The comparative effects of methohexital, propofol, and etomidate for electroconvulsive therapy

The influence of anaesthetic choice on seizure duration of electroconvulsive therapy; etomidate versus methohexital

Background

Many of the anaesthetic drugs used for electroconvulsive therapy have anticonvulsant properties and may influence efficacy of electroconvulsive therapy. With this study we aim to provide more information on the effect of etomidate and methohexital on seizure duration. We explore the relationship between induction drug, motor and electroencephalography seizure duration. Moreover, we study the relationship of seizure duration and number of therapies.

Methods

In this retrospective study we collected data from patient records from 2005 until 2016. Inclusion criteria were the use of etomidate and/or methohexital and documentation of dosage, electroconvulsive therapy dosage and seizure duration. Exclusion criteria were missing data on either induction drug, dosage or seizure duration.

Results

Thirty seven patients were analysed. The mean age was 52 years and seventy six percent were female. Most patients were suffering from affective disorders (81%). Motor and electroencephalography seizure duration were analysed in 679 and 551 electroconvulsive therapies, respectively. Compared to methohexital, motor and electroencephalography seizures under etomidate were 7 and 13 s longer, respectively. Furthermore, there was a negative association between seizure duration and number of treatment and a negative association between seizure duration and electroconvulsive therapy dosage.

Conclusions

This study demonstrates significant longer motor and electroencephalography seizure duration using etomidate compared to methohexital. Etomidate might therefore increase the effectiveness of electroconvulsive therapy. Moreover, we observed a negative association between seizure duration, number of treatment and electroconvulsive therapy dosage. With this study we contribute to the available literature comparing methohexital and etomidate as induction agents for electroconvulsive therapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-022-01745-y.

Bi-Spectral Index-Guided Comparison of Propofol versus Etomidate for Induction in Electroconvulsive Therapy

Background:

Previous studies have compared varying doses of propofol and etomidate for electroconvulsive therapy (ECT) without monitoring the depth of anesthesia. Seizure duration may vary with the depth of anesthesia.

Aim:

This study aimed to compare the effects of bi-spectral index (BIS)-guided induction with propofol and etomidate on various parameters of ECT.

Settings and Design:

This was a prospective, randomized, double-blind study.

Materials and Methods:

Sixty patients undergoing ECT were randomly allocated to two groups. Group P received intravenous propofol 1–2 mg.kg ⁻¹ and Group E received etomidate 0.1–0.3 mg.kg ⁻¹ to attain a BIS of 40–60. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and BIS were recorded at various time points intraoperatively till 30 min following ECT. Seizure duration, recovery time, and adverse effects were also recorded.

Statistical Analysis:

Quantitative data were compared using unpaired t-test. Chi-square test or Fisher's exact test was used to compare categorical data. P < 0.05 was considered statistically significant.

Results:

The mean induction time and seizure duration were shorter (P < 0.001), and recovery time to obey commands was longer in Group P as compared to that of Group E (P = 0.031). HR, SBP, and DBP for 10 min after ECT had elevated more in Group E than that in Group P (P < 0.05). The incidence of myoclonus was higher in Group P compared to that of Group E (P = 0.012).

Conclusion:

During ECT, BIS-guided induction with propofol provides more stable hemodynamics than etomidate, but reduces induction time, seizure duration, and recovery time more as compared to that of etomidate.

Etomidate and its Analogs: A Review of Pharmacokinetics and Pharmacodynamics

Etomidate is a hypnotic agent that is used for the induction of anesthesia. It produces its effect by acting as a positive allosteric modulator on the γ-aminobutyric acid type A receptor and thus enhancing the effect of the inhibitory neurotransmitter γ-aminobutyric acid. Etomidate stands out among other anesthetic agents by having a remarkably stable cardiorespiratory profile, producing no cardiovascular or respiratory depression. However, etomidate suppresses the adrenocortical axis by the inhibition of the enzyme 11β-hydroxylase. This makes the drug unsuitable for administration by a prolonged infusion. It also makes the drug unsuitable for administration to critically ill patients. Etomidate has relatively large volumes of distributions and is rapidly metabolized by hepatic esterases into an inactive carboxylic acid through hydrolyzation. Because of the decrease in popularity of etomidate, few modern extensive pharmacokinetic or pharmacodynamic studies exist. Over the last decade, several analogs of etomidate have been developed, with the aim of retaining its stable cardiorespiratory profile, whilst eliminating its suppressive effect on the adrenocortical axis. One of these molecules, ABP-700, was studied in extensive phase I clinical trials. These found that ABP-700 is characterized by small volumes of distribution and rapid clearance. ABP-700 is metabolized similarly to etomidate, by hydrolyzation into an inactive carboxylic acid. Furthermore, ABP-700 showed a rapid onset and offset of clinical effect. One side effect observed with both etomidate and ABP-700 is the occurrence of involuntary muscle movements. The origin of these movements is unclear and warrants further research.

