Intraoperative determination of intestinal viability: a comparison with transserosal pulse oximetry and histopathological examination.

BACKGROUND

In this study, we aimed to measure the O2 saturation of ischemic intestinal segments and the relationship between these measures and concomitant pathological gradings.

MATERIALS AND METHODS

We used 14 New Zealand White rabbits, anesthetized with a combination of 80 mg/kg (i.m.) Ketamine hydrochloride and 10 mg/kg Acepromazine (i.m.). The superior mesenteric artery (SMA) was explored, and O2 saturation was measured by pulse oximetry 5 cm proximal to the ileocecal valve at the 0th hour. At the same time a 0.5-cm full-thickness wedge biopsy was taken from the same region. Thereafter, the SMA was ligated and the abdomen was closed. All rabbits were undertaken relaparotomy at the 4th hour; O2 saturation was measured by pulse oximetry at 5 cm away from the region of the first biopsy and a 0.5-cm full-thickness wedge biopsy was taken. The abdomen was then closed. The same procedure was performed at the 8th and the 12th hour. Mucosal hemorrhage, transmural congestion, mucosal necrosis, and transmural necrosis were examined in the specimens.

RESULTS

Pathologically, transmural necrosis was concomitant with 64% O2 saturation (sensitivity: 100%; specificity: 86%). Mucosal necrosis was concomitant with 76% O2 saturation values (sensitivity: 100%; specificity: 75%). Transmural congestion was concomitant with 81% O2 saturation values (sensitivity: 89%; specificity: 58%). Mucosal hemorrhage was concomitant with 91% O2 saturation (sensitivity: 100%; specificity: 31%).

CONCLUSION

O2 saturation measures > 76% may indicate reversible changes as mucosal necrosis, transmural congestion, or mucosal hemorrhage, and O2 saturation measures < 64% may indicate permanent transmural necrosis. As a result, intraoperative evaluation of intestinal viability by pulse oximetry may give us an idea about the degree of pathological changes and subsequently might reduce the number of second-look operations.