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

Project Open Air

projectopenair.org

Post reply on HN
Print view View original

21–30 of 31 posts

Re: Project Open Air

#21

Post by cameldrv »

tgsovlerkhgsel wrote: post #14
ggreer wrote: post #4

Neat idea, though I think it will be quite some time before it produces something that people can build or use. Another option might be to figure out ways to adapt existing ventilators to be used by multiple patients. If you find 4 patients with similar tidal volumes and body size, you can grab some Y tubing, attach them to the same ventilator, then set it to 4x the tidal volume and breathe for all of them. This has…

My understanding is that what a ventilator does is basically: - supply pressurized air to patient - turn off the pressure, open exhalation valve and let patient exhale Given that every hospital I've seen has compressed air outlets, wouldn't it be possible to get acceptable results with a pressure regulator and a timed set of valves? Or is the pressure required to fill a patient's lungs so high that the volume must be…

My layman's understanding is that ventilation is a fairly complex art/science, and that modern ventilators have multiple modes that are effectively different control laws.

I think that the pressure required to fill a patient's lungs is quite different in a COVID patient than a normal patient, because the disease has caused huge flow restriction in the lungs. I think that generally you want to control flow rate, because you need to get a particular respiration rate, and the lungs can hold a certain amount of air. You then use whatever pressure gets that respiration rate.

If the pressure or flow rate is too high, I think that that can cause lung damage, so one option is to increase the oxygen concentration in the air you're delivering. My understanding is that the downside is that although this will lead to more oxygenation, it doesn't help any with removing CO2. If you reach this limit, the only option is then ECMO.

Re: Project Open Air

#24

Post by jariel »

mike_d wrote: post #15

"Open source ventilators" are a really really bad idea. Patients on ventilators need to be intubated first, which involves using a specialized tool to insert a tube down past the vocal cords and inflating a balloon that seals the airway. You can kill a person before you've even turned on your nifty machine. Once you have a patient tubed, you have full control of their respiration. If your calculations are wrong you e…

This is not a fair assessment and I think it sidesteps the point.

"This is very admirable and I appreciate the desire to help, but I can't stress enough how dangerous this is."

Indicating that 'medical equipment requires specialization' is not a special insight that most people are going to miss.

Assuming that the product will be designed by those who lack credibility or that such equipment might not be of sufficient quality of design, construction, or that it may be misused is unwarranted.

'Open source' encryption and other systems are behind the entire world's financial systems, it has integrity partly because it's 'open source'. It's not designed by fools, and just because jokers and everyone else can 'fork and do something' doesn't mean it will be implemented anywhere that matters. Obviously regulations, security, risk etc. play a role 'where it matters'.

Any kind of medical equipment development is going to require some kind of oversight, regulatory approvals, and special manufacture, but this is all feasible within the concept of 'open source'. There are plenty of highly credible and knowledgeable people, possibly even those who have worked on 'closed source' ventilators can possibly contribute.

Sheppard through some kind of regulatory process, manufacturing setup, and possibly deployment and training, it's not infeasible at all that something like this could help.

Even the availability of high-quality, unlicensed equipment designs, with parts pre-designed for manufacture and ready to be made by qualified entities ... could feasibly make all the difference in the world.

For example, once a design is complete and approved, the medical wing of a poor country, or possibly an NGO could facilitate the actual manufacture and distribution to medical staff in various places.

There are massive margins (bordering on criminal) in medical equipment and supplies these days, hospital beds now cost more than automobiles (!), it's high time there was an open approach to such issues.

I can absolutely see medical researchers and PhD's at universities, teaming with Engineers, MDs, and manufacture/supply chain specialists to produce this kind of stuff.

Obviously there's a limit to complexity here, but I hope they figure out not only ventilators, by any number of other kinds of gear.

Though odds are it will fail, it's not a bad idea, it's a great idea.

