How does the measurement of anesthetic depth using the patient state index influence the course of electroconvulsive therapy in patients with major depressive disorder?

Abstract

Background: Determining anesthetic depth has been used to assess the optimal timing of electrical stimulus application in electroconvulsive therapy (ECT). This has improved the quality and effectiveness of seizures, as some anesthetics used can decrease efficacy. This study evaluated the influence of the Patient State Index (PSi) on the course of ECT in patients with major depressive disorder (MDD).

Methods: this was an experimental prospective study with a control group involving 47 patients (22 assessed with the PSi, 25 controls) admitted and diagnosed with MDD. Clinical evolution variables, procedural characteristics, cognitive variables, and seizure adequacy were analyzed using mixed-effects linear models and Kaplan-Meier survival curves.

Results: the PSi group had fewer restimulations during treatment, higher values of seizure concordance, and higher "time to peak coherence" as parameters of seizure quality. No significant differences were observed between the two groups regarding improvement in depression, intra-ECT awareness, or adverse cognitive effects.

Conclusion: the use of the PSi for measuring anesthetic depth in modified ECT with propofol appeared to improve procedure effectiveness without increasing the incidence of intra-ECT awareness or cognitive side effects.

Keywords: Anesthesia depth; Awareness; Electroconvulsive therapy; Patient state index; Propofol; Seizure concordance.