Background: Advantages of laparoscopic surgery have, among other factors, been attributed to a shorter length of abdominal incision and the use of CO2 versus air. An analysis of these factors taking pressure-induced alterations into account is lacking. The objective of the study was to determine the impact of laparoscopy and laparotomy with exposure to CO2 and room air under a similar pressure on local, systemic, and distant organ immune responses.
Methods: Twenty piglets were randomized into four groups: CO2 laparoscopy, air laparoscopy, CO2 laparotomy, and air laparotomy. Laparotomy was performed in a sterile balloon pressurized similar to laparoscopy. Peritoneal interleukin-1, interleukin-6, tumor necrosis factor-a, and counts of polymorphnuclear cells (PMNs), and macrophages (MFs) were determined in abdominal lavage fluids at 0, 2, and 48 h. Macrophages were assessed for reactive oxygen species (ROS) production. Systemic responses were gauged by white blood cell count (WBC) and cytokines. Alveolar lavage was performed at 48 h to determine cytokine levels, cell counts, and MF ROS production. Blood, lavage fluids, and mesenteric lymph nodes were tested for bacterial translocation.
Results: Regarding the peritoneal response, laparotomy versus laparoscopy when performed with CO2 significantly increased PMN and decreased the percentage of macrophages (%MF) up to 48 h. There was a significant increase in interleukin-6, and there was a fourfold increase in MF ROS production. Similar differences between the procedures were found with exposure to air. The use of air versus CO2 in laparoscopy, but not in laparotomy, resulted in an increase of peritoneal PMN and a decrease of the %MF up to 48 h. Air increased the local interleukin-6 release in both procedures and increased MF ROS production fourfold. Regarding the systemic response, laparotomy produced a significant increase in WBC, which was significantly more pronounced with exposure to air. No alteration of other systemic cytokines was seen. Regarding the pulmonary response, the number of MFs and MF ROS production were significantly increased after air versus CO2 laparoscopy. There were no such differences between the laparotomy groups. Regarding bacterial translocation, no bacteria were cultured from peritoneal fluids, lymph nodes, or blood.
Conclusions: Inflammatory responses were reduced by a laparoscopic approach and by exposure to CO2 versus air. Peritoneal responses were affected to a larger degree than systemic parameters. Laparotomy overruled the effects of CO2 on chemotaxis and distant organ injury but not on peritoneal cytokine release.