Effects of pneumoperitoneum on hemodynamic and systemic immunologic responses to peritonitis in pigs

Experimental evidence supporting the safety of laparoscopic intervention during sepsis is limited. The purpose of this study was to evaluate the effects of pneumoperitoneum on immunologic and hemodynamic responses to peritoneal sepsis.

A porcine model of peritonitis was created using an intraperitoneal autologous fecal inoculum. Pigs were then subjected to one of four procedures 24 h postinoculation (n = 6 per group): laparotomy, CO(2) laparoscopy, helium laparoscopy, and anesthesia only (1.5% isoflurane in 100% O(2), mechanical ventilation). Venous blood samples were obtained prior to inoculation, and at 24 (prior to procedure), 30, 48, 72, and 96 h postinoculation to determine white blood count (WBC) with differential, C-reactive protein (CRP), tumor necrosis factor, and bacteremia. Heart rate, end-tidal CO(2) (ETCO(2)), mean arterial blood pressure (MAP), and arterial blood gas variables were also measured at baseline and every 30 min throughout the procedure.

Postoperative blood cultures confirmed systemic bacteremia in all groups at all time periods postinoculation. Following inoculation, WBC, band cell count, and CRP remained elevated above baseline in all groups throughout the study (P < 0.01). However, no significant differences in these parameters were observed among groups. In the CO(2) laparoscopy group, MAP, ETCO(2), and arterial pCO(2) were increased above baseline, while pH was decreased throughout the procedure (P < 0.01).

In this animal model of peritonitis, CO(2) pneumoperitoneum induced hypercapnia, acidemia, and systemic hypertension intraoperatively, without a discernable effect on systemic immune function.