ISOFLURANE DECREASES THE DURATION OF LEFT VENTRICULAR DYSFUNCTION AFTER GLOBAL ISCHEMIA IN DOGS

Abstract

INTRODUCTION. Previous data indicate that isoflurane (ISO) exposure prior to regional ischemia and reperfusion enhances return of regional contractile function [1]. This study examined the effect of ISO pretreatment on recovery of left ventricular (LV) pump function following global ischemia and reperfusion in dogs. METHODS. After Animal Care Committee approval, 11 dogs anesthetized with alpha-chloralose/morphine/nitrous oxide were instrumented for measurement of mean arterial pressure (MAP) and stroke volume index (SVI). After thoracotomy and baseline measurements, 5 dogs received 1.5% ISO for one-half hour and treatment measurements were obtained, while 6 control animals did not receive ISO. Ventricular fibrillation (VF) was then induced by rapid pacing current applied to the LV. After 8 minutes of VF, epinephrine (20[micro sign]g/kg) and sodium bicarbonate (1 meq/kg) were injected and open chest cardiopulmonary resuscitation was performed for 3 minutes. Internal defibrillation was then performed, and measurements were obtained at hourly intervals for 12 hours. During this time, all animals were ventilated with room air alone. RESULTS. Data are shown in Figure 1, Figure 2, Figure 3, and Figure 4. Following VF, both groups demonstrated similar changes in MAP and heart rate. However, control animals experienced a substantially greater decrease in SVI and LV stroke work index (SWI) between 3 and 10 hours post-VF than did dogs pretreated with ISO.Figure 1Figure 2Figure 3Figure 4DISCUSSION. These data indicate that ISO pretreatment prior to global ischemia accelerates recovery of LV function after an initial period of dysfunction.