
Open-source “pandemic ventilator” - ericb
https://www.instructables.com/id/The-Pandemic-Ventilator/
======
7a1c9427
The naiveté being expressed in the comments here and as the premise behind the
ventilator is astounding. I though I would share some information to put
things in perspective:

\- If you are unwell enough to need a ventilator then the ventilator itself is
going to the least of your worries. You will need the drugs and expertise to
care for you. The current respiratory illnesses going around aren’t like polio
and the iron lungs where all you need is help breathing.

\- If you can sort the above to have any hope of survival you need a “modern”
ventilator that can operate in way that this simple homebrew device is
physically not capable of offering. Most of the improvement in caring for
people with ARDS is based upon careful and tight control of ventilatory
parameters to prevent secondary lung injury.

\- Modern ventilators have a price tag of if you have to ask you can’t afford
it.

So in summary this is a nice build but serves no practical purpose.

~~~
prostheticvamp
This is correct.

Particularly the “if you are unwell enough to need the vent, the vent is the
least of Your worries.”

The vent keeps you oxygenating while we address the (usually multiple,
overlapping and interacting) severe issues that led to you needing the vent.
This is ICU-level care. A vent without an ICU doc and appropriate medications
(and ideally a resp tech and a nurse) might as well be an origami crane.

Hospitals will run out of one those other things, on average, before they run
out of vents.

~~~
jfim
Thanks for chiming in.

If I understand what you're saying correctly, you're saying that in the case
where one would be so sick as to require a ventilator, they'd be in a
situation where the ventilator only buys more time before the condition
worsens, but doesn't actually address the root cause of the problem. As such,
even if someone were to find a hospital-grade ventilator that fell off the
back of a truck and managed to properly use it, the non-ventilator care is
what makes the difference in outcome, not the ventilator itself.

Is that correct?

~~~
prostheticvamp
Not quite. The vent process itself requires careful management to provide net
benefit (eg, controlling the level of sedation, avoiding secondary lung
injury).

So while the non-vent care is what makes the difference, improper use of a
hospital grade vent is more likely to do harm than good. Eg, Vents frequently
clog. It requires a little bit of clinical experience to recognize that as
what’s happening, and intervene appropriately. It’s not a complicated thing,
and anyone that’s worked the ICU for a bit can recognize and handle it, but it
would be a killer in the hands of a layman, and it’s only one out of a hundred
issues.

Additionally, I’d hesitate to describe it as buying time, because that implies
a linear sequence. Let’s say you have condition X that implies oxygenation and
blood perfusion. Vent manages oxygenation while I work on maintaining
perfusion and the underlying X, but if all I have is the vent, the patient
will still die from lack of perfusion. The vent didn’t buy any additional
time, it just closed off one route of death temporarily.

When a patient needs a vent, it’s very rare that the vent is the only route to
death that is being proceeded along.

This was pretty stream of consciousness, but I’m typing in the bathroom, so
... sorry if it’s a bit of a mess.

~~~
malandrew
How do you maintain perfusion?

~~~
prostheticvamp
It depends on the precise mechanism of failure, but generally a combination of
fluids of various concentrations and extravasation characteristics, and drugs
that either cause the constriction of blood vessels, or increased heart
pumping strength, or both (these often pop up in popular media as “pressors”).

------
Confiks
Here [1] is another interesting low-cost version of ventilator. It's an
immersion two-phase continuous positive airway pressure (CPAP) device, of
which all the parts are printable. The patient still needs to be able to
initiate breaths themselves, but it will cost a lot less energy to breath.

Combine it with a (admittedly lot harder to make) homemade pressure swing
adsorbtion system that delivers high-oxygen air, using zeolite sieves and
alternating pressure [2].

[1]
[https://www.youtube.com/watch?v=CHiRTMQCf1Y](https://www.youtube.com/watch?v=CHiRTMQCf1Y)

[2]
[https://www.youtube.com/watch?v=ylj4oOnlIY0](https://www.youtube.com/watch?v=ylj4oOnlIY0)

~~~
Gravityloss
Not a medical professional but the CPAP route sounds more promising to me.
Simpler, less risk.

