[abstract] EFFECT OF DECOMPRESSION UPON INERT GAS ELIMINATION AT CONSTANT INSPIRED PO2.

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[abstract] EFFECT OF DECOMPRESSION UPON INERT GAS ELIMINATION AT CONSTANT INSPIRED PO2.

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Title: [abstract] EFFECT OF DECOMPRESSION UPON INERT GAS ELIMINATION AT CONSTANT INSPIRED PO2.
Author: Hills, BA
Abstract: A number of recent studies of the effect of decompression per se upon the rate of elimination of inert gas from men and other mammals have produced conflicting results. However these studies have all involved changes in the inspired oxygen partial pressure (PIO2), when the differences can be explained by vasoconstriction and transcutaneous transfer. This explanation has been confirmed in measurements of the washout of nitrogen from ten conscious yet restrained guinea pigs exposed to 100 fsw for one hour on 95:5 N2:02 and then switched to the appropriate He:O2 mix to maintain a PIO2 of 0.2 Atm during elimination. This was followed by continuous analysis of chamber gas using a mass spectrometer, thus obviating the need to differentiate between expired N2 and that derived transcutaneously. Thus nitrogen elimination was measured with the skin and the lungs exposed to the same gas mixture consisting of oxygen at a pa of 0.2 Atm and 'topped up' with helium to a hydrostatic pressure equivalent to 0, 40 or 100 feet of sea water. It was found that nitrogen elimination was significantly lower (6 percent; pless than0.05) at 40 feet compared with 100 feet and even lower (14 percent; pless thanO.O1) at the "surface" equivalent. This essentially confirms the original studies of Willmon and Behnke (1948) and is compatible with the statistical thermodynamic concept of random nucleation in tissue in which those regions with gas 'dumped' from solution have lower driving forces for inert gas elimination. Since micro-regions of tissue in phase equilibrium should have a constant elimination rate, washout profiles enable a rough estimate to be made of their preponderance relative to those retaining gas in supersaturated solution and the dependence of this ratio upon the extent of decompression.
Description: Abstract of the Undersea and Hyperbaric Medical Society, Inc. Annual Scientific Meeting held May 13-16, 1977. Holiday-Inn, Toronto, Ontario, Canada (http:www.uhms.org)
URI: http://archive.rubicon-foundation.org/4160
Date: 1977

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  • UHMS Meeting Abstracts
    This is a collection of the published abstracts from the Undersea and Hyperbaric Medical Society (UHMS) annual meetings.

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