Is it possible to make a non-invasive ventilator?

I drove my daughter to work today. We often go on some intellectual exercise and today it was whether it would be possible to make a home brew ventilator. we read about Italy running short of ICU beds and ventilators.

Let’s assume that we have all of Home Depot, Woodcraft and a welding supply at our disposal. Let’s further assume that we have a full wood and machine shop at our disposal. Finally, we can assume that, for a short while, we can have an attendant.

in my case, I also have several Arduino microcontrollers on hand as well as the stuff to drive relays. I also have a Microcenter nearby for electronics. Leveraging Home Depot, that gives me sprinkler valves to turn air on and off.

reading about ventilators, there is a lot of nuance and sophistication there. I’m thinking that if operate on the assumption that we have nothing to lose, we can dispense with the details and make something very basic.

feedback is important. We happen to have an Owlet which is a pulse oximitry device for infants. It would be easy to tape the sensor to a hand or foot.

ideas? How basic could you get to save a life? The assumption is that there is no alternative and that something is better than nothing.

I don't know what a ventilator does, and I may not be the only one on this board who doesn't. You might describe what one is.

Sorry,
in cases of severe pneumonia, patients can’t breath on their own and need mechanical assistance. There are two basic flavors: invasive where they intubate and non-invasive where they use a mask.

it seems that someone out there is working on the idea.

https://panvent.blogspot.com/

loads of good information. In the car, I was going a very different direction. Imagine a rubber dust mask with the two filters. Take one filter off and fit a HVLP pump up. If you turn the air flow on, the idea would be to overcome the leakage through the other filter and inflate the lungs. Turn the flow off and the patient exhales. My idea would require the air source, two sprinkler valves, a microcontroller to run the valves and various stuff to control the pressure.

Well, as the guys on the old Top Gear used to say "how hard can it be?". Disaster & hilarity followed :D

I am old enough to remember "iron lungs" and the unfortunates that got trapped in them. They were and are non-invasive ventilators. Not sure they are any quicker to supply than the current invasive types.

Anyone who has ever used, or slept next to someone who used, a CPAP will have no trouble thinking of one possible solution.

Then there's SCUBA gear.

Quote:

---

Originally Posted by Alan Rutherford

Anyone who has ever used, or slept next to someone who used, a CPAP will have no trouble thinking of one possible solution.

Then there's SCUBA gear.

---

A CPAP machine, as the name implies, provides continuous pressure, I wouldn't think that would work as a ventilator as you need to have the ventilator exhale.....Rod.

Quote:

---

Originally Posted by mike holden

I am old enough to remember "iron lungs" and the unfortunates that got trapped in them. They were and are non-invasive ventilators. Not sure they are any quicker to supply than the current invasive types.

---

MIke, I read a piece about the few iron lungs still in use. They’ve been keeping them running using very old parts, some made of leather. The parts are running out and the people who can work on the machines are getting scarce.

Quote:

---

Originally Posted by Rod Sheridan

A CPAP machine, as the name implies, provides continuous pressure, I wouldn't think that would work as a ventilator as you need to have the ventilator exhale.....Rod.

---

Given some desperation along with a few Arduinos and someone who knows what to do with them, we could work that out.

Ventilators are not my field, but I believe oxygen is usually continuous flow. With a ventilator which provides positive pressure, I'd think exhaling would take care of itself if you interrupt the pressure.

Quote:

---

Originally Posted by Roger Feeley

I drove my daughter to work today. We often go on some intellectual exercise and today it was whether it would be possible to make a home brew ventilator. we read about Italy running short of ICU beds and ventilators.

Let’s assume that we have all of Home Depot, Woodcraft and a welding supply at our disposal. Let’s further assume that we have a full wood and machine shop at our disposal. Finally, we can assume that, for a short while, we can have an attendant.

in my case, I also have several Arduino microcontrollers on hand as well as the stuff to drive relays. I also have a Microcenter nearby for electronics. Leveraging Home Depot, that gives me sprinkler valves to turn air on and off.

reading about ventilators, there is a lot of nuance and sophistication there. I’m thinking that if operate on the assumption that we have nothing to lose, we can dispense with the details and make something very basic.

feedback is important. We happen to have an Owlet which is a pulse oximitry device for infants. It would be easy to tape the sensor to a hand or foot.

ideas? How basic could you get to save a life? The assumption is that there is no alternative and that something is better than nothing.

---

Some years ago, the hospital where I worked did a capital overhaul of the respiratory therapy department, and part of it was replacing the legacy fleet of ventilators made by Puritan Bennett with a (then) new technology vent called the Pulmonetics LTV. The PB was the size of a full crash cart, and the LTV was about the size of a laptop computer so the difference was stunning. Also the PB required a compressed air incoming line, and the LTV did not. I was in one of the meetings with the Pulmonetics rep and he said the reason for not needing compressed air was that the LTV was turbine driven. The unit had been developed as a transport vent for use among paramedics in the field but the inpatient hospitals caught on and it became widely adopted.

So as a woodworker, thinking about the turbine driven HVLP spray systems, perhaps your home brew brainstorming could make use of a paint spraying system, even a budget one the likes of which you might find in HD or Harbor Freight. Just an idea, and hat's off for your innovative thinking. That's how many great inventions come to be.

As an aside: the Pulmonetics rep told me the unit had basically been invented by a non-medical engineer whose father became ventilator dependent due to COPD. The LTV was a big breakthrough, but his dream was to develop a ventilator small enough to fit in a pocket, so the patient could come closer to resuming normal life activities. Although I will point out, the LTV was still an invasive ventilator used on intubated patients, at least in standard practice.

After doing some general noodling on the internet, I find that the one site that already linked is about the only diy effort out there. I found one link on the site that some might overlook called “Design of Vinnie”
https://panvent.blogspot.com/2007/12...ss-report.html
Vinnie is a very nice refinement of his general concept.
1. He got rid of an expensive PLC and went to a microcontroller
2. He replaced micro switches on his bellows with hall effect sensors.
3. The layout is really clean.
the woodworking aspect is pretty trivial and easily reproduced in any good shop.
the electronics are simple to reproduce.
I would replace his valves with sprinkler valves if possible. I don’t know how sprinkler valves would handle very low pressure.

CPAP machines do allow you to exhale. One way valves.

Quote:

---

Originally Posted by Stan Calow

CPAP machines do allow you to exhale. One way valves.

---

Stan, I know less than I should about CPAP but I’m pretty sure they wouldn’t function as a respirator. But, your post made me think of a variant of CPAP called BIPAP. That’s a CPAP with two pressure settings for inhale and exhale. BIPAP is supposed to help people who need a bit of breathing help. So for mild cases of pneumonia where full ventilation isn’t required, a BIPAP would suffice.

I’m in the Dc area inside the beltway and I don’t think I’ve ever heard this much low flying aircraft. We get a lot of choppers out of Quantico and other installations around here. Usually, I hear a half dozen per day. Today it’s been every ten minutes or so.

All ICUs already have non-invasive ventilators. They are insufficient for the kind of respiratory failure that SARS-CoV-2 (the virus causing COVID-19) causes, so the current recommendation for severe cases in the ICU is to intubate as early as possible. What's scary is that people are recovering from the respiratory failure only to die from as-yet-unexplainable heart failure. That report got my attention!