Implication Statement: Use of the bispectral electroencephalogram during modified electroconvulsive therapy (MECT) under propofol anesthesia was found to be an accurate predictor of seizure duration and awakening. This may have potential clinical implications on therapeutic success and elimination of the undesirable effects associated with this treatment modality.
Background and Objectives: Propofol anesthesia when compared with barbiturates may induce relatively shorter duration seizures during MECT. This study was designed with the intent to test the hypothesis that the bispectral index (BIS) electroencephalogram (EEG) could predict MECT-induced seizure duration and awakening under propofol anesthesia.
Methods: Twenty-five patients, between 16 and 60 years of age (American Society of Anesthesiologists physical status I or II), underwent a total of 100 MECT sessions (4 sessions each) under propofol anesthesia (1.0 mg/kg) in a prospective, observational study. The BIS was monitored continuously, and average BIS values of each of the 4 sessions of MECT that each patient received were analyzed. Bispectral index values were recorded at T0 (baseline), T1 (before induction), T2 (after propofol), T3 (preictal), T4 (postictal), T5 (awakening), and T6 (1 minute after awakening). Motor seizure duration was measured by isolated forearm technique and electrical seizure duration by BIS EEG.
Results: The mean preictal BIS was 50 (SD, 14), which was found to have a significant positive correlation (P < 0.01) with motor (r = 0.707) as well as electrical seizure duration (r = 0.736). A significant negative correlation was also found between the preictal BIS value and the time to eye opening (3.53 [SD, 1.8] minutes) (r = −0.397; P < 0.05). Awakening occurred at mean BIS value of 52 (SD, 17) (range, 20-97) during this procedure.
Conclusions: The mean pre-ECT BIS values correlate significantly with the durations of both the motor and electrical seizure activity and awakening time under propofol anesthesia. Before extrapolation to daily clinical practice, further large controlled clinical trials need to be done to establish the role of BIS monitoring in predicting seizure duration and awakening time during MECT.