11 ms·

Pandemic Ventilator Project

318 points by mhb 7y ago

sigmaprimus 7y ago
Good idea using a large AC blower. I would think a small brand new or very clean wet dry shop, vac using the blower attachment might be even better. It would be noisy but would allow the design to incorporate negative pressure of the vacuum side to assist with exhaling. Maybe the shop vac could be plugged into a speed controller to improve duty cycle and reduce noise but controlling an AC motors speed is quite a bit more complicated(expensive) than controlling a DC one.
- mhb 7y ago
  What about using an air compressor? These should still be readily available and is an off-the-shelf air pressure solution. The air couldn't be used directly (oil in it) - there would need to be an isolation bellows or something similar.
  - sigmaprimus 7y ago
    Thats a good idea too, and they do make oil-less compressors they are typically smaller but years ago I came across many of these attached to dry sprinkler systems in small parkades.
- bacon_waffle 7y ago
  > It would be noisy... > controlling an AC motors speed is quite a bit more complicated(expensive) than controlling a DC one. That type of motor is so noisy because it's a universal motor[1] - they can be controlled with light dimmer type circuit[2], but they're basically always noisy and inefficient. A cordless drill would be a good starting point for a variable speed power train. [1] https://en.wikipedia.org/wiki/Universal_motor https://en.wikipedia.org/wiki/Universal_motor [2] If you're actually using a light dimmer to control a universal motor, use the highest current rated dimmer possible. The motor will be more inductive than the typical lighting circuit that the dimmer is designed for.
trevyn 7y ago
Any thoughts about using a regular sleep apnea CPAP device for this type of situation, where one has access to the pressure settings?
- inamberclad 7y ago
  I have heard that these can aerosolize the virus, which is dangerous to other people. https://hackaday.com/2020/03/12/ultimate-medical-hackathon-how-fast-can-we-design-and-deploy-an-open-source-ventilator/ https://hackaday.com/2020/03/12/ultimate-medical-hackathon-h...
- sigmaprimus 7y ago
  CPAP stands for continuous positive airway pressure, one of the problem with SARS(Severe acute respitory syndrom) or Wuhan Fever is it stiffens the lungs making it hard to exhale. This in turn allows the lungs to fill up with fluid, a sort of viral pneumonia. I believe a ventilator uses a negative pressure or vacuum to assist with exhalation and air exchange.
  - bearsnowstorm 7y ago
    Actually exhalation is passive, not active, in modern day ICU ventilation.
    - elric 7y ago
      Interesting. How does that work? Does the pressure drop to let air out or something?
      - haldujai 7y ago
        To keep it simple you have a device that increases pressure through a closed circuit to push air into the lungs, when its time to exhale it drops pressure (although is still positive pressure i.e PEEP) that is weaker than the natural recoil/elasticity of the chest wall combined with gravity in a supine patient and allows exhalation.
enchiridion 7y ago
https://www.projectopenair.org/ https://www.projectopenair.org/
- westurner 7y ago
  > https://www.projectopenair.org/ https://www.projectopenair.org/ From https://app.jogl.io/project/121#about https://app.jogl.io/project/121#about >> Current Status of the project >> The main bottleneck currently (2020-03-13) is organization / management. >> […] This is an organization of experts and hobbyists from around the globe.
  - MockObject 7y ago
    The link https://app.jogl.io/project/121#about https://app.jogl.io/project/121#about doesn't go anywhere anymore. And there are no results for "ventilator" in the app.jogl.io search.
    - westurner 7y ago
      I see a "Ventilator Project" heading? (edit) here's the link to their 'Ventilator' document: https://docs.google.com/document/d/1RDihfZIOEYs60kPEIVDe7gmsxdYgUosF9sr45mgFxY8 https://docs.google.com/document/d/1RDihfZIOEYs60kPEIVDe7gms...
semi-extrinsic 7y ago
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 proven track record. Here is a video with schematic showing how it works: https://youtube.com/watch?v=CrUfblki6Zs https://youtube.com/watch?v=CrUfblki6Zs
- bamboozled 7y ago
  It’s cooler if you roll your own. Ask programmers, they’ll get you up to speed.
- kokey 7y ago
  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 carbon scrubbing stage to feed back the gasses. The carbon scrubbing stage is the tricky one, it's something that requires good chemistry and not mechanics and electronics.
  - robryk 7y ago
    I am ignorant as far as the use of inhalable medications is concerned. However, I find it weird that you'd want to recycle oxygen: carbon dioxide removal is either hard or requires consumables, while oxygen can be concentrates from air using a simple process that consumers only energy (by adsorbing nitrogen on surfaces of particular minerals).
  - semenko 7y ago
