Bubbles in circulating blood: stabilization and simulations of
cyclic changes of size and content.
Liew, Hugh D. Van, and Mark E. Burkard.
Department of Physiology, University at Buffalo, State University
of New York, Buffalo, NY 14214
APStracts 2:0186A, 1995.
Van Liew, Hugh D. and Mark E. Burkard. Bubbles in circulating blood:
stabilization and simulations of cyclic changes of size and content.
J. Appl. Physiol. XX(X): XXX-XXX, 199X.--Surface tension, blood
pressure, and inherent unsaturation due to O2 metabolism promote
diffusion of gases out of bubbles in the blood stream. We review the
mechanisms that can overcome the absorptive tendencies so small
spherical bubbles can persist. One general type of stabilizer is a
mechanical structure at the gas / liquid interface which can support
a negative pressure so that gases inside can be in diffusion
equilibrium with their counterparts outside; one possibility for
mechanical stabilizers are surfactant films. We show that a slowly
-permeating gas is analogous to a mechanical stabilizer; it allows
equilibration of other gases inside-to-outside by diluting the gases
inside. Using numerically-solved equations based on physics of
diffusion, we demonstrate how non-rigid, stabilized bubbles change
size as they move through the circulatory system. In small pulmonary
vessels, the bubbles enlarge because blood pressure is low, there is
no inherent unsaturation, and O2 and N2 diffuse from lung gas into
the bubble; these gases diffuse out again in the systemic
circulation.
Received 10 August 1994; accepted in final form 19 April 1995.
APS Manuscript Number A839-4.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 9 May 1995.