Abstracts
1998 Digestive Disease Week

#977

BASIC ELECTRICAL RHYTHM (BER) ACTIVITY AS A MEASURE OF BOWEL VIABILITY DURING MESENTERIC ISCHEMIA AND REPERFUSION. JK Ladipo*, SA Seidel*, LA Bradshaw*#, S Halter_, WO Richards*_. Depts. of Surgery* and Physics & Astronomy#, Vanderbilt University, and Depts. of Pathology_ and Surgery_, Veterans Administration Medical Center, Nashville, Tennessee.

Previous studies have shown that the intestinal Basic Electrical Rhythm (BER) decreases during mesenteric ischemia. BER activity has not been fully characterized during ischemia and reperfusion, and correlated with histopathology. We hypothesized that BER parameters could be used to determine bowel viability during mesenteric ischemia and reperfusion. METHODS: Electrical activity of rabbit ileum was measured using serosal electrodes. Recordings were taken at baseline, during ischemia (with prior heparinization) and during reperfusion. The rabbits (n = 30) were divided into 6 groups subjected to varying periods of ischemia (30-180 minutes). All groups had post-ischemia reperfusion for 6 hours. Biopsies were taken from the ileal segments before ischemia, at the end of ischemia, and every hour during reperfusion. A histopathologist, blinded to the specimen identity, graded all biopsies on a scale of 0-6 (Grade 0 = no histological changes; 6 = transmural necrosis). The mean, ± SEM, of the BER frequency (cycles per minute, cpm) and amplitude (millivolts, mv) were calculated. Paired t-test and Fisher's r to z test were used for statistical significance where appropriate. RESULTS: BER frequency and amplitude decreased significantly by 15 minutes of ischemia, and became undetectable after 90 minutes. These changes in BER activity preceded histopathologic changes. Worsening pathologic grade was highly correlated with increasing ischemia time (r=0.95, p< 0.05), but the pathologic grade change from baseline became significantly different only when ischemia was prolonged to _ 150 minutes (p < 0.05). During reperfusion BER frequency returned to baseline values after short periods (30-60 minutes) of ischemia while amplitude did not. Both parameters were worse when longer periods of ischemia preceded reperfusion. There was no return of BER activity when ischemia lasted for _ 150 minutes. There was an acute worsening of histopathologic changes in the bowel when reperfusion was preceded by ischemia of _ 90 minutes. CONCLUSIONS: Changes in BER frequency and amplitude accurately reflect bowel viability after ischemic injury and reperfusion. Thus it holds promise for use in the intra- and postoperative evaluation of bowel viability.

Copyright 1996 - 1998, SSAT, Inc. Revised 29 June 1998.