CO2 Pneumoperitoneum Modifies the Inflammatory Response to Sepsis

Objective: To analyze the effect of CO₂ pneumoperitoneum on the inflammatory response induced by sepsis during laparoscopy. Summary Background Data: A growing body of evidence challenges the once generally accepted notion that smaller incisions alone account for the observed benefits of the laparoscopic approach. Furthermore, laparoscopic surgery is now being applied to a broad spectrum of patients, including those in whom the inflammatory response is ignited. Delineation of the effects of CO₂ pneumoperitoneum on the inflammatory response induced by sepsis is needed. Methods: Sepsis was induced in rats by cecal ligation and puncture (CLP) performed either open or laparoscopically using CO₂ or helium as insufflation gases. Animals were killed 24 hours postoperatively, at which time whole blood was collected for complete blood cell counts and livers were harvested for analysis of hepatic expression of the rat acute phase genes α2-macroglobulin and β-fibrinogen. Results: Laparoscopic CLP using CO₂ resulted in significantly reduced hepatic expression of the rat acute phase gene α2-macroglobulin compared to both laparoscopic CLP using helium and open CLP. Hepatic expression of another rat acute phase gene, β-fibrinogen, paralleled that of α2-macroglobulin and was significantly reduced following laparoscopic CLP using CO₂ compared to laparoscopic CLP using helium. Total white blood cell and neutrophil counts following CLP were both significantly higher when CLP was performed laparoscopically using CO₂ than when CLP was performed open or laparoscopically using helium. Conclusions: Intra-abdominal CO₂ present during laparoscopy attenuates the acute phase inflammatory response associated with perioperative sepsis.