Effects of Propofol and Propofol-Remifentanil Combinations on Haemodynamics, Seizure Duration and Recovery during Electroconvulsive Therapy

Objective

This study aimed to evaluate the effects of adding different doses of remifentanil to propofol treatment compared with propofol alone with regard to parameters, including the seizure duration, haemodynamic changes and recovery time, in patients undergoing electroconvulsive therapy (ECT).

Methods

This study was designed as a self-controlled, prospective, double-blind investigation of 17 patients between the ages of 20 and 65 years who had planned treatment with ECT at a psychiatric clinic. Group P (propofol) was administered 10 mL of normal saline after 0.5 mg kg⁻¹ intravenous (IV) bolus of propofol. Group R I (propofol plus remifentanil-1) was administered 1.5 μg kg⁻¹ of remifentanil, and group R II (propofol plus remifentanil-2) was given 2 μg kg⁻¹ of remifentanil after 0.5 mg kg⁻¹ IV bolus of propofol. The haemodynamic variables after seizure and the seizure duration were recorded. Time to return to spontaneous respiration, eye opening and achieving Aldrete score >9 were recorded.

Results

The electroencephalography seizure duration was significantly longer in groups R I (34.7±13 s) and R II (34.9±12) than in group P (24±7.5). Motor seizure duration was longer in groups R I (29.70±12.8) and R II (28.1±10) than in group P (21±7.3). The amount of total propofol was 121±21 mg in group P, 69.4±2 mg in group R I and 67±17 mg in group R II. Times to eye opening, following simple commands, and achieving Aldrete score >9 were significantly shorter in groups R I and R II than in group P.

Conclusion

ECT is a safe and effective treatment for patients with psychiatric disorders. Propofol-remifentanil anaesthesia prolongs the seizure duration and shortens the recovery time, suggesting that this combination may particularly be well suited for use in this patient group.

Successful bilateral electroconvulsive therapy in a patient with a seizure disorder taking levetiracetam, lorazepam, and zonisamide: A case report

Electroconvulsive therapy (ECT) may be considered for treatment of severe, treatment-resistant, and emergent depression associated with MDD or bipolar disorder. Patients with epilepsy usually take medications that raise the seizure threshold, which poses challenges during ECT. We report a 66-year-old male with epilepsy taking levetiracetam extended-release (XR), lorazepam, and zonisamide requiring ECT for severe MDD. After literature review, the XR form of levetiracetam was changed to higher doses of the immediate-release (IR) formulation, and zonisamide was discontinued 2 days prior to ECT in the hospital and was resumed when the patient underwent outpatient continuation ECT. The patient was treated to remission after receiving 8 acute bilateral ECT treatments before being transitioned to continuation ECT. We provide a brief review of medication management of antiepileptic drugs and other medications that increase the seizure threshold during ECT. To our knowledge, this is the first reported case describing the management of levetiracetam, lorazepam, and zonisamide concomitantly during ECT. Our case suggests that utilizing the IR formulation of levetiracetam, administering the evening dose early the day prior to the procedure, and temporarily discontinuing zonisamide prior to bilateral ECT is effective for the treatment of severe MDD while maintaining seizure prophylaxis.

