Journal of Applied Physiology, Vol 46, Issue 6 1157-1163, Copyright © 1979 by American Physiological Society
Inert gas transport in the microcirculation: risk of isobaric supersaturation
R. S. Tepper, E. N. Lightfoot, A. Baz and E. H. Lanphier
This paper is concerned with the theretical background and implications of
isobaric supersaturation and bubble formation in the microcirculation
following an abrupt shift from one inspired inert gas to another. The use
of more than one inert gas, simultaneously or sequentially, has become
common in diving and presents risks as well as potential benefits. A review
of microcirculatory model useds, theoretical approaches to decompression,
and order of magnitude calculations indicates that present empiricisms are
inadequate for predicting such supersaturation phenomena. This is true
whether based on the familiar assumption of perfusion-limited behavior or
its diffusion-limited counterpart. The "chromatographic" model used here,
which considers both perfusion and axial diffusion in tissue cylinders,
shows that these combined effects can produce unexpectedly high local
supersaturation. The implications include new possibilities for the
experimental evaluation of gas transport models as well as practical risks
of inert gas shifts in diving and certain diagnostic procedures.
