DIY Ventilator project

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BlinkyBill

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#2459298 11-Apr-2020 11:32

I came across this article which notes that Covid-19 patients on ventilators die at a higher rate than expected and in comparison to other pulmonary-type issues.

https://qz.com/1833147/doctors-fighting-coronavirus-face-a-ventilator-catch-22/?utm_source=email&utm_medium=daily-brief

Posting in case anyone is interested - I haven’t read this article and the linked studies carefully.

ezbee

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#2459307 11-Apr-2020 11:46

frankv: Something like pilots' G suits, which inflate around the abdomen (and legs, but ignore that part)?

Yep , bang on Frank.

There would be more complexity as you have to have some parts rigid some not and then alternating direction of force.
You need to create a negative pressure to pull on the chest and thereby inflate the lungs as muscles normally would.

A prosthetic artist/engineer at Weta Workshop should have the right skills.
If air driven special effects are still a thing.
If anyone knows one.

Problem for patent is they need to breathe more deeply and lungs adn muscles working like an athelete might hour after hour without rest to try to get oxygen in the blood.

They can't keep it up.

Rigid solution like the link above mini iron lung might be easier to build.
( Hey Elon can we borrow that mini submarine you aren't using )

Idea of in inflatable device seemed a worthy alternative.

Going further out another idea would be some of the soft materials that robotics guys experiment with to simulate muscle that change shape under electrical stimulation.

ezbee

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#2459319 11-Apr-2020 12:06

Blinkybill, Yes

CV19 is a tough opponent when it gets a foothold , plus your own bodies reactions late in the piece can be counter-productive.

Traditional Ventilator has a lot of downsides and left as last resort when things are really bad.
In the Kim Hill RNZ interview Chris Smith covered some of this too, thus his interest in the possibility of the updated Iron Lung.

""
The product of the University of Warwick, Marshall Aerospace & Defence Group, the Imperial NHS Trust, the Royal National Throat Nose and Ear hospital, and teams of citizen scientists, medical clinicians, academics, manufacturers, and engineers, the new NPV device, called the "exovent," has already reached the prototype stage and will be tested at two intensive care clinics in the UK.

Unlike ventilators, the exovent doesn't require intubation and is much simpler in design and operation. According to the consortium responsible for its design, patients can remain awake, take medications, eat and drink, and talk to their loved ones on the phone. In addition, the machine improves heart efficiency by 25 percent over conventional ventilators, which can adversely affect cardiac functions.

Looks like something that can be used early and that itself has to be a very big plus.

Gurezaemon

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#2459327 11-Apr-2020 12:21

Interesting comments on ventilator design, reinforcing the damage that can be done by any positive pressure into the lungs, and the exquisite timing necessary.

ezbee

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#2459423 11-Apr-2020 15:54

Gurezaemon,

That was a great video very informative. Thank you.

Its great to see people learning new skills and spending time to think about new approaches.
I highly commend them, though as noted in video a whole bunch of other stuff needs to be added to get a practical product.
Not the least is considerable input from experts in the field.

It did cite a long term need for low cost ventilation for much of the world that can't afford present systems.
So new ideas are welcome, its a kind of physical brainstorming, people will learn something for their later projects.

Mr Musk I don't really have it in for you or Tesla.
Your submarine was great team building and creative exercise, a plus on its own.
Some humility when contacting those who might use it would have saved you looking like you did.
Then you could have seen the great need was for what you already had powerwalls to keep the pumps running.
Maybe you had some pump tech that could have been adapted quickly.

I heard something on Google X projects.
One of the criteria is something that can be constructed and tested quickly with low resource.
Learnings from that can quickly go into next step then next step. Dead ends get revealed quicker too.
Projects that need big resource long timelines upfront before something can be tested don't get passed.

Maybe there is also an intermediate approach below a full ventilator capability for short term use.

Video actually makes me like the Iron Lung idea more and more if an innovation made this smaller and portable.

afe66

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#2459751 12-Apr-2020 12:25

ezbee:

frankv: Something like pilots' G suits, which inflate around the abdomen (and legs, but ignore that part)?

Yep , bang on Frank.

