The ictal EEG in ECT: A systematic review of the relationships between ictal features, ECT technique, seizure threshold and outcomes

Repurposing General Anesthetic Drugs to Treat Depression: A New Frontier for Anesthesiologists in Neuropsychiatric Care

During the last 100 years, the role of anesthesiologists in psychiatry has focused primarily on facilitating electroconvulsive therapy and mitigating postoperative delirium and other perioperative neurocognitive disorders. The discovery of the rapid and sustained antidepressant properties of ketamine, and early results suggesting that other general anesthetic drugs (including nitrous oxide, propofol, and isoflurane) have antidepressant properties, has positioned anesthesiologists at a new frontier in the treatment of neuropsychiatric disorders. Moreover, shared interest in understanding the biologic underpinnings of anesthetic drugs as psychotropic agents is eroding traditional academic boundaries between anesthesiology and psychiatry. This article presents a brief overview of anesthetic drugs as novel antidepressants and identifies promising future candidates for the treatment of depression. The authors issue a call to action and outline strategies to foster collaborations between anesthesiologists and psychiatrists as they work toward the common goals of repurposing anesthetic drugs as antidepressants and addressing mood disorders in surgical patients.

Ketamine as an Alternative Anesthetic for Augmenting Seizure Durations During Electroconvulsive Therapy: A Retrospective Observational Study

OBJECTIVE

Electroconvulsive therapy (ECT) is highly effective for severe psychiatric disorders; however, short seizure durations may lead to ineffective therapy. This retrospective study aimed to examine the risks and benefits of switching to ketamine anesthesia to augment seizure durations during an acute course of ECT.

METHODS

We included 33 patients who underwent ketamine anesthesia due to suboptimal seizures during an acute course of ECT. We assessed seizure duration, stimulus dose, hemodynamic variability, and postseizure complications before and after switching to ketamine.

RESULTS

Age was significantly associated with suboptimal seizures during ECT ( P = 0.040). After switching to ketamine, 32 patients (97%) experienced prolonged seizure duration. Ketamine significantly prolonged both electroencephalogram and motor seizure durations with a mean difference of 34.6 seconds (95% confidence interval [CI], 26.4-42.7 seconds; P < 0.001) and 26.6 seconds (95% CI, 19.6-33.6 seconds; P < 0.001), respectively. It also significantly reduced stimulus dose (mean difference, -209.5 mC [95% CI, -244.9 to -174.1 mC]; P < 0.001). In addition, maximum changes in systolic blood pressure and heart rate during ECT sessions significantly increased with ketamine (mean difference, 27.2 mm Hg [95% CI, 12.0-42.4 mm Hg; P = 0.001]; 25.7 beats per minute [95% CI, 14.5-36.8 beats per minute; P < 0.001], respectively). Patients reported more headaches with ketamine ( P = 0.041).

CONCLUSIONS

Our results provide evidence that ketamine as an alternative anesthetic can augment seizure durations in specific patients experiencing suboptimal seizures during an acute course of ECT. However, its use requires greater attention to circulatory management and postseizure complications.

Exploring New Electroencephalogram Parameters in Electroconvulsive Therapy

OBJECTIVE

This pilot study aims to evaluate a novel metric based on the power spectrum of the EEG recordings from ECT-induced seizures-its association to volume changes in the hippocampus after ECT and improvement in depression rating scores.

METHODS

Depressed patients treated with ECT underwent brain magnetic resonance imaging before and after treatment and the EEG from each seizure was recorded (N = 29). Hippocampal volume changes and EEG parameters were recorded in addition to clinician-rated and self-reported measures of depressive symptoms. The slope of the power law in the power spectral density of the EEG was calculated. Multivariate linear models relating seizure parameters to volume change or clinical outcome were systematically and successively simplified. The best models were selected according to Akaike information criterion.

RESULTS

The slope of the power law was steeper in the right than the left hemisphere (P < 0.001). Electroencephalogram measures were included in the best models of volume change for both hippocampi as well as in the models explaining clinical outcome ( P = 0.014, P = 0.004).