    Physician here; this isn't true for the ventilation of COVID patients, or ICU patients in general. There's a difference between simple ventilator [1], and an anesthesia machine [2] that adds gas mixing, scavenging, etc. ICU patients are anesthetized using IV sedation (a common regimen in the US is fentanyl/propofol), not inhalational anesthetics. Most vents only have simple inline filters to reduce contamination. [1] A classic vent in the US is the Puritan Bennett 840. Here's its manual showing filters: https://www.medtronic.com/content/dam/covidien/library/us/en/product/acute-care-ventilation/PB840_Technical_Reference_Manual_EN_10067720D00.pdf https://www.medtronic.com/content/dam/covidien/library/us/en... [2] https://en.wikipedia.org/wiki/Anaesthetic_machine https://en.wikipedia.org/wiki/Anaesthetic_machine
dang 7y ago
Some related submissions: https://news.ycombinator.com/item?id=22573926 https://news.ycombinator.com/item?id=22573926 "Low-cost portable ventilator (2010)" https://news.ycombinator.com/item?id=22573656 https://news.ycombinator.com/item?id=22573656 "Low-cost ventilator wins Sloan health care prize (2019)"
- 0xWTF 7y ago
  Is there some way HN can bend to support the pandemic? A flag or something?
Yuioup 7y ago
I'm surprised there's no emoji for Corina
nopinsight 7y ago
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 the same. Italy closed schools when they had just 150 confirmed cases but still in a tragic crisis because people kept socializing. See a timeline & analysis here: https://www.luca-dellanna.com/how-bad/ https://www.luca-dellanna.com/how-bad/
- sitkack 7y ago
  Every ad network and every social media platform need to be saying as much world wide to everyone, 10 times a day.
- chimprich 7y ago
  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
  - chimprich 7y ago
    Care to explain the downvote? It's a bit depressing trying to do something positive in the current climate.
    - kazagistar 7y ago
      Why not say it instead of keeping it secret?
    - sowbug 7y ago
      I didn't downvote, but I can see why others did. If you have an idea to share, share it. Don't make people jump through the hoop of sending email. If you are concerned about others stealing your idea, then your comment is essentially spam, because you're using HN as a recruiting tool to build your team. Only YC companies can do that here. Your motivation might be something other than either of these possibilities. It's easier to downvote and stop thinking about it than to figure out your true intentions.
tommaho 7y ago
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 between feed-to-patient and return. Put a blowoff mechanism inline around the flow meter. If the capacity is there and there's such a thing as a common or global delivery 'frequency', maybe it could support more than one person. Again, I might as well be from another planet in terms of knowledge in this domain. I'm just confused at the apparent complexity around the servo, linkage, and waste-gating. I DO get that delivery can be tailored nearly entirely in software with this design. That's cool.
- derefr 7y ago
  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.
projektfu 7y ago
I would imagine an epidemic of ventilator associated lung injury if people started rolling out homemade ventilators in quantity.
- oxymoran 7y ago
  I mean, it would only be used as a last resort. So lung injury or death seems like a pretty easy choice.
- jtms 7y ago
  if my choices were risk of lung injury or probable death, i think id likely pick risk of lung injury
- yourapostasy 7y ago
  Please don't take this as a personal address to your specific comment. Yours was simply the last drop of water that tipped the scales in me to comment on an overall trend I'm seeing. What I'm beginning to see in a lot of these types of discussions is those calling for caution/compliance are missing the term "in extremis". I've seen no one is suggesting that these DIY/hacking efforts of all stripes replace the existing healthcare infrastructure. What I see is concern the existing infrastructure is not scaled to handle what we anticipate will happen even in a moderate scenario. We have in this very thread a real MD who confirms that post-ICU ventilation is not being addressed but still needs to be, yet that confirmation seems to fly by those who say that DIY isn't advisable. My position on the mitigation however, starts from these two premises: In Extremis, any action is better than no action at all. In Extremis, don't let perfect be the enemy of good. When asked, I believe many will opt for a 1% chance of living on a DIY ventilator intubated by recently-out-of-license nurses emergency-authorized during the pandemic when no other intubation staff are available in the time required to attempt saving a life, than a 100% chance of dying with no ventilation option whatsoever. What I'm not seeing are any alternative solutions offered by those who want to stick to the "official" script. Let's in about 6-8 weeks from now our healthcare infrastructure