fresco fresco come l'ovetto di giornata: J Appl Physiol 2007;103757-762

Appl Physiol 103: 757-762, 2007. First published June 28, 2007;
doi:10.1152/japplphysiol.00155.2007

Effect of hypobaric air, oxygen, heliox (50:50), or heliox (80:20)
breathing on air bubbles in adipose tissue
[by] O. Hyldegaard and J. Madsen *



Submitted 6 February 2007 ; accepted in final form 21 June 2007


The fate of bubbles formed in tissues during decompression to altitude
after diving or due to accidental loss of cabin pressure during flight
has only been indirectly inferred from theoretical modeling and clinical
observations with noninvasive bubble-measuring techniques of
intravascular bubbles. In this report we visually followed the in vivo
resolution of micro-air bubbles injected into adipose tissue of
anesthetized rats decompressed from 101.3 kPa to and held at 71 kPa
corresponding to 2.750 m above sea level, while the rats breathed air,
oxygen, heliox (50:50), or heliox (80:20). During air breathing, bubbles
initially grew for 30–80 min, after which they remained stable or began
to shrink slowly. Oxygen breathing caused an initial growth of all
bubbles for 15–85 min, after which they shrank until they disappeared
from view. Bubble growth was significantly greater during breathing of
oxygen compared with air and heliox breathing mixtures. During heliox
(50:50) breathing, bubbles initially grew for 5–30 min, from which point
they shrank until they disappeared from view. After a shift to heliox
(80:20) breathing, some bubbles grew slightly for 20–30 min, then shrank
until they disappeared from view. Bubble disappearance was significantly
faster during breathing of oxygen and heliox mixtures compared with air.
In conclusion, the present results show that oxygen breathing at 71 kPa
promotes bubble growth in lipid tissue, and it is possible that
breathing of heliox may be beneficial in treating decompression sickness
during flight.









*1Laboratory of Hyperbaric Medicine, Department of Anaesthesia, Centre
of Head and Orthopaedics, Copenhagen University Hospital,
Rigshospitalet, Copenhagen; and 2Department of Medical Physiology, The
Panum Institute, University of Copenhagen, Copenhagen, Denmark