Effects of carbon dioxide pneumoperitoneum in pigs with impaired pulmonary function

The objective of our study was to investigate the possible adverse hemodynamic effects of a CO2 pneumoperitoneum in an experimental model in pigs with impaired pulmonary function. Thirteen animals were anesthetized with azaperon/ketamine and ventilated with 67% nitrous oxide in oxygen. By intravenous injection of dextran microspheres, a capillary pulmonary embolism was induced. After embolization, three animals served as controls (Group 1), five underwent open nephrectomy (Group 2), and five underwent laparoscopic nephrectomy (Group 3). Intra-abdominal pressure was kept constant at 15 mm Hg. At intervals, hemodynamic parameters were measured, and blood gas measurements were performed. Data were analyzed using a general linear model analysis of variance for differences between groups, and a paired t-test was applied for differences within groups from one condition to the next. The groupwise comparison revealed a significant rise of cardiac output in the laparoscopy group compared with the open nephrectomy group. No differences were noted for heart rate, systemic arterial pressure, central venous pressure, mean pulmonary arterial pressure, or pulmonary arterial wedge pressure. Impairment of pulmonary function caused no negative hemodynamic effect during laparoscopic nephrectomy.