Recovery of LV contractility in man is enhanced by preischemic administration of enflurane

Background. Volatile anesthetics enhance postischemic functional recovery i n animal models; this effect has not been investigated in man. Methods. Twe nty-two patients undergoing coronary surgery were randomized to enflurane a dministration (0.5% to 2%) for 5 minutes to reduce systolic blood pressure by 20% to 25% immediately before cardioplegic arrest. Left ventricular cont ractility was assessed by pressure-area relations using echocardiographic a utomated border detection during inflow occlusion before and after cardiopu lmonary bypass. Linear regression analysis in 16 patients with paired data sets assessed changes in contractility. Results. The relation was highly li near (r = 0.95 +/- 0.02). A change of slope versus the change in x intercep t was detected in controls (mean difference, 16.1 mm Hg/cm(2), 95% confiden ce limits, 5.9 to 26.3; 2.2 cm(2), 95% confidence limits, -1.1 to 5.5; p = 0.007), which was different from those of treated patients (mean difference , 0.7 mm Hg/cm(2) 95% confidence limits, -2.2 to 3.7; -0.06 cm(2), 95% conf idence limits, -1.6 to 1.5; p > 0.2). Analysis of covariance in the overall group confirmed a significant effect of treatment (p = 0.002). Conclusions . Enflurane enhances postischemic functional recovery, possibly through pha rmacologic preconditioning of myocardium. (C) 1999 by The Society of Thorac ic Surgeons.