Laparoscopic insufflation with room air causes exaggerated interleukin-6 response

Background: The gut is a central organ in the postoperative stress reaction . We previously reported that measuring gut-mucosal cytokines may more accu rately reflect the response to operative stress. Additionally, we have show n that the gut demonstrates a blunted cytokine response after laparoscopy a s compared with laparotomy. Methods: To further investigate whether this differential response is cause d by exposure of the peritoneal cavity to general atmospheric air during la parotomy, 80 A/J mice were randomized equally into four groups: CD (carbon dioxide [CO2] pneumoperitoneum), RA (room air pneumoperitoneum), AP (anesth esia and port insertion only), and PC (pure control, no intervention). Pneu moperitoneum was established and maintained at 3 mmHg for 60 min. All the m ice were killed 4 h after the intervention. Jejunal mucosa and serum sample s were collected and analyzed for interleukin-6 (IL-6) levels. Results were analyzed by analysis of variance (ANOVA). Results: Gut-mucosal IL-6 in the RA group was signifi cantly higher than in all other groups: RA, 1,354.5 +/- 117.9* vs. CD, 964.3 +/- 114.0 vs. AP, 9 60.2 +/- 86.2 vs. PC, 908.0 +/- 83.6; *p < 0.05. The CD group did not show a significant increase in gut-mucosal IL-6 as compared with the AP and PC g roups. Similarly, RA resulted in significant increases in serum IL-6 as com pared with AP and PC, whereas CD showed no significant difference: RA, 161. 3 +/- 66.2* vs. 95.1 +/- 1 vs. AP, 10.6 +/- 5.3 vs. PC, undetectable; *p < 0.05. There was no difference in serum IL-6 level between CD or any of the other groups. Conclusions: Exposure of the peritoneal cavity to atmospheric air, independ ently of the trauma of abdominal access, causes an exaggerated serum and gu t mucosal IL-6 response 4 h after intervention. The beneficial effect of CO 2 laparoscopy may be caused by the exclusion of general atmospheric air fro m the peritoneal cavity.