EFFECTS OF NICARDIPINE AND LABETALOL ON THE ACUTE HEMODYNAMIC-RESPONSE TO ELECTROCONVULSIVE-THERAPY

Study Objective: To examine the acute hemodynamic effects of intraveno us (IV) nicardipine and ifs ability to attenuate the hyperdynamic resp onse to electroconvulsive therapy (ECT), when used alone or in combina tion with labetalol. Design: Prospective, randomized double-blind, pos itive-control, clinical investigation Setting: University hospital. Pa tients: 36 patients undergoing ECT. Interventions: In a series of thre e studies, the hemodynamic effects of nicardipine were assessed prior to, during, and after ECT After administration of glycopyrrolate 0.1 m g IV, placebo (saline) or nicardipine was administered by rapid infusi on (1, 2.5, 5, 10, and 15 mg) or bolus injection (1.25, 2.5, and 5 mg) , either alone or in combination with labetalol 10 mg IV. Unconsciousn ess was induced with methohexital 1 mg/kg IV; succinylcholine 1.2 to 1 .5 mg/kg IV was administered for muscle relaxation. A bilateral electr ical stimulus was delivered and the durations of motor and elecltroenc ephalographic (EEG) seizures were noted. Measurements and Main Results : Mean arterial pressure (MAP) and heart rate (HR) values were recorde d at 1- to 5-minute intervals throughout the study period. When admini stered as a rapid infusion, nicardipine 5 mg IV produced a significant decrease in MAP; however, nicardipine dosages of 10 to 15 mg IV did n ot produce a significantly greater decrease in MAP than 5,ng. Bolus ad ministration of nicardipine 1.25 to 5 mg produced a rapid onset of its hemodynamic effects without exacerbating the cardiovascular depressan t effects of methohexital. However, the decrease in MAP was accompanie d by an increase in HR after administration of the 5 mg nl bolus dose. The acute hyperdynamic response to ECT was most effectively controlle d by nicardipine 2.5 to 5 mg IV bolus, in combination with labetalol 1 0 mg IV. Seizure duration was not significantly altered by the use of nicardipine as part of the anesthetic regimen for ECT. Conclusion: Nic ardipine 2.5 mg IV bolus in combination with labetalol 10 mg IV was th e most effective pretreatment regimen for preventing the acute hyperdy namic response to ECT. However, this combination produced a 20 % decre ase in MAP immediately prior to ECT and a lower MAP at the time of dis charge. (C) 1998 by Elsevier Science Inc.