is overwhelmed by severe respiratory distress cases, starting in the June timeframe. What do you suggest we do to prepare for that starting now instead of any of the DIY efforts you deem too risky/non-compliant? I'm honestly asking in response your specific post, now. Even an answer like "triage non-comorbid over comorbid patients, let the comorbid patients die" is acceptable. Even if your response is, "I'm no domain expert, I'm leaving it all up to the experts", that works for me, too. I'm just trying to figure out what your mitigation angle is. What doesn't help improve our probabilities nor mesh with my personal philosophy is giving criticisms with either no alternatives or no position statement of what you believe is an acceptable protocol going forward. It's in my nature to seek answers and address my curiosity, even if it only leads to a partial answer. If that's not you, then you live your best life, and thanks for the note of caution, it is definitely a concern to manage as best as we can.
agumonkey 7y ago
Do you guys have seen similar devices with embedded sanitizing modules ? heating wire, UVC led or plasma blade to clean air intake ? the air version of that https://www.youtube.com/watch?v=d1RoEgxax60 https://www.youtube.com/watch?v=d1RoEgxax60
opendomain 7y ago
I am working on one now. The problem is that ventilators require tubes to be inserted into the patients lung. This requires a very skilled doctor and has a risk of infection and injury. So I am making an wooden lung - like an iron lung but made from plywood. I can share the plans and sourcing for the parts if you want
- burfog 7y ago
  Make it like a turtle shell, hooked up to something like this: https://en.wikipedia.org/wiki/Rotary_woofer https://en.wikipedia.org/wiki/Rotary_woofer That lets you use both positive and negative pressure. You could even support fast pulses for clearing out gunk from the lungs.
deleted 7y ago
[deleted]
_red 7y ago
Great idea. Simultaneous to these types of home-brew projects...we also need someone (President? eCelebs? etc) to promote and organize fund raising efforts to simply buy and distribute cheap but effective ventilators. Imagine a WWII style "war bonds" effort, but instead to build and distribute say 5M ventilators over the next 6 weeks. In addition to this, we must re-purpose closed schools (gyms, cafeterias, etc) into make-shift CoVid19 triage centers where affected patients can be put on cots with saline drip, drugs, and ventilation. This is doable, but we need to do it.
- squarefoot 7y ago
  "we also need someone (President? eCelebs? etc) to promote and organize fund raising" Fund raising won't help if too many people get infected. What you need right now is for those in charge to stop playing Rambo and pretend they have it in control (they don't) then grow up, tell people to stop behaving like there is nothing going on. Schools, stadiums, all non vital businesses should close and people should stay home. This virus propagates at very high speed; as for now there is no cure, and I'm sorry for believers but prayers won't work (ironically, "healing" pools at Lourdes are already closed since days). This is serious, folks. We can only slow infections to a level in which people recover at faster pace than those who get infected, otherwise ICU numbers won't be enough and a lot more people will die.
  - sneak 7y ago
    Plan for the big peak, hope for the small one. There is no indication that leadership in the US is going to suddenly start behaving sensibly.
pcj-github 7y ago
I'm surprised we haven't seen anything detailing the supply chain involving O2. This is as important than the actual machine.
- DataDrivenMD 7y ago
  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.
  - duckymcduckface 7y ago
    Where do hospitals get their O2 supply from out of curiosity? Do they buy it from one of the major gas suppliers like praxair or airliquide and store it in the back as GOX/LOX or can it also be produced on site?
    - khwerou098 7y ago
      In the past they had large tanks of liquid O2. More recently, many have a large oxygen concentrator machine on site which just takes it from the air.
DataDrivenMD 7y ago
As an anesthesiologist and hacker, I love the enthusiasm here. I’m less concerned about the hospital use-case. It would be helpful to crowdsource solutions to address the need for ventilators after patients leave the ICU. Based on current practice patterns, some patients will undergo tracheostomy tube placement, and then need to be discharged to respiratory rehab facilities. We will need to increase capacity in this setting, and I’m not seeing or hearing anyone address this area. If we don’t solve this problem, we will find ourselves with a backlog of patients who could be discharged from the ICU, but with nowhere to go.
- rectang 7y ago
