Evaluation of the effects of a pneumoperitoneum with carbon dioxide or helium in a porcine model of endotoxemia

Background: The expansion of the laparoscopic techniques to the critically ill patient is currently under debate. In order to evaluate the potential risks of performing laparoscopy in a body with signs of sepsis, the effects of the pneumoperitoneum were studied in a porcine model of mild endotoxemia. Methods: Twenty-eight pigs were separated into four groups of seven animals: untreated control (C), 2 mu g/kg/h endotoxin (E), endotoxin and a pneumoperitoneum (3 h, 15 mmHg) with CO2 (EC) or with helium (EH). Hemodynamic and homeostatic variables were studied for a period of 5.5 h. Primary endpoints were arterial and mucosal pH and the ATP content of the bowel wall. Statistical evaluation was performed using analysis of variance and the Bonferroni test. Results: Endotoxin infusion induced characteristic symptoms of early sepsis: increase of arterial CO2, pulmonary arterial, portal venous, and pulmonary artery wedge pressure, and decrease of arterial pressure, cardiac output, arterial and mucosal pH. An additional pneumoperitoneum led to aggravation of all criteria with significant alterations in arterial and mucosal pH, arterial CO2, wedge and portal venous pressure. The most striking derangement of mean values was observed for mucosal pH (EC: 7.40, EH: 7.54) and arterial pH (EC: 7.15, EH: 7.18). In group EC, two animals died in septic shock. Conclusion: Applying a pneumoperitoneum during an ongoing sepsis significantly deteriorates hemodynamic and homeostatic variables, thus enhancing the risk of severe complications.