Demonstration of a Positive Relationship Between Cardiac Output and Oxygen Consumption

Conclusions

1. Regardless of the methods used in measuring cardiac output and oxygen consumption a significant positive relationship was demonstrated for 3 different methods between oxygen consumption and cardiac output. 2. Maximum variation explicable in cardiac output by variation in oxygen consumption was approximately 50%. This coefficient of determination reveals that only one-half of the variance in cardiac output could be explained by changes in oxygen consumption. The amount of variation in cardiac output explicable by oxygen consumption might be improved if in addition to basal conditions, uniform environmental temperature and humidity were maintained during the study. 3. The calculation of the regression equation for each series of data demonstrates a striking constancy of change. Despite variance in methods for determining cardiac output and oxygen consumption, and varying basal or nonbasal conditions of the subjects, the ratios of change are the same. For each 10% increase in oxygen consumption an average increase of 7.07% in cardiac output results. 4. Relative changes in cardiac output are the same regardless of whether one uses the ballistocardiograph, right heart catheterization, or ethyl iodide method in the determination of cardiac output.