What about just oxygen bottles or oxygen enrichment? They have their own
dangers though.

~~~
kortex
I would imagine in a situation where you need ersatz CPAP, bottled oxygen is
harder to come by and/or less affordable.

PSA oxygen generators are simple to construct and provide continuous oxygen as
long as you power them.

------
zelienople
In the initial studies out of Wuhan, about 15% of Covid-19 patients required
critical care. These patients were treated with a ventilator, antiviral
medications, and the support of an ICU. The mortality rate was about 2-3%.

This scenario does not scale very well in a pandemic because there are simply
not enough resources to provide this level of care to those who need it.

There are about 5000 ventilators in Canada, for example, meaning that the
country can effectively treat, at most, about 33,000 cases, assuming that the
15% ratio of total sick patients to those requiring critical care holds true.

The mortality figures that we have so far are based upon everyone who needs it
receiving critical care. As the pandemic scales, the mortality figures could
easily reach 15% as the number of sick greatly exceeds the capacity to treat
them.

This project shows, therefore, that someone understands the real problem of
Covid-19 and is attempting to solve it.

I'll take a plywood ventilator over no ventilator any day of the week, even
without the other resources of an ICU.

I suspect a jet ventilator would be easier to build and more effective under
the circumstances, so maybe that should be version 2.

------
Delariva
While well intentioned, I really don’t think this should be built by anyone
for use on an actual patient. As mentioned in other posts, mechanical
ventilation is only part of “life support” with a typical ICU admission for
ARDS requiring: establishing peripheral IVs, central venous line (giant IV in
neck to heart placed under sterile conditions), intubation (Which requires
expertise and advanced equipment), oxygen (lots in terms of liters),
medications (inotropes, sedatives, paralytics, nutritional support,
bronchodilators, etc.) urine/foley catheter, the ability to suction the
airway, nasogastric tube, bedside monitoring (arterial line, capnography, etc)
potentially chest tube, dedicated bedside staff and access to X-rays and CT,
blood work (particularly Arterial blood gas analysis for mech vent) to guide
process, specialists for consults and this doesn’t include what else is needed
when other systems fails (as is this case in ARDS: kidneys can fail which
needs dialysis). Also, mechanical ventilation needs heat and humidification
(requiring about 1L or sterile water every 12-24 hours) so you don’t jam up
the airways with a mucus plug; so you need a temperature probe on the vent
circuit as well.

Also, mechanical ventilation is an aerosol generating medical procedure and
even with the proper filters can still expose people in the surrounding meter
or so to a virus.

There’s also a great little unit that was used in Vietnam war called the Bird
after the inventor - simple and clever and should be able to be cheaply
manufactured or even potentially DIY but I think it required a high pressure
gas source to drive the tidal volume.

~~~
Diederich
Thanks for a detailed, well considered response.

> intubation

Do you think a laryngeal mask airway would useful in these kinds of
situations?

------
DoreenMichele
I get that people are scared and trying to reassure themselves. This is really
not the way to go.

I don't know how to foster some kind of constructive discussion of preventive
best practices or whatever, but medical devices that aren't cleaned properly
and kept sterile cause horrifying and deadly infections regularly. This even
happens in hospital settings.

This article doesn't even seem to be bothering to address the need to
disinfect everything. With lung issues, that's a not unimportant detail.

------
lukevp
This is maybe unrelated, but is there a diy version of a mask for filtering
air? What I want is a full face mask with filtered air for working on cars,
around solvents and paints, and such, but the masks usually require the force
of your own lungs to pull the air through the filter and through a 1 way valve
when you exhale. I want something battery powered that does the air filtering.
What am I looking for and how much does this cost? And would something like
this be usable for what I had envisioned when I read “pandemic ventilator”
which would be like something you could wear while you were out and about and
it would filter everything you’re breathing.

~~~
viklove
What would the battery be for?