Electroconvulsive Therapy for a Patient with Suicide by Drinking Bleach During Treatment of COVID-19: A Case Report

Electroconvulsive therapy (ECT) was first experienced in 1938 and had been conducting without anesthesia for 30 years. In this study, the most common indication for ECT was mood disorder (major depressive disorder and bipolar I disorder). We introduce a patient with a history of COVID-19 and suicide who required emergency ECT. Electroconvulsive therapy can be life-saving in patients with suicide history or catatonic schizophrenia. Health workers are at the front line of the COVID-19 outbreak control and must follow health instructions. Aerosol-producing procedures such as suction in anesthesia for ECT may facilitate the transmission of infectious diseases such as COVID-19. When performing aerosol-producing procedures during the pandemic of novel coronavirus, every patient should be considered suspicious.

Management strategies for the treatment and prevention of postoperative/postdischarge nausea and vomiting: an updated review

Postoperative nausea and vomiting (PONV) and postdischarge nausea and vomiting (PDNV) remain common and distressing complications following surgery. The routine use of opioid analgesics for perioperative pain management is a major contributing factor to both PONV and PDNV after surgery. PONV and PDNV can delay discharge from the hospital or surgicenter, delay the return to normal activities of daily living after discharge home, and increase medical costs. The high incidence of PONV and PDNV has persisted despite the introduction of many new antiemetic drugs (and more aggressive use of antiemetic prophylaxis) over the last two decades as a result of growth in minimally invasive ambulatory surgery and the increased emphasis on earlier mobilization and discharge after both minor and major surgical procedures (e.g. enhanced recovery protocols). Pharmacologic management of PONV should be tailored to the patient’s risk level using the validated PONV and PDNV risk-scoring systems to encourage cost-effective practices and minimize the potential for adverse side effects due to drug interactions in the perioperative period. A combination of prophylactic antiemetic drugs with different mechanisms of action should be administered to patients with moderate to high risk of developing PONV. In addition to utilizing prophylactic antiemetic drugs, the management of perioperative pain using opioid-sparing multimodal analgesic techniques is critically important for achieving an enhanced recovery after surgery. In conclusion, the utilization of strategies to reduce the baseline risk of PONV (e.g. adequate hydration and the use of nonpharmacologic antiemetic and opioid-sparing analgesic techniques) and implementing multimodal antiemetic and analgesic regimens will reduce the likelihood of patients developing PONV and PDNV after surgery.

Thiopental is better than propofol for electroconvulsive therapy

Background and aim of the work:

electroconvulsive therapy is a psychiatric procedure requiring general anesthesia. The choice of the hypnotic agent is important because the success of the intervention is associated to the occurrence and duration of motor convulsion. However, all available anesthetic agents have anti-convulsant activity. We compared the effect of thiopental and propofol on seizures.

Methods:

We designed a retrospective study at Mood Disorders Unit of a teaching Hospital. Fifty-six consecutive patients undergoing electroconvulsive therapy were enrolled. Patients received fentanyl followed by either thiopental or propofol. We evaluated the incidence and the duration of seizure after electric stimulus at the first session of electroconvulsive therapy for each patient. Adverse perioperative effects were recorded.

Results:

Patients were 60±12.1 years old and 64% was female. There was a statistically significant higher number of patients who had motor convulsion activity in the thiopental group when compared to the propofol group (25 vs 13, p=0.023). Seizure duration was statistically significant longer in the thiopental group than in the propofol group (35 sec vs 11 sec, p=0.046). No hemodynamic instability, oxygen desaturation episodes, prolonged recovery time from anesthesia and adverse effects related to anesthesia were recorded.

Conclusions:

Thiopental induction has a favourable effect on seizure when compared to propofol in patients undergoing electroconvulsive therapy. (www.actabiomedica.it)

Effectiveness of sodium thiopentone, propofol, and etomidate as an ideal intravenous anesthetic agent for modified electroconvulsive therapy

Introduction:

Electroconvulsive therapy (ECT) is a well-established psychiatric treatment in which seizures are electrically induced in patients for therapeutic effects. ECT can produce severe disturbances in the cardiovascular system and a marked increase in cerebral blood flow and intracranial pressure. These cardiovascular changes may be altered using various anesthetic drugs.

Aim and Objectives:

This study was undertaken to compare the effects of intravenous (IV) sodium thiopentone, propofol, and etomidate, used as IV anesthetic agents in modified ECT as regards, induction time and quality of anesthesia, alteration of hemodynamics, seizure duration, and recovery time.