CONCLUSIONS

In this pilot study, novel EEG measures were explored and contributed in models explaining the variation in volume change in the hippocampus and in clinical outcome after ECT.

How electroconvulsive therapy works in the treatment of depression: is it the seizure, the electricity, or both?

We have known for nearly a century that triggering seizures can treat serious mental illness, but what we do not know is why. Electroconvulsive Therapy (ECT) works faster and better than conventional pharmacological interventions; however, those benefits come with a burden of side effects, most notably memory loss. Disentangling the mechanisms by which ECT exerts rapid therapeutic benefit from the mechanisms driving adverse effects could enable the development of the next generation of seizure therapies that lack the downside of ECT. The latest research suggests that this goal may be attainable because modifications of ECT technique have already yielded improvements in cognitive outcomes without sacrificing efficacy. These modifications involve changes in how the electricity is administered (both where in the brain, and how much), which in turn impacts the characteristics of the resulting seizure. What we do not completely understand is whether it is the changes in the applied electricity, or in the resulting seizure, or both, that are responsible for improved safety. Answering this question may be key to developing the next generation of seizure therapies that lack these adverse side effects, and ushering in novel interventions that are better, faster, and safer than ECT.

Does Lidocaine Shorten Seizure Duration in Electroconvulsive Therapy?

BACKGROUND

Electroconvulsive therapy (ECT) is an effective short-term treatment for schizophrenia and depression, amongst other disorders. Lidocaine is typically added to reduce pain from intravenous propofol injection. However, depending on the dose used in the ECT setting, it can shorten seizure duration. The aim of this study was to investigate the effect of lidocaine dose on seizure duration.

METHODS

This retrospective, naturalistic cohort study included 169 patients treated with ECT. We examined 4714 ECT sessions with propofol or propofol plus lidocaine. Ictal quality was manually rated by visual inspection. The main outcome of this study was the relation of lidocaine with seizure duration after controlling for socio-demographic, ECT, and other anesthetic variables.

RESULTS

There was a significant negative association between lidocaine usage and seizure duration. Multivariate analyses showed that seizure duration was shortened by an average of 3.21 s in sessions with lidocaine. Moreover, in this subgroup, there was a significant negative dose-dependent association between lidocaine dose and seizure length. Complementarily, a significant positive association between preictal BIS and seizure length was found in the subgroup of sessions where preictal was used.

CONCLUSIONS

We provide additional evidence highlighting the importance of caution regarding lidocaine dosing due to the effect on seizure length in the ECT setting. It is advisable for clinicians to exercise caution when administering lidocaine regarding its dosing and seizure length in ECT settings. Future investigation is needed to assess causal relationships by studying certain vulnerable groups or employing other charge calculation techniques, such as the titration method.

Electric Field, Ictal Theta Power, and Clinical Outcomes in Electroconvulsive Therapy

BACKGROUND

Electroconvulsive therapy (ECT) is efficacious for treatment-resistant depression. Treatment-induced cognitive impairment can adversely impact functional outcomes. Our pilot study linked the electric field to ictal theta power from a single suprathreshold treatment and linked ictal theta power to changes in phonemic fluency. In this study, we set out to replicate our findings and expand upon the utility of ictal theta power as a potential cognitive biomarker.

METHODS

Twenty-seven participants (18 female and 9 male) received right unilateral ECT for treatment-resistant depression. Pre-ECT magnetic resonance imaging and finite element modeling determined the 90th percentile maximum electric field in the brain. Two-lead electroencephalographs were digitally captured across the ECT course, with the earliest suprathreshold treatment used to determine power spectral density. Clinical and cognitive outcomes were assessed pre-, mid-, and post-ECT. We assessed the relationship between the electric field in the brain, ictal theta power, clinical outcome (Inventory of Depressive Symptomatology), and cognitive outcomes (phonemic and semantic fluency) with linear models.

