Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Pandemic Ventilator Project

panvent.blogspot.com

Post reply on HN
Print view View original

51–60 of 111 posts

Re: Pandemic Ventilator Project

#51

Post by chimprich »

chimprich wrote: post #45
nopinsight wrote: post #23

4x resources delay a crisis by 2 doublings. If a doubling takes 7 days, that’s just 2 weeks. R0 (reproduction rate) overwhelms everything. The only way out safely is to greatly reduce R0: - social distancing: 6-9 feet away from everyone - avoiding crowds - Never share utensils; no buffets - hygienic routines: wash hands, use wipes, close toilet lid before flushing (see Amoy Gardens), etc. And convince others to do th…

I've got an idea for a way to reduce R0 with some voluntary people tracking. I could do with some other developers to plan it. If anyone's interested, please drop me an email: rls at hwyl.org

Care to explain the downvote? It's a bit depressing trying to do something positive in the current climate.

Re: Pandemic Ventilator Project

#52

Post by jtms »

projektfu wrote: post #29

I would imagine an epidemic of ventilator associated lung injury if people started rolling out homemade ventilators in quantity.

if my choices were risk of lung injury or probable death, i think id likely pick risk of lung injury

Re: Pandemic Ventilator Project

#53

Post by marvin »

pujjad wrote: post #20
trevyn wrote: post #3

Any thoughts about using a regular sleep apnea CPAP device for this type of situation, where one has access to the pressure settings?

Someone dear to me needs a ventilator per tracheostomy (Trilogy 100). Her Consultant Aenesthesist who was in Italy four weeks ago and works on an Intensive Care Unit told me that 6 out 10 Covid-19 affected ITU patients require an ECMO ( https://en.m.wikipedia.org/wiki/Extracorporeal_membrane_oxyg... ). This is very bad. I could sense his unease, these are machines you don't come by easily. His ITU is preparing for wa…

You sure about the ECMO situation? That's the first time I've heard it's that bad. I understood that some 25% of ICU patients required ventilation, but that ECMO-patients had very poor outlook.

Re: Pandemic Ventilator Project

#54

Post by ajross »

dwheeler wrote: post #48
ajross wrote: post #36

Earlier quoted context omitted.

FWIW: in the kind of disaster these kind of home brew devices are targetted at, they're unlikely to be used on sedated patients. I read this as "how to save a life with a vaccuum cleaner in extremis", and not "here's a good ventilator design". Is it a good idea? I dunno. I'll check on the vaccuum today just in case. Also FWIW: the air path doesn't seem like the critical piece here. My (amateur) intuition tells me tha…

If amateur ventilators are only used when ventilation is required and standard ventilators are not available, that still may be a good answer.. still, I am sure that there are better and worse designs for amateur ventilators, it would be best if someone who knew they were doing reviewed various designs and could recommend the best of the bad situations.

More amateur intuition: there are probably more available trained health care providers (e.g. radiologists who put tubes in as med students) than there are devices. These things aren't going to be needed by "us", but by them. They need to be the ones coming up to speed.

Again: I'd be sort of OK with a ventilator manufactured by a HN reader. Under no circumstances do I want a software geek putting a tube in me.

Re: Pandemic Ventilator Project

#55

Post by kazagistar »

chimprich wrote: post #51
chimprich wrote: post #45

Earlier quoted context omitted.

I've got an idea for a way to reduce R0 with some voluntary people tracking. I could do with some other developers to plan it. If anyone's interested, please drop me an email: rls at hwyl.org

Care to explain the downvote? It's a bit depressing trying to do something positive in the current climate.

Why not say it instead of keeping it secret?

Re: Pandemic Ventilator Project

#56

Post by DataDrivenMD »

wbl wrote: post #38
kokey wrote: post #31

Earlier quoted context omitted.

I suppose that's good news then for potential emergency use of unapproved makeshift alternatives to ventilators, I guess it also makes hand ventilation viable if you have enough volunteers available to do the bagging.

Bagging is hard to do for extended periods.

