Cardiac output estimation after off-pump coronary artery bypass: a comparison of two different techniques.

The present study compares the cardiac output (CO) estimated by a new, non-invsive continuous Doppler device (Ultrasonic cardiac output monitor-USCOM) with that by bolus thermodilution technique (TD). Thirty post off-pump coronary artery bypass graft surgery patients were studied in this prospective nonrandomized study. Right heart CO estimation by USCOM and TD was performed and measured in quadruplet. A total of 120 paired observations were made. The mean CO was 4.63 and 4.76 Llmin as estimated by TD and USCOM respectively. For TD and USCOM, the CO had a mean bias (tendency of one technique to differ from other) of -0.13 L/min and limits of agreement (mean bias +/- 2SD) at -0.86 and 0.59 L/min. The study reveals very good agreement between the values of CO estimated by USCOM and TD.