breathing water

[boobesque]

just watched the film 'the abyss' and it raised a question for me.
in the film the navy seals have a fluid which you can breath. Now, when we breath air, our lungs expand, drawing in the air and the oxygen is absorbed from the air into the blood stream. the excess waste air is then expelled and the process repeats.
So why cant we breath water? Why cant we extract the oxygen from water.
One thing i thought of was the concentration of oxygen in air as opposed to water but surely water with excess oxygen (one water company sells water with 8X more oxygen) which is used as sports drinks would provide enough oxygen.

[kempie]

It appears that the problem is not the extraction of Oxygen but rather the inability to eliminate CO2 at a fast enough rate...

http://en.wikipedia.org/wiki/Liquid_breathing

[Gef]

"one water company sells water with 8X more oxygen which is used as sports drinks ."

Sounds like a total rip off to me.

[Law Student]

i suspect that it is the solubility of O2 and CO2 in the water that causes the problem. There are a number of polyfluorinated hydrocarbons which, when suitably oxygenated, can be 'breathed'.

[theprof]

Breathed by who, Law Student? Don't you find it odd that there is no documented case of in vivo elective consent for liquid breathing to be found?

Yes, trials have occurred, but they have taken place with either patients who are gravely ill or in premature babies. Don't you consider that odd?

I was in the USA when the FDA stopped one such trial because of ethical issues involved, a matter that seems to have escaped the compilers of Wikipedia. Until we overcome such issues, the procedure will remain highly experimental.

Regretfully, "The Abyss" has much to answer for.

[WaldoMcFroog]

I have to dispute the Prof's answer, but unfortunately, I have no way to prove this top notch bit of irrefutable evidence (*ahem*).

I recall seeing a deep sea diver having one lung filled with some sort of liquid-breathing substance on the children's programme Blue Peter. He said that he felt lopsided by otherwise fine. Now, as I say, I can't substantiate this - Google has no mention (and let's face it if it's not verifiable using Google... (this is sarcasm about my laziness to bother checking with a more reputable source)) - and nor can I recall when it was. I know I was probably far too old to be watching it though.

[theprof]

I don't doubt that there has been the odd "demonstration" of liquid breathing Waldo for entertainment purposes. I've got fond memories of Blue Peter myself and this would be an great way of demonstrating technological advances to children. Tomorrow's World worked on a similar basis.

However, the point I was trying to make that no recognised controlled trials in volunteers has ever been undertaken as far as I can establish. Strict protocols have to be observed during these trials so that correct conclusions can be drawn and from what I understand, the FDA in the USA has never been entirely happy with the idea. One of the reasons for this was that fatalities occurred amongst those gravely ill patients and premature babies I mentioned in my earlier post and the cost to their lives outweighed any possible gain.

One of the stumbling blocks in finding human guinea-pigs is the fear that virtually all of us have of drowning. The idea of allowing someone to fill one's lung's with liquid would send most people running out the door.

I know I wouldn't take part in such a trial even though I've spent many years diving myself.

[kempie]

I'm not certain that "cost of... lives" was the reason that Alliance Pharmaceutical Corp. discontinued their development/marketing of LiquiVent� after completion of Phase 2-3 clinical studies into partial liquid ventilation (PLV).

The study enrolled 311 adult ARDS (Acute Respiratory Distress Syndrome) patients; 90 patients were randomized (65 for the PLV group, 25 for the conventional ventilation group) and saw mortality rates drop from a widely accepted 40% to 19% using PLV. However, the study coincided with changes in the way mechanical ventilation strategies were utilised which saw the conventional group mortality rate drop to 15%.

It was noted that the PLV-treated patients were more likely to experience hypoxia, respiratory acidosis and bradycardia, prompting the conclusion that PLV required further evaluation for safety and efficacy.

Nothing further transpired as Alliance deemed LiquiVent� unprofitable in light of PLV not providing incremental benefit when compared to the new ventilation strategies.

[theprof]

I think there may be some confusion arising here.

PLV has been highly acclaimed since the pioneering work of Clark and Gollan in 1965. Liquivent has been fast tracked by the FDA despite the fact that we are not completely certain how the technique works from a physiological standoint. Nevertheless, PLV invariably is used as an adjunct in patients undergoing mechanical ventilation.

Perhaps I should have clarified in my initial post in this thread that I was not referring to PLV. I have been discussing TLV. The need for additional mechanical ventilation and associated equipment limits somewhat the practical application of PLV for undersea breathing.

In addition, gravity appears to play a major role during lung clearance during TLV cycle breathing and experimental heating and ventilation equipment has had to be specifically designed for the purpose.

When all these factors are taken into consideration, the true feasibility of TLV for underwater breathing should be apparent and it is noteworthy that little further information on its practical application in humans for this purpose has been published in recent years.