Re: Project Open Air

#25

Post by Peradine »

ICU ventilators are surprisingly complicated machines, we've just brought some HAMILTON-C6 machines at work if you want an idea of the top of the line

I would consider the following a bare-minimum feature set for a COVID patient ventilator, any less and it would do more harm than good:

- cycle between an inspiratory and expiratory phase

- during the inspiratory phase, deliver an adjustable volume of gas (in the region of 6 ml per kg of patient's body weight) using as little pressure as possible, with an adjustable upper limit of pressure (in the region of 30 cmH2O)

- during the expiratory phase provide an adjustable pressure against exhalation (in the region of 0-30 cmH2O)

- allow blending of air and oxygen to deliver an adjustable inspired oxygen fraction

- allow the timing of the inspiratory and expiratory phases to be independently varied, thereby allowing the respiratory rate and the ratio of inspiration to expiration time to be controlled. Permit respiratory rates in the range of 8-60 breaths per minute

- measure and display the pressures and volumes within the respiratory system

- allow adjustable alarm-limits for pressures and volumes, and provide clear audible and visual alarms if these values are exceeded

For added patient safety and benefit, the following would be helpful

- measure inspired and expired oxygen and carbon dioxide content, and display both on a continuous waveform graph

- allow the patient to initiate the inspiratory phase by sensing patient inspiratory effort and providing pressure support for inhalation; ie sense when the patient inhales and deliver 10-15 cmH2O pressure for 0.5 seconds to augment inhalation

Re: Project Open Air

#27

Post by ericb »

Gatsky wrote: post #6

This is madness. You can’t scale up ICU based ventilatory support to keep up with a pandemic. All resources should be going towards infection control measures, a quick and highly scalable diagnostic test, and antiviral therapy. In that order.

> You can’t scale up ICU based ventilatory support to keep up with a pandemic.

It's almost like people think individual lives matter and don't have control over the larger response?

Re: Project Open Air

#28

Post by UncleMeat »

jariel wrote: post #24
mike_d wrote: post #15

"Open source ventilators" are a really really bad idea. Patients on ventilators need to be intubated first, which involves using a specialized tool to insert a tube down past the vocal cords and inflating a balloon that seals the airway. You can kill a person before you've even turned on your nifty machine. Once you have a patient tubed, you have full control of their respiration. If your calculations are wrong you e…

This is not a fair assessment and I think it sidesteps the point. "This is very admirable and I appreciate the desire to help, but I can't stress enough how dangerous this is." Indicating that 'medical equipment requires specialization' is not a special insight that most people are going to miss. Assuming that the product will be designed by those who lack credibility or that such equipment might not be of sufficient…

> Assuming that the product will be designed by those who lack credibility or that such equipment might not be of sufficient quality of design, construction, or that it may be misused is unwarranted.

Given the number of software engineers who have written detailed and strongly opinionated analyses of the situation rather than relying on expert opinions... I'm not so sure we can assume that this project is operated by experts.

Re: Project Open Air

#29

Post by mike_d »

jariel wrote: post #24
mike_d wrote: post #15

"Open source ventilators" are a really really bad idea. Patients on ventilators need to be intubated first, which involves using a specialized tool to insert a tube down past the vocal cords and inflating a balloon that seals the airway. You can kill a person before you've even turned on your nifty machine. Once you have a patient tubed, you have full control of their respiration. If your calculations are wrong you e…

This is not a fair assessment and I think it sidesteps the point. "This is very admirable and I appreciate the desire to help, but I can't stress enough how dangerous this is." Indicating that 'medical equipment requires specialization' is not a special insight that most people are going to miss. Assuming that the product will be designed by those who lack credibility or that such equipment might not be of sufficient…

Ventilators are not lacking a design. There are many functional designs across a variety of medical device manufactures (most of which are sub-$1000). China is already ramping up production to assist other countries.

The only thing open sourcing a design does is encourage DIY home builds, which is wildly irresponsible in a time of panic.

Re: Project Open Air

#30

Post by VectorLock »

davak wrote: post #23
VectorLock wrote: post #17

I keep wondering if existing CPAP/BiPAP machines can be software adapted to serviceable ventilators. Some BiPAP machines are identical to units produced for NIV.

Yes. Very easily.

Has anybody done it? Is there any effort to collect them incase ventilators get scarce, I wonder?
Post reply on HN