Question (Diving adjacent) Does mechanical ventilation need invasive procedures?

[Mobulai]

Inspired by some earlier discussions about diving „innovation“, I had me a think
(dusty hamster wheels churning, look away it aint pretty)
This is not necessarily diving related (well depending on the initial answer y/n), so I don’t know where to ask — and I wanna account for the opinions of the intersection of diving and medical pros (looking at Anesthesiologists/pulmonologists especially here), so I’ll take my chances posting here:

Can mechanical ventilation (assisted breathing) be achieved without the use of an inter tracheal tube (is that the right term)?

The imagined usecase/why I ask:
Gas density at depth/unconscious diver/high WOB… is there a chance some form of a ventilator helping them out (without turning diving into a whole procedure of shoving a tube down the throat)
Don’t know if that idea has been explored before so any leads welcome

Happy holidays everyone

 

[rongoodman]

You can certainly ventilate a patient for the short term with a mask which fits over the mouth and nose. The problem is that it's not easy to do and air can easily be forced into the stomach, which can lead to regurgitation and the stomach contents making their way into the lungs, a very bad thing. Passing an endotracheal tube down the throat not only allows air and some meds to be easily delivered to the lungs, but protects them from anything else getting down there by means of small inflatable cuff which sits below the vocal cords.

 

[Mobulai]

so,

but protects them from anything else getting down there by means of small inflatable cuff which sits below the vocal cords.

Dynamic airway compression would still be a factor without „supporting“ the trachea then
Adding the stomach part makes (eg. convulsions) makes it a horrible combo

Now I can see why this is dead in the tracks idea

At least my curiosity is satisfied

 

[rjack321]

Not applicable to diving in any way shape or form but there are forms of ventilation that don't require an ET tube cpap is one form you may know for sleep apnea. Bipap is another. https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/bipap

Neither are applicable to an unconscious or seizing patient.

 

[Nic2750]

I'm not an anesthesiologist, pulmonologist or a dive professional, but I fell down a rabbit hole a while back and found some interesting papers that looked at in-water resuscitation using scuba regulators. I am not suggesting anyone tries whatever's suggested in the papers - they're just fun to read.

Oxylator and SCUBA dive regulators: useful utilities for in-water resuscitation (2012)

The Scuba Regulator as a Resuscitator for In-Water Rescue Breathing. (1982)

And this one for using a modified regulator for IPPV:

Modification of scuba regulator for IPPV. (1985)

And CPR, just to round it off:

Feasibility study of CPR in the water. (1980)

I'm sure there's a reason most of the studies are from the early '80s, but they kept me entertained for a bit.

 

[justinthedeeps]

Are you referring to in-water ideas, or a surfaced diver?
Is it possible to ensure an open airway underwater and protect it?
Does the PADI on-surface 'rescue breaths tow' actually achieve either of those things either? Strong 'maybe' (less so in chop)

 

[Mobulai]

No I’m wasn’t thinking of resuscitation (as a main thing), I’m trying to imagine assisted breathing (at depth), more or less active mechanisms to lower WoB (and also in case of a seizing diver it might have helped)
Think.. that thing from the Abyss but without drowning as a predive ritual

For surface resuscitation I wouldn’t hesitate to use my soft free diving snorkel (sits in my pocket/butt pouch) if remote & m2m/cpr aren’t helping (my dad taught me how to do it years ago), but probably on shore not on surf

But more and more I realize that the dream device from the Abyss stays scifi

 

[justinthedeeps]

Tubes into airway probably not gonna fly recreationally (YMMV)

Perhaps some wearable intravenous mainline 'heart/lung machine' that reconditions the blood directly? Who needs pesky airways underwater?

Supposedly 'good' open circuit second stage regulators already assist breathing all of the time, thru a bit of positive pressure above ambient once cracked open. Enough so that we're cautioned to not use them for in-water forced ventilations!

I hear chest mount rebreathers operate on positive pressure because the counterlung sits deeper than the lungs? Does this assist ventilation and reduce WOB (inhale)?

 

[Mobulai]

The inhalation side is easier for sure, eothr CM or OC regs

But afaik the exhalation (on high density) is where things get clunky
So if some machine can apply the right amount of negative pressure, the density limitation can be mitigated

Perhaps some wearable intravenous mainline 'heart/lung machine' that reconditions the blood directly? Who needs pesky airways underwater?

True, maybe a dialysis machine retrofitted for blood oxygenation might work effectively — instead of a counterlung we’ll dive an outerlung
It’s time we evolve into whales as well

 

[Chrisk919]

But more and more I realize that the dream device from the Abyss stays scifi

Do you mean the suit with the PFC breathing liquid?

If I remember correctly from the Bluray commentary and some digging the liquid was real (and the rat really breathed it for a bit), but IIRC - after going down some internet/research-paper rat-hole a while ago = there were some issues with it still (notably consistent PFC refresh of oxygenation in the lungs, clearing the lungs of the liquid after-the-fact, and some potential for post-dive pneumonia due to the liquid remaining in alveoli)

Regardless of those issues - due to this (or any) liquid's density vs air, wouldn't you still have an issue with WOB under load? You still need to remove CO2 from your body, and under a work load I assume that is an issue with a liquid breathing medium. I'm not sure IPE would still be a problem because your whole set of lungs are filled with liquid, but I'm no pulmonologist/medical professional.

ETA: Well as of 2022 researchers are still looking at it for some medical pulmonary use-cases - so maybe some day.