Anesthesiologist here - true, I was a Stanford medical student on an ICU rotation when a Tesla employee crashed his plane into high voltage power lines while attempting to land at San Carlos airport. Electrical power on the peninsula was out for an extended period of time. Battery backups eventually failed, then gas powered generators started failing so everyone with a pair of hands took turns manually ventilating the patients. If push comes to shove, we could get by with a Jackson-Reese circuit and a pair of hands. Obviously we don’t want to find ourselves in this situation.

Re: Pandemic Ventilator Project

#57

Post by derefr »

tommaho wrote: post #50

I posted directly via the contact form on the blog, not sure if it made it through. I'm way out of my lane even commenting on this, but maybe you can dramatically simplify the air delivery side of this design, if you're willing to under-engineer. A single air chamber with an inlet (blower in) and two outlets (patient out and return out). Low rpm motor slow rotating a sealed disc with holes in it balancing outflow bet…

Not by any means an expert here either, but my impression is that, to call something a “ventilator” in a medical context, it has to have a software-controlled rate of flow. “Ventilator” is to “air pump” as “CNC router” is to “regular router.” It needs to be integrated as part of a control system, feeding out forced air-pressure (thrust?) data, and getting fed back a PWM control signal. (Sort of like a CPU fan, but with air pressure in place of on-die temperature.)

Keep in mind, the use of these things is that you hook this up to a patient and then leave them in a room while you go handle other emergencies. It needs to tell you if it’s having a problem (through hookups to monitoring equipment.)

I think it also needs to not try to force air into a blocked airway (i.e. to blow open the patient’s larynx the moment they try to swallow), and/or needs to let up on the air pressure in a sinusoid pattern so the patient can exhale—though I might be wrong about either/both of those, given that they’re not really problems doctors encounter with hand-pumped ventilation. But either of those, in combination with the flywheel-like momentum of a big blower fan, would explain the waste gate.

Re: Pandemic Ventilator Project

#58

Post by DataDrivenMD »

kokey wrote: post #14
semi-extrinsic wrote: post #10

I've been looking over the designs being put forward in the various places now, and I cannot understand why people aren't just planning to copy the Manley ventilator. This was the standard ventilator in Europe for decades. It is simple to design, does not even require electricity (mechanical solution driven by air from central compressed air system) so all parts can be sourced locally, and the design has a clinically…

The issue is that with the kind of ventilation required you need to sedate the patient with gasses and you need to recycle those gasses and unused oxygen. With the length of time patients have to be on this you don't want to lose those gasses and also pump it out into the atmosphere. The Manley design could be a good starting point I suppose, you just have to replace the weight system with controllers and add a carbo…

Anesthesiologist here - sedation is ideal for managing patients in respiratory failure, though volatile anesthesia is not commonly used in an ICU setting (at least not in the US). It is more common to use IV drugs such as dexmedetomidine, fentanyl, or dilaudid.

Re: Pandemic Ventilator Project

#59

Post by UncleOxidant »

wbl wrote: post #39
fghorow wrote: post #22

Earlier quoted context omitted.

Ok, so what is the best way, in your opinion, for a still healthy hacker/maker geek to contribute something (anything?) to helping our local ICUs from being overwhelmed with patients? Edited to add: Spoken as the Dad of a 28 week premie who spent 8 weeks on a ventilator in a NICU.

There is a manufacturer of emergency ventilators. Why they aren't working triple shifts to make millions is beyond me.

Which manufacturer is this? What country is it in?

Re: Pandemic Ventilator Project

#60

Post by DataDrivenMD »

pcj-github wrote: post #46

I'm surprised we haven't seen anything detailing the supply chain involving O2. This is as important than the actual machine.

Anesthesiologist here: yes and no. It depends on whether the patient is having difficulty clearing CO2, in which case ventilation is more important. If the patient’s lungs are unable to extract sufficient oxygen from the air such that the blood oxygen levels drop below a certain threshold, then supplemental oxygen becomes important. In fact, excessively high oxygen concentrations in inhaled gas has the potential to damage lung tissue. Hopefully this helps to explain why the ability to titrate oxygen flows is important. If we can do that effectively, we can conserve our oxygen supply for those who need it.
Post reply on HN