A retrospective comparison of remifentanil versus methohexital for anesthesia in electroconvulsive therapy

The electroconvulsive therapy (ECT) service at West Virginia University conducted a retrospective analysis of 24 patients who received bilateral ECT between November 1998 and December 2003. Patients were treated with a standard methohexital-based anesthetic. Twenty-four patients became completely or relatively refractory to maximum settings on the ECT device and were then switched to remifentanil as the sole induction agent. Seizure threshold was established by stimulus dose retitration. Stimulus dose in total charge (mC) and dynamic energy (J) was significantly lower with the remifentanil anesthetic versus methohexital. (P < 0.0001) Resulting motor and EEG seizure duration in patients was significantly longer receiving the remifentanil anesthetic versus methohexital. (P < 0.0001) Previous reports describe a rise in seizure threshold in patients for repeated ECT. Although this rise occurred during the treatment course using a methohexital anesthetic, this effect was greatly diminished when remifentanil was used as the sole anesthetic agent. We conclude that remifentanil can provide improved seizure response to ECT in patients who are refractory to seizure induction after a standard methohexital anesthetic. We also conclude that the increase in stimulus dose typically required with repeated treatments is related to the anesthetic regimen.