No more deep diving deaths

[underwaterfrank]

Hmmm, some years I ago i drowned (nearly drowned is probably the correct term but I was stuck underwater until I started to drown and blacked-out). How do you comfortably make a transition from breathing air to breathing liquid? The scene in the Abbyss with the mouse is real, but you can see how the little animal is gasping and coughing as it makes the transition.
I clearly remember every gasp and cough from when i drowned. It wasn't easy and even though your lungs scream for air, you can't actually inhale liquid voluntarily. All you body reflexes stop you from taking that first gasp until your lungs are actually convulsing from the excess CO2 build-up. Once I took that first gasp, some water shot into my lungs but immediately after my throat locked-up and I coughed but every time I gasped for more it felt like there was a blockage in my airway chocking me. It was not until I was maybe 10-15 seconds from blacking-out that I managed to suck some water into my lungs. Strangely that felt great and it immediately relieved most of my desire for air, but after 3 small and labourous breaths I lost consciousness.
maybe if the liquid is at body temperature it would be more comfortable but still pretty much a drowning experience i would thnk.
I doubt that oxygenated liquid would have kept me conscious after I finally started inhaling liquid. Inhaling water really took a lot of effort, kind of like trying to breather through a drinking straw.

Also, breathing liquids are actually used for babies with lung deficiencies, so it is definitely no science fiction. Obviously it can work under certain conditions, but I think with a fully conscious adult person it would be more torture than pleasure.
Not sure what the Navy divers did, but maybe you need a treatment to relax the larynx first so there is no spasm from inhaling that first amount of liquid?
Would you need a strong tranquilizer first so you don't bail-out from the feeling of panic as you transition from air to liquid in a way like you're chocking on a drink?

When they can make it work, I'll be the first one to try.

Would be keen to learn more. Does anyone have any references to actual Navy research studies on this?

 

[Anti-Hero]

Hmmm, some years I ago i drowned (nearly drowned is probably the correct term but I was stuck underwater until I started to drown and blacked-out). How do you comfortably make a transition from breathing air to breathing liquid? The scene in the Abbyss with the mouse is real, but you can see how the little animal is gasping and coughing as it makes the transition.
I clearly remember every gasp and cough from when i drowned. It wasn't easy and even though your lungs scream for air, you can't actually inhale liquid voluntarily. All you body reflexes stop you from taking that first gasp until your lungs are actually convulsing from the excess CO2 build-up. Once I took that first gasp, some water shot into my lungs but immediately after my throat locked-up and I coughed but every time I gasped for more it felt like there was a blockage in my airway chocking me. It was not until I was maybe 10-15 seconds from blacking-out that I managed to suck some water into my lungs. Strangely that felt great and it immediately relieved most of my desire for air, but after 3 small and labourous breaths I lost consciousness.
maybe if the liquid is at body temperature it would be more comfortable but still pretty much a drowning experience i would thnk.
I doubt that oxygenated liquid would have kept me conscious after I finally started inhaling liquid. Inhaling water really took a lot of effort, kind of like trying to breather through a drinking straw.

Also, breathing liquids are actually used for babies with lung deficiencies, so it is definitely no science fiction. Obviously it can work under certain conditions, but I think with a fully conscious adult person it would be more torture than pleasure.
Not sure what the Navy divers did, but maybe you need a treatment to relax the larynx first so there is no spasm from inhaling that first amount of liquid?
Would you need a strong tranquilizer first so you don't bail-out from the feeling of panic as you transition from air to liquid in a way like you're chocking on a drink?

When they can make it work, I'll be the first one to try.

Would be keen to learn more. Does anyone have any references to actual Navy research studies on this?

Dude, that is gnarly. Mind if I ask what were the circumstances of your near drowning? You can PM if you don't want to go off topic in the thread.

 

[Deefstes]

Dude, that is gnarly. Mind if I ask what were the circumstances of your near drowning? You can PM if you don't want to go off topic in the thread.

Or start a new thread and post the link here. I'd also be fascinated to know.

