A modified rebreathing technique using an infrared gas
analyzer.
Barazanji, Khalid W., Murugappan Ramanathan, Robert L. Johnson, Jr.,
and Connie C. W. Hsia.
Department of Internal Medicine, University of Texas Southwestern
Medical Center, Dallas, Texas 75235
APStracts 2:0524A, 1995.
In order to lower the cost and improve accessibility of the
rebreathing technique for measuring cardiopulmonary function during
exercise, we implemented a fast-response Infrared gas (IR) analyzer
system to simultaneously measure lung diffusing capacity (DL),
cardiac output (c), lung tissue volume (Vt), and lung volume by a
rebreathing technique in five healthy subjects at rest and during
steady state exercise. Interferences by water vapor and CO2 on the
analyzer were determined and corrected for. During rebreathing, a gas
mixture of 0.4% C2H2, 0.3% CH4, 9% He, 30% O2, and either 0.3% C18O
or 0.3% C16O in a balance of N2 was simultaneously sampled by both
the mass spectrometer (MS) and the IR analyzer, permitting paired
comparisons. Measurements obtained by the two devices were not
significantly different. We conclude that this modified rebreathing
technique using the IR analyzer is accurate for the measurement of
cardiopulmonary function at rest and exercise.
Received 21 July 1995; accepted in final form 22 November 1995.
APS Manuscript Number A796-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 8 December 95