RESULTS

Ictal theta power in the Fp1 and Fp2 channels was associated with the electric field, antidepressant outcome, and phonemic and semantic fluency. The relationship between ictal theta power and phonemic fluency was strengthened in the longitudinal analysis. The electric field in the brain was directly associated with phonemic and semantic fluency but not with antidepressant outcome.

CONCLUSIONS

Ictal theta power is a potential cognitive biomarker early on in the ECT course to help guide parameter changes. Larger studies are needed to further assess ictal theta power's role in predicting mood outcome and changes with ECT parameters.

Ictal Electroencephalogram Visual Pattern Recognition of Seizure Adequacy During Electroconvulsive Therapy Treatment: A Step-by-Step Approach

Background

The NEURON (Neuropsychiatry and Neuromodulation Unit) electroconvulsive therapy electroencephalogram (ECT-EEG) Algorithmic Rating Scale (NEARS) is a step-by-step approach to ictal electroencephalogram visual pattern recognition of seizure adequacy based on recruitment, amplitude, symmetry, duration and degree of post-ictal suppression. The objectives of this clinical audit were to determine the degree of agreement on the NEARS operational criteria between two neuropsychiatrists, the reliability of electroconvulsive therapy practitioners' administration of NEARS during ECT procedures and the correlation of NEARS scores with Clinical Global Impression scale scores after each ECT treatment session.

Methods

Systematic random sampling was conducted. Even numbers of ictal tracings were selected for analysis from the total samples collected over 8 consecutive days of ECT overseen by a total of eight different ECT practitioners. Cohen's kappa coefficient was used to measure the inter-rater reliability of the two neuropsychiatrists and determine the level of agreement between NEARS scores and those of the ECT practitioners. The correlation using NEARS scores and post-ECT Clinical Global Impression scores was measured with Spearman's test. The significance level was set at P < 0.05.

Results

Cohen's kappa showed perfect agreement between the two neuropsychiatrists, at κ = 1.00 (SE = 0.001; P < 0.001), and strong agreement between NEARS scores of overall seizure adequacy and the scores interpreted by the ECT practitioners, at κ = 0.83 (95% CI: 0.66, 0.99; P < 0.001). Spearman's test showed a weak negative association between NEARS scores and post-ECT Clinical Global Impression scores (r = -0.018; P = 0.900).

Conclusion

NEARS may facilitate a brief, objectively reliable and practical assessment of ictal electroencephalogram quality. The scale is readily applicable by any trained ECT practitioner during an ongoing ECT procedure, especially when a prompt treatment decision is required.

Comparison of etomidate and methohexital as anesthetic agents for continuation and maintenance electroconvulsive therapy: A retrospective analysis of seizure quality and safety

BACKGROUND

The ideal hypnotic agent for electroconvulsive therapy (ECT) is still under debate and previous studies comparing etomidate and methohexital have produced conflicting results. This retrospective study compares etomidate and methohexital as anesthetic agents in continuation and maintenance (m)ECT with regard to seizure quality and anesthetic outcomes.

METHODS

All subjects undergoing mECT at our department between October 1st, 2014 and February 28th, 2022 were included in this retrospective analysis. Data for each ECT session were obtained from the electronic health records. Anesthesia was performed with either methohexital/succinylcholine or etomidate/succinylcholine. Standard seizure quality parameters, anesthesiological monitoring data, pharmacological interventions and side-effects were recorded.

RESULTS

573 mECT treatments in 88 patients were included (methohexital n = 458, etomidate n = 115). Seizures lasted significantly longer after using etomidate (electroencephalography: +12.80 s [95 %-CI:8.64-16.95]; electromyogram +6.59 s [95 %-CI:4.14-9.04]). Time to maximum coherence was significantly longer with etomidate (+7.34 s [95 %-CI:3.97-10.71]. Use of etomidate was associated with longer procedure duration (+6.51 min [95 %-CI:4.84-8.17]) and higher maximum postictal systolic blood pressure (+13.64 mmHg [95 %-CI:9.33-17.94]). Postictal systolic blood pressure > 180 mmHg, the use of antihypertensives, benzodiazepines and clonidine (for postictal agitation), as well as the occurrence of myoclonus was significantly more common under etomidate.

