Effects of physical properties of the breathing gas on
decompression-sickness bubbles.
Burkard, Mark E., and Hugh D. Van Liew.
Department of Physiology, University at Buffalo, State University
of New York, Buffalo, New York 14214 USA.
APStracts 2:0263A, 1995.
To explore the relative dangers of different inert gases, we developed
mathematic relationships concerned with bubble growth, using
equations that separate gas properties from other variables.
Predictions for saturation exposures: 1) Peak volume of a bubble is
proportional to solubility in tissue when bubble density is high, and
to the 3/2 power of the ratio of the permeation coefficient to the
partition coefficient when density is low. 2) Bubble duration is
inversely proportional to the partition coefficient for the inert
gas. 3) Sizes and durations of bubbles for one inert gas relative to
another depend on whether the tissue is aqueous or lipid, but are
independent of the magnitude of the decompression and tissue
halftime. 4) Helium should give smaller bubbles than N2, except in
aqueous tissue with low bubble density; our prediction correlates
qualitatively with relative dangers observed with animals but seems
to overestimate the safety afforded by He. Numerical simulations
illustrate how non-saturation dives are less predictable because more
variables are involved.
Received 12 December 1994; accepted in final form 26 May 1995.
APS Manuscript Number A1267-4.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 6 July 1995.