Lavage by laparoscopy fares better than lavage by laparotomy: experimental evidence

Although carbon dioxide (CO2) pneumoperitoneum is proposed increasingly for treatment of secondary peritonitis, associated deleterious effects have been reported in experimental models, with the hypothesis that increased intraperitoneal pressure might facilitate bacterial translocation. The purpose of this study was to compare the outcome (and qualitative microbiologic analysis) from peritonitis in rats after lavage by laparoscopy with the outcome after lavage by laparotomy.

After determination of the standard innoculum for this study in 30 animals, 120 male Wistar rats received 1 ml of Escherichi coli 10(6) colony-forming unit (CFU), Bacteroides fragilis 10(7) CFU, Enterococcus faecalis 10(7) CFU in a sterile rat feces-barium sulfate suspension adjuvant, were anesthetized with intramuscular ketamine, and then underwent peritoneal lavage by either laparotomy (n = 60) or laparoscopy (n = 60). The duration of peritonitis defined two groups: group A: duration less than 3 h (n = 20) and group B: duration 3 h or more (n = 40). Both groups underwent successive lavage with 10-ml aliquots (total, 50 ml) of 0.9% saline solution at 37 degrees C. Five 2-ml samples of liquid lavage were drawn for culture and microbiologic analysis. Blood (0.2 ml) and peritoneal liquid lavage samples were incubated 48 h at 37 degrees C and cultured.

All the animals survived. Mean duration of peritoneal lavage was 13.2 min (range, 6-25 min) for laparoscopy and 9.7 min (range, 6-15 min) and for laparotomy. The difference was not statistically significant. The mean duration of operation was significantly longer with laparoscopy than with laparotomy: 44.5 min (range, 35-62 min) and 25 min (range, 16-40 min), respectively (p = 0.0001). The collected lavage volumes were not statistically different: 48.5 ml (range, 40-54 ml) and 46.7 ml (range, 37-56 ml), respectively. No statistically significant differences were found between the laparoscopy and laparotomy groups in terms of E. coli bacteremia, irrespective of peritonitis duration. The rates of positive blood culture for B. fragilis and E. faecalis were signficantly lower after laparoscopy than after laparotomy, both in the overall group (p = 0.025 and p = 0.045, respectively) and when duration of peritonitis exceeded 3 h (p = 0.001 and p = 0.044, respectively).

In this animal model of secondary peritonitis, lavage by laparoscopy was associated with less bacteremia for B. fragilis and E. faecalis than peritoneal lavage by laparotomy.