthetized?

~~~
hello-radio
Very important question, surprised it hasn’t been asked. Yes they do, the gag
reflex is very strong. Source, wife is a nurse.

------
JohnBooty
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 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...)

~~~
jmnicolas
> for the even worse pandemics that are sure to follow

This is the first world pandemic in a hundred year, why should it become
common ?

~~~
ashwoods
I think Climate change, population growth, travel, antimicrobial resistance
are all good candidates in increasing the risk of this happening more often.

~~~
Roark66
Everything else, yes, but climate change? I can't imagine how climate change
can significantly affect probability of next pandemic.

~~~
underwater
Displaced people? Displaced animal populations?

~~~
JohnBooty
Also, warmer temperatures will benefit a lot of diseases in a lot of places.

------
shaneprrlt
Looks like similar portable ventilators already exist in the market:
[https://mfimedical.com/products/allied-healthcare-
epv200-por...](https://mfimedical.com/products/allied-healthcare-
epv200-portable-ventilator-with-assist-control)

~~~
iqster
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.

~~~
DoreenMichele
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](https://news.ycombinator.com/item?id=22640905)

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.

~~~
l_davis
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](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.

~~~
DoreenMichele
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.

~~~
l_davis
And hopefully we can improve our practices based on their experience. Thanks
for bringing it up, I may need to know this as the virus spreads.

------
pontifier
I keep wondering if the Iron Lung is going to make a comeback.

~~~
mirimir
They're for people with paralysis or muscle problems. And they'd be ~useless
for COVID-19.

------
swalsh
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.

~~~
notatoad
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)

~~~
enchiridion
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).

~~~
numpad0
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

~~~
enchiridion
You could have a workable system up in a matter of days.

Supply chains take a long time to spin up.

Why not both?

------
eyeball
Can a sleep apnea machine (cpap, bipap) help if you get it and run into
problems?

~~~
GoodOldNe
Yes, and in theory could be rigged to serve as a very simple ventilator.

------
ta1234567890
Is it possible to kill the virus inside the body, the same way we kill it
outside?

For example, if one could hypothetically spray alcohol everywhere inside
someone's lungs, would that kill the infection?

If so, could a liquid/gas mixture be developed to deliver the right virus-
killer substance directly to the lungs?

Does anyone here know about PFCs-breathing treatments?[0]

0:
[https://www.realclearscience.com/blog/2019/08/15/can_humans_...](https://www.realclearscience.com/blog/2019/08/15/can_humans_breathe_liquid.html)

~~~
adrianN
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.

