ECMO for Deep Sea Scuba diving?

[Stormer]

TL;DR Summary

Can ECMO be used as a better solution for extended and deep for scuba diving than liquid breathing?

I have taken an interest in technology for improving Scuba diving both to avoid the bends, nitrogen narcosis, oxygen toxicity, and other pressure problems, as well as increasing dive times and decrease the amount of bulky gear you have to bring with you.
The solution is usually rebreathers and helium gas mixes, but I am not satisfied width that. So on the more exotic end of the tech explored is liquid breathing. But there is a lot of problems with that such as removing CO2 and the extra effort to push a liquid with the lungs compared to a gas.

So why not take the lungs totally out of the question (other than filling them with something to equal the outside pressure of the water) and use a portable ECMO (Extracorporeal membrane oxygenation) device to supply oxygen and remove CO2 directly from the blood? Why have i not seen this solution sugested anywhere? Yes you have to install some "connection plug" to be able to plug in and out of the bloodstream, but i don't think this is much more impractical and unpleasant than the sugested liquid breathing solution and the subsequent problems with emptying out the liquid from the lungs again after the dive. But is it possible to remove the breathing reflex when the oxygen and CO2 stuff is done for you without the need for the lungs to cycle air?

 

[berkeman]

Do you have any links to journal articles on research with fluid-filled human lungs (whether for gas exchange or just for pressure tolerance)? Are you a scuba diver? (I am)

I'm only familiar with ECMO in a controlled hospital environment, not an ambulatory athletic environment like scuba diving. Do you have any links with more exotic uses of ECMO like the one you are proposing? Thanks.

https://medlineplus.gov/ency/article/007234.htm

https://www.mayoclinic.org/tests-procedures/ecmo/about/pac-20484615

 

[Stormer]

Yes i am a recreational scuba diver. Not that i see how that is relevant to the question here?

Liquid breathing has been researched since the 60's or 70's I think.

No I obviously don't have any links to ECMO use for scuba. That is what i am asking for the viability for. I think it should be pretty obvious from my post that i am asking for a novel use of ECMO, not a current use.

 

[BillTre]

Here is a wiki-link to liquid breathing.

They both sound like rather intrusive and technically demanding techniques that would have to be failsafe.
One requires a tap into one's blood stream (an infection risk) and exchange gas in a high tech manner.
The other requires replacing the air in the lungs with a liquid the lung tissue is not used to. Not clear to me, for how long this could be done. I think the machinery also has to aid or drive the breathing of the more non-gas fluid.
Equipment maintenance may also be demanding.

They would both seem to have the possibility of damage to lung tissue, but the liquid breathing at least has been used in dives.

 

[jim mcnamara]

If you've ever seen an ECMO as they exist right now, you might want to wait quite a while. It requires sedation and surgery to get hooked up. Actually coming up with this idea is okay -- maybe in 20 years it will be safe enough to apply to something like your suggestion. It will still require an $O_2$ source and a $CO_2$ sink. So you are gaining quite bit of mass over your existing SCUBA hardware. From that POV I do not see a big win.

To see one, try a google search 'picture of ECMO machine' They are not simple, not small, not lightweight, as the technology exists right now.

Prior to the current pandemic, ECMO was mostly reserved for neonatal patients, and some ARDS and transplant patients - AFAIK. Now, ECMO can also be used for severe cases of COVID-19. So. As far as extending ECMO applicability is concerned, we are making lots of progress. And helping sick people, too.

...Maybe the 20 year guesstimate above is more like 10 years.

 

[sysprog]

What about Dalton's, Charles', and Boyle's (and others') gas pressure laws? PADI article on gas laws

The first (padi example page) PADI book I read before going underwater with scuba gear explained about that $-$

I think that it's important that we here reinforce something that everyone already knows: it's very freaking dangerous, but if you heed the safety requirements, you too can probably become able to do it safely enough $-$ please learn well, have a competent and fully experienced buddy with you $-$ please breathe continuously and calmly $\dots$

 

[Stormer]

It requires sedation and surgery to get hooked up.

Yes of course. But that is a one time procedure, and after that you are "ready to connect" the rest of your life. And with todays medical tech there is still a continues infection risk of anything that brakes the skin barrier like this connectors will have to do. So that is a downside, but they still do sockets connecting to bone for amputees so I'm guessing they are getting pretty good at managing the infection risks.

It will still require an O2 source and a CO2 sink. So you are gaining quite bit of mass over your existing SCUBA hardware.

The O2 tank will be as small as on a rebreather system. And the CO2 scrubber does not have to be so big either. Comparing it to current medical equipment that is meant for use in hospitals is not really relevant, because there is no incentive there for shrinking the size, and there needs to be extra monitoring and failsafes because it is used for medical treatments. So i don't really think the system will have to be that large. Especially considering how much stuff divers today use on deep dives:

 

[sysprog]

Yes of course. But that is a one time procedure, and after that you are "ready to connect" the rest of your life.

Would the body area near the 'permanent' IV hookup not soon start showing necrosis and soon thereafter become gangrenous ??

 

[Stormer]

Would the body area near the 'permanent' IV hookup not soon start showing necrosis and soon thereafter become gangrenous ??

I don't know. How do they manage this for hart pumps for example?

 

[sysprog]

I don't know. How do they manage this for hart pumps for example?

You're apparently attempting to refer to extreme measures taken for severe heart conditions $-$ how could that have bearing on the question here? $-$ your idea seems to me to be that you can get an IV fitting, and walk around with it permanently installed, and experience no damaging consequences therefrom $-$ I'm skeptical regarding that $\dots$

 

[BillTre]

I don't know. How do they manage this for hart pumps for example?

