Increased systemic inflammation after laparotomy vs laparoscopy in an animal model of peritonitis.

OBJECTIVE To study the influence of laparotomy and laparoscopy on local and systemic inflammation in a rat model of peritonitis. DESIGN Bacteremia, peripheral leukocyte subpopulations, tumor necrosis factor alpha (TNF-alpha) plasma levels, and ex vivo secretion of peripheral blood mononuclear cells were investigated after laparotomy and laparoscopy in a prospective randomized experimental study. SETTING Surgical department of a university hospital. ANIMALS 60 male inbred Wistar rats. INTERVENTIONS Standardized fecal inoculum was injected intraperitoneally and rats underwent laparotomy (n=20), laparoscopy (n=20), or no further manipulation (control group, n=20). Blood samples were obtained during the perioperative course to determine bacteremia, leukocytic subpopulations, TNF-alpha plasma levels, and ex vivo secretion. The number of intraperitoneal abscesses was determined in each animal after 1 week. MAIN OUTCOME MEASURE The hypothesis of the experiment was that laparoscopy with carbon dioxide leads to an increase of local and systemic inflammation in comparison with the laparotomy and control groups. RESULTS One hour after intervention, bacteremia was significantly higher in the laparotomy and laparoscopy groups compared with the control group (P=.01). Fecal inoculum caused significant monocytopenia and lymphocytopenia in all groups within 1 hour after intervention (P<.05), with complete recovery on day 2 only in the laparoscopy and control groups. Laparotomy caused a significant increase in TNF-alpha plasma levels and decrease of ex vivo production of TNF-alpha compared with the other 2 groups (P<.05). CONCLUSIONS Laparotomy and laparoscopy increased the incidence of bacteremia and systemic inflammation in this peritonitis model. The inflammatory response was significantly higher in the laparotomy group compared with the laparoscopy group.