COOLING STRANGULATED INTESTINE BEFORE AND FOLLOWING RELEASE OF AN OBSTRUCTION PROTECTS FROM ISHEMIA REPERFUSION INJURY/

Objective: To evaluate whether cooling of ischemic intestine before an d immediately after the release of the obstruction is more advantageou s than is warming in an isolated ileal loop rat model. Design: Prospec tive randomized experimental trials. Setting: Laboratory. Materials: M ale Sabra rats. Interventions: An isolated loop of ileum was created i n rats and constantly perfused with warmed normal saline (37 degrees C ). Intestinal ischemia was caused by clamping of the superior mesenter ic artery for 15 minutes. Cooling of the isolated ileal loop to 32 deg rees C by the application of cold saline was done for the last half of the ischemic period and continued during the first 10 minutes of repe rfusion. The intestine was warmed to 37 degrees C for the next 20 minu tes of reperfusion. Main Outcome Measures: The chromium 51-labeled eth ylenediaminetetraacetic acid (Cr-51-EDTA) plasma-to-lumen clearance ra te was used for the evaluation of intestinal mucosal injury. Multiple intestinal samples were harvested at the end of the reperfusion period , and the histological features were evaluated. Results: The Cr-51-EDT A plasma-to-lumen clearance rates were significantly lower (P<.001) in the rats in which cooling of the ischemic intestine was performed in comparison with the control group, indicating reduced intestinal mucos al injury in all three 10-minute reperfusion periods. Cooling also sig nificantly changed the resultant histological damage to the intestinal mucosa exerted by ischemia (P<.001). Conclusion: Cooling of the ische mic intestine before the release of the obstruction and for a short pe riod during reperfusion provides significant protection from ischemia/ reperfusion injury compared with the traditional method of warming the ischemic intestine.