Respiratory mechanics during laparoscopic nephrectomy

ABSTRACT

37 adult ASA I or II patients divided into 3 groups and subjected to laparoscopic nephrectomy were assigned for this study. Oral diazepam was used for premedication. Induction with thiopentone sodium, suxamethonium sequence and maintenance of anesthesia were achieved differently in each group. In group 1, it was N2O O2 halothane 0.5- 1%, while in group 2 N2O O2 morphine were used. In group 3, lumber epidural analgesia [using bupivacain 0.8 mg/kg + 2 mg morphine] preceded general anesthesia, N2O O2 was used for maintenance. Pancuronium was the non-depolarizing muscle relaxant used. Intraperitoneal CO2 insufflation was performed in lateral decubitus position. Respiratory mechanics including total chest compliance, peak inspiratory pressure, respiratory and expiratory resistance were recorded for every patient, before and after maximal CO2 insufflation and after deflation of CO2. Significant decrease in total chest compliance and significant increase in both peak inspiratory pressure and expiratory resistance were recorded with maximal CO2 insufflation. This was recorded in all groups studied irrespective to the mode of balanced anesthesia used. CO2 pneumoperitoneum during laparoscopic nephrectomy adds to the ventilatory impairment induced by anesthesia and lateral decubitus position which mandate careful adjustment of patient ventilation during the procedure