Neuromonitoring-guided anesthesia depth versus four-minute anesthesia-to-stimulation time interval in electroconvulsive therapy for depressive disorders – A single-blinded, prospective, randomized and controlled study

Abstract

Background

Anesthesia depth influences seizure quality in patients undergoing electroconvulsive therapy (ECT). EEG-based neuromonitoring has been shown to detect adequate anesthesia depth for ECT. Anesthesia depth-guided ECT management may therefore be a reliable alternative to the predetermined anesthesia-to-stimulation time interval.

Methods

Patients with depressive disorders and a Montgomery-Asberg Depression Rating Score ≥ 18 were randomly assigned. The anesthesia depth-guided group received stimulation between Narcotrend™ index ratings of 41 and 64 and was compared to the control group with a predetermined anesthesia-to-stimulation time interval of four minutes. The primary endpoint was seizure quality.

Results

A total of 225 interventions were conducted in 30 patients. Significant differences were observed between the two groups regarding stimulation intervals (225.0 ± 34.2 s vs. 240.0 ± 0 s; p < 0.001) and the index before electric stimulation (45.0 ± 15.7 vs. 35.0 ± 13.0; p < 0.001). No significant differences in overall seizure quality were found between the groups. The midictal amplitude was higher in the anesthesia depth-guided group (209.2 ± 92.6 vs. 152.6 ± 80.0; p = 0.009). Because of inadequate anesthesia depth, 54 interventions were discontinued for safety reasons.

Limitations

The number of per protocol completed interventions is small due to high exclusion rate from protocol violations.

Conclusions

Anesthesia depth-guided ECT management did not significantly improve overall seizure quality compared to a four-minute anesthesia-to-stimulation time interval.