Effect of combined recompression and air, oxygen, or heliox breathing on air
bubbles in rat tissues.
Hyldegaard, O., D. Kerem, and Y. Melamed.
The Israeli Naval Hyperbaric Institute,2 Haifa, Israel and The Institute of Medical
Physiology,1 The Panum Institute, University of Copenhagen, Denmark 2200
APStracts 8:0055A, 2001.
The fate of bubbles formed in tissues during the ascent from a real or simulated air dive
and subjected to therapeutic recompression has only been indirectly inferred from
theoretical modeling and clinical observations. We visually followed the resolution of
micro air bubbles injected into adipose tissue, spinal white matter, muscle, and tendon of
anesthetized rats recompressed to and held at 284 kPa while rats breathed air, oxygen,
heliox 80:20, or heliox 50:50. The rats underwent a prolonged hyperbaric air exposure
before bubble injection and recompression. In all tissues, bubbles disappeared faster
during breathing of oxygen or heliox mixtures than during air breathing. In some of the
experiments, oxygen breathing caused a transient growth of the bubbles. In spinal white
matter, heliox 50:50 or oxygen breathing resulted in significantly faster bubble resolution
than did heliox 80:20 breathing. In conclusion, air bubbles in lipid and aqueous tissues
shrink and disappear faster during recompression during breathing of heliox mixtures or
oxygen compared with air breathing. The clinical implication of these findings might be
that heliox 50:50 is the mixture of choice for the treatment of decompression sickness.
Received 10 June 1999; accepted in final form 27 November 2000
APS Manuscript Number A0460-9.
Article publication pending J Appl Physiol
ISSN 1080-4757 Copyright 2001 The American Physiological Society.
Published in APStracts on 29 January 2001