Determination of Small Bowel Viability Using Quantitative Myoelectric and Color Analysis

Abstract

Intraoperative assessment of viability in ischemic bowel remains a major unsolved problem in general surgery. Bowel viability was assessed in 31 dogs 24 hr after mesenteric arterial ligation in a 40-cm segment of ileum. The purpose of this study was to evaluate two new quantitative methods of viability assessment, electromyography (EMG) and reflection densitometry. These methods were compared with traditional methods of bowel viability assessment. EMG was measured using a specially designed probe which contains an electronic control unit for computer-assisted data acquisition. A computer algorithm quantified the EMG. Reflection densitometry quantified bowel color in the red and blue spectrum. Presence of visible peristalsis, Doppler ultrasound, and a visual color grading system were also used in viability assessment. Each parameter was measured at 2-cm intervals along the ischemic segment. Resection and anastomosis of ischemic bowel were then performed. There were nine deaths from anastomotic leak, all resulting from further bowel necrosis. EMG was the only viability assessment parameter that correlated with survival. EMG at the resection margin in survivors was 29 ± 3% vs 23 ± 4% at the resection site of nonsurvivors (P ≤ 0.047 by unpaired Students t test). These results suggest that quantitative EMG measurements may be useful in assessment of viability in ischemic bowel.