Factors Predicting Ictal Quality in Bilateral Electroconvulsive Therapy Sessions

Abstract

In electroconvulsive therapy (ECT), ictal characteristics predict treatment response and can be modified by changes in seizure threshold and in the ECT technique. We aimed to study the impact of ECT procedure-related variables that interact during each session and might influence the seizure results. Two hundred and fifty sessions of bilateral ECT in forty-seven subjects were included. Seizure results were evaluated by two different scales of combined ictal EEG parameters (seizure quality index (SQI) and seizure adequacy markers sum (SAMS) scores) and postictal suppression rating. Repeated measurement regression analyses were performed to identify predictors of each session’s three outcome variables. Univariate models identified age, physical status, hyperventilation, basal oxygen saturation, days between sessions, benzodiazepines, lithium, and tricyclic antidepressants as predictors of seizure quality. Days elapsed between sessions, higher oxygen saturation and protocolized hyperventilation application were significant predictors of better seizure quality in both scales used in multivariate models. Additionally, lower ASA classification influenced SQI scores as well as benzodiazepine use and lithium daily doses were predictors of SAMS scores. Higher muscle relaxant doses and lower applied stimulus intensities significantly influenced the postictal suppression rating. The study found several modifiable procedural factors that impacted the obtained seizure characteristics; they could be adjusted to optimize ECT session results.

No Effect of Serum Electrolyte Levels on Electroconvulsive Therapy Seizure Quality Parameters

“…However, our results are at odds with the results of Belz et al, 16 who found that serum sodium levels had an effect on interhemispheric coherence in a prospective trial with 31 patients. Comparable with their study and in line with other studies, 13,14,17 we also consistently found significant effects of age and dose on seizure quality markers. One possible explanation for the differing results is the larger sample size and larger serum electrolyte level variability in the present study.…”

“…These include younger age and better physical status. 14 To date, only few studies have examined the role of serum electrolyte levels on seizure quality, with available studies yielding conflicting results. A retrospective study of 207 patients undergoing ECT found no correlation between baseline sodium and seizure threshold or seizure duration at their first ECT session.…”

“…In addition to these treatment characteristics, certain patient characteristics also seem to contribute to higher seizure quality. These include younger age and better physical status 14 …”