There would be more complexity as you have to have some parts rigid some not and then alternating direction of force.
You need to create a negative pressure to pull on the chest and thereby inflate the lungs as muscles normally would.

A prosthetic artist/engineer at Weta Workshop should have the right skills.
If air driven special effects are still a thing.
If anyone knows one.

Problem for patent is they need to breathe more deeply and lungs adn muscles working like an athelete might hour after hour without rest to try to get oxygen in the blood.

They can't keep it up.

Rigid solution like the link above mini iron lung might be easier to build.
( Hey Elon can we borrow that mini submarine you aren't using )

Idea of in inflatable device seemed a worthy alternative.

Going further out another idea would be some of the soft materials that robotics guys experiment with to simulate muscle that change shape under electrical stimulation.

Not sure about ventilating people by increasing pressure on their abdomen.

First concern is aspiration risk where the increased abdominal pressure forces stomach contents up the eosophagus into the larynx and some will leak passed the endotracheal cuff and into the lungs. The cuff are not perfect seals. These patients will also be fed using nasogastric tubes which interfere with the oesophageal sphinceters and increase reflux even with normal abdominal pressures.

This reflux with increased intra abdominal pressures is not infrequently seen when patients have longer laparoscopic operations. ie prior to extubation we suction the back of throat and often find gastric secretions.

The second issue with repeatedly pushing on the stomach is that your insides havent evolved to be resistant to that. Remember sausages originally used intestines as the cases and your intestines are very thin. Your repeatedly pushing on them. Ileus where the intestine slow down is common in severely ill patients and the intestines can fill with fluid, so you are now repeatedly poking very thin wall fluid filled sausages...

I also wonder how the blood supply would be affected ie end arteries in your intestines are very small. Venous blood pressure would also be very low and raising the intra abdominal pressure might affect venous flow.

Remember may of these patients are elderly and their end organ visceral blood supply might not impaired.

Increased abdominal pressure would worsen small airway collapse which is a big problem with ventilated patients and why we use PEEP and CPAP

Would increasing the abdominal pressure have effects of venous return from the lower legs? ?increased DVT risk.

Obesity. How would this work with obese patients. You have to push hard enough on the skin to move fat and increase intra abdominal pressure sufficient to move the lungs.

How do you know how much air is being moved? You would still need spirometry on the ET and a method of measuring O2 CO2.

How do you increase the tidal volume other than pushing harder?

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afe66

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#2459754 12-Apr-2020 12:32

ezbee:

Gurezaemon,

Video actually makes me like the Iron Lung idea more and more if an innovation made this smaller and portable.

RE Iron lung - this was a treatment for a single problem of inability to move the diaphragm. They didnt have the multitude of other problems critical ill patients have.

How do you access the patient in an iron lung?

ICU patients have multiple lines running in to them. Arterial lines, Central lines into the neck, dialysis lines, urinary catheters. How do you insert them ? Troubleshoot them. We are constant fiddling with them.

How do you listen to their heart, lungs? Touch them? Feel their skin temperature, small pulses in their feet

Can you prone a patient in an iron lung?

Can your CPR or defibrillate them?

ezbee

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#2459915 12-Apr-2020 14:55

afe66

Good points.

Most of the work is done by negative pressure , expanding the chest and helping diaphragm.
The amount of pressure, positive or negative is just enough to assist and do the job.
The weight of chest and natural movement may mean you don't have to assist much on excellation anyway.

Problem is patents muscles grow tired of maintaining the exertion of breathing.
You need something like the assist an electric bike gives going up hill.
Does not have to do all the work.

The patent is not sedated so normal autonomic functions including shallow breathing still operate.
To the lungs and sensitive tissues within this is all quite natural.

So sensors to synch with natural movement , as the patent is mostly awake.

Pictures on the links below give a better idea, with modern design you only need to cover the chest area.
The UK design is smaller box like structure, than the large Iron Lung from black and white movies.
You can have hatches in the structure so access is not such a problem.

https://newatlas.com/medical/british-engineers-modern-iron-lung-covid-19-ventilator-alternative/

https://www.cambridge-news.co.uk/news/local-news/cambridge-coronavirus-ventillators-exovent-hawking-18029014

What I was brainstorming was if you could use a soft structure that is inflated by pressure also , much like a Zorb or Airbed is , and the negative pressure can work against this rather than a box made of hard materials.

