Defining the Dose Range for Esmolol Used in Electroconvulsive Therapy Hemodynamic Attenuation

We evaluated the clinical effectiveness of esmolol, an ultra-short-acting, β-adrenergic receptor blocking drug, to control the sinus tachycardia and increase in arterial blood pressure induced by electroconvulsive therapy (ECT). Each of 20 patients, ASA physical status IIII, participated in a double-blind, randomized Latin-Square study involving two matched-pair trials (placebo versus esmolol given as a 500-μg/kg bolus followed by either 300 μg-kg-min [high dose], 200 μg-kg-min [medium dose], or 100 μg-kg-min [low dose] infusion of esmolol) during ECT. Each patient acted as his or her own control (total number of ECT procedures were 160). We administered a 1-min bolus of placebo (normal saline) or esmolol at the rate of 500 μg-kg-min followed by either high-, medium-, or low-dose esmolol or placebo for an additional 3 min. We then induced anesthesia with methohexital (1 mg/kg) and succinylcholine (0.5 mg/kg) IV. Ninety seconds after the administration of succinylcholine, the electrical stimulus was applied to induce seizure. The infusion of placebo or esmolol was discontinued 3 min after the electrical stimulus. Significant decreases were found in mean heart rate from minute 3 until minute 7 and in the maximum heart rate. The mean of each patientʼs maximum heart rate after seizure changed from 147 ± 18 bpm in placebo patients to 112 ± 20 bpm in high-dose esmolol patients; to 121 ± 23 bpm in medium-dose esmolol patients; and to 124 ± 20 bpm in low-dose esmolol patients. Mean arterial blood pressure was significantly lower in the high-dose esmolol patients (100 ± 18 mm Hg) compared with the same patients given placebo (122 ± 25 mm Hg). Finally, the side effect of clinically determined length of seizures decreased in the high- (36 ± 14 s) and medium-dose (34 ± 14 s) esmolol patients as compared with placebo (42 ± 11 s) patients. Low-dose esmolol did not significantly reduce the clinically determined length of seizure (38 ± 11 s). We conclude that the 100-μg-kg-min infusion following a 500-μg/kg bolus of esmolol effectively controls the hyperdynamic response to ECT.