
A Novel Mechanical Ventilator Designed for Mass Scale Production - cozzyd
https://arxiv.org/abs/2003.10405
======
ineedasername
Why do we need more designs? We have designs. We need more production. If we
need simpler designs, brush off the proven designs for 40 year old emergency
field medicine ventilators and manufacture them. To paraphrase, designs are
easy; manufacturing is hard. Stop tossing around unproven designs that are
unlikely to roll off the assembly line any time in the next few months and
focus on getting current manufacturers anything _they_ need to scale existing
production. It's not like there aren't simpler, emergency-ready rapid
deployment models already on the market: use them! [0]

[0] [http://www.alliedhpi.com/mcv.htm](http://www.alliedhpi.com/mcv.htm)

~~~
BooneJS
The US has become engineering/design while manufacturing is overseas. Broad
stereotype, but I hope this is an opportunity for the US to recognize that
manufacturing may actually be an issue of national sovereignty.

~~~
Dahoon
This wont change in a capitalist society. The only ways to fix this that have
a chance to actually work that I can think off is 1) Americans work for as low
wages as workers in China to compete or 2) non-capitalism. I would love to
learn of any other ways but this has been discussed by people way smarter than
me for ages and I have seen no other solutions that wouldn't sink the US
economy or cause a revolution.

~~~
nutjob2
You seemed to have missed the option that has been driving economic growth for
centuries: improved worker productivity through improved technology and
methods. A machine can work cheaper and faster than any Chinese worker.
Eliminating work is even more efficient than that.

So basically work smarter than harder or cheaper. The way to compete with the
Chinese is through better ideas.

~~~
varjag
That's the theory we heard since 1980s: then Japanese robots will run over
everyone. In practice however, you have Chinese workers instead. Outside some
very high volume, certain simplicity manufacturing processes it's still mostly
manual labor on assembly line.

~~~
nutjob2
Yes manual labor is used when it makes economic sense and automation is the
same. Robots did indeed take over many tasks, but people still exist and still
want to work so they do stuff too.

The idea that automation means people can't or don't work is a fallicy.

------
zackbloom
We are working on a version of this which does not require any electronics:
[https://twitter.com/zackbloom/status/1242156904782139395?s=2...](https://twitter.com/zackbloom/status/1242156904782139395?s=20)

It uses fluid dynamics rather than a sensor system, simplifying manufacture at
scale.

~~~
chemeng
Nice idea, better approach than I've seen popping up everywhere and clearly
meant to be an emergency only device. I'm sure everyone has made clear how
complicated and dangerous proper ventilation care is. I don't have time to get
involved at the moment even though I would love to (expecting a newborn any
day now), but a few thoughts.

\- Consider the failure-modes of the device. (If inspiration pressure set
screw is not mechanically fixed and fails open, you will irrevocably damage
the individuals lungs and likely kill them. Similarly, exhalation pressure
drop could collapse alveoli and suffocate them). Could also put pressure
relief/vacuum break valves on the device, but hard to do accurately and
cheaply at small pressure ranges.

\- Fail indication. Need indicators in the field to understand whether device
is functioning as designed or not. Particularly with high PEEP settings,
visual indications of respiration are pretty much non-existent and no way to
tell if pressures are causing barotrauma.

\- You may want to include guidelines for proper air supply intended for this
device as well. Modern ventilation systems have fail-over and redundancy for
all critical aspects (electricity, oxygen source, pressure regulation, etc)
for respiration. This may be done at the device (taking feeds from multiple
continuous supplies) or in the oxygen supply system (multiple compressors
connected to a header system, high volume compressed oxygen tank etc).

~~~
gridlockd
> If inspiration pressure set screw is not mechanically fixed and fails open,
> you will irrevocably damage the individuals lungs and likely kill them.
> Similarly, exhalation pressure drop could collapse alveoli and suffocate
> them

Seems like a worthwhile risk to take on a patient that is going to die within
minutes of going off a ventilator that is needed for a patient with a better
chance of survival.

Unfortunately, that's a common scenario playing out in Italy right now.

------
adammunich
I have been building something very similar to this! We have someone working
on the controller PCB right now, and I am waiting for a few parts to arrive
Friday so I can finish the proof of concept. Once the bugs are hammered out we
will publish the design and build instructions on civilpedia.

I can say for sure, the solenoid valves specified here in this paper are too
small to work well enough. This problem has slowed our progress down by a
week.

If anyone has questions please ask them here.

~~~
justinclift
As an aside, your adammunich.com website just displays a "Please click the
allow button to show you're not a robot" message. With no Allow button
anywhere.

With variations on it (but same problem) with each page load.

