Objective: To investigate the potential role of endogenous prostacyclin (PGI2) released after mesenteric traction during major abdominal surgery on perioperative endotoxemia and bacterial translocation.
Design: Prospective, randomized, double-blind clinical study.
Setting: Operating room and surgical intensive care unit in a university hospital.
Patients: Fifty consecutive patients scheduled for major abdominal surgery (pancreas resection, abdominal aortic surgery).
Interventions: Fifteen minutes before skin incision, either 400 mg of ibuprofen or a placebo equivalent were administered intravenously. Immediately after peritoneal incision, eventration and action of the small bowel was intentionally performed in a uniform fashion.
Measurements and main results: Baseline values were obtained before induction of anesthesia. Additional measurements, along with assessments of hemodynamics and gas exchange, were performed before incision of the peritoneum and at 5, 30, and 45 mins and 3, 6, and 24 hrs after mesenteric traction. Arterial plasma concentrations of 6-keto-prostaglandin F1 alpha and thromboxane B2 (stable metabolites of PGI2 and thromboxane A2) were determined by radioimmunoassay. Endotoxin was measured by limulus amebocyte lysate test. Mesenteric lymph nodes were sampled in 31 patients (ibuprofen n = 14, placebo n = 17) and sent for culture under sterile conditions. Transient hypotension and a marked increase of plasma 6-keto-prostaglandin F1 alpha concentrations occurred up to 6 hrs after mesenteric traction in untreated patients with median peak concentrations (2243 vs. 72 ng/L [p < .0001, placebo vs. ibuprofen], observed 5 mins after mesenteric traction). Endotoxemia occurred in both study groups. However, after mesenteric traction, plasma endotoxin concentrations were significantly higher in the ibuprofen group. Median peak concentrations (0.12 vs. 0.27 EU/mL [p < .001, placebo vs. ibuprofen]) were observed 3 hrs after mesenteric traction. Gram-negative bacteria in mesenteric lymph nodes were detected exclusively in the ibuprofen group (n = 5, p < .01).
Conclusions: In ibuprofen-pretreated patients, significantly higher endotoxin concentrations as well as bacterial translocation to mesenteric lymph nodes occurred, despite the absence of a transient decrease in mean arterial pressure that had been associated with PGI2 release. Therefore, we hypothesized that during major abdominal surgery, endogenous PGI2 released in response to mesenteric traction may play a crucial role in maintaining splanchnic microcirculation and thus preserving gut mucosal barrier function.