Materials and Methods:

A total of 90 patients in the age group of 16–60 years of either sex, who had to undergo ECT therapy were divided randomly into three equal groups. Group A received propofol 1% - 1.5 mg/Kg, Group B received etomidate - 0.2 mg/Kg, and Group C received thiopentone 2.5% - 5 mg/Kg. All the patients were monitored for changes in heart rate, systolic blood pressure, diastolic blood pressure, and oxygen saturation at basal, after induction and 1 min, 2 min, 3 min, 5 min, 10 min, 20 min, and 30 min following ECT. Quality of anesthesia, seizure duration, and recovery times were also recorded.

Conclusion:

We found that propofol had the advantage of smooth induction, stable hemodynamic parameters and rapid recovery as compared to etomidate and thiopentone. Thiopentone had the advantage over propofol of having longer seizure duration at the cost of a relatively prolonged recovery period. Etomidate had a definite advantage of longer seizure duration.

Remifentanil in electroconvulsive therapy: a systematic review and meta-analysis of randomized controlled trials

In electroconvulsive therapy (ECT), remifentanil is often used concurrently with anesthetics. The objective of this study was to provide an up-to-date and comprehensive review on how the addition of remifentanil to anesthetics affects seizure duration and circulatory dynamics in mECT. We performed a meta-analysis of RCTs that investigated seizure duration and circulatory dynamics in patients treated with ECT using anesthetics alone (non-remifentanil group) and with anesthetics plus remifentanil (remifentanil group). A total of 13 RCTs (380 patients and 1024 ECT sessions) were included. The remifentanil group showed a significantly prolonged seizure duration during ECT compared to the non-remifentanil group [motor: 9 studies, SMD = 1.25, 95 % CI (0.21, 2.29), p = 0.02; electroencephalogram: 8 studies, SMD = 0.98, 95 % CI (0.14, 1.82), p = 0.02]. The maximum systolic blood pressure (SBP) was significantly reduced in the remifentanil group compared to the non-remifentanil group [7 studies, SMD = -0.36, 95 % CI (-0.65, 0.07), p = 0.02]. Substantial heterogeneity was observed for meta-analyses for seizure durations, but a pre-planned subgroup analysis revealed that seizure duration was prolonged only when the use of the anesthetic dose was reduced in the remifentanil group. The results of our study suggest that addition of remifentanil to anesthesia in ECT may lead to prolonged seizure duration when it allows the use of reduced anesthetic doses. Further, the addition of remifentanil was associated with reduced maximum SBP.

Inhibition of astrocyte metabolism is not the primary mechanism for anaesthetic hypnosis

Astrocytes have been promoted as a possible mechanistic target for anaesthetic hypnosis. The aim of this study was to explore this using the neocortical brain slice preparation. The methods were in two parts. Firstly, multiple general anaesthetic compounds demonstrating varying in vivo hypnotic potency were analysed for their effect on "zero-magnesium" seizure-like event (SLE) activity in mouse neocortical slices. Subsequently, the effect of astrocyte metabolic inhibition was investigated in neocortical slices, and compared with that of the anaesthetic drugs. The rationale was that, if suppression of astrocytes was both necessary and sufficient to cause hypnosis in vivo, then inhibition of astrocytic metabolism in slices should mimic the anaesthetic effect. In vivo anaesthetic potency correlated strongly with the magnitude of reduction in SLE frequency in neocortical slices (R(2) 37.7 %, p = 0.002). Conversely, SLE frequency and length were significantly enhanced during exposure to both fluoroacetate (23 and 20 % increase, respectively, p < 0.01) and aminoadipate (12 and 38 % increase, respectively, p < 0.01 and p < 0.05). The capacity of an anaesthetic agent to reduce SLE frequency in the neocortical slice is a good indicator of its in vivo hypnotic potency. The results do not support the hypothesis that astrocytic metabolic inhibition is a mechanism of anaesthetic hypnosis.

