Journal of Applied Physiology, Vol 73, Issue 3 1047-1051, Copyright © 1992 by American Physiological Society
Respiration and measurement of cardiac output by thermodilution and central or peripheral dye dilution
T. Delhaas, G. A. Mook and W. G. Zijlstra
Department of Medical Physiology, University of Groningen, The Netherlands.
Cardiac output as measured by indicator dilution methods during artificial
ventilation shows differences up to +/- 35%. We studied the influence of
spontaneous breathing on measurement of cardiac output by thermodilution
(TD) and central (CDD) and peripheral dye dilution (PDD) in seven
anesthetized dogs. Injection of indicator was timed at one of five chosen
moments in a respiratory cycle. The indicator for TD was also used as
solvent for indocyanine green. Results were normalized by the value
obtained with injection at inspiratory onset. Results of the central
dilution methods showed a slight but not significant difference between
values measured with injection at 25 and 75% of the respiratory cycle:
105.7 and 98.0%, respectively, (TD) and 102.3 and 97.2% (CDD). Mean cardiac
output determined by TD, CDD, or PDD was not significantly different. We
conclude that 1) a reasonable estimate of cardiac output may be obtained by
means of a single indicator-dilution curve and 2) the choice of the
dilution method may be determined by practical considerations.