I believe that most heart pumps and other internal medical gear are installed so that there are not skin penetrations after the install.
Breaks in the skin are much more likely to be an avenue for infection, something tubing connections to the vasculature require.

 

[Stormer]

I believe that most heart pumps and other internal medical gear are installed so that there are not skin penetrations after the install.
Breaks in the skin are much more likely to be an avenue for infection, something tubing connections to the vasculature require.

Well they do use skin penetrating sockets attached to the bone a lot today for amputees:

So I'm guessing that they manage to keep the risk of infection down to an acceptable level, or they would have just been sticking to the traditional cup sockets with no skin penetration with the disadvantages that has.

 

[kayvaan]

https://www.independent.co.uk/news/...ng-suit-that-turns-men-into-fish-2139167.html

There is a patent for it

 

[hutchphd]

...Maybe the 20 year guesstimate above is more like 10 years.

Or perhaps never

So I'm guessing that they manage to keep the risk of infection down to an acceptable level, or they would have just been sticking to the traditional cup sockets with no skin penetration with the disadvantages that has.

Deer antlers are a more promising model.
But this idea makes very little sense. The requirement to maintain a gas at pressure in the lung is fraught .with problems (regardless of the gas I believe) and then you want to do ECMO in addition?? A new idea perhaps but not a good idea. Good enough for bad Sci-Fi though!

 

[TeethWhitener]

Well they do use skin penetrating sockets attached to the bone a lot today for amputees:
View attachment 276603
So I'm guessing that they manage to keep the risk of infection down to an acceptable level, or they would have just been sticking to the traditional cup sockets with no skin penetration with the disadvantages that has.

Actually, chronic infection is a huge problem for osseointegrative prosthetics. There's millions of dollars in research being poured into it.

Deer antlers are a more promising model.

Teeth are probably the most promising human model. And in fact, a lot of expertise in research dentistry has been tapped to deal with osseointegration problems.

Liquid breathing has its own set of problems; IIRC, the main problem is that the fluorocarbon liquids tend to dissolve lung surfactant so that the alveoli collapse after evacuation of the liquid (this at least was the problem with mouse models--I haven't heard of anyone trying these experiments with humans).

Summary:: Can ECMO be used as a better solution for extended and deep for scuba diving than liquid breathing?

So why not take the lungs totally out of the question (other than filling them with something to equal the outside pressure of the water) and use a portable ECMO (Extracorporeal membrane oxygenation) device to supply oxygen and remove CO2 directly from the blood? Why have i not seen this solution sugested anywhere?

(Full disclosure: I do (unrelated) research for the Navy, so I'm somewhat familiar with some of the programs they have going on in this area.) The main problem with OP's idea is that it still doesn't prevent the bends, oxygen toxicity, nitrogen narcosis, HPNS, etc. You still end up with gases dissolved in the blood at a high pressure (the main cause of oxygen toxicity, nitrogen narcosis, and HPNS), and when that pressure decreases, you risk forming gaseous embolisms throughout the body (the main cause of the bends). Basically, the lungs aren't the problem. It's the fact that you have gas dissolved in your bloodstream at high externally applied pressures that is the root cause of all the issues.

 

[Godot_]

Can ECMO be used as a better solution for extended and deep for scuba diving than liquid breathing?
[...]

You'd have several technical issues here:
1) You'd still have to pressurize the ribcage. Else rib fractures, the resulting lung punctures and hemorrhagia, and cardiac "dislocation" would kill the diver.
2) You'd need high calibre access cannulae...You might want to watch this teaching video of an initial cannulation (further down on the page): https://edecmo.org/logistics/vv-ecmo/. Not for the squeamish...
3) You can't just implant suitable high volume "cannula receptacles" in the circulatory system. There is a reason why dialysis patients have to suffer the pain each time they come in... Even with standard port systems implanted e.g. for regular chemotherapy patients, they'll eventually shut themselves down thanks to coagulation. Stagnant blood tends to clot. Heparin coating etc. do a decent enough job to extend the lifetime of these ports to a practicable timespan, but there's a reason that these ports are removed ASAP once they're no longer needed... ...they always pose a risk for thromboembolism.
4) You'd create a high risk port of entry for infections with whatever access to the circulatory system you choose. And ...at least the size used in e.g. dialysis. And ECMO-patients either get off the machine in a timely manner - or eventually succumb to septicaemia, even with the best aseptic techniques eventually one of the germs will get through...
5) ECMO machinery is bulky, too. And, apart from an (electric) energy feed, it either needs a constant feed of air (when it has an integrated O2-concentrator) or pure oxygen. While this oxygen could technically also be collected from the surrounding seawater, that would have to be actively circulated too - which in turn needs quite some energy.
7) The diaphragm is a delicate muscle, and tends to atrophy pretty fast... ...in less then two weeks in the case of simple intubation ventilation on young to middle-aged patients. Weaning the patient off the respirator is quite a time consuming process. So this idea probably won't hold water for long-term dives, either...

IMHO, the devil you know is the better way here, at least for the foreseeable future.

[...]But is it possible to remove the breathing reflex when the oxygen and CO2 stuff is done for you without the need for the lungs to cycle air?

Any potent opioid you choose can do that. That's exactly what kills overdosing people...

 

[jim mcnamara]

@Godot_ - Here is a readable reference on respiratory suppression from opioid overdose:
https://www.scientificamerican.com/article/how-opioids-kill/