  Anecdotally: My mother is a retired RN with an "inactive" license in Washington state. She does elder care as a side gig for individual clients. She recently had to turn someone down because the patient was intubated; it's not legal for her to care for such a patient. If anything went wrong she could be both at risk of a lawsuit and in trouble with the state for practicing medicine without a license. (She's also in her seventies herself, putting her in the high-risk category, but that's a different issue.) I'm at a loss as to how our legal and licensing institutions can be adapted to allow for a quick increase in the number of personnel who can care for intubated patients.
  - DataDrivenMD 7y ago
    You raise a related issue, which is critical to address as well. That is, we need people to help manage patients before, during, and after their hospital stay. I’m less concerned about the licensing issues because public health emergency declarations make it possible for state officials to clear the way for someone like your mom. Where you, and fellow hackers can help, is by offering tech solutions that solve the issue of coordinating/figuring out where your mom’s skills could be most helpful. We will also need to collect information, such as when your mom is available to help. Could be a good time to revisit the concept of an Uber-like platform for healthcare delivery, assuming that it can be up an running in a few days. Hack-a-thon, anyone?
    - 7y ago
nx20593 7y ago
This whole sticking a tube down someone's throat without proper qualifications or equipment seems pretty dicey. Would an old fashion wooden iron lung work better? It's pretty primitive technology that doesn't seem too difficult to build. https://blog.sciencemuseum.org.uk/a-wooden-iron-lung/ https://blog.sciencemuseum.org.uk/a-wooden-iron-lung/
gentleman11 7y ago
My parents both have lung conditions. If this were Italy, and they got infected and needed ICU, they would not get treatment at the moment. What is the most promising home made gear I might be able to scrap together in the worst case scenario?
Peradine 7y ago
I'm an anaesthetics and intensive care trainee, so I know something about ventilation. The reason COVID-19 patients need to get ventilated is due to a failure of oxygenation - the infection causes direct lung injury (ARDS) which impairs oxygen absorption in the lung tissue. Normally we breathe room air, which is 21% oxygen, this drops to around 10% oxygen in the arterial blood due to inefficiencies in the absorption in the lungs. In a normal healthy patient breathing 100% Oxygen, their arterial oxygen content would be around 90%. ARDS significantly impairs oxygen uptake by the lungs, in severe cases patients breathing 100% oxygen may have arterial oxygen concentrations of just 8-10%. The purpose of ventilation in these severe ARDS patients is to augment oxygenation of the blood, using a combination of techniques including end-expiatory positive pressure and inverse-ratio ventilation, among others, and support the fatiguing respiratory muscles. Because the lungs of COVID-19 patients are already injured by the infection, they are very prone to further ventilator-associated injury. Modern intensive care ventilators have complicated computer-controlled 'modes', which allow precise regulation of ventilatory volumes, pressures, rates, timing, and gas blending. The ARDSnet trials in the early 2000s demonstrated the importance of carefully managed 'lung protective' ventilation, poor quality ventilation is likely to cause further lung injury and make the patient worse, not better. Therefore amateur ventilators are unlikely to be beneficial in COVID-19 unless they can provide similar lung protective ventilation, which would make them quite complicated. Additionally, ventilation is just one component of the management of sick COVID-19 patients. First you need to pass a breathing tube into their trachea, which is a challenging and risky procedure when performed by a skilled operative in a otherwise well patient, let alone someone on the brink of respiratory failure. Once intubated you will need to keep them deeply sedated, otherwise they will strain against the ventilator and make effective ventilatory care impossible. This requires equipment, drugs, and skilled staff, all of which are going to be in short supply.
- solotronics 7y ago
  As someone with asthma this is terrifying. My worst nightmare is not being able to breathe.
- jmccorm 7y ago
  Any thoughts as to the early treatment with a medical BiPAP when full-function respirator therapy is not available?
ilan1966 7y ago
i am an anaesthetist i trained using a manley ventilator covid patients apparently are easy to ventilate the issue is their gas exchange not their compliance a manley ventilator will do just fine for many patients, not all i accept but many
- ilan1966 7y ago
  BTW ICU doenst use volatile anaesthetics to sedate people we tend to use opioids & benzos to sedate
ilan1966 7y ago
i recon you could build a manley in your shed with some decent mech eng skills and it could certainly be printed
niutech 7y ago
There is a working open source ventilator prototype called VentilAid made in Poland: http://www.ventilaid.org http://www.ventilaid.org

