Original Contributions *Associate Professor, Department of Anes- thesiology †Fellow, Department of Anesthesiology ‡Assistant Professor of Psychiatry and Behav- ioral Sciences, Department of Psychiatry §Professor, Department of Anesthesiology Address correspondence to Dr. Lemmens at the Department of Anesthesia, Stanford Uni- versity Medical Center, 300 Pasteur Dr., Rm. 3580, Stanford, CA 94305-5640. E-mail: hlemmens@leland.stanford.edu Received for publication March 7, 2002; re- vised manuscript accepted for publication August 5, 2002. The Timing of Electroconvulsive Therapy and Bispectral Index After Anesthesia Induction Using Different Drugs Does Not Affect Seizure Duration Harry J. M. Lemmens, MD, PhD,* David C. Levi, MD,† Chuck Debattista, PhD,‡ John G. Brock-Utne, MD, PhD§ Department of Anesthesia, Stanford University Medical Center, Stanford, CA Study Objective: To determine the association between bispectral index (BIS) and seizure duration obtained by electroconvulsive therapy (ECT) administered sooner or later after anesthetic induction. Design: Prospective, randomized, crossover study. Setting: University-affiliated medical center. Patients: Nine ASA physical status I, II, and III patients undergoing a total of 31 ECTs. Interventions: ECT was administered soon (210 sec) or later (between 210 sec and 360 sec) after anesthetic induction. In each individual patient, drug regimens and ECT machine settings were identical. Measurements: BIS immediately before the start of the ECT and the duration of the EEG seizure were recorded, as well as the time period between loss of consciousness and ECT administration. Main Results: There was no relationship between BIS level and seizure duration. Moreover, seizure duration was not dependent on the time of ECT administration in the time window between one and 6 minutes after loss of consciousness. Conclusion: The hypnotic drug effect measured by the BIS is not correlated to the seizure duration obtained by ECT. © 2003 by Elsevier Science Inc. Keywords: Bispectral index monitoring; electroconvulsive therapy. Introduction Electroconvulsive therapy (ECT) is a treatment for depression in patients who fail to respond to pharmacotherapy. 1 ECT is performed after administration of a short-acting anesthetic. Unfortunately, the intravenous (IV) hypnotic drugs that are used possess anticonvulsant properties. Because large doses of these drugs stop ECT-induced seizures, it has been suggested that there is a relation- ship between anesthesia depth and ECT seizure duration. 2 Thus, ECT per- formed shortly after induction of anesthesia, while the concentration of the Journal of Clinical Anesthesia 15:29 –32, 2003 © 2003 Elsevier Science Inc. All rights reserved. 0952-8180/03/$–see front matter 655 Avenue of the Americas, New York, NY 10010 doi:10.1016/S0952-8180(02)00477-4