Continuous air tonometry of the sigmoid colon during abdominal aortic surgery.

Background: The aim of this study was to record the changes in the mucosal intracellular (pHi) of the sigmoid colon during operations of the abdominal aorta, using the air tonometry method.

Methods: Patients with abdominal aortic aneurysm (AAA), and with aortoiliac occlusive disease (AIOD) were included in the study. The tonometric catheter was placed in the sigmoid colon under colonoscopy, and its position was confirmed during operation. The pHi records were divided into certain phases: 1) beginning; 2) clamping; 3) declamping; 4) Intensive Care Unit (ICU); 5) 1st day in the ICU; 6) 2nd day in the ICU.

Results: A total of 30 male patients (15 with AAA, 15 with AIOD) were enrolled in the study. Dyslipidemia, arterial hypertension and coronary heart disease were present in the majority of the patients in both groups. In the AAA group, a significant difference (P=0.004) was present between at least two time phases regarding the pHi time course. A comparison of the difference between regional pH and arterial pH (pH(r-a)) in both groups of patients showed a statistically significant result (P=0.008). As for the difference between partial pressure of regional CO2 (PCO2) and partial pressure of arterial CO2 (PaCO2) (P(r-a)CO2), a statistically significant difference in the P(r-a)CO2 course from one time phase to another in both groups was noticed (P<0.001).

Conclusions: Air tonometry (Tonocap monitor, Datex-Ohmeda, GE Healthcare, Little Chalfont, England, UK) is an effective and easily applicable method, allowing the surgeon to be better informed of the tissue oxygenation of the intestinal wall, for the prevention of colon ischemia complications and to take the appropriate measures.