Integrity of gut mucosa during anaesthesia in major abdominal surgery.

The aim of the study was to examine a perfusion and integrity of small bowel in 60 subsequent patients during the major open abdominal surgery which lasted from 2 to 7 hours. Two samples of the intestinal mucosa were removed: at the beginning, and at the end of the surgical procedure in general anaesthesia. A mucosal injury was classified into 4 grades. pH, PCO2 and lactate level were measured in the blood samples from the arterial and mesenteric vein in one hour time intervals. The changes of intestinal mucosa were found in 31 patients (51.7%): in 19 patients (31.7%) grade 1 changes were recorded, in 10 patients (16.7%) grade 2, and in 2 patients (3.3%) grade 3. Grade 4 lesions were not recorded. There was a statistically significant correlation between grades of the mucosal damage and the surgery duration (p = 0.001). Analysis during the one hour intervals showed that there was no exact time point when the significant aggravation of the pathohistological changes in intestinal mucosa occurred. However, when patients were allocated into two subgroups with surgical procedures lasting less than 4 hours and more than 4 hours, there was a statistically significant difference in the grades of mucosal damage between subgroups (p < 0.05). More biopsies without pathohistological changes were observed in the patients whose procedure duration was < 4 hours. A significantly higher lactate concentrations in arterial and mesenteric venous blood were observed in the patients with pathohistological changes at 6 hours time point as compared to 2 hour time point in the patients without pathohistological changes (p < 0.05). During the open abdominal surgery in general anaesthesia, the length of the procedure influences the grade of the intestinal mucosa injury. Deterioration of the pathohistological findings in the intestinal mucosa correlates with high lactate blood level, suggesting that the cause of these changes may result from tissue hypoxia.