~~~
lukevp
To power some type of air pressurization system so that it’s not my lungs that
are pressurizing the air, this is because filtering the air requires
additional pressure to force the air through the filter.

------
Cass
If it comes to that, you can also share a conventional ventilator between two
people. It's an ugly hack, because you have to use the same settings on both
patients, so it doesn't allow for the sort of precise control you want if
you're managing ARDS, but probably still a better solution than using a home-
made ventilator.

It was successfully used when the ER ran out of ventilators in the wake of the
Vegas shooting[1], but is probably better used in the sort of emergency where
you just need to win a few hours' time than a sustained crisis.

1: [https://epmonthly.com/article/not-heroes-wear-capes-one-
las-...](https://epmonthly.com/article/not-heroes-wear-capes-one-las-vegas-ed-
saved-hundreds-lives-worst-mass-shooting-u-s-history/)

------
Altjira
I live in Vietnam. They do not have anywhere near the capacity needed to deal
with ventilating. In HCM with a population of 9 million the largest hospital,
Cho Ray, has 1000 beds ready but only 200 intensive, and 20 ventilators. Even
fewer ECMO kits. Its one of the best equipped hospitals in the country. If
things get bad, thousands will be sent home, thousands will die. Currently we
are working on ways to repurpose industrial bottles and work with local gas
and liquid oxygen manufacturers to come up with stop gap solutions to get
oxygen to several thousand people at once, across the whole city, using
existing propane gas distribution systems and grab app for monitoring and
delivery. This is our ONLY option. For those pointing out how dangerous
homemade ventilators and oxy kits can be, assume that WE KNOW that already,
and that we wouldnt be looking at this unless it looked like there being no
other option. We have under 700 large hospitals, but over 35,000 local
clinics, many of which are run by local doctors with training and their own
oxygen gear. We dont need them to be perfect, we dont need them to last
forever, we just need them to work. If they save more than they harm, when
people without them would die anyway, thats a meaningful impact. And yes, Viet
doctors and government will use WHATEVER they need to get sh*t done and save
lives.

------
sitkack
The number one issue with ventilators is bacteria and second is if they fail
you die.

This absolutely the measure of last resort, but as the pandemic spreads there
will be ventilator shortages and people that don’t have to die will die.

------
jaekwon
Thank you, creating a directory here:
[https://github.com/wikirona/wikirona/blob/master/oxygen/READ...](https://github.com/wikirona/wikirona/blob/master/oxygen/README.md)

------
kortex
Wow, some of the comments/downvotes here are astounding, especially for a
group of people priding themselves on problem solving and FOSS.

Obviously, a plywood vent isn't hygenic. But R&D isn't a zero to one jump, you
gotta start somewhere. Often it's that first spark of "wait this is something
that needn't be only the domain of hospital gear companies" to inspire others
to work on the problem.

Sure, a vent alone is probably not gonna improve your chance of living without
the right care, but if there was a set of condensed instructions and WHO
essential meds, yeah, maybe you have a shot.

This is also more about developing countries / rolling pandemics / CME-
Carrington event than cov19 alone. Tell me, when was the last time you saw a
panic in a trace/log to the effect of, "This should never occur." ? No one
wants to be in the situation to need backups. This is part of a backup plan.

The defeatism in this thread already makes me want to go and improve the
design. For one, you can get pneumatic valves which take the place of 2 or
maybe even 3 of the valves on the machine.

------
greesil
I was thinking that with the shortage of antiviral masks in the consumer
space, if there was a way to diy one. Extra points if it involves a 3d
printer.

~~~
JshWright
Masks are not for keeping healthy people safe from pathogens. They are for
keeping sick people from spreading virus laden droplets when they
cough/sneeze.

A mask that's capable of keeping a virus out is a a) much more expensive than
a typical surgical mask, b) easy to wear improperly, negating its usefulness,
and c) only good for a limited time before needing to be thrown out.

~~~
mike_d
> Masks are not for keeping healthy people safe from pathogens

All the doctors and nurses having to wear masks will be so relieved to hear
this.

