Early detection of major complications after abdominal aortic surgery: predictive value of sigmoid colon and gastric intramucosal pH monitoring.

The early detection and reversal of gastrointestinal ischaemia is thought to play a key role in minimizing the incidence of complications after abdominal aortic surgery. In an open prospective non-selective study intramucosal pH (pHi) was monitored in 27 patients undergoing elective aortic surgery and in seven submitted to emergency procedures. The pHi was monitored in the sigmoid colon in all 34 patients and in the stomach in 26. Eight patients developed major complications, four of whom had ischaemic colitis, and five died. Sigmoid acidosis (pHi below 7.10) served as an early warning; if acidosis was reversed within 2 h no major complication developed, if prolonged it was predictive of major morbidity (sensitivity 100 per cent, specificity 92 per cent). A colonic pHi below 6.86 predicted endoscopically detectable ischaemic colitis. A gastric pHi below 7.20 predicted major complications with a sensitivity of 100 per cent and specificity of 81 per cent. Both monitoring procedures were considered feasible, although monitoring in the sigmoid colon was found to be superior for the patients studied.