The hard box ( like a big systema plastic box ), probably wins out as you can have more opening hatches that are easier to build. Though not impossible in the soft structure, yeh its a bit fussy.

Beyond this it would need a real engineer and real ICU specialist to take this anywhere.
I'm just enthusiastic conceptualist.
Any commercial or non-profit open source effort would also need to navigate any patents on this updated style of design, the old Iron Lung ones surely expired though.

ezbee

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#2459923 12-Apr-2020 15:07

afe66

Oh thinking back to Gurezaemon's excellent video posted earlier.

There was mention of benefit of slight positive pressure not completely evacuating the lungs for sure.

So it may even more be a case of only assisting on inhalation , and letting exhalation mainly look after itself.

I think idea of this is it can be used much earlier than traditional last resort of ventilator, as you don;t need to sedate and all the risks that go with that 50/50 shot at life.

jondoublew

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#2459931 12-Apr-2020 15:21

ventilators are a bit more complicated than just redirecting air to the lungs. you need to vary the pressure throughout the breath, detect O2 and CO2, etc.

Basic ventilators like BPAP are found everywhere, used commonly in homes for sleeping problems- and can be useful for mild covid patients. but the ones that hospitals need are for those patients that are fully unconscious and depend on a ventilator to keep them alive! i highly doubt DIY versions will be approved by hospitals for these patients.

if you are really keen to go with it, medtronics (makers of one of the world's most popular ventilators) is open sourcing one of their models so you can tinker with it. better than reinventing the wheel as their model has is already in use in hospitals. their link is https://www.medtronic.com/us-en/e/open-files.html

afe66

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#2459963 12-Apr-2020 15:46

Its an interesting project to think of ways of ventilating patients but as someone who uses ventilators, I very much doubt anyone will sign off on a home brew ventilator.

Rather than everyone reinventing the wheel I think we should be looking at established plans from major firms or modifications of ventilators that were in use 20-30 years ago.

We are very lucky in nz in having essentially no current burden of covid ICU cases. I expect we have far more patients post cardiac arrest in our units.

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ezbee

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#2460001 12-Apr-2020 16:28

afe66,

I agree , my view is its more learning exercise for those tossing ideas around than practical.

The 3D printing for face shield if you have a bunch of old overhead slides gather dust, and printer is probably more practical.
For those workers in areas outside the core that have a degree of need to preserve certified stuff for those that have to have it.

This swab 3D printing , not for the home situation, was done by professional team as it has to be.
https://spectrum.ieee.org/the-human-os/biomedical/devices/healthcare-team-designed-3dprinted-tested-covid19-swabs-one-week

Appreciate your work , and if we keep up our social distancing we can avoid putting your team in danger.

Thank you.

Kia Kaha

ezbee

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#2464150 17-Apr-2020 13:40

New from the TRON

A Ventilator that has been tested on a Sheep already !

RadioNZ segment just being broadcasted, will be up on their podcasts , pity they don't do transcripts.

It will show on this link today.

https://www.rnz.co.nz/national/programmes/afternoons

Photo about 25% down the page above.

https://www.rnz.co.nz/assets/news/228421/eight_col_Screen_Shot_2020-04-17_at_12.21.32_PM.png?1587082994
Jeff Sharp, Dr Martyn Harvey and Dr Giles Chanwai working on the protototype

A ventilator prototype in the Waikato

An engineer and two medical specialists in the Waikato, who all happen to be neighbors, have teamed up to create a new emergency ventilator prototype.

We speak to Jeff Sharp, who is the managing director of the Hamilton plastics engineering firm ES Plastics.'

Rurakura got involved and it was approved to be tested on a Sheep so far.

Seems the low potential cost still makes this worthwhile for 3rd world, even if 1st world maybe over ventilator peak ( Fingers firmly crossed )

Well at very least a boon for veterinary sector.

Go the TRON !

Edit to add link to photo .... Plus separating my comments out from that cut from radionz web.

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