ABSTRACT : To evaluate the effect of pneumoperitoneum and Trendelenburg position on respiratory mechanics during pelviscopic surgery in patients with a normal body mass index (BMI) by determining the changes in peak inspiratory pressure, plateau pressure, lung compliance, end-tidal carbon dioxide partial pressure.

METHODS : The study as carried out in 40 patients scheduled for elective gynecologic laparoscopy. The patients had no history of previous cardiopulmonary pathology and were of ASA grade I AND II. General anesthesia was administered with propofol, lidocaine,fentanyl, Succinylcholine and vecuronium was administered. The peak inspiratory pressure, plateau pressure, heart rate, mean arterial pressure , dynamic lung compliance and end-tidal CO2 were measured before and after creation of pneumoperitoneum with an intraabdominal pressure of 12 mmHg, then after 10 minutes and 30 minutes in the 20o Trendelenburg position, and after deflation of pneumoperitoneum.

RESULTS : Following creation of pneumoperitoneum, there was a significant increase in peak inspiratory pressure (4.75 cmH2O), plateau pressure ( 3.73 cmH2O), and end-tidal CO2 (4.45 mmHg), while dynamic lung compliance decreased (by 13.2 .ml/cmH2O). Overall, the Trendelenburg position induced no significant hemodynamic or pulmonary changes.

CONCLUSIONS : The effects of pneumoperitoneum significantly reduced dynamic lung compliance and increased peak inspiratory and plateau pressures. The Trendelenburg position did not change these parameters