But seriously the advice of not wearing N95 masks when you are healthy is not
because they are ineffective, but because they are trying to discourage
hoarding. Even current CDC recommendations for healthcare workers suggest N95
masks for only patient intake and direct care, with all others wearing
surgical masks to help protect the supply of N95s.

~~~
JshWright
This discussion wasn't targeted at healthcare workers, and I never said N95
masks weren't effective (when worn properly). N95's are the type of mask I'm
referring to in the second half of my comment. Worn properly, they are an
essential piece of PPE.

The difference is, healthcare workers are trained in the use of N95 masks,
undergo annual fit testing, etc.

~~~
mike_d
You might be interested in this [1] training video showing that proper use of
N95 masks is basically how people put them on.

Additionally - this [2] new search shows that if 80% of uninfected persons
wore a mask for a few days, the pandemic would be over.

1\.
[https://www.youtube.com/watch?v=zoxpvDVo_NI](https://www.youtube.com/watch?v=zoxpvDVo_NI)

2\.
[https://www.ncbi.nlm.nih.gov/pubmed/30229968](https://www.ncbi.nlm.nih.gov/pubmed/30229968).

------
arcticbull
Very cool project, and a fun article, though I can't help feel like this thing
is more likely to kill you than nCoV-19. It's got a mortality rate of 0.7%
(same order of magnitude as the garden variety flu) and I'm betting there's a
much more than 0.7% chance this thing blows your lungs clean out haha.

~~~
divbzero
0.7% mortality rate for 2019-nCoV is inaccurate.

We do not know the mortality rate with any precision at this point and early
estimates place it far higher than 0.7%.

Let’s be neither alarmist nor complacent, but above all get our facts right
and avoid spreading misleading information.

~~~
arcticbull
The WHO pins it at 0.7% and falling as understanding thereof and treatment
improves [1 - page 12, graph on page 13]. This makes a lot of sense as the
earliest numbers were based only on people presenting severe symptoms, and
huge quantities of people with nCoV are completely and totally asymptomatic.

As with the flu, mortality is highest in older people, and the
immunocompromised.

[1] [https://www.who.int/docs/default-source/coronaviruse/who-
chi...](https://www.who.int/docs/default-source/coronaviruse/who-china-joint-
mission-on-covid-19-final-report.pdf)

~~~
divbzero
Thank you for providing the source. This helps tremendously in clarifying and
advancing the discussion.

We need to be careful about what exactly the WHO is reporting. In this case,
they are reporting estimates of the _crude fatality rate_ defined as _deaths_
/ _total cases_. This will equal the mortality rate once the outbreak is over,
but has limited use during the outbreak as they call out in footnote:

> The Joint Mission acknowledges the known challenges and biases of reporting
> crude CFR early in an epidemic.

During the outbreak, a better but still imperfect estimate is _deaths_ /
_settled cases_ where _settled cases_ is the sum of deaths and recoveries. [1]

[1]:
[https://news.ycombinator.com/item?id=22399755](https://news.ycombinator.com/item?id=22399755)

~~~
arcticbull
Indeed, I am basing my confidence on the trendline in the graph on page 13.
The number of people infected (41K) is about two thirds now as compared to the
peak (58K), and the CFR is dropping exponentially as cases resolve.

------
mjmdavis
This has genuinely given me hope. It would be great to see more ideas and work
around this.

~~~
ficklepickle
It reminds me of the baby incubator made from car parts.

[https://blogs.scientificamerican.com/news-blog/babys-hot-
whe...](https://blogs.scientificamerican.com/news-blog/babys-hot-wheels-an-
incubator-made-2008-12-16/)

------
im3w1l
Wow to think someone wrote this 12 years ago. I feel there is a lesson here
but I don't know what.

~~~
arcticbull
The lesson is diseases happen, and then they go away and we forget all about
them. Bird flu, swine flu, SARS, MERS and soon nCoV-19. The number of active
cases is approaching half of what it was at peak, and the mortality rate is
now close to 0.7% - and largely weak/immunocompromised patients, the same
order of magnitude as the normal flu. Further, a few groups claim a vaccine is
only a few months away, and it responds to some existing antiviral
medications.

~~~
wbl
In Qoom nothing has been done. The Iraniam government refuses to take even the
most basic control measures.

