Minimally invasive laparoscopic surgery has been expanded to the elderly and high-risk surgical patients with underlying cardiac and pulmonary disease. However, possible cardiovascular changes during CO2 pneumoperitoneum necessitate close intraoperative monitoring. In this prospective study, 55 patients (mean age 62.52 years, range 26-82) undergoing laparoscopic surgery were included. Patients were categorized into 3 groups of low (group A: 12 patients, mean age 55.5 years), moderate (group B: 22 patients, mean age 59.5 years), and high (group C: 21 patients, mean age 69.71 years) surgical risk according to ASA physical status classification. Similar anesthetic agents and anesthetic techniques were used in the above cases. An esophageal Doppler (ODM II, Abbott Laboratories) was used to measure aortic blood flow velocity and thereby estimating stroke volume (SVe) and cardiac output (COe) throughout anesthesia, in addition to traditional monitoring. After abdominal insufflation (peak intra-abdominal pressure: 13-15 mm Hg) COe values decreased from the initial value after induction of anesthesia by 22%, 20%, and 18% for groups A, B, and C, respectively (P < 0.05). The above values further deteriorated (25%, 28%, and 30% for groups A, B, and C, respectively) in the anti-Trendelenburg positioning of the patient. The peak aortic blood flow velocity (PV) followed the changes, thus indicating that heart muscle contractility is affected during the procedure. Stabilization of the above values was achieved after 20 minutes of CO(2) pneumoperitoneum and improvement was noted only after deflation of the abdomen. Heart rate and blood pressure essentially remained unchanged throughout the procedure, although the final values were increased compared with initial. Insufflation of the abdomen with CO(2) produces measurable effects on the cardiovascular system that require reappraisal of hemodynamic monitoring during anesthesia. ODM II offers a reliable, relatively noninvasive, cost-effective tool for intraoperative monitoring of the hemodynamic changes with a potential for future application for improvement of intraoperative hemodynamic status of patients.