Effect of the Addition of Ketamine to Sevoflurane Anesthesia on Seizure Duration in Electroconvulsive Therapy.

OBJECTIVES: We evaluated the effects of a subanesthetic dose of ketamine, which was administered as an adjunct to sevoflurane, on duration of seizure activity, hemodynamic profile, and recovery times during electroconvulsive therapy in patients with major depression.

METHODS: Patients were randomly allocated to a group receiving either sevoflurane-ketamine (group SK) or sevoflurane-saline (group SS). Sevoflurane was initiated in both groups at 8% for anesthesia induction until loss of consciousness was achieved, at which point it was discontinued. After loss of consciousness, ketamine was administered to the group SK in the form of a 0.5-mg/kg intravenous bolus. Patients in the group SS received saline in the same manner. Mean arterial pressure (MAP) and heart rate were recorded before anesthetic induction (T1); after anesthetic induction (T2); as well as 0, 1, 3, and 10 minutes after the seizure had ended (T3, T4, T5, and T6, respectively). Motor and electroencephalogram seizure durations were recorded.

RESULTS: Motor and electroencephalogram seizure durations in the group SS were similar to those observed for the group SK. The heart rate increased significantly during T2 to T6 in both group SS and group SK compared with the baseline. The MAP increased in the group SS during the period between T3 and T6 as well as in the group SK during the same period compared with the baseline. The MAP increased more in the group SK, in comparison with the group SS, during T2 (P < 0.05).

CONCLUSIONS: The addition of ketamine at subanesthetic doses, for the purposes of anesthetic induction with sevoflurane, yielded results similar to those in the control group in terms of both seizure duration and hemodynamic stability.