Capture fail, or joke website?

~~~
jshevek
Worse, I'm getting a pop-up requesting I allow notifications. No, thank you.
It seems that if I don't allow notifications, I can't view the site - and I'll
keep getting the pop-up. This is one of the more intrusive and off putting
experiences I've had on the first time load of a site.

Edit: After clicking "Block notifications" about 10 times, and being
redirected to a different "redfundchicken" address each time, I finally end on
skyprize22.live, an obvious scam site.

I believe adammunich.com redirects to a scam site.

------
helsinkiandrew
As many have said it seems everyone is creating designs for ventilators, but
few are producing large numbers that are being used.

But I'd guess that 99% of the effort required to create a ventilator is not
the design of the mechanism pumping air into lungs but guaranteeing it is
reliable, maintainable, easy to use, is hygienic and can be cleaned safely,
obeys regulations and manufactured.

It doesn't matter if there's a crisis on or not - hospitals will get sued if
your Heath Robinson style ventilator breaks and kills a person, however sick
that person is.

~~~
fsh
It is also worth noting that the fatality rate of cases that get artificial
ventilation is about 50 % even in ideal conditions. While it can save a lot of
lifes, keeping the total number of cases low is still absolutely crucial.

~~~
helsinkiandrew
Agreed, It would make seem to make more sense for people to think about how to
make people stay further apart, or designing and creating face masks or other
'gadgets' that stopped the spread of the disease.

~~~
nicoburns
Given that the recommended distance is 2 metres, I thought it might be fun to
provide everyone with a metre stick, and if you can only just touch sticks
then you're the right distance away. + it gives an alternative to the
handshake!

~~~
gvb
If you are an adult, a meter stick is attached to your shoulder - just extend
it.

~~~
nicoburns
Being pedantic, arm lengths vary from ~60cm to ~90cm. So not quite / only if
you're a very large human!

~~~
projektfu
Thankfully, in the US the recommended distance is only 6 feet (1.8m) :)

------
beenBoutIT
Anyone have any idea how different mechanical ventilators are from CPAP
machines? A lot of people given CPAP machines can't tolerate CPAP therapy and
as a result there's a shitload of barely used and unused CPAP machines all
over the US.

~~~
gamedori
The ventilators used for severe cases of COVID run at much higher pressures.

------
anonsubmit2671
Even AvE got into the fabricobbled ventilator prototype business.

[https://youtu.be/N1OFMZDNKvU](https://youtu.be/N1OFMZDNKvU)

[https://youtu.be/t324iJOYoXI](https://youtu.be/t324iJOYoXI)

~~~
hoseja
And it looks rather similar to this one.

------
DoreenMichele
Just as a kind of PSA:

In light of ventilator shortages, I encourage you to look up non invasive
airway clearance methods. These are medically recommended for people with
serious, chronic lung issues. They've been around a long time. I'm not seeing
them get much attention compared to the ventilators.

------
helsinkiandrew
As useful background, here's the UK's Medicines Agency "Specification for
Rapidly Manufactured Ventilator System (RMVS)" that need to be followed before
any hospital would use one of these devices:

[https://www.gov.uk/government/publications/specification-
for...](https://www.gov.uk/government/publications/specification-for-
ventilators-to-be-used-in-uk-hospitals-during-the-coronavirus-
covid-19-outbreak)

------
rkagerer
This paper is 7 pages long and has only 4 diagrams. Here are the testing
videos: [https://tinyurl.com/uurapy3](https://tinyurl.com/uurapy3)

I applaud the initiative, but even for something macgyvered together in a
hurry, I think a more rigorous approach is needed before deploying something
like this en-mass.

------
gridlockd
_" Our design is optimized to permit large sale production in short time and
at a limited cost, relying on off-the-shelf components, readily available
worldwide from hardware suppliers."_

Those shelves, I'm afraid, are going to be empty. Manufacturing is optimized
for "just-in-time" production, not "just-in-case" stockpiling. Perhaps I'm the
wrong person to consult, but I wouldn't know how to procure ample amounts of
"Medical Care Flow Meters" or "Spirometers".

Somebody figure out a way to solve the problem with plastic bags, PET bottles,
outdated smartphones and old PC fans. I've got a strategic stockpile of those
to give away, just like every other nerd on the planet.

------
rapjr9
I've read that one ventilator requirement for COVID-19 is an output filter
that prevents the virus (and other viruses and bacteria) from getting into the
room air. Otherwise a ventilator is pumping virus into the room air which
increases risk for other patients nearby and medical personnel. I'd imagine
that worst case these ventilators might be used in large arena's filled with
beds rather than positive pressure ICU rooms. Maybe HEPA filters for air
purifiers would work? Or HEPA vacuum bags? Or the big filters trucks use for
air intake, I think those were used in some early HEPA air filter devices. Not
sure if they are fine enough filtering to stop a virus though.

------
paulgerhardt
I recently saw the three component ventilator[1] and was immediately
impressed.

No electronics - huge plus for scalability

1-to-N - one ventilator can serve a hundred or more intubated patients - again
a massive boon to scalability and dovetails nicely with the armies approach to
retrofit empty hotel rooms with negative pressure kit.

PEEP and moisture control - this was in the version 2 model

Love the groundswell of new ideas here. Traditional designs were made for
individual patients with and a broken procurement process - these new versions
can address a large volume of patients in a distressed supply chain.

[1] [https://youtu.be/N1OFMZDNKvU](https://youtu.be/N1OFMZDNKvU)

