Pilot study with air-automated sigmoid capnometry in abdominal aortic aneurysm surgery.

Background: and objective Ischaemic colitis can be a serious complication after aortic surgery. The paucity of clinical symptoms makes its diagnosis particularly difficult and often delayed. Automated on-line tonometry is now proposed to monitor intestinal perfusion. This study was designed to assess the use of semi-continuous sigmoid-to-arterial [P(r-a)CO(2)] PCO(2) gap monitoring in aortic surgery to detect colonic ischaemia.

Methods: This prospective clinical study was realized at the University Hospital of Lille, France, including eight males scheduled for abdominal aortic aneurysm surgery. Intraoperative and postoperative P(r-a)CO(2) values were compared with conventional monitoring and colonic mucosa aspect performed by sigmoidoscopy 48 h after surgery. Haemodynamic variables, O(2) delivery (DO(2)), O(2) consumption (VO(2)), O(2) extraction (ERO(2)), lactate, P(v-a)CO(2), P(r-a)CO(2) were measured peroperatively and every 4 h during a 48-h postoperative period.

Results: Intraoperative P(r-a)CO(2) values increased significantly with the highest value (4.36 +/- 3.42 kPa) observed during aortic clamping when DO(2) was the most altered. P(r-a)CO(2) continued to deteriorate after surgery with the maximal values between 8 (4.79 +/- 3.85 kPa) and 12 (4.68 +/- 3.26 kPa) h after surgery. This peak was associated with a significant ERO(2) increase counterbalancing an increase of VO(2) whereas DO2 tended to decrease. P(r-a)CO(2) values began to decrease only at the end of the study. The highest values of P(r-a)CO(2) were registered in patients with the most altered haemodynamic variables, severe ischaemic colitis along with higher hospital lengths of stay.

Conclusion: Taken together, these data suggest that regional and automated capnometry may be easily used non-invasively to detect peroperative intestinal ischaemia in aortic surgery.