CONCLUSIONS

Due to longer procedure duration and an unfavorable side effect profile, etomidate appears inferior to methohexital as an anesthetic agent in mECT despite longer seizure durations.

Predictors of cognitive changes in patients with schizophrenia undergoing electroconvulsive therapy

INTRODUCTION

Previous studies on the effects of electroconvulsive therapy (ECT) on cognition in schizophrenia have been inconclusive. This study aimed to identify factors that may predict cognitive improvement or deterioration in patients with schizophrenia after-ECT.

MATERIALS & METHODS

Patients with schizophrenia or schizoaffective disorder with predominantly positive psychotic symptoms, who were treated with ECT at the Institute of Mental Health (IMH), Singapore, between January 2016 and January 2018, were assessed. Montreal Cognitive Assessment (MoCA), Brief Psychiatric Rating Scale (BPRS) and Global Assessment of Function (GAF) were performed before and after ECT. Patients with clinically significant improvement, deterioration or no change in MoCA scores were compared on demographics, concurrent clinical treatment and ECT parameters.

RESULTS

Of the 125 patients analysed, 57 (45.6%), 36 (28.8%) and 32 (25.6%) showed improvements, deterioration and no change in cognition respectively. Age and voluntary admission predicted MoCA deterioration. Lower pre-ECT MoCA and female sex predicted MoCA improvement. Patients showed improvements in GAF, BPRS and BPRS subscale scores on average, except for the MoCA deterioration group, who did not show statistically significant improvement in negative symptom scores. Sensitivity analysis showed that nearly half the patients (48.3%) who were initially unable to complete MoCA pre-ECT were able to complete MoCA post-ECT.

CONCLUSIONS

The majority of patients with schizophrenia demonstrate improved cognition with ECT. Patients with poor cognition pre-ECT are more likely to see improvement post-ECT. Advanced age may be a risk factor for cognitive deterioration. Finally, improvements in cognition may be associated with improvements in negative symptoms.

National Network of Depression Centers' Recommendations on Harmonizing Clinical Documentation of Electroconvulsive Therapy

ABSTRACT

Electroconvulsive therapy (ECT) is a highly therapeutic and cost-effective treatment for severe and/or treatment-resistant major depression. However, because of the varied clinical practices, there is a great deal of heterogeneity in how ECT is delivered and documented. This represents both an opportunity to study how differences in implementation influence clinical outcomes and a challenge for carrying out coordinated quality improvement and research efforts across multiple ECT centers. The National Network of Depression Centers, a consortium of 26+ US academic medical centers of excellence providing care for patients with mood disorders, formed a task group with the goals of promoting best clinical practices for the delivery of ECT and to facilitate large-scale, multisite quality improvement and research to advance more effective and safe use of this treatment modality. The National Network of Depression Centers Task Group on ECT set out to define best practices for harmonizing the clinical documentation of ECT across treatment centers to promote clinical interoperability and facilitate a nationwide collaboration that would enable multisite quality improvement and longitudinal research in real-world settings. This article reports on the work of this effort. It focuses on the use of ECT for major depressive disorder, which accounts for the majority of ECT referrals in most countries. However, most of the recommendations on clinical documentation proposed herein will be applicable to the use of ECT for any of its indications.

Effects of electroconvulsive therapy on cognition and quality of life in schizophrenia

INTRODUCTION

The effects of electroconvulsive therapy (ECT) on quality of life (QoL), and its relationship with symptom and cognitive change remains unclear. We aim to examine the association of QoL changes with psychiatric symptom and cognitive changes among patients with schizophrenia who underwent ECT.

METHODS

This is a retrospective cohort study of 132 patients who received ECT from July 2017 to December 2019. Sociodemographic and clinical characteristics were obtained from medical records. Changes in QoL, psychiatric symptoms and cognition function were examined after 6 sessions of ECT. Generalised linear regression was used to examine the associations of Brief Psychiatric Rating Scale (BPRS) scores and Montreal Cognitive Assessment (MoCA) scores with QoL as measured by EQ-5D scores.