The general anesthetic propofol induces ictal-like seizure activity in hippocampal mouse brain slices

The general anesthetic propofol has been in clinical use for more than 30 years and has become the agent of choice for rapid intravenous induction. While its hypnotic and anti-convulsant properties are well known, the propensity for propofol to promote seizure activity is less well characterised. Electroencephalogram-confirmed reports of propofol-induced seizure activity implicate a predisposition in epileptic subjects. The aim of this study was to investigate the seizure-promoting action of propofol in mouse brain slices—with the goal of establishing an in vitro model of propofol pro-convulsant action for future mechanistic studies. Coronal slices were exposed to either normal artificial cerebrospinal fluid (aCSF) or no-magnesium (no-Mg) aCSF—and extracellular field potential recordings made from the hippocampus, entorhinal cortex and neocortex. Propofol (and etomidate for comparison) were delivered at three stepwise concentrations corresponding to clinically relevant levels. The main finding was that propofol induced ictal-like seizures in seven out of ten hippocampal recordings (p = 0.004 compared to controls) following pre-exposure to no-Mg aCSF—but strongly inhibited seizure-like event (SLE) activity in the neocortex. Propofol did not induce seizure activity in slices exposed to normal aCSF. The results support the contention that propofol has the capacity to promote seizure activity, particularly when there is an underlying seizure predisposition. This study establishes an in vitro model for exploring the mechanisms by which propofol promotes subcortical seizure activity.

Post-electroconvulsive therapy recovery and reorientation time with methohexital and ketamine: a randomized, longitudinal, crossover design trial

OBJECTIVES

Methohexital, a barbiturate anesthetic commonly used for electroconvulsive therapy (ECT), possesses dose-dependent anticonvulsant properties, and its use can interfere with effective seizure therapy in patients with high seizure thresholds. Ketamine, an N-methyl-d-aspartate antagonist with epileptogenic properties not broadly used for ECT inductions, is a commonly used induction agent for general anesthesia. Recent studies suggest that the use of ketamine is effective in allowing successful ECT treatment in patients with high seizure thresholds without an increase in adverse effects. In this preliminary study, we directly compared the recovery and reorientation times of subjects receiving ketamine and methohexital for ECTs.

METHODS

Twenty patients were randomized in a crossover design to receive methohexital and ketamine for ECT inductions in alternating fashion in 6 trials. Primary outcome measures were recovery time (voluntary movement, respiratory effort, blood pressure, consciousness, and O2 saturation) and reorientation time. Secondary outcome measures were individual recovery variables, adverse effect occurrence, and seizure duration.

RESULTS

Overall recovery time was not significantly different between the 2 treatment arms (F(1, 17) = 0.72; P = 0.41). Reorientation time was faster in the methohexital arm (F(1, 17) = 9.23; P = 0.007).

CONCLUSION

Ketamine inductions resulted in higher number of adverse effects, higher subject dropout rates, and a longer reorientation time with respect to methohexital inductions. No significant difference in postanesthesia recovery time was found between the ketamine and methohexital arms. Intolerability to ketamine affected a significant proportion of subjects and suggests that ketamine should remain as an alternative or adjunctive agent for patients with high seizure thresholds.

Different regimens of intravenous sedatives or hypnotics for electroconvulsive therapy (ECT) in adult patients with depression

BACKGROUND

Depression is a common mental disorder. It affects millions of people worldwide and is considered by the World Health Organization (WHO) to be one of the leading causes of disability. Electroconvulsive therapy (ECT) is a well-established treatment for severe depression. Intravenous anaesthetic medication is used to minimize subjective unpleasantness and adverse side effects of the induced tonic-clonic seizure. The influence of different anaesthetic medications on the successful reduction of depressive symptoms and adverse effects is unclear.

OBJECTIVES

This review evaluated the effects of different regimens of intravenous sedatives and hypnotics on anti-depression efficacy, recovery and seizure duration in depressed adults undergoing ECT.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2012, Issue 12); MEDLINE via Ovid SP (from 1966 to 31 December 2012); and EMBASE via Ovid SP (from 1966 to 31 December 2012). We handsearched related journals and applied no language restrictions.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) and cross-over trials evaluating the effects of different intravenous sedatives and hypnotics for ECT. We excluded studies and trials using placebo or inhalational anaesthetics and studies that used no anaesthetic.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. When possible, data were pooled and risk ratios (RRs) and mean differences (MDs), each with 95% confidence intervals (CIs), were computed using the Cochrane Review Manager statistical package (RevMan).