318 points by mhb 7y ago

Good idea using a large AC blower. I would think a small brand new or very clean wet dry shop, vac using the blower attachment might be even better. It would be noisy but would allow the design to incorporate negative pressure of the vacuum side to assist with exhaling. Maybe the shop vac could be plugged into a speed controller to improve duty cycle and reduce noise but controlling an AC motors speed is quite a bit more complicated(expensive) than controlling a DC one.

mhb 7y ago
What about using an air compressor? These should still be readily available and is an off-the-shelf air pressure solution. The air couldn't be used directly (oil in it) - there would need to be an isolation bellows or something similar.
- sigmaprimus 7y ago
  Thats a good idea too, and they do make oil-less compressors they are typically smaller but years ago I came across many of these attached to dry sprinkler systems in small parkades.
bacon_waffle 7y ago
> It would be noisy... > controlling an AC motors speed is quite a bit more complicated(expensive) than controlling a DC one. That type of motor is so noisy because it's a universal motor[1] - they can be controlled with light dimmer type circuit[2], but they're basically always noisy and inefficient. A cordless drill would be a good starting point for a variable speed power train. [1] https://en.wikipedia.org/wiki/Universal_motor https://en.wikipedia.org/wiki/Universal_motor [2] If you're actually using a light dimmer to control a universal motor, use the highest current rated dimmer possible. The motor will be more inductive than the typical lighting circuit that the dimmer is designed for.

trevyn 7y ago

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

inamberclad 7y ago
I have heard that these can aerosolize the virus, which is dangerous to other people. https://hackaday.com/2020/03/12/ultimate-medical-hackathon-how-fast-can-we-design-and-deploy-an-open-source-ventilator/ https://hackaday.com/2020/03/12/ultimate-medical-hackathon-h...
sigmaprimus 7y ago
CPAP stands for continuous positive airway pressure, one of the problem with SARS(Severe acute respitory syndrom) or Wuhan Fever is it stiffens the lungs making it hard to exhale. This in turn allows the lungs to fill up with fluid, a sort of viral pneumonia. I believe a ventilator uses a negative pressure or vacuum to assist with exhalation and air exchange.
- bearsnowstorm 7y ago
  Actually exhalation is passive, not active, in modern day ICU ventilation.
  - elric 7y ago
    Interesting. How does that work? Does the pressure drop to let air out or something?
    - haldujai 7y ago
      To keep it simple you have a device that increases pressure through a closed circuit to push air into the lungs, when its time to exhale it drops pressure (although is still positive pressure i.e PEEP) that is weaker than the natural recoil/elasticity of the chest wall combined with gravity in a supine patient and allows exhalation.

enchiridion 7y ago

https://www.projectopenair.org/ https://www.projectopenair.org/

westurner 7y ago
> https://www.projectopenair.org/ https://www.projectopenair.org/ From https://app.jogl.io/project/121#about https://app.jogl.io/project/121#about >> Current Status of the project >> The main bottleneck currently (2020-03-13) is organization / management. >> […] This is an organization of experts and hobbyists from around the globe.
- MockObject 7y ago
  The link https://app.jogl.io/project/121#about https://app.jogl.io/project/121#about doesn't go anywhere anymore. And there are no results for "ventilator" in the app.jogl.io search.
  - westurner 7y ago
    I see a "Ventilator Project" heading? (edit) here's the link to their 'Ventilator' document: https://docs.google.com/document/d/1RDihfZIOEYs60kPEIVDe7gmsxdYgUosF9sr45mgFxY8 https://docs.google.com/document/d/1RDihfZIOEYs60kPEIVDe7gms...

