I read something once (can’t remember if it was ‘future science’ or ‘science fiction’) about a method of filling our lungs up with an oxygen enhanced water solution which allows us to extract enough oxyen to live without having to breathe. This would aloow external deep-sea diving without worrying about lungs collapsing under pressure at depth. And it probably had other practical uses too which escape me at the moment.
Now, is this in any way a viable technology? Has it even been used or tested? Would it be hell removing the water solution from the lungs afterwards, even if it did work? Can our lungs even extract oxygen from water as they would from air, if the concentration levels are high enough, or would we merely drown?
It is currently possible with oxygenated perfluorocarbons (as used, or allegedly used, in the movie The Abyss) - there are potential health risks of long-term contact between delicate lung tissue and such compounds, IIRC.
I have no comment to make, except that removing such a solution would probably take a good deal of surfactant with it, thus altering the surface tension of the lungs and making breathing much more difficult.
One use for it is for treating people with damaged lungs (severe smoke inhalation, near-drowning and such) It’s in “Phase 3” testing now so I guess you could call it “near reality” rather than “science fiction.”
When it’s no longer needed, it’s allowed to simply evaporate. The site above makes it sound like only a little of the stuff is used.
Then, in David Brin’s Brightness Reef, there’s the “oxywater” that the mixed human/cetacean crew of the Streaker filled the ship’s cabin with so that both could breathe and remain motile.
Brightness Reef was my introduction to Brin’s fascinating series of Uplift novels, and I recommend it to any SF fan. Or cetacean-lover.
As others have pointed out the technique uses fluorocarbons, not water. The extraction process itself isn’t all that difficult, simply allow the subject to cough the water out. The problem comes when the surfactants and mucus are removed form the lung. There is a risk of the lung collapsing and a high risk of pneumonia. Humans can’t extract enough oxygen from water to survive. The effort required to move liquid in and out of the lungs uses more oxygen than can be extracted from the water.