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

Background. Volatile anesthetics enhance postischemic functional recovery in animal models; this effect has not been investigated in man. Methods. Twenty-two patients undergoing coronary surgery were randomized to enflurane administration (0.5% to 2%) for 5 minutes to reduce systolic blood pressure by 20% to 25% immediately before cardioplegic arrest. Left ventricular contractility was assessed by pressure-area relations using echocardiographic automated border detection during inflow occlusion before and after cardiopulmonary bypass. Linear regression analysis in 16 patients with paired data sets assessed changes in contractility. Results. The relation was highly linear (r = 0.95 ± 0.02). A change of slope versus the change in x intercept was detected in controls (mean difference, 16.1 mm Hg/cm2, 95% confidence limits, 5.9 to 26.3; 2.2 cm2, 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/cm2, 95% confidence limits, −2.2 to 3.7; −0.06 cm2, 95% confidence 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 pharmacologic preconditioning of myocardium.