Cardiac output estimation with a new Doppler device after off-pump coronary artery bypass surgery

Objective: To compare cardiac output (CO), stroke volume (SV), and cardiac index (CI) as estimated with a new, non-invasive Doppler device (Ultrasonic Cardiac Output Monitor [USCOM]; USCOM Ltd, Sydney, Australia) with those measured with the bolus thermodilution (TD) technique. Design: Prospective nonrandomized study. Setting: Postcardiac surgery recovery unit of a tertiary cardiac center. Participants: Fifty patients after off-pump coronary artery bypass (OPCAB) surgery. Measurement and Main Results: Both right-sided and left-sided CO were estimated with a USCOM continuous-wave (CW) Doppler device, and CO was determined with the bolus TD technique performed in triplicate. On comparing the right-sided CO, SV, and Cl with those of TD, the mean bias was 0.03 L/min, 1.6 mL, and 0.02 L/min/m(2), respectively. The comparison of left-sided CO, SV, and Cl with those of TD revealed a means bias of 0.14 L/min, 1.0mL, and 0.08 L/min/m(2), respectively. Conclusion: This study showed excellent agreement between the values for CO, SV, and Cl as determined with USCOM and TD. Since there was only 1 time period for CO estimation in each patient with both methods, the stability of this correlation needs to be further investigated over time. (C) 2006 Elsevier Inc. All rights reserved.