dil@mace.cc.purdue.edu (Perry G Ramsey) (02/05/91)
In article <1991Jan31.182145.10405@everexn.com>, mike@everexn.com (Mike Higgins) writes: > >>My question is, does such equipment really exist? If so, who uses it and > >>for what purposes? > As I recall, most of the > mice subjected to this DIED of pnumonia or other lung complications afterwards. After seeing all of this, I found a real source. A text entitled "Animal Physiology: Adaptation and Environment" by Knut Schmidt-Nielsen, Cambridge U. Press, devotes a page to liquid breathing. Incidentally, this is a great book for engineers, because it takes a systems engineering approach to life. Anyway, below are a few passages relevant to the discussion. If water is equillibrated with pure oxygen at 8 atm, it will dissolve about 200 ml O2/liter, about the same amount of oxygen as 1 l of normal air. ... we must use a balanced salt solution similar to blood plasma. Complete submersion in oxygen-supersaturated water has been tried with success with both mice and dogs, and the animals have survived for several hours. ... A major drawback to liquid breathing is that water is approximately 50 times more viscous than air, and the work of breathing is correspondingly increased. Another problem is that the normal surfactants that line the lungs are washed away during liquid breathing; this causes no difficulty during the experiment, but after return to air breathing the lungs tend to collapse. A more important limitation on liquid breathing is caused by the need to eliminate carbon dioxide at the same rate as oxygen is taken up. If the pco2 of blood is to be maintained at the normal 40mm Hg, several times as much liquid must be moved in and out of the lungs. [Experiments show] that the carbon dioxide concentration increases greatly. Another approach ... involves ... fluorocarbons. Oxygen is extremely soluble ... the solubility of carbon dioxide is not as great. Such liquids have been tried with animals, which have survived several hours' breathing without complications. -- Perry G. Ramsey Department of Earth and Atmospheric Sciences perryr@vm.cc.purdue.edu Purdue University, W. Lafayette, IN USA dil@mace.cc.purdue.edu *** IMAGINE YOUR LOGO HERE ****** Ten thousand low-lifes a day read this space.
tmartin@lims03.lerc.nasa.gov (DONALD MARTIN) (02/06/91)
Just completed some recent diving training. I had asked the instructor the same questions that have been recently posted after seeing the abyss. His response was that the equipment had indeed been tested on both humans and rodents. The technical hangup from preventing its use is the method and equipment for removing the CO2, etc. from the liquid solution. It is either not available or does not lend itself to being carried on one's person (or rodent as the case may be)