Effects of the Anaesthetic-ECT time interval and ventilation rate on seizure quality in electroconvulsive therapy: A prospective randomised trial.

BACKGROUND: The anaesthetic approach adopted in ECT practice has the potential to influence patient outcomes. However, the impact of the time interval between anaesthetic induction and ECT stimulus administration has not been studied prospectively to date. This variable may represent an indirect measure of anaesthetic concentration at the time of stimulation, and therefore may influence the quality of seizures induced. OBJECTIVE: To examine the impact of the anaesthetic to ECT stimulus time interval, and ventilation rate pre-treatment, on ictal seizure quality. METHODS: In a prospective, crossover trial, 54 depressed participants were randomised to variations in anaesthetic technique at four sequential ECT treatment sessions, in a 2 x 2 design: randomisation to a short or long anaesthetic-ECT time interval, and randomisation to normal ventilation or hyperventilation during anaesthetic induction with thiopentone. Ictal EEG data were collected at each study session and assessed by a blinded rater for ictal quality (seizure amplitude, regularity, post-ictal suppression and general seizure quality), using a quantitative-qualitative structured rating scale. Linear mixed effects models were used to analyse the effect of the anaesthetic-ECT time interval, and that of ventilation rate, on seizure quality indices. RESULTS: The anaesthetic-ECT time interval had a significant impact on ictal EEG quality indices (p < 0.01), with longer time intervals producing higher quality seizures. Ventilation rate did not significantly influence quality measures. CONCLUSION: The time between anaesthetic induction and ECT stimulus administration has a significant impact on ictal EEG seizure quality. Conversely, manipulations of ventilation rate did not significantly affect seizure quality. These results suggest the anaesthetic-ECT time interval should be routinely monitored clinically and potentially optimised for maximising seizure quality with ECT.

The anaesthetic-ECT time interval with thiopentone-Impact on seizure quality.

BACKGROUND: The time between anaesthetic induction and ECT stimulus administration has been hypothesised to significantly impact ictal EEG quality. In this study, our aim was to examine the effect of the time interval between anaesthetic induction and the ECT stimulus for ictal seizure quality in ECT sessions utilising thiopentone anaesthesia. METHODS: 413 EEG traces from 42 patients, collected retrospectively, were manually rated using a quantitative-qualitative structured rating scale (indices including seizure amplitude, regularity, post-ictal suppression and general seizure quality). Linear Mixed Effects Models were used to analyse the effect of the anaesthetic-ECT time interval on seizure quality indices, seizure duration and orientation scores after ECT, controlling for patient and ECT treatment factors. RESULTS: The anaesthetic-ECT time interval had a significant impact on ictal EEG quality indices (p < 0.05), with longer times producing higher quality seizures. Seizure duration and orientation scores after ECT were not significantly influenced by the anaesthetic-ECT time interval. Age, anaesthetic dose, ECT type and ECT treatment number also had a significant impact on measures of seizure quality (p < 0.05). LIMITATIONS: The effect of ventilation technique was not explicitly measured. Only manual ratings of ictal quality were analysed. CONCLUSIONS: The time between anaesthetic induction and ECT stimulus administration has a significant impact on the ictal EEG seizure quality observed, with thiopentone anaesthetic. These results are consistent with prior findings with propofol anaesthesia, and suggest a need for routine clinical monitoring of this time interval. This variable warrants consideration when interpreting ictal EEGs, which often informs subsequent dosing decisions.

The Anaesthetic-ECT Time Interval in Electroconvulsive Therapy Practice--Is It Time to Time?

BACKGROUND: Because most common intravenous anaesthetics used in ECT have anticonvulsant properties, their plasma-brain concentration at the time of seizure induction might affect seizure expression. The quality of ECT seizure expression has been repeatedly associated with efficacy outcomes. The time interval between the anaesthetic bolus injection and the ECT stimulus (anaesthetic-ECT time interval) will determine the anaesthetic plasma-brain concentration when the ECT stimulus is administered. OBJECTIVE: The aim of this study was to examine the effect of the anaesthetic-ECT time interval on ECT seizure quality and duration. METHODS: The anaesthetic-ECT time interval was recorded in 771 ECT sessions (84 patients). Right unilateral brief pulse ECT was applied. Anaesthesia given was propofol (1-2 mg/kg) and succinylcholine (0.5-1.0 mg/kg). Seizure quality indices (slow wave onset, amplitude, regularity, stereotypy and post-ictal suppression) and duration were rated through a structured rating scale by a single blinded trained rater. Linear Mixed Effects Models analysed the effect of the anaesthetic-ECT time interval on seizure quality indices, controlling for propofol dose (mg), ECT charge (mC), ECT session number, days between ECT, age (years), initial seizure threshold (mC) and concurrent medication. RESULTS: Longer anaesthetic-ECT time intervals lead to significantly higher quality seizures (p < 0.001 for amplitude, regularity, stereotypy and post-ictal suppression). CONCLUSIONS: These results suggest that the anaesthetic-ECT time interval is an important factor to consider in ECT practice. This time interval should be extended to as long as practically possible to facilitate the production of better quality seizures. Close collaboration between the anaesthetist and the psychiatrist is essential.