Xref: utzoo sci.med:14170 sci.bio:2606 Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!rex!ames!dftsrv!mimsy!chris From: chris@mimsy.umd.edu (Chris Torek) Newsgroups: sci.med,sci.bio Subject: Re: Breathing liquid? Message-ID: <21433@mimsy.umd.edu> Date: 25 Dec 89 19:08:09 GMT References: Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742 Lines: 36 In article bfu@ifi.uio.no (Thomas Gramstad) writes: >Sometimes in science fiction etc. one encounters the idea of >deep divers breathing liquid instead of gas (the last example >is in the movie The Abyss). What is the rationale for this >idea, if any? Is it at all possible for a human being to >breathe and obtain oxygen from a liquid? As others have said, the technique is real, although if experiments have been done on human subjects, the experimenters are keeping quiet. No one has answered the first question, however: why? The answer lies in the fact that oxygen is toxic, and nitrogen is a narcotic---fortunately, not at normal atmospheric pressure. At high pressures ordinary air can make you act drunk; at still higher pressures, it will kill you. Even a moderate increase in pressure is dangerous, because nitrogen dissolves in blood, and gets into body tissues. When the pressure is reduced, it can form bubbles, typically in the joints: this is caled the `bends', because a person with this condition has severe joint pain and stays in a bent position to alleviate the pain. These effects occur because higher pressures compress the gases, increasing the concentration of each of its components. Although gases compress, liquids do not. The idea, then, is to dissolve the necessary oxygen in an otherwise-inert liquid, keeping the concentration below the point where it is toxic, and keeping the nitrogen concentration at or below that of air at normal atmospheric pressure. Problems abound: removal of waste products (CO2), circulation of fluid, oxygenation of fluid, and so forth. I believe the middle one of the above list is the most pressing problem at the moment, at least as far as diving goes. `Breathing' the liquid used is simply too much effort. -- In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163) Domain: chris@cs.umd.edu Path: uunet!mimsy!chris