RESULTS

The mean (standard error) improvements after ECT were statistically significant for the assessment scales of EQ-5D utility score: 0.77 (0.02) to 0.89 (0.02), P<0.001; EuroQol-5-Dimension (EQ-5D) visual analogue scale score: 66.82 (2.61) to 73.05 (1.93), P=0.012; and EQ-5D subdomain scores. Both improvement in BPRS (adjusted β coefficient -0.446, 95% confidence interval [CI] -0.840 to -0.052) and MoCA (adjusted β 12.068, 95% CI 0.865 to 12.271) scores were significantly associated with improvement in EQ-5D utility scores after adjustment for sociodemographic and clinical characteristics. Improvement of BPRS scores (psychiatric symptoms) was significantly associated with improvement of the patients' mental health that was assessed by EQ-5D subdomain scores of pain (adjusted β coefficient 0.012, 95% CI 0.004 to 0.021) and anxiety (adjusted β coefficient 0.013, 95% CI 0.002 to 0.024). Improvement of MoCA scores (cognitive function) was significantly associated with patients' physical health as assessed by EQ-5D subdomain score of usual activity (adjusted β coefficient -0.349, 95% CI -0.607 to -0.09).

CONCLUSION

ECT was associated with an overall improvement of QoL among patients with schizophrenia. The improvement of psychiatric symptoms was found to be significantly associated with better mental health while the improvement of cognitive function was associated with better physical health.

Ictal Theta Power as an Electroconvulsive Therapy Safety Biomarker: A Pilot Study

OBJECTIVE

Electroconvulsive therapy (ECT) remains the benchmark for treatment resistant depression, yet its cognitive adverse effects have a negative impact on treatment. A predictive safety biomarker early in ECT treatment is needed to identify patients at cognitive risk to maximize therapeutic outcomes and minimize adverse effects. We used ictal electroencephalography frequency analysis from suprathreshold treatments to assess the relationships between ECT dose, ictal power across different frequency domains, and cognitive outcomes.

METHODS

Seventeen subjects with treatment resistant depression received right unilateral ECT. Structural magnetic resonance imaging was obtained pre-ECT for electric field modeling to assess ECT dose. Serial assessments with 24-lead electroencephalography captured ictal activity. Clinical and cognitive assessments were performed before and after ECT. The primary cognitive outcome was the change in Delis Kaplan Executive Function Verbal Fluency Letter Fluency.

RESULTS

Ictal theta (4-8 Hz) power in the Fp1/Fp2 channels was associated with both whole-brain electric field strength (t(2,12) = 19.5, P = 0.007)/(t(2,10) = 21.85, P = 0.02) and Delis Kaplan Executive Function Verbal Fluency Letter Fluency scores (t(2,12) = -2.05, P = 0.05)/(t(2,10) = -2.20, P = 0.01). Other frequency bands (beta, alpha, delta, and gamma) did not demonstrate this relationship.

CONCLUSIONS

This pilot data identify ictal theta power as a potential safety biomarker in ECT and is related to the strength of the ECT dose. Ictal theta power could prove to be a convenient and powerful tool for clinicians to identify those patients most susceptible to cognitive impairment early in the treatment series. Additional studies are needed to assess the role of longitudinal changes in ictal theta power throughout the ECT series.