MAIN RESULTS

We included in the review 18 RCTs (599 participants; published between 1994 and 2012). Most of the included trials were at high risk of bias.We analysed the results of studies comparing six different intravenous anaesthetics.Only a few studies comparing propofol with methohexital (four studies) and with thiopental (three studies) could be pooled.No difference was noted in the reduction of depression scores observed in participants treated with propofol compared with methohexital (low-quality evidence). These four studies were not designed to detect differences in depression scores.The duration of electroencephalograph (EEG) and of motor seizures was shorter in the propofol group compared with the methohexital group (low-quality evidence). No difference was seen in EEG seizure duration when propofol was compared with thiopental (low-quality evidence).Time to recovery (following commands) was longer among participants after anaesthesia with thiopental compared with propofol (low-quality evidence).For the remaining comparisons of anaesthetics, only single studies or insufficient data were available. Adverse events were inadequately reported in eligible trials, and none of the included trials reported anaesthesia-related mortality.

AUTHORS' CONCLUSIONS

Most of the included studies were at high risk of bias, and the quality of evidence was generally low. The studies were not designed to detect clinically relevant differences in depression scores. Anaesthetic agents should be chosen on the basis of adverse effect profile, emergence and how these medications affect seizure duration. If it is difficult to elicit an adequately long seizure, methohexital may be superior to propofol (low-quality evidence). If a patient is slow to recover from anaesthesia, propofol may allow a faster time to follow commands than thiopental (low-quality evidence). A factor of clinical concern that was not addressed by any study was adrenal suppression from etomidate. Optimal dosages of intravenous sedatives or hypnotics have not yet been determined.Larger well-designed randomized studies are needed to determine which intravenous anaesthetic medication leads to the greatest improvement in depression scores with minimal adverse effects.

Comparison of anesthetics in electroconvulsive therapy: an effective treatment with the use of propofol, etomidate, and thiopental

OBJECTIVES

Electroconvulsive therapy (ECT) is considered to be one of the most effective treatments in psychiatry. Currently, three medications for anesthesia are used routinely during ECT: propofol, etomidate, and thiopental. The objective of this study was to evaluate the effects of the anesthetics used in ECT on seizure threshold and duration, hemodynamics, recovery from ECT, and immediate side effects.

METHODS

Our study is a retrospective cohort study, in which a comparison was made between three groups of patients who underwent ECT and were anesthetized with propofol, etomidate, or thiopental. The main effect compared was treatment dose and seizure duration. All patients were chosen as responders to ECT.

RESULTS

Data were gathered about 91 patients (39 were anesthetized with thiopental, 29 with etomidate, and 23 with propofol). Patients in the thiopental group received a lower electrical dose compared to the propofol and etomidate group (mean of 459 mC compared to 807 mC and 701 mC, respectively, P<0.001). Motor seizure duration was longer in the thiopental group compared to propofol and etomidate (mean of 40 seconds compared to 21 seconds and 23 seconds, respectively, P=0.018). Seizure duration recorded by electroencephalography was similar in the thiopental and etomidate groups and lower in the propofol group (mean of 57 seconds in both groups compared to 45 seconds, respectively, P=0.038).

CONCLUSION

Patients who were anesthetized with thiopental received a lower electrical treatment dose without an unwanted decrease in seizure duration. Thiopental might be the anesthetic of choice when it is congruent with other medical considerations.

A comparison of propofol and thiopentone for electroconvulsive therapy

Objectives:

To compare propofol and thiopental as anesthetic agents for electroconvulsive therapy (ECT) with respect to seizure duration, stimulus charge, and clinical effects.

Materials and Methods:

Randomized, blinded study of 28 patients of depression treated with bilateral ECT. In group P (n = 14), sedation was achieved with propofol 1.5 mg/kg, whereas in group T (n = 14), it was achieved with thiopentone 3 mg/ kg IV. Succinylcholine 0.4 mg/kg intravenous was given in all patients as for neuromuscular blockade.

