
Liquid Breathing - codezero
https://en.wikipedia.org/wiki/Liquid_breathing
======
tjradcliffe
The critical bit for many interesting practical applications is this:

    
    
        A significant problem, however, arises from the high 
        viscosity of the liquid and the corresponding reduction 
        in its ability to remove CO2.[3][20] All uses of liquid 
        breathing for diving must involve total liquid 
        ventilation (see above). Total liquid ventilation, 
        however, has difficulty moving enough liquid to carry 
        away CO2, because no matter how great the total pressure 
        is, the amount of partial CO2 gas pressure available to 
        dissolve CO2 into the breathing liquid can never be much 
        more than the pressure at which CO2 exists in the blood 
        (about 40 mm of mercury (Torr)).[20]
    

This has been a known issue since the 50's and shows no sign of going away.
The paragraph is a bit muddled--it's the diffusion coefficient, not the
viscosity, that is relevant--but the inability of oxygenated liquids to carry
away CO2 has so far been the major impediment to doing any of the really cool
things this technology has promised for so long.

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spdub
What I instantly thought of was `The Abyss`. It was referenced towards the end
and it appears the rat -and not the actor- was submerged in this fluid. Very
cool! [http://www.nytimes.com/1989/08/06/movies/film-the-abyss-a-
fo...](http://www.nytimes.com/1989/08/06/movies/film-the-abyss-a-foray-into-
deep-waters.html)

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joshschreuder
For me it reminds me of the LCL in anime series Evangelion. I have seen it pop
up a few times in modern sci-fi.

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M4v3R
Same. NGE is actually referenced in the "Fiction" section of the wiki entry,
along with others.

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rtb
How would you return to breathing normal air after having your lungs flooded
with this liquid?

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aaron695
From memory when they do it with babies they just let it evaporate out.

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rtb
In babies, I would guess that some of the amniotic fluid is also absorbed into
the blood stream. Both that and evaporation seem much less likely to work with
perfluorocarbons.

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corobo
Forgive me for being a bit too simple on this subject - wouldn't having a
liquid in your lungs, throat and mouth really make it difficult or impossible
to talk?

Not sure using it for diving or space travel is a great plan if that's the
case. Sure you could have a text or flashing lights method of talking but
there's no communication method faster than yelling "HELP!" into your radio
that I can think of

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relet
Divers don't talk that much, actually.

See, there is an air intake in your mouth - and trying to talk under water
does not exactly result in the noises you expect when you're talking into air.

The sign used by divers to alert others is banging your knife against the air
tank. There are actual hand signs for 'I'm in trouble' or 'I'm out of air'.

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corobo
Fair enough, like I say I'm not familiar with the subject but curious. I was
more picturing the masks that look a bit like gas masks that have radios in
them. My extent of diving knowledge is limited to movies and Mythbusters, I'll
admit.

Thanks for that information :)

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reustle
While I find this kind of stuff interesting, I still don't see why it is being
posted here.

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edanm
People like you finding it interesting is literally the definition of what
should be posted on HN.

That said, I would love it if the OP game some additional context on why they
submitted it - is this a response to something? Was there a new advance here?
Just something cool they saw?

