Objectives: Electroconvulsive therapy (ECT) is standard treatment of severe depression. The induction of a seizure is a core event in successful ECT. Although propofol is a frequently used anesthetic agent, one of its limitations is a reduction of seizure duration. No such effects have been reported regarding remifentanil, an ultrarapid-acting opioid that is used to induce and maintain anesthesia. The simultaneous administration of propofol and remifentanil may have similar safety and efficacy in terms of induction of anesthesia during ECT as propofol alone and significantly increase seizure duration.
Methods: Twenty-one ECT patients (10 men, 11 women, aged 24 to 81 years) were recruited. Muscle paralysis was achieved with succinylcholine (0.5-0.75 mg/kg intravenously [IV]). Unconsciousness was induced by either propofol (1 mg/kg IV) or propofol (0.5 mg/kg IV) + remifentanil (1 microg/kg) in a crossover format. ECT was administered according to established clinical protocols at the Sheba Medical Center, Israel. No changes in ECT current were permitted in the 2 protocols of each patient. Statistical analysis was based on paired t tests.
Results: In all but 2 cases, seizure duration was significantly longer in the remifentanil group than in the control group (motor seizure 53.7 +/- 28.3 seconds vs. 29.5 +/- 10.9 seconds, t = 4.017, P = 0.0007; Electroencephalographic (EEG) seizures 60.8 +/- 25.1 seconds vs. 40.1 +/- 17.0 seconds, t = 3.971, P = 0.001). No significant differences were found in mean recovery time, post-treatment elevation in blood pressure, heart-beat, or oxygen saturation.
Conclusion: During anesthesia, the addition of remifentanil to propofol appears to be as effective as propofol alone with regard to anesthesia efficacy and cardiovascular function while significantly increasing seizure duration. Whether this discovery is of relevance to the clinical efficacy of ECT remains to be tested.