THE NORMAL RESTING CARDIAC OUTPUT: SERIAL DETERMINATIONS BY A DYE DILUTION METHOD

Abstract
A simple method for serial estimation of the cardiac output, using an earpiece cuvette and Coomassie Blue dye is described. In 23 normal resting subjects 115 dye dilution curves were made. The average standard error of the mean in all subjects was [plus or minus] 6%, or, if only the last 4 determinations for each individual are analyzed to minimize actual changes in the cardiac output, [plus or minus] 3%. The cardiac output of hospital patients fell an average of 7% on the 2nd determination and remained relatively stable thereafter. In 10 subjects absolute values were obtained with this method: the average cardiac output was 5.74 1/minute and the average cardiac index was 3.17 [plus or minus] 0.22 1/minute/m2 body surface.