Evaluation of quantitative approaches to assessment of bowel viability.

Predicting the survivability of intestine that has been made ischemic by impairment of blood flow is a major unsolved problem in gastrointestinal surgery. Currently, the surgeon must rely on qualitative, often subjective assessments that are known to have marginal reliability. This review describes various approaches to quantitatively assess the survivability of intestine compromised by ischemic disease. Much of the review centers on work done in the authors' laboratory to evaluate various approaches to predicting long-term survival and to develop new assessment parameters. Towards that end the authors have designed and developed techniques based on intestinal contractility and myoelectric activity (the intestinal EMG). Their evaluations of these and other methods of viability assessment utilize a highly representative canine model of intestinal ischemia that closely follows the development and treatment of ischemic intestinal disease in humans. Results to date suggest that the myoelectric measurements are more reliable than parameters based on blood flow or visual evaluation in terms of predicting bowel survival. However, improvements in instrumentation and technique are needed before this approach is suitable for clinical use.