COMPARISON OF BLOOD-FLOW AND MYOELECTRIC MEASUREMENTS IN 2 CHRONIC MODELS OF MESENTERIC LIGATION

Objective: To determine whether the predictive accuracy of intestinal motility and blood flow measurements is altered by the magnitude of is chemic damage. Design: Inception cohort study (dogs). Motility was mea sured using a probe that quantifies both the electromyographic (EMG) m easurements and the magnitude of evoked contractile response (ECR). In testinal blood now was assessed using Doppler ultrasonography in the m arginal artery and perfusion fluorometry, which quantifies fluorescein in the bowel wall in dye fluorescence units. Setting: Vivarium animal research facilities at a medical school, Interventions: The blood sup ply of a 40-cm length of ileum was ligated in 102 dogs: 52 in which th e marginal artery was ligated at two points 8 cm apart (severe model), and 50 in which the marginal artery was ligated only once (moderate m odel). Twenty-four hours after ligation, the motility and blood flow p arameters were measured in normal bowel and at 2-cm intervals within t he 40-cm ischemic segment. Resection and anastomosis of ischemic bowel was then performed using either EMG, ECR, or fluorometry to determine the site of resection. Outcome Measure: Anastomotic leak from progres sive ischemia. Results: There were 26 fatal anastomotic leaks, all due to necrosis at the anastomosis. Perfusion fluorometry and ECR measure ments did not correlate with survival in either model. An audible Dopp ler pulse in the marginal artery correlated with survival in the moder ate (P less than or equal to.02) but not the severe model (P=.59). The EMG measurements were significantly greater in survivors vs nonsurviv ors in both models. Conclusions: The EMG measurements may be useful in bowel viability assessment. Correlation of Doppler ultrasonographic f indings with survival in the moderate model suggests that blood flow m easurements may be more reliable in predicting viability in less ische mic bowel.