Results:

The mean seizure duration of the patients in the thiopental group was 83 ± 34.43 seconds vs. 94.45 ± 21.37 seconds in the propofol group (P < 0.01). The energy delivered per treatment was 10.88 ± 4.78 J in the thiopental group vs. 12.20 ± 4.53 J in the propofol group (P < 0.05). Number of ECTs required were significantly higher in propofol group (9.71 ± 2.87) as compared to thiopental group (5.86 ± 0.36) P < 0.0001. No significant difference in duration of hospitalization was seen in both groups. The mean score on Mini-Mental State Examination (MMSE) was 29.14 in the thiopental group vs. 29.57 in the propofol group (P > 0.05). The mean score on Beck Depression Inventory (BDI) was 7.14 in the thiopental group vs. 3.29 in the propofol group (P < 0.05).

Conclusions:

Propofol significantly increases number of ECT required to treat although the patients received higher electrical charge and had longer seizure duration. BDI scores suggest this resulted in better outcome. Results, however, might be confounded by the differences in pharmacological treatment in the groups.

Propofol protects against impairment of learning-memory and imbalance of hippocampal Glu/GABA induced by electroconvulsive shock in depressed rats

PURPOSE

General anesthetics are believed to induce amnesia. However, propofol can ameliorate cognitive deficits induced by electroconvulsive therapy (ECT), a treatment for mental disorders. This study aimed at investigating the possible molecular mechanism as well as the effects of propofol on learning-memory impairment in depressed rats induced by ECS (electroconvulsive shock, the analog of ECT to animals).

METHODS

Rats were treated with ECS (or sham ECS) pretreated with intraperitoneal injection of propofol (100 mg/kg) (or normal saline, 0.01 l/kg) after being treated with chronic unpredictable mild stresses to reproduce an animal model of depression. Sucrose preference test, open field test, and Morris water maze were used to assess behavioral changes. Hippocampal glutamate (Glu) and γ-aminobutyric acid (GABA) levels were measured with liquid chromatography, and glutamic acid decarboxylase 65 (GAD65) was assayed immunohistochemically. Additionally, rats undergoing ECS that were pretreated with pentobarbital sodium (45 mg/kg) were included for behavioral tests and electroencephalogram recording for comparison with rats undergoing ECS that were pretreated with propofol or normal saline.

RESULTS

ECS rats pretreated with propofol or pentobarbital sodium exhibited similar decreased seizure durations as compared with ECS rats pretreated with normal saline. ECS pretreated with normal saline aggravated learning-memory deficits whereas ECS pretreated with propofol or pentobarbital sodium did not. Rats undergoing ECS pretreated with propofol showed better memory than those undergoing ECS after pretreatment with pentobarbital sodium. ECS pretreated with normal saline downregulated the ratio of Glu/GABA and upregulated GAD65 expression; all these molecular changes were nearly normalized to the level of control group by ECS pretreated with propofol. There were no significant differences of depressive behaviors between groups treated with ECS.

CONCLUSIONS

The data suggest that propofol alleviated ECS-induced learning-memory impairment without interfering with the antidepressant efficacy of ECS, possibly by inhibiting excessive expression of GAD65 and maintaining the balance between glutamatergic and GABAergic amino acids neurotransmitters in the hippocampus.

General anesthesia and altered states of arousal: a systems neuroscience analysis

Placing a patient in a state of general anesthesia is crucial for safely and humanely performing most surgical and many nonsurgical procedures. How anesthetic drugs create the state of general anesthesia is considered a major mystery of modern medicine. Unconsciousness, induced by altered arousal and/or cognition, is perhaps the most fascinating behavioral state of general anesthesia. We perform a systems neuroscience analysis of the altered arousal states induced by five classes of intravenous anesthetics by relating their behavioral and physiological features to the molecular targets and neural circuits at which these drugs are purported to act. The altered states of arousal are sedation-unconsciousness, sedation-analgesia, dissociative anesthesia, pharmacologic non-REM sleep, and neuroleptic anesthesia. Each altered arousal state results from the anesthetic drugs acting at multiple targets in the central nervous system. Our analysis shows that general anesthesia is less mysterious than currently believed.

Identification and characterization of anesthetic targets by mouse molecular genetics approaches

PURPOSE

It is now generally accepted that proteins are the primary targets of general anesthetics. However, the demonstration that the activity of a protein is altered by general anesthetics at clinically relevant concentrations in vitro does not provide direct evidence that this target mediates pharmacological actions of general anesthetics. Here we report on advances that have been made in identifying the contribution of individual ligand-gated ion channels to defined anesthetic endpoints using molecular mouse genetics.

