Abstract 350: Remote Ischemic Pre-Conditioning Reduce Myocardial Ischemic Injury During and Following Hemorrhage Shock in a Rat Model

Abstract

Introduction: Myocardial ischemic injury following severe hemorrhage shock is often represented by acute changes of ST-segment and fractional shortening (FS). In this study, we investigated whether remote ischemic pre-conditioning (RIPC) reduces myocardial ischemic injury by measuring changes in ST-segment and fractional shortening during and following severe hemorrhage shock in a rat model. Hypothesis: RIPC reduces myocardial ischemic injury during and following severe hemorrhage shock as measured by changes of ST-segment and FS. Methods: Fourteen male Sprague-Dawley rats were randomized to receive RIPC, or sham control. RIPC was induced by four cycles of 5 mins of limb ischemia, followed by 5 mins of reperfusion. Fifty percent of estimated blood volume was then removed over an interval of 1 hour. Thirty mins after bleeding was completed, the animals were resuscitated by reinfusion of shed blood within 30 mins. Electrocardiographic tracings, and haemodynamics were continuously recorded for up to 2 hours. FS was measured by echocardiography at baseline, bleeding 60 mins, 30 mins before and after reinfusion and 1 and 2 hours after resuscitation. Results: Depression of ST-segment was observed during hemorrhage and followed with elevation of ST-segment after infusion in all animals. However, depression of ST-segment during hemorrhage and subsequent elevation after resuscitation were significantly better in the RIPC group than in the Control group. The compensative capacity of FS was significantly greater in the RIPC group than the Control group during and following hemorrhage (Table). Conclusion: RIPC reduces myocardial ischemic injury during and following severe hemorrhage shock.