Hemodynamic effects of carbon dioxide pneumoperitoneum during mechanical ventilation and positive end-expiratory pressure.

Laparoscopy is frequently used for diagnosis and treatment of critically ill trauma patients. Its effects on cardiopulmonary performance in the intensive care unit patient population, however, are not well-defined. This study evaluated the effects of positive end-expiratory pressure (PEEP) and carbon dioxide (CO2) pneumoperitoneum on hemodynamic function during mechanical ventilation. Five anesthetized, mechanically ventilated adult swine were monitored with pulmonary artery and arterial catheters at 0, 5, 10, 15, and 20 cm H2O PEEP without, and then with 15 mm Hg CO2 pneumoperitoneum. A hemodynamic profile, analyses of arterial and mixed venous blood gases and mixed venous hemoglobin oxygen saturation values were obtained at each data point. Compared with the non-insufflated group, CO2 pneumoperitoneum significantly increased central venous pressure, mean arterial pressure, mean pulmonary artery pressure, pulmonary vascular resistance index, and stroke index for the range of PEEP levels. With PEEP of 10 cm H2O, hemodynamic changes in non-insufflated animals were not statistically significant, but with CO2 pneumoperitoneum, stroke index and left ventricular stroke work index were decreased at 5 cm H2O PEEP, as was cardiac index at 10 cm PEEP. Pulmonary gas exchange was not affected by CO2 pneumoperitoneum. The results indicate that, in this paradigm, CO2 pneumoperitoneum for laparoscopy increases ventricular afterload and exacerbates the adverse effects of PEEP. These findings could be clinically significant in critically ill patients.