BACKGROUND: To measure hemodynamic changes during a laparoscopic cholecystectomy (LC), we used a new, noninvasive esophageal doppler monitor (EDM). METHODS: Under general anesthesia, 17 patients undergoing a LC were prepared by inserting an EDM probe into the esophagus. Cardiac index (CI), corrected flow time (FTc), systemic vascular resistance (SVR), mean arterial pressure (MAP), and heart rate (HR) were measured 6 times-before pneumoperitoneum, 5 minutes after pneumoperitoneum, 5, 15, and 30 minutes after the reverse trendelenberg position and after exsufflation of CO2 gas. Complication and insertion time of the EDM were also recorded. Data was analyzed using a repeated measure ANOVA. RESULTS: CO2 gas insufflation resulted in an abrupt increase of SVR (51%), MAP (17%) and a decrease of CI (29%), FTc (13%). These changes were gradually restored, except the MAP. HR was not changed significantly. These findings correlated well with other studies using a thermodilution technique or transesophageal echocardiography. There was no complication with the EDM and insertion time was 182 32.3 sec. CONCLUSIONS: Since MAP and HR do not offer accurate hemodynamic information during pneumoperitoneum, other adequate cardiovascular monitors are required. An EDM can be used during LC because it provides CI and FTc by a simple and noninvasive method.