Effect of CO2 insufflation on bacteremia and bacterial translocation in an animal model of peritonitis

Background: The widespread adoption of the laparoscopic approach has created some concern over the potential for increased risk of bacteremia and sepsis due to increased intraabdominal pressure in patients with intraabdominal infection and peritonitis. This study examines the effect of the CO₂ pneumoperitoneum on bacteremia and bacterial translocation. Methods: New Zealand white rabbits were assigned into three groups of 10 animals. In group 1, 100 ml of sterile saline was infused into the peritoneal cavity under 10 mmHg CO₂ insufflation for 1 h. Group 2 received 100 ml of saline containing 10⁹ CFU/ml (colony-forming units) E. coli strain 0163 and 10 mmHg CO₂ insufflation for 1 h. Group 3 received an identical bacterial inoculum, followed by a 10-cm midline laparotomy. Blood samples were taken for culture by cardiac puncture at various intervals during the experiment. At 6 h after being subjected to the experimental procedures, the rabbits were killed and their organs were cultured quantitatively for translocating bacteria. Results: In group 1, neither blood nor organ cultures were positive, whereas in group 2 all blood cultures became positive in 1 h, and intraperitoneally infused bacteria translocated to the lung and kidney in all rabbits. In group 3, blood cultures became positive in 1 h, all but two of the rabbits had translocated bacteria in their lungs, and kidney samples from two of the rabbits were culture-positive. Conclusions: Our results indicate that both CO₂ pneumoperitoneum and laparotomy increase the incidence of bacterial translocation from the peritoneal cavity into the bloodstream. Thus, the risk of translocation to extraperitoneal organs such as lung and kidney is increased significantly by laparoscopy. Therefore, laparoscopic surgery should be avoided or used cautiously in the setting of acute peritonitis.