pHi monitoring of the sigmoid colon after aortoiliac surgery. A five-year prospective study

Objectives: to determine whether sigmoid-pHi diagnose colon ischaemia after aortoiliac surgery? Design: single-centre, non-randomised, prospective study. Patients and Methods: of 83 patients operated on between 1994 and 1998, 41 with risk factors for the development of colon ischaemia were monitored per i- and/or postoperatively with sigmoid-pHi. Peri-operative mortality was 26 % (8/31) after operation for a ruptured abdominal aortic aneurysm (AAA), ni l after operation for non-ruptered AAA. Thirty-five postoperative colonosco pies were performed. All non-survivors were examined post-mortem. Results: of six patients developing colon ischaemia after emergency operati ons (five for ruptured AAA) all had pHi-values <7.1 for 16-80 h. In two pat ients with transmural gangrene, and who had pHi-values below 6.6, pHi-monit oring permitted early diagnosis, colectomy and recovery. Three patients wit h mucosal gangrene were treated conservatively and recovered. Nine patients without ischaemic lesions had pHi-values <7.1, during 16 h, w ithout adverse outcome. Bilateral ligation of the internal iliac arteries i ncreased the risk of colon ischaemia (p < 0.0001). Conclusions: pHi-monitoring was diagnostic for colon ischaemia. Mucosal and transmural gangrene were distinguished. The importance of the internal ili ac circulation was demonstrated. The low mortality rate, and the fact that no patient died from bowel ischaemia, suggests that sigmoid pHi-monitoring may improve survival after ruptured AAA.