In Reply:—
We thank Dr. Kempen for his letter to the editor, which again draws attention to the importance of careful planning when providing anesthesia care for electroconvulsive therapy (ECT). We agree that our case report1raised several unmentioned issues. The first key point in Dr. Kempen’s letter is that as soon as we appreciated that the patient was awake and aware, an additional dose of methohexital could have been given to restore unconsciousness. In general, additional doses are appropriate for restoring unconsciousness and are well within standards of care. For example, a typical clinical recommendation for adult methohexital administration is 1–1.5 mg/kg intravenous for induction, and 20–40 mg intravenous every 4–7 min for maintenance.2However, in our case, the patient was completely awake, responsive to complex yes/no questions with toe response, and therefore not treatable by a small additional methohexital dose. A concern there was that additional methohexital doses might lead to a reduction in seizure duration, possibly to a point where the duration was inadequate.
The relation between anesthetic agent and effect on seizure duration is an important issue. In our case, the patient, who may have had a high anesthetic threshold, would have required a second induction dose, not a small additional maintenance dose. Etomidate is a commonly used anesthetic for ECT and has been shown to provide longer seizure durations.3The same study also found a dose-dependent reduction of seizure duration by methohexital in the dose range 0.75–1.50 mg/kg. Indeed, a 2003 randomized, double-blind, crossover study of middle-aged patients found that using remifentanil with a reduced methohexital dose of 0.625 mg/kg markedly improved the marginally acceptable seizure duration that results from a methohexital dose of 1.25 mg/kg.4Anecdotally, we have also had excellent experience with a combination of fentanyl and etomidate.
Finally, there was a concern related to Dr. Kempen’s second key point: the importance of having properly conducted the informed consent process. Interestingly, the State of California mandates that the psychiatrist’s informed consent for ECT include the possibility of amnesia, muscle aches, nausea, headache, and post-ECT confusion. Awareness–recall during anesthesia for the procedure is not listed. Perhaps it would be a good thing to add to the ECT consent, although it certainly is covered in the informed consent discussion with anesthesia providers. As noted in Dr. Kempen’s letter as well as in the case report’s first citation,5one cannot depend on retrograde amnesia being provided by the electroshock and seizure.
All things considered, it was thought during the case that the preferred course of action would be to wake the patient, review the situation with him, and then, with the patient’s informed consent, switch to etomidate. This was done, and the outcome was completely satisfactory, in terms of both anesthesia and ECT response. Dr. Kempen’s letter highlights several important aspects of providing ECT anesthesia care, and we are deeply grateful for his observations and comments.
*University of California, San Francisco, California. Larry.Litt@ucsf.edu