~~~
Yoric
> 1-to-N - one ventilator can serve a hundred or more intubated patients -
> again a massive boon to scalability and dovetails nicely with the armies
> approach to retrofit empty hotel rooms with negative pressure kit.

That's... scary. I seem to remember that each ventilator needs to be tuned to
a patient's pulmonary capacity. Otherwise, you risk either not providing
enough air or exploding the lungs.

~~~
naasking
Couldn't that be handled my modifying the oxygen mixture per patient? My
concern would be contamination between patients on the same system. People are
ventilators are typically immune compromised. The positive pressure helps
avoid this, but I'm not sure it's enough pressure.

------
rogerrethinker
I propose a shared manifold ventilator based on plumbing and pneumatic parts
and pieces. I just wanted to point out that such a device could handle 20 or
more patients at once and uses well-established principles of reliability.
[https://bit.ly/c19ventilator](https://bit.ly/c19ventilator)

------
mariopt
I noticed the "O2 Therapy Humidifier" and other components. How does this
ventilator fares against a AMBU bag ventilator?

Right I'm making an effort to acquire DIY to build a ventilator that squeezes
an AMBU bag. I found it incredible easy to make and scale, total cost around
300 euros/324 USD.

~~~
RobertoG
Maybe you would be interested in this:

[https://www.oxygen.protofy.xyz/](https://www.oxygen.protofy.xyz/)

------
Mvandenbergh
I understand people's needs to do something and if this helps people feel
better I am all in favour of it. The engineer in distress builds.

But this design is missing some fundamental things which makes me wonder if
they've really understood the requirement.

The first is that there is no flow monitoring so no way to adjust tidal
volume. Since this is the most important parameter to adjust and control in
treating ARDS, that lack is worrying.

Their taxonomy of ventilatory modes is wrong.

All the diagrams and text refer to a non-invasive ventilation using a mask but
that is not where the greatest shortage is. There are a lot of BIPAP and CPAP
machines which can be used for that sort of thing.

There is a consistent reference to a PEEP of 5cm which is too low for the
desired use case. I know the design is adjustable but the fact that this is
not acknowledged is again a sign that they may not have understood what is
needed.

There is no blending arrangement for running on an O2/air mix. I don't
understand why they did not add that.

I don't object to this stuff, it's all a bit of fun, but the ventilator
shortage is going to be fixed if it is by combining the resources of idled
factories with mass production capabilities with the knowledge of ventilator
manufacturers.

When we did this in WWII, we did not ask Ford and GM, "Could you build us a
bomber, please?". They collaborated with plane manufacturers to convert their
factories to produce existing designs.

If I was in charge of this effort, here is what I would do:

First, in the near terms, make sure that existing manufacturers have what they
need to boost their own production.

-People who work in aerospace (or F1 racing, of a few other things) for instance have experience in hand assembly of critical components following procedures precisely. This is a better resource to draw on than other manufacturing workers such as auto workers. You could bulk out the assembly teams in existing manufacturers with these people.

-What parts will they soon run out of? If their supply chain can't deliver, what alternatives can be rapidly qualified for use? Valves and sensors could be sourced from non-medical-grade manufacturers, preferably aviation or other safety critical because again - they live in a similar world as far as traceability and quality goes.

In parallel you work on a basic design that meets the requirements of treating
ARDS. You do that using the engineers who design ventilators anyway, together
with supply chain and manufacturing experts from your other industries so that
you design something that the supply chain can either produce or more likely
they can produce sub-assemblies and/or parts.

------
BooneJS
I understand these devices take 2-3 years not reach market. What’s the risk
that some of these devices aren’t effective or too overpowering? Is there a
test harness that can grade these devices?

------
aichi
There is Czech initiative to provide same and being available under Open
Hardware license soon.

