A catheter mounted Doppler system for the continuous measurement of cardiac output

Since the introduction of a flow-directed pulmonary artery catheter in 1970, the most extensively used technique for the invasive measurement of cardiac output (CO) has involved the measurement of the thermal dilution of chilled saline injected into the right heart. The authors report the successful combination of the ultrasound Doppler measurement of pulmonary artery velocity profile with thermal-dilution CO measurements to permit the tracking of changes in heart output and thus the continuous monitoring of CO.<>