Cardiac output and mixed venous O2 content measurements by a tracer bolus method: animal validation study

Abstract

A bolus method for noninvasive measurement of cardiac output (CO) and mixed venous oxygen content ([Formula: see text] [Formula: see text]) has been tested against absolute CO and[Formula: see text] [Formula: see text]standards in dogs. No statistical differences in CO were found between bolus method and electromagnetic flowmeter measurement comparisons in an 18-dog study in which CO varied from 0.5 to 3.0 l/min. The SD for all paired differences was 0.14 l/min; however, data averaging over 10-min intervals were found to reduce the CO measurement uncertainty to <0.08 l/min. The ability of the bolus method to follow rapid CO changes, experimentally produced by control of a pump (surgically placed between the superior and inferior vena cava and the right atrium), was documented and found to satisfy CO monitoring requirements of unstable subjects.[Formula: see text] [Formula: see text]bolus values were found to be statistically equivalent to reference measurements.