semi-extrinsic 7y ago

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 proven track record. Here is a video with schematic showing how it works: https://youtube.com/watch?v=CrUfblki6Zs https://youtube.com/watch?v=CrUfblki6Zs

bamboozled 7y ago
It’s cooler if you roll your own. Ask programmers, they’ll get you up to speed.
kokey 7y ago
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 carbon scrubbing stage to feed back the gasses. The carbon scrubbing stage is the tricky one, it's something that requires good chemistry and not mechanics and electronics.
- robryk 7y ago
  I am ignorant as far as the use of inhalable medications is concerned. However, I find it weird that you'd want to recycle oxygen: carbon dioxide removal is either hard or requires consumables, while oxygen can be concentrates from air using a simple process that consumers only energy (by adsorbing nitrogen on surfaces of particular minerals).
- semenko 7y ago
  Physician here; this isn't true for the ventilation of COVID patients, or ICU patients in general. There's a difference between simple ventilator [1], and an anesthesia machine [2] that adds gas mixing, scavenging, etc. ICU patients are anesthetized using IV sedation (a common regimen in the US is fentanyl/propofol), not inhalational anesthetics. Most vents only have simple inline filters to reduce contamination. [1] A classic vent in the US is the Puritan Bennett 840. Here's its manual showing filters: https://www.medtronic.com/content/dam/covidien/library/us/en/product/acute-care-ventilation/PB840_Technical_Reference_Manual_EN_10067720D00.pdf https://www.medtronic.com/content/dam/covidien/library/us/en... [2] https://en.wikipedia.org/wiki/Anaesthetic_machine https://en.wikipedia.org/wiki/Anaesthetic_machine

dang 7y ago

Some related submissions: https://news.ycombinator.com/item?id=22573926 https://news.ycombinator.com/item?id=22573926 "Low-cost portable ventilator (2010)" https://news.ycombinator.com/item?id=22573656 https://news.ycombinator.com/item?id=22573656 "Low-cost ventilator wins Sloan health care prize (2019)"

0xWTF 7y ago
Is there some way HN can bend to support the pandemic? A flag or something?

Yuioup 7y ago

I'm surprised there's no emoji for Corina

nopinsight 7y ago

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 the same. Italy closed schools when they had just 150 confirmed cases but still in a tragic crisis because people kept socializing. See a timeline & analysis here: https://www.luca-dellanna.com/how-bad/ https://www.luca-dellanna.com/how-bad/

sitkack 7y ago
Every ad network and every social media platform need to be saying as much world wide to everyone, 10 times a day.
chimprich 7y ago
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
- chimprich 7y ago
  Care to explain the downvote? It's a bit depressing trying to do something positive in the current climate.
  - kazagistar 7y ago
    Why not say it instead of keeping it secret?
  - sowbug 7y ago
    I didn't downvote, but I can see why others did. If you have an idea to share, share it. Don't make people jump through the hoop of sending email. If you are concerned about others stealing your idea, then your comment is essentially spam, because you're using HN as a recruiting tool to build your team. Only YC companies can do that here. Your motivation might be something other than either of these possibilities. It's easier to downvote and stop thinking about it than to figure out your true intentions.

tommaho 7y ago

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 between feed-to-patient and return. Put a blowoff mechanism inline around the flow meter. If the capacity is there and there's such a thing as a common or global delivery 'frequency', maybe it could support more than one person. Again, I might as well be from another planet in terms of knowledge in this domain. I'm just confused at the apparent complexity around the servo, linkage, and waste-gating. I DO get that delivery can be tailored nearly entirely in software with this design. That's cool.

derefr 7y ago
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.

projektfu 7y ago

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

oxymoran 7y ago
I mean, it would only be used as a last resort. So lung injury or death seems like a pretty easy choice.
jtms 7y ago
if my choices were risk of lung injury or probable death, i think id likely pick risk of lung injury
yourapostasy 7y ago
Please don't take this as a personal address to your specific comment. Yours was simply the last drop of water that tipped the scales in me to comment on an overall trend I'm seeing. What I'm beginning to see in a lot of these types of discussions is those calling for caution/compliance are missing the term "in extremis". I've seen no one is suggesting that these DIY/hacking efforts of all stripes replace the existing healthcare infrastructure. What I see is concern the existing infrastructure is not scaled to handle what we anticipate will happen even in a moderate scenario. We have in this very thread a real MD who confirms that post-ICU ventilation is not being addressed but still needs to be, yet that confirmation seems to fly by those who say that DIY isn't advisable. My position on the mitigation however, starts from these two premises: In Extremis, any action is better than no action at all. In Extremis, don't let perfect be the enemy of good. When asked, I believe many will opt for a 1% chance of living on a DIY ventilator intubated by recently-out-of-license nurses emergency-authorized during the pandemic when no other intubation staff are available in the time required to attempt saving a life, than a 100% chance of dying with no ventilation option whatsoever. What I'm not seeing are any alternative solutions offered by those who want to stick to the "official" script. Let's in about 6-8 weeks from now our healthcare infrastructure is overwhelmed by severe respiratory distress cases, starting in the June timeframe. What do you suggest we do to prepare for that starting now instead of any of the DIY efforts you deem too risky/non-compliant? I'm honestly asking in response your specific post, now. Even an answer like "triage non-comorbid over comorbid patients, let the comorbid patients die" is acceptable. Even if your response is, "I'm no domain expert, I'm leaving it all up to the experts", that works for me, too. I'm just trying to figure out what your mitigation angle is. What doesn't help improve our probabilities nor mesh with my personal philosophy is giving criticisms with either no alternatives or no position statement of what you believe is an acceptable protocol going forward. It's in my nature to seek answers and address my curiosity, even if it only leads to a partial answer. If that's not you, then you live your best life, and thanks for the note of caution, it is definitely a concern to manage as best as we can.

