Studies on Dye Dilution Curves Using a Digital Computer

In order to assess the magnitude of error in the estimation of cardiac output from dye dilution curves due solely to area calculations, an IBM 7040 Computer was directed to perform the calculations following various programs for determining the downslope and locating the point of recirculation. Comparison was made between manually and machine calculated values in subjects of various age groups and under various physiological conditions. According to the analysis by the computer, differences-between values from two dilution curves must exceed 8 percent if the 95 percent confidence limit is to apply to the difference between them.