['The ultrasonic cardiac output monitor (USCOM; USCOM Pty. Ltd., Sydney, NSW, Australia) has been accepted as a noninvasive device for measuring cardiac function in various clinical conditions. The present study aimed at comparing the accuracy of this device with that of the thermodilution technique in recipients in the early postoperative period after liver transplantation.', 'Fifteen mechanically ventilated patients were studied on the first postoperative day after liver transplantation. We compared the left-sided and right-sided cardiac output (CO) determined by USCOM with that obtained from the thermodilution technique with a pulmonary artery catheter every 8 hours in the intensive care unit. Each patient received a total of four paired measurements. Bland-Altman analysis was used for bias and precision testing. The CO measured by USCOM and the thermodilution method were considered interchangeable if the limits of agreement lay within +/- 1 L per minute or 20% of the mean CO.', 'Forty-eight paired left-sided CO measurements were obtained from 12 patients. Three patients were excluded due to unacceptable signals. Comparison of these two techniques revealed a bias of 0.13 L per minute and limits of agreement at -0.65 L and 0.92 L per minute. Fifty-six paired right-sided CO measurements were obtained from 14 patients with one patient excluded due to an unobtainable optimal signal. A bias of 0.11 L per minute with limits of agreement at -0.51 L and 0.72 L per minute were found for these two techniques.'] Does ultrasonic cardiac output monitor provide accurate measurement of cardiac output in recipients after liver transplantation?