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Ventilation-perfusion matching in long-term microgravityWe studied the ventilation-perfusion matching pattern in normal gravity (1 G) and short- and long-duration microgravity (microG) using the cardiogenic oscillations in the sulfur hexaflouride (SF(6)) and CO(2) concentration signals during the phase III portion of vital capacity single-breath washout experiments. The signal power of the cardiogenic concentration variations was assessed by spectral analysis, and the phase angle between the oscillations of the two simultaneously expired gases was obtained through cross-correlation. For CO(2), a significant reduction of cardiogenic power was observed in microG, with respect to 1 G, but the reduction was smaller and more variable in the case of SF(6). A shift from an in-phase condition in 1 G to an out-of-phase condition was found for both short- and long-duration microG. We conclude that, although the distribution of ventilation and perfusion becomes more homogeneous in microG, significant inhomogeneities persist and that areas of high perfusion become associated with areas of relatively lower ventilation. In addition, these modifications seem to remain constant during long-term exposure to microG.
Document ID
20040112676
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Verbandt, Y.
(Universite Libre de Bruxelles Brussels 1070, Belgium)
Wantier, M.
Prisk, G. K.
Paiva, M.
West, J. B.
Date Acquired
August 21, 2013
Publication Date
December 1, 2000
Publication Information
Publication: Journal of applied physiology (Bethesda, Md. : 1985)
Volume: 89
Issue: 6
ISSN: 8750-7587
Subject Category
Life Sciences (General)
Distribution Limits
Public
Copyright
Other
Keywords
Mir Project
Flight Experiment
Non-NASA Center
Soyuz TM22 Project
long duration
short duration
NASA Experiment Number 178198 2/2
NASA Discipline Cardiopulmonary
manned
STS-58 Shuttle Project

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