The authors evaluated the effi ciency and reproducibility of cardiac output measurement by esophageal continuous-wave Doppler ultra sonography (ECO). A total of 114 si multaneous measurements of ECO and thermodilution cardiac output (TDCO) were compared in 25 surgi cal patients undergoing general anes thesia in the supine position. ECO could be obtained easily with mini mal experience by means of a com mercially available Doppler cardiac output monitor. There was a signifi cant correlation between ECO and TDCO (<0.001). The regression equation obtained was Y = 0.992X- 0.029, and the correlation coefficient was 0.935. ECO was more reproduc ible than TDCO, because the aver aged value for coefficient of variation (CV) was 5.2% for ECO and 8.3% for TDCO, and these values were sta tistically significant. Their results in dicate that the esophageal Doppler method provides noninvasive, safe, and continuous cardiac output moni toring in patients during anesthesia in the supine position. This method is more useful in patients for whom in vasive cardiac output monitoring is considered inappropriate.
