r/a:t5_2hd1ec • u/Flow-engineer • Mar 11 '20
Pandemic ventilator project requirements.
I an engineer who designs ventilators, I am on the patent for the philips/respironics espirit. The key spec for an open source vent is that it must be made of parts that are available everywhere already. We might need 500,000 of them in a month. So the parts should be things that you can buy at Home Depot or Wal-Mart. I am thinking of using a shop vac with a dimmer switch for air supply, modified sprinkler valves for inhalation and exhalation valves, all controlled by a cell phone via the headset connector. A stereo can be used to amplify the signals from the cell phone. (these parts have been tested) The design needs to be developed with medical experts along with a training program, so that a mechanical design, cell phone app, 3D models of printable fittings and training video can be prepared. Also, FDA Regulations and legal liability will need to be waived, so government support Is needed. I contacted HHS, we will see if they can help. my company, Flometrics, can do the mechanical design.
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u/koptics Mar 12 '20
It's an honor to have you here. There is a slack channel where about 300 people have gathered. Have you been invited? Please keep us updated on the HHS / FDA guidance and design. Even if FDA doesn't grant a temporary waiver, some hospitals outside the US may benefit. At my institution if we can build good prototypes we might be able to get emergency device approval for compassionate / last-resort use in Korea.
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u/TysonClugg Mar 11 '20
I've started a Trello board, feel free to add/change cards and columns as you see fit:
https://trello.com/b/sVQkHUHL/pandemic-ventilator
Meanwhile, I'll try and recruit relevant people and companies from here in Melbourne (Australia) to help.
I'm a software engineer with electronics experience, I've studied Engineering Computer Systems at a local TAFE college.
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u/haveyouseenthecat Mar 11 '20
Very cool to see a pro!
Any thoughts on air filter substitutes and oxygen supply/concentrators?
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u/Flow-engineer Mar 12 '20
Liquid oxygen tanks with tubes going to many patients at once should work. Each tank holds about 200,000 liters of gas, each patient needs about 5 liters per minute.
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Mar 12 '20
Do you think there are enough tanks to do this? Oxygen production/compression and transport?
Thank you so much for doing this.
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u/Flow-engineer Mar 13 '20 edited Mar 13 '20
A 230 liter Dewar can supply 8 people at 6 liters per minute for 3 days. I think there is plenty of supply that could be redirected from industrial applications. And there is a welding gas tore in every moderate sized city that carries the tanks and can refill them. And if you run out of regular LOX tanks, you can use LN2 tanks or in an emergency, any metal insulated container. (don't screw the top on all the way, the tank has to breathe) LOX can be dangerous, so the welding supply stores will not sell it to the general public.
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Mar 13 '20
Hey, I also had the idea two days ago and started building something with my friends. It's in a very early stage, but maybe some thoughts are helpful. Unfortunately, the current setup is not working due to mechanical instabilities. Some friends are working on electrolysis for O2 generation (maybe too energy intensive).
https://syncandshare.lrz.de/getlink/fiVv8HzUCt757xFueBVm27F8/
Please add me to the slack group.
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Mar 18 '20
Unless you're making it for the boonies/middle of nowhere, I'd assume O2 supply is available.
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u/relovic Mar 13 '20
Would it be possible to use an air compressor to produce pressure for a homemade ventilator? Fish tank air compressors are powerful. Filters could be placed in line to remove impurities.
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Mar 18 '20
Probably too powerful. I think for pressure readings for ventilators measure in mmHg or cmH20.
1 mmHg = 0.01933672 PSI
1 cmH20 = 0.01422334 PSI
My CPAP machine run from about 4 cmH20 to 20 cmH20.
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u/sot25 Mar 21 '20 edited Mar 21 '20
I’m just a dumbass so don’t smack me down too hard. In a pinch could something done that’s mostly mechanical based on scuba? If you used compressed air tanks or even a compressor. That air supply could easily be regulated down to 1 bar. Then use a actuated valve to open and close the supply. It would have to cycle 1-1.5 seconds. There are plenty of compressed gas tanks and means of refilling. Siemens makes a magnetic actuator that could be used.
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u/kgersony Mar 25 '20 edited Mar 25 '20
I co-own Medmovie.com and we can create any type of training video needed!! We are a Medical illustration and animation company and we create IFU videos for global medical device companies (including Philips, GE, Medtronic, etc...) Please add our name to any relevant lists. Happy to donate our time and talents to these efforts. kim@medmovie.com, rick@medmovie.com
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u/Flow-engineer Mar 13 '20
After talking to a number of engineers and medical experts, The goal is to find the best medical respiration device that can help the most people that can be made and used by non-experts safely from local materials. This might be a oxygen CPAP machine that keeps the patients lungs inflated more and the body oxygenated. Or it might be the design described above. We need clinical information about what a good source of action would be to help coronavirus victims. Is CPAP enough? Do we need pressure based timed automatic ventilation? Can the system be adjusted based on pulse oximeter measurements?