 

[JollyWaffl]

... The advantage of using a liquid breathing media is that other gasses from the breathing media are not diffused into the tissues while under pressure. Hgh partial pressure of gaseous breathing media are not required to avoid pulmonary compression (since the media is non-compressible). This would negate the need for decompression and possibly alleviate HPNS...

HPNS is the first thing I thought of, but I lack the medical background to know the details. I nonetheless had the impression that HPNS is caused by a change in the behavior of nerves when under pressure. A liquid medium wouldn't help, in that case, because the diver would still experience the same absolute pressure. Have I misunderstood something, or been misinformed?

 

[DevonDiver]

I'm not sure how it would help HPNS... as surely the gas diffusion into the body would still be the same?

If the liquid was created with a lower nitrogen content (for purposes of eliminating narcosis), then that might have a knock-on towards HPNS. I believe that nitrogen can have a role in reducing HPNS?

What it might allow is longer duration diving, as simular to a rebreather, you could recirculate the breathing liquid and add more oxygen as required. It might also allow deeper diving (physiological impacts aside), as you wouldn't need a pressurized cylinder to deliver gas.

 

[JanK]

As far as I understand this, I'd say that breathing a liquid solves most of the problems with various gasses in scuba, including HPNS.

Breathing gas performs two functions: provides means of gas exchange (O2 into blood, CO2 from blood) and keeps the lungs inflated. In order to keep the lungs inflated at greater dephts, you need to start fiddling with the gas mixture and balance between different tradeoffs (HPNS, nitrogen narcosis, oxygen toxicity), as different gasses in the "diluent" (borrowing a term from rebreathers) cause different effects on the body. So you make an "optimal" mix and use that.

Breathing liquid performs the same functions, but in a very different manner. It keeps the lungs inflated with a substance that does not enter the organism through the lungs. So if you make sure that the liquid is clear of dissolved gasses other than O2, you don't have to worry about N2, He,... you just need to keep ppO2 between 1.4 and 0.2 and you're OK.

 

[JollyWaffl]

But isn't HPNS, despite also being called the "helium tremors", unrelated to the gas you're breathing and instead caused by pressure on the body? Nitrogen helps, but I thought because it acts as a narcotic and not because it removes helium. I've tried searching google scholar for more info, but no luck - can anyone point me towards relevant research or literature?

If helium exposure's the cause, then yeah I can see how this would help. Wonder if they're looking for test subjects...

 

[JanK]

An excellent source of information is The Rubicon Research Repository

From one article (with a small sample of 4 people):

The same men in November-December 1973 were exposed in 27 mins (plus 6 mins. for stages) to 1000 ft. with trimix (18% N2), heliox and to 200 ft. (air). Decompression after 1 hour at 1000 ft. was in 4 days. The presence of N2 suppressed the tremors completely compared with He/ 02. Psychomotor tests showed an improvement and the nausea and dizziness stopped. Some decrement in performance, especially intellectual, was still present with trimix due to nitrogen narcosis.

and

Thus N2 suppressed signs and symptoms of HPNS but the N2 partial pressure was too high in the present dives resulting in unnecessary narcosis.

 

[underwaterfrank]

It's pretty much been explained already but as i see it, in the liquid breathing solution you have no nitrogen, no helium, etc., so none of the toxic effects related to gasses under pressure are present so very deep dives should be possible.
No such gasses in the liquid means no gasses to be absorbed in your blood, so no sudden release of gasses during rapid decompression, so no embolisms.
Oxygen in the blood is carried on heamoglobin as far as I know, chemically bonded, and not in the form of dissolved gas, so there is not risk of bubbles generating from oxygen during rapid ascent. there only other gas involved would be the CO2 which is produced in your body and expelled in the lungs, so would end up in the breathing liquid. during rapid decompression maybe that would form bubbles inside the liquid, but that would not be an issue.
I'm not a technical diver so not sure if there is a need to add any gases to function at depth. I assume not.

 

[diverdoug1]

But isn't HPNS, despite also being called the "helium tremors", unrelated to the gas you're breathing

No, incidence of HPNS is changed with variation of breathing gas composition. Use of anticonvulsants and 5HT1a receptor antagonists have also decreased incidence in animal experiments.