A Continuous Cardiac Output Recorder Employing the Fick Principle

Abstract

A continuous cardiac output recorder has been developed utilizing an oxygen consumption recorder, an arteriovenous oxygen difference recorder and a computer. The computer continuously derives and records the cardiac output by dividing the rate of oxygen consumption by the A-V oxygen difference. Calibration of the continuous cardiac output recorder against a Ludwig stromuhr showed that under many different conditions and many different levels of cardiac output the 305 individual calibration points had a mean deviation from the regression line of ± 7.7 per cent. This correlation is as satisfactory as previously reported correlations between the intravenous dye method for recording cardiac output and the direct Fick method.