A Retrospective Study of Postictal Suppression during Electroconvulsive Therapy

Background: electroconvulsive therapy (ECT) is the most effective treatment in treatment-resistant depression (TRD), but its response remains partial. Identifying useful indicators to guide decision making for treatment and improve clinical response remains a major issue. The objective of the present retrospective study was to determine if clinical response—early (after 5 ECT sessions) or longer-term (after 12 ECT sessions)—was associated with postictal suppression during the first ECT course and/or with postictal suppression frequency during the whole ECT course. Methods: in a retrospective study, the data of 42 patients suffering from treatment-resistant depression and receiving at least 5 ECT sessions were collected. Two sessions per week of bitemporal brief-pulse ECT sessions were administered to patients. Each of the electroencephalography (EEG) recordings were assessed to determine the presence of postictal suppression. Results: the postictal suppression from the first ECT session predicted a better long-term clinical response (after 12 ECT sessions), but not early clinical response (after only 5 ECT sessions). The postictal suppression frequency was associated with neither the short- nor the long-term clinical response. In addition, postictal suppression and short-term cognitive performances were not associated. Conclusions: this EEG indicator is clinically useful if it appears in the first ECT sessions, but it is no longer relevant in the following sessions.

'Rapid speed of response to ECT in bipolar depression: A chart review

OBJECTIVE

To validate a faster speed of response to electroconvulsive therapy (ECT) for bipolar depression (BPD) compared to major depressive disorder (MDD) METHOD: Retrospective chart review on an ECT cohort in an academic hospital setting. Speed of response was defined by the number of ECT treatments needed for response or remission.

RESULTS

Sixty-four depressed patients were included, of whom 53 (MDD: 40, BPD: 13) could be analyzed. The bipolar group responded faster with a mean difference of 3.3 fewer ECT treatments to meet response criteria (MDD 10.4 vs. BPD 7.1, p = 0.054). When using mixed effects regression models for the response/remitter group (n = 35), a faster response for the bipolar group (AIC 252.83 vs 258.55, χ² = 11.72, p = 0.008) was shown. Other factors, such as psychotic features or comorbidity, did not influence the speed of response.

CONCLUSION

This chart review of an ECT cohort in an naturalistic academic hospital setting shows an evident and clinically relevant faster speed of response in bipolar depression.

Biomarkers for Deep Brain Stimulation in Animal Models of Depression

OBJECTIVES

Despite recent advances in depression treatment, many patients still do not respond to serial conventional therapies and are considered "treatment resistant." Deep brain stimulation (DBS) has therapeutic potential in this context. This comprehensive review of recent studies of DBS for depression in animal models identifies potential biomarkers for improving therapeutic efficacy and predictability of conventional DBS to aid future development of closed-loop control of DBS systems.

MATERIALS AND METHODS

A systematic search was performed in Pubmed, EMBASE, and Cochrane Review using relevant keywords. Overall, 56 animal studies satisfied the inclusion criteria.

RESULTS

Outcomes were divided into biochemical/physiological, electrophysiological, and behavioral categories. Promising biomarkers include biochemical assays (in particular, microdialysis and electrochemical measurements), which provide real-time results in awake animals. Electrophysiological tests, showing changes at both the target site and downstream structures, also revealed characteristic changes at several anatomic targets (such as the medial prefrontal cortex and locus coeruleus). However, the substantial range of models and DBS targets limits the ability to draw generalizable conclusions in animal behavioral models.

CONCLUSIONS

Overall, DBS is a promising therapeutic modality for treatment-resistant depression. Different outcomes have been used to assess its efficacy in animal studies. From the review, electrophysiological and biochemical markers appear to offer the greatest potential as biomarkers for depression. However, to develop closed-loop DBS for depression, additional preclinical and clinical studies with a focus on identifying reliable, safe, and effective biomarkers are warranted.

Evaluating Factors Affecting the Time Interval Between Propofol Injection and Induction of Electro-convulsion and Relationship Between These Factors and Duration of Convulsion

Background

Current evidence on the effect of anesthetic-ECT time interval (AETI) is controversial. This study aimed to investigate the factors affecting the time interval between propofol injection and electro-convulsion induction and the relationship between these factors and the duration of convulsion.

Methods

In this study, 102 patients (616 sessions of ECT) were studied. Demographic and clinical data (age, gender, receiving or not receiving medications that affected the seizure threshold, the total number of ECT sessions, clinical severity of admission scores, clinical diagnosis, propofol dose, seizure duration, and AETI) were collected in special forms and analyzed by appropriate statistical methods.

