The relationship between sigmoidal intramucosal pH and intestinal arterial occlusion during aortic reconstructive surgery.

OBJECTIVES: To investigate the effects of perioperative occlusion of intestinal arteries on clinical outcome and changes in sigmoidal intramuscular pH (pHi). To determine the value of sigmoidal pHi measurement in predicting ischaemic colitis after aortic reconstructive surgery. DESIGN: Prospective, non-selective, open study. MATERIALS: Forty patients undergoing elective aortic infrarenal surgery were monitored with pHi. Pre- and postoperative digital venous subtraction angiography was combined with operative data to evaluate perioperative occlusion of intestinal arteries. RESULTS: All patients had a significant (p< 0.05) drop in pHi after aortic clamping which returned to baseline 2-4 h after declamping. None of the patients had clinical signs of ischaemic colitis postoperatively. All patients had angiographically proven, patent superior mesenteric arteries pre- and postoperatively. Patients were divided into three groups: patients with no changes in intestinal arteries (n=13), patients with perioperative occlusion of the inferior mesenteric artery (n=22) and patients with perioperative occlusion of the inferior mesenteric and one or both iliac arteries (n = 5); there were no significant differences in pHi values between the groups. CONCLUSIONS: Return of the sigmoidal pHi to baseline values within 6-12 h after declamping probably predicts a postoperative course without ischaemic colitis. Perioperative occlusion of the inferior mesenteric artery alone, or in combination with occlusion of one or both internal iliac arteries, does not cause ischaemic colitis in patients whose sigmoidal pHi rises after declamping.