agumonkey 7y ago

Do you guys have seen similar devices with embedded sanitizing modules ? heating wire, UVC led or plasma blade to clean air intake ? the air version of that https://www.youtube.com/watch?v=d1RoEgxax60 https://www.youtube.com/watch?v=d1RoEgxax60

opendomain 7y ago

I am working on one now. The problem is that ventilators require tubes to be inserted into the patients lung. This requires a very skilled doctor and has a risk of infection and injury. So I am making an wooden lung - like an iron lung but made from plywood. I can share the plans and sourcing for the parts if you want

burfog 7y ago
Make it like a turtle shell, hooked up to something like this: https://en.wikipedia.org/wiki/Rotary_woofer https://en.wikipedia.org/wiki/Rotary_woofer That lets you use both positive and negative pressure. You could even support fast pulses for clearing out gunk from the lungs.

deleted 7y ago

[deleted]

_red 7y ago

Great idea. Simultaneous to these types of home-brew projects...we also need someone (President? eCelebs? etc) to promote and organize fund raising efforts to simply buy and distribute cheap but effective ventilators. Imagine a WWII style "war bonds" effort, but instead to build and distribute say 5M ventilators over the next 6 weeks. In addition to this, we must re-purpose closed schools (gyms, cafeterias, etc) into make-shift CoVid19 triage centers where affected patients can be put on cots with saline drip, drugs, and ventilation. This is doable, but we need to do it.

squarefoot 7y ago
"we also need someone (President? eCelebs? etc) to promote and organize fund raising" Fund raising won't help if too many people get infected. What you need right now is for those in charge to stop playing Rambo and pretend they have it in control (they don't) then grow up, tell people to stop behaving like there is nothing going on. Schools, stadiums, all non vital businesses should close and people should stay home. This virus propagates at very high speed; as for now there is no cure, and I'm sorry for believers but prayers won't work (ironically, "healing" pools at Lourdes are already closed since days). This is serious, folks. We can only slow infections to a level in which people recover at faster pace than those who get infected, otherwise ICU numbers won't be enough and a lot more people will die.
- sneak 7y ago
  Plan for the big peak, hope for the small one. There is no indication that leadership in the US is going to suddenly start behaving sensibly.

pcj-github 7y ago

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

DataDrivenMD 7y ago
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.
- duckymcduckface 7y ago
  Where do hospitals get their O2 supply from out of curiosity? Do they buy it from one of the major gas suppliers like praxair or airliquide and store it in the back as GOX/LOX or can it also be produced on site?
  - khwerou098 7y ago
    In the past they had large tanks of liquid O2. More recently, many have a large oxygen concentrator machine on site which just takes it from the air.