Results

Sessions with long-term AETI had longer seizure time than sessions with short-term AETI (33.47 ± 8.46 vs. 28.68 ± 9.74, P value < 0.05). The duration of seizures was significantly longer in the group with long AETI in sessions 1, 2, and 4 than in the other group (P value < 0.05). There was a significant relationship between the duration of seizures and propofol dose, AETI, and receiving drugs effective in the seizure threshold (P value < 0.05).

Conclusions

The results showed that increasing AETI and injecting a lower dose of propofol to induce anesthesia would increase the duration of seizures. Also, taking medications that would affect the seizure threshold reduces the duration of seizures.

Sevoflurane in electroconvulsive therapy: A systematic review and meta-analysis of randomised trials

Sevoflurane is the most commonly used inhaled anaesthetic in electroconvulsive therapy (ECT). The objective of this study was to provide an up-to-date and comprehensive review on how the use of sevoflurane affects seizure adequacy (seizure duration and postictal suppression index [PSI]) and circulatory dynamics in ECT. We performed a meta-analysis of RCTs that investigated seizure adequacy and circulatory dynamics in patients treated with ECT using sevoflurane (sevoflurane group) and intravenous anaesthetics (non-sevoflurane group). A total of 12 RCTs (377 patients and 1339 ECT sessions) were included. Sevoflurane significantly decreased the electroencephalogram (EEG) seizure durations in comparison with intravenous anaesthetics, whereas no significant difference was observed in PSI (EEG: 9 studies, standardized mean difference (SMD) = 0.74, 95% confidence interval (CI) = -1.11 to -0.38, p = 0.0002; PSI: 4 studies, SMD = -0.06, CI -0.13 to 0.25, p = 0.59). The use of sevoflurane in ECT significantly increased heart rate (HR) compared with intravenous anaesthetics (9 studies, SMD = 0.31, CI 012-0.51, p = 0.004). In the pre-planned subgroup analysis, sevoflurane significantly reduced seizure duration compared with other types of anaesthetics, including propofol, barbiturates and ketamine. Furthermore, it was found that the risk of adverse events in ECT with sevoflurane were not significantly different from intravenous anaesthetics (6 studies, risk ratio = 1.33, CI 0.95-1.86, p = 0.09), with agitaion being the most common adverse effects. The results of our study suggest that using sevoflurane for ECT significantly reduces seizure duration, increases maximum HR and brings about no difference in the adverse event risk compared with those using intravenous anaesthetics for ECT. Therefore, there may not be compelling evidence favouring sevoflurane use for ECT, except in cases where intravenous access is difficult.

Changes in seizure duration during acute course electroconvulsive therapy

BACKGROUND

Seizure duration has long been measured as a potential marker of ECT treatment efficacy, with concern that short seizures may be clinically ineffective. Relatively small studies have documented a trend towards shorter seizures during acute course ECT, but data from large cohorts would help provide normative data on seizure duration changes during treatment.

OBJECTIVE

This study analyzes the effects of age, sex, ECT dose, and treatment number on the duration of electrographic seizures during acute course ECT in a large single-center cohort.

METHODS

A single-center retrospective chart review was conducted of adult patients receiving a first course of ECT from 2000 to 2017 at a large freestanding psychiatric hospital.

RESULTS

3648 patients met inclusion criteria, receiving 32,879 acute course ECT treatments. There was a shortening of mean ECT seizure duration over the acute course, with the greatest decrease in duration over the first 3 treatments but continuing decreases over the entire acute course. Older age, higher ECT dose, and increasing treatment number were all associated with shorter seizures, while sex was not significantly associated. Increasing treatment dose was associated with shorter seizures relative to no dose increase, with those patients receiving the highest cumulative doses also having the shortest cumulative seizure time.

CONCLUSIONS

Among patients undergoing acute-course ECT treatment, seizure duration decreased over the treatment course, and increases in applied electrical charge were associated with shorter seizures.