Journal of Applied Physiology, Vol 50, Issue 1 200-202, Copyright © 1981 by American Physiological Society
Evaluation using dogs of a method for estimating cardiac output from a single breath
M. M. Mohammed, L. M. Wood and R. Hainsworth
We have evaluated the single-breath method of Kim, Rahn, and Fahri (J.
Appl. Physiol. 21: 1338, 1966) using anesthetized dogs (avg wt 26 kg). The
systematic error was determined by comparing the single-breath estimates of
cardiac output with values obtained by the dye-dilution method. In some
dogs the effects of moderate exercise were stimulated by joining the
circulations of two dogs. From paired estimates, the random error of the
single-breath method was +/- 12% (95% tolerance limits; 23 pairs) over a
range of outputs 1.1-5.0 l/min. There was no significant difference between
values of cardiac output by the single-breath method and by dye dilution,
and in four dogs the dye-dilution values were not significantly different
from values of pulmonary blood flow controlled by perfusion. These results
indicate that under carefully controlled conditions the single-breath
method is capable of providing reliable estimates of cardiac output.