[https://www.corovent.eu/](https://www.corovent.eu/)

~~~
RobertoG
Another one:

[https://www.oxygen.protofy.xyz/](https://www.oxygen.protofy.xyz/)

------
killjoywashere
If you have not submitted yet, consider submitting to the DoD Hack-a-Vent
challenge: [https://vulcan-
sof.com/login/ng2/submission?collectionUuid=2...](https://vulcan-
sof.com/login/ng2/submission?collectionUuid=24028d51-267f-4f10-a455-230a13055c12)

------
robomartin
Unbelievable stuffy I keep reading on ventilators. Just unbelievable. If you
want to kill people by the thousands, please continue. The good news is no
medical professional in their right mind would use one of the hot messes so
many are "inventing". Parts from Home Depot? Really?

These are life critical systems designed with serious fault tolerance in mind.
Home Depot parts, randomly sourced solenoids, valves and fucking Arduino's?
Has everyone gone insane?

Here, go read the Wikipedia page on ventilators:

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

Let me highlight a few sections. Like this one:

"Because failure may result in death, mechanical ventilation systems are
classified as life-critical systems, and precautions must be taken to ensure
that they are highly reliable, including their power-supply."

"Mechanical ventilators are therefore carefully designed so that no single
point of failure can endanger the patient. They may have manual backup
mechanisms to enable hand-driven respiration in the absence of power (such as
the mechanical ventilator integrated into an anaesthetic machine). They may
also have safety valves, which open to atmosphere in the absence of power to
act as an anti-suffocation valve for spontaneous breathing of the patient.
Some systems are also equipped with compressed-gas tanks, air compressors or
backup batteries to provide ventilation in case of power failure or defective
gas supplies, and methods to operate or call for help if their mechanisms or
software fail."

I mean, seriously, read that again right now. If you have zero experience in
fault-tolerant design of electronics, mechanics, pneumatic, hydraulic and
software systems, please recognize the dangers of the Dunning-Kruger effect
and stop.

If that wasn't enough, there's this:

"In Canada and the United States, respiratory therapists are responsible for
tuning these settings, while biomedical technologists are responsible for the
maintenance. In the United Kingdom and Europe the management of the patient's
interaction with the ventilator is done by critical care nurses."

In case the point isn't obvious, what this means is that certified
professionals have to operate these devices. They are not going to get
anywhere close to a pile of parts from Home Depot and the local auto repair
shop. They are trained to operate reasonably standardized equipment and expect
form, function and reliability that comes with time-tested, certified and well
proven professionally manufactured equipment.

Want to build something to help? Maybe figure out how to make hospital beds.
My guess is there's far less likelihood of killing people with a frame and a
matress than with a pile of Home Depot parts and an Arduino pretending to be a
ventilator.

Why are these posts even permitted on HN? This is unproductive dangerous
quackery. Nobody is going to invent anything useful. Go help existing
companies stamp out more units of their designs. I'm sure they can use the
help.

~~~
cozzyd
I agree that a well-seasoned ventilator design would be much preferable. The
question is, can we get that? I'm not involved in this effort (I found out
about it through a forwarded email that's being passed around between
physicists), but I suspect that nobody involved has the ability to speed up
medical device manufacturer's production or supply chain. The point of "parts
from Home Depot" is to bypass the likely specialized supply chain that may be
difficult or impossible to scale up.

~~~
robomartin
I don't mean this in a disparaging way. I took a look at the list of authors
and my first thought was "A bunch of physicists without a clue". There is a
massive difference between bolting a bunch of parts together to mass
manufacturing a reliable life-critical device to deploy to hospitals. We
seriously need to stop with these pointless games and throw resources at real
proven designs by real companies with experienced multidisciplinary teams.
Seriously, I don't know how else to say it.

Let me give you an idea of just how stupid it is for a bunch of guys pulling
parts out of Home Depot to decide they are going to make a ventilator for mass
manufacturing:

Elon Musk decided to make ventilators at SpaceX. I've done work there. I know
exactly what capabilities exist at Hawthorne. Let's just say that, compared to
Home Depot, it's a universe apart.

Did he go off to invent them from scratch? No, they had high level engineering
meetings with Medtronic. His opinion is summarized in one comment and one
action. First, among other things, he said, "Impressive team". Next, he bought
1,200 ventilators from China and brought them into the US.

He also recognized you can't Superman ventilators. Not that simple. Not if you
want to keep people alive. Not if you want to get them to market when needed.

There are consequences for allowing our industrial base (I include Europe) to
erode to such an extent that we depend on China for just about everything.
Here's the perfect storm that is going to show us just how stupid our
political class has been for the last 50 years. And somehow everyone is angry
at Trump. Medtronic can't scale their ventilator manufacturing because the
imbeciles going back decades before him were incompetent political actors who
only cared about their own careers and political goals rather than the
interests and needs of a nation. Now we get to pay for it.

Superman does not exist. We might just have to face a reality that will be
cruel punishment for our failings. I hope we learn something by the time this
is over.

~~~
riskneutral
> Here's the perfect storm that is going to show us just how stupid our
> political class has been for the last 50 years.

Doubtful. Once all this blows over the older patterns will resume.

~~~
a9h74j
Known supply-chain vulnerability hasn't transformed the US defense industry.
Search "report on us defense supply chain vulnerability"

