Factors Associated With Seizure Adequacy Along the Course of Electroconvulsive Therapy

Objectives Eliciting a generalized seizure is essential to electroconvulsive therapy (ECT), but there is still a need to understand how patient and session variables interact to generate a seizure of adequate quality. Here, we investigate factors associated with motor seizure length as a measure of quality in a large database of patients who underwent ECT. Methods This is a retrospective cohort including data from all adult inpatients who underwent ECT at a university hospital in Brazil from 2009 to 2015. We used linear mixed models to investigate the effects of patient, session, and medication on seizure length. Results Session information was available for 387 patients, a total of 3544 sessions and 4167 individual stimulations. Multiple stimulations were necessary in 12.4% of sessions. Median seizure length was 30 seconds. Seizure length was directly correlated with stimulus dosage and inversely correlated with the session number, patient age, prescription of anticonvulsants in the day before and β-blockers during the session, and the thiopental dose. Use of benzodiazepines was not associated with a shorter seizure duration, irrespective of dose. Conclusions We demonstrate here how motor seizure length evolves during a course of ECT. With a large number of sessions, we are able to integrate a host of factors in a prediction model. Seizure quality was influenced by a number of the studied factors, many of which are potentially modifiable and could be assessed before initiating and handled during treatment.