DataDrivenMD 7y ago

As an anesthesiologist and hacker, I love the enthusiasm here. I’m less concerned about the hospital use-case. It would be helpful to crowdsource solutions to address the need for ventilators after patients leave the ICU. Based on current practice patterns, some patients will undergo tracheostomy tube placement, and then need to be discharged to respiratory rehab facilities. We will need to increase capacity in this setting, and I’m not seeing or hearing anyone address this area. If we don’t solve this problem, we will find ourselves with a backlog of patients who could be discharged from the ICU, but with nowhere to go.

rectang 7y ago
Anecdotally: My mother is a retired RN with an "inactive" license in Washington state. She does elder care as a side gig for individual clients. She recently had to turn someone down because the patient was intubated; it's not legal for her to care for such a patient. If anything went wrong she could be both at risk of a lawsuit and in trouble with the state for practicing medicine without a license. (She's also in her seventies herself, putting her in the high-risk category, but that's a different issue.) I'm at a loss as to how our legal and licensing institutions can be adapted to allow for a quick increase in the number of personnel who can care for intubated patients.
- DataDrivenMD 7y ago
  You raise a related issue, which is critical to address as well. That is, we need people to help manage patients before, during, and after their hospital stay. I’m less concerned about the licensing issues because public health emergency declarations make it possible for state officials to clear the way for someone like your mom. Where you, and fellow hackers can help, is by offering tech solutions that solve the issue of coordinating/figuring out where your mom’s skills could be most helpful. We will also need to collect information, such as when your mom is available to help. Could be a good time to revisit the concept of an Uber-like platform for healthcare delivery, assuming that it can be up an running in a few days. Hack-a-thon, anyone?
  - 7y ago

nx20593 7y ago

This whole sticking a tube down someone's throat without proper qualifications or equipment seems pretty dicey. Would an old fashion wooden iron lung work better? It's pretty primitive technology that doesn't seem too difficult to build. https://blog.sciencemuseum.org.uk/a-wooden-iron-lung/ https://blog.sciencemuseum.org.uk/a-wooden-iron-lung/

gentleman11 7y ago

My parents both have lung conditions. If this were Italy, and they got infected and needed ICU, they would not get treatment at the moment. What is the most promising home made gear I might be able to scrap together in the worst case scenario?

Peradine 7y ago

I'm an anaesthetics and intensive care trainee, so I know something about ventilation. The reason COVID-19 patients need to get ventilated is due to a failure of oxygenation - the infection causes direct lung injury (ARDS) which impairs oxygen absorption in the lung tissue. Normally we breathe room air, which is 21% oxygen, this drops to around 10% oxygen in the arterial blood due to inefficiencies in the absorption in the lungs. In a normal healthy patient breathing 100% Oxygen, their arterial oxygen content would be around 90%. ARDS significantly impairs oxygen uptake by the lungs, in severe cases patients breathing 100% oxygen may have arterial oxygen concentrations of just 8-10%. The purpose of ventilation in these severe ARDS patients is to augment oxygenation of the blood, using a combination of techniques including end-expiatory positive pressure and inverse-ratio ventilation, among others, and support the fatiguing respiratory muscles. Because the lungs of COVID-19 patients are already injured by the infection, they are very prone to further ventilator-associated injury. Modern intensive care ventilators have complicated computer-controlled 'modes', which allow precise regulation of ventilatory volumes, pressures, rates, timing, and gas blending. The ARDSnet trials in the early 2000s demonstrated the importance of carefully managed 'lung protective' ventilation, poor quality ventilation is likely to cause further lung injury and make the patient worse, not better. Therefore amateur ventilators are unlikely to be beneficial in COVID-19 unless they can provide similar lung protective ventilation, which would make them quite complicated. Additionally, ventilation is just one component of the management of sick COVID-19 patients. First you need to pass a breathing tube into their trachea, which is a challenging and risky procedure when performed by a skilled operative in a otherwise well patient, let alone someone on the brink of respiratory failure. Once intubated you will need to keep them deeply sedated, otherwise they will strain against the ventilator and make effective ventilatory care impossible. This requires equipment, drugs, and skilled staff, all of which are going to be in short supply.

solotronics 7y ago
As someone with asthma this is terrifying. My worst nightmare is not being able to breathe.
jmccorm 7y ago
Any thoughts as to the early treatment with a medical BiPAP when full-function respirator therapy is not available?

ilan1966 7y ago

i am an anaesthetist i trained using a manley ventilator covid patients apparently are easy to ventilate the issue is their gas exchange not their compliance a manley ventilator will do just fine for many patients, not all i accept but many

ilan1966 7y ago
BTW ICU doenst use volatile anaesthetics to sedate people we tend to use opioids & benzos to sedate

ilan1966 7y ago

i recon you could build a manley in your shed with some decent mech eng skills and it could certainly be printed

niutech 7y ago

There is a working open source ventilator prototype called VentilAid made in Poland: http://www.ventilaid.org http://www.ventilaid.org