PRINCIPAL FINDINGS

Gamma-aminobutyric acid (GABA)(A) receptor subtypes defined by the presence of the α1, α4, α5, β2, and β3 subunits and two-pore domain potassium channels (TASK-1, TASK-3, and TREK) have been discovered to mediate, at least in part, the hypnotic, immobilizing or amnestic actions of intravenous and volatile general anesthetics. Moreover, using tissues from genetically modified mice, specific functions of GABA(A) receptor subtypes in cortical and spinal neuronal networks were identified.

CONCLUSION

Genetically modified mice have been very useful for research on mechanisms of anesthesia and have contributed to the functional identification of general anesthetic targets and of the role of these targets in neuronal networks.

Augmentation of seizure induction in electroconvulsive therapy: a clinical reappraisal

OBJECTIVE

Missed or abortive seizures during electroconvulsive therapy (ECT) may preclude completion of an effective course of treatment in some cases. Seizure augmentation, using proconvulsant agents, has been used to overcome resistance to the induction and continuation of seizure activity. In this review, we analyze published clinical data on the effects and safety of seizure augmentation techniques.

METHOD

Clinical studies and case reports were obtained through a MEDLINE literature search from 1966 to 2001, cross-referencing ECT and proconvulsant agents. Article references were also scanned for relevant studies.

RESULTS AND CONCLUSIONS

Data from clinical trials indicate that augmentation facilitates seizure induction when maximal electrical stimuli fail. Anesthetic modifications, including hyperventilation and substitution with etomidate, ketamine, or other agents, often are successful in overcoming seizure resistance and compare favorably with the use of caffeine. In a few studies, augmentation enabled the use of lower stimulus intensities and fewer treatments without loss of efficacy, even in patients not resistant to seizure induction. However, effects of proconvulsants must be reconciled with increasing evidence of the importance of stimulus dosing relative to seizure threshold and other parameters, now considered key to the efficacy of ECT. Further investigations of pharmacologic augmentation could facilitate the administration of ECT and could provide further insights concerning parameters of seizure efficacy and the mechanism of action underlying convulsive therapies.

A switch from propofol to etomidate during an ECT course increases EEG and motor seizure duration

INTRODUCTION

Of 58 patients treated at our electroconvulsive therapy (ECT) unit early in the year 2000, 12 patients under propofol did not achieve a seizure duration of >30 s [electroencephalogram (EEG)] with a maximum stimulation charge of 504.0 mC (100%).

METHOD

A switch from propofol to etomidate was therefore undertaken in these patients at the next treatment to achieve longer seizure duration.

RESULTS

In 11 of the 12 patients, a remarkable increase in seizure duration was recorded after the change of anesthetic. The mean seizure duration increased from 18.6 to 43.4 s and remained at that level for the following ECT session. The increase was highly significant (t11 = 3.772, p < 0.001). The mean motor seizure also changed from 11.6 to 27.5 s (t11 = 5.560, p < 0.003) and remained there for the next treatment.

DISCUSSION

Our data show that the switch more than doubles EEG seizure duration and suggest that etomidate can be used instead of methohexital as an alternative in patients with short seizure duration. It is also a potential option to avoid the pain frequently associated with the injection of propofol.

Propofol [correction of propfol] versus methohexital for electroconvulsive therapy: a meta-analysis

A systematic search (Medline, Cochrane library, Embase, bibliographies, to 5.2000, no language restriction) was performed for published reports of randomized comparisons of propofol and methohexital for anesthesia during electroconvulsive therapy. We analyzed 15 trials with data on 706 patients. The duration of motor seizure was shorter with propofol (range, 18-39 seconds) than with methohexital (range, 26-48 seconds, weighted mean difference 8.4 seconds [95% CI, 6.6-10.0]). With both propofol and methohexital, there was little evidence of an association between dose and duration of motor seizure (for propofol: r2 = 0.25, P = .08; for methohexital: r2 = 0.11, P = .27). Two small trials investigated clinical outcome; results were inconclusive. Data on adverse effects were sparse. Duration of seizure was not proven to be a useful measure of treatment success in the study of electroconvulsive therapy with propofol or methohexital. The impact of the technique of anesthesia on the underlying disease needs to be established.