~~~
arcticbull
It also has a 0.7% case fatality rate in China (and 0.6% outside) on par with
H1N1 at 0.45%. Nothing really _needs_ to be done -- this time. The situation
would be far, far worse with a disease that actually killed a lot of healthy
individuals.

~~~
blagie
Worldwide, there were 2,979 deaths and 42,576 recovered. That math suggests
you might have an extra decimal point there. There are many ways to do the
math, but 0.7% is not really a sensible number to work from. General consensus
hovers at 2-3%.

Aside from that, a much larger (as of yet unknown) number have permanent lung
scarring. That's not a joke. Read about SARS and MERS long-term prognosis from
similar scarring.

~~~
arcticbull
That's unfortunately a common misunderstanding of how CFR or case fatality
rate works. It begins huge as only the most serious cases are identified as
nCoV and it falls as the long tail comes into view.

Over the last few days, we've seen thousands of recoveries and tens of deaths.
Marginally, it's 0.6% globally from the latest WHO data. The media is
sensationalizing this and playing on peoples fears and emotions.

Check out the graph on page 13 of the WHO report:
[https://www.who.int/docs/default-source/coronaviruse/who-
chi...](https://www.who.int/docs/default-source/coronaviruse/who-china-joint-
mission-on-covid-19-final-report.pdf)

> Aside from that, a much larger (as of yet unknown) number have permanent
> lung scarring. That's not a joke. Read about SARS and MERS long-term
> prognosis from similar scarring.

To your own point, we have no idea if it's even a thing. Just because SARS,
MERS and nCoV are all coronaviruses doesn't mean they act the same way. MERS
has a 35% fatality rate vs. and I can't stress this enough 0.6%, so two whole
orders of magnitude less fatal.

------
popotamonga
Can you actually buy a consumer ventilator? I would see myself paying up to
10k for a ventilator to have at home just in case...

~~~
TylerE
A cpap, or especially s bipap will come pretty close. Not the same in that
isn’t true life support, but it does make breathing _much_ easier.

I use a cpap at home for sleep apnea and was on a bipap for about 48 hours
when hospitalized for pnuemonia.

Machines cost about $500-1500 dollars. Do require a percription though.

~~~
JshWright
CPAP is a good way to prevent someone from getting intubated later on. It
doesn't reduce the risk entirely, but early and aggressive CPAP usage can
definitely reduce the likelihood of a pt needing intubation further down the
line (more common w/ asthma/COPD, but there is some evidence supporting its
use w/ ARDS pt's as well)

~~~
anonuser123456
In not sure this is true. CPAP/PEEP are used for first line mild ARDS. But it
seems hard to find any conclusive evidence for efficacy. It definitely makes
people more comfortable, but it's hard to say if the clinical efficacy is
really there.

~~~
JshWright
The evidence is stronger in the case of mild ARDS (early NIVPP reduces
intubation rates), by the time it has progressed to moderate/severe ARDS, it's
too late and NIVPP isn't going to do any good.

Apologies that I'm on my phone right now and don't have links at hand, but I
have done some reading on this topic recently.

~~~
JshWright
Outside the edit window, but this is one of the studies I was referring to:
[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4057073/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4057073/)

From the conclusion:

> Intubation rates did not exceed 35% in non-ARDS and mild ARDS and NIV may
> thus be used as the first-line ventilatory support ... By contrast, 84% of
> severe ARDS required intubation and NIV does not appear beneficial in this
> subset of patients ... In patients with moderate ARDS, NIV may be worth
> attempting in those having a PaO2/FiO2 ratio >150 in the absence of
> hemodynamic instability or altered consciousness ...

There are definitely significant shortcoming to that study (single facility,
etc), but it definitely points in the direction of CPAP being a viable
treatment, especially if it's used aggressively (initiated early, high PEEP,
etc)

