Etomidate and seizure duration in electroconvulsive therapy: is there a dose-dependent relation?

OBJECTIVE: The objective of this study was to determine if there is a dose-dependent relation between etomidate and motor and electroencephalogram (EEG) seizure duration in electroconvulsive therapy (ECT).

METHODS: Seventy-four patients who received at least 3 ECT treatments with etomidate as an anesthetic were included. The association between seizure duration established by EEG and the cuff method, and etomidate dose (in mg/kg) was assessed retrospectively within individual patients, using mixed-effects model analysis with random intercept and random slope. Generalized estimating equation analysis was used to assess whether chances of reaching an adequate seizure depended on dose.

RESULTS: A small negative association between dose of etomidate and motor and EEG seizure duration was found with a maximum correlation of -0.21. This correlation is considered weak and therefore lacks clinical significance. Higher doses of etomidate decreased the chances of an adequate seizure with an odds ratio of 0.68 per 0.1-mg/kg increase in etomidate (95% confidence interval, 0.52-0.90, P-value: 0.007). With a maximum dose of 0.3 mg/kg, 94.1% of the seizures were adequate (95% confidence interval, 91.0-96.2).

CONCLUSIONS: Our data confirm that there is no clinically relevant dose-dependent relation between etomidate and seizure duration in ECT when etomidate is administered as advised in current international guidelines.