Effects of propofol anesthesia on cognitive recovery of patients undergoing electroconvulsive therapy

Neurosurgical Anesthesia: Optimizing Outcomes with Agent Selection

Anesthesia in neurosurgery embodies a vital element in the development of neurosurgical intervention. This undisputed interest has offered surgeons and anesthesiologists an array of anesthetic selections to utilize, though with this allowance comes the equally essential requirement of implementing a maximally appropriate agent. To date, there remains a lack of consensus and official guidance on optimizing anesthetic choice based on operating priorities including hemodynamic parameters (e.g., CPP, ICP, MAP) in addition to the route of procedure and pathology. In this review, the authors detail the development of neuroanesthesia, summarize the advantages and drawbacks of various anesthetic classes and agents, while lastly cohesively organizing the current literature of randomized trials on neuroanesthesia across various procedures.

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.

Predictors of Seizure Threshold in Right Unilateral Ultrabrief Electroconvulsive Therapy: Role of Concomitant Medications and Anaesthesia Used

BACKGROUND

An individualized approach to maximize electroconvulsive therapy (ECT) efficacy and minimize cognitive side effects is to treat patients relative to their seizure threshold (ST). However, although Right Unilateral-Ultrabrief (0.3 ms) (RUL-UB) ECT is increasingly used in clinical settings as an effective form of ECT with minimal cognitive effects, there is sparse data regarding predictors of ST.

OBJECTIVE

To analyze the relationship between ST and clinical and demographic factors in a sample of patients treated with RUL-UB ECT.

METHODS

Clinical, demographic and ECT data from 179 patients in ECT research studies were examined. Seizure threshold was titrated at the first ECT session. ECT was performed with a Thymatron(®) or Mecta(®) device, with thiopentone (2.5-5 mg/kg) or propofol (1-2 mg/kg) anaesthesia. Medications taken at the time of ST titration were documented. The association between ST and candidate predictor variables was examined with regression analysis.

RESULTS

Multiple regression analyses showed that 34% of the variance in ST (P < 0.001) could be predicted. Older age (R(2) = 0.194, P < 0.001), propofol (vs thiopentone) (R(2) = 0.029, P ≤ 0.01) and higher anaesthetic dose (mg in propofol equivalents) (R(2) = 0.029, P < 0.05) were found to be predictors of higher initial ST. Treatment with lithium (R(2) = 0.043, P < 0.01) and study site (R(2) = 0.019, P < 0.05) significantly predicted lower initial ST.

CONCLUSIONS

Empirical titration is recommended for accurate determination of ST in patients receiving RUL-UB ECT. Novel findings of this study are that propofol anaesthesia resulted in higher ST than thiopentone and concomitant treatment with lithium treatment lowered ST.

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.

Relationship between blood levels of propofol and recovery of memory in electroconvulsive therapy

AIM

Memory impairment is a potential major adverse effect of electroconvulsive therapy (ECT). Some reports have suggested that propofol, an intravenous anesthetic widely used for general anesthesia in ECT, can minimize adverse effects on memory and cognitive function following ECT. The relation between propofol blood level during ECT and memory impairment after the procedure is unknown. We aimed to determine the relation between predicted blood level of propofol administered by target-controlled infusion during ECT and memory impairment after the procedure.

METHODS

Thirty-six patients who underwent a total of 260 series of ECT were enrolled as subjects. Anesthesia was induced with intravenous injection of propofol with a target-controlled infusion pump for predicting blood levels. Orientation and memory testing were performed after completion of ECT. In a subsequent analysis, subjects were divided into early memory recovery (n = 195) and late memory recovery (n = 65) groups. Likewise, for orientation testing,subjects were divided into early recovery (n = 193) and late recovery (n = 67) groups. In both groups, predicted blood propofol levels, total propofol dose, and other variables, such as number of ECT treatments, stimulus energy volume, and spike and slow wave time, were determined for comparison.

RESULTS

Predicted blood propofol levels and propofol total dose were significantly higher in the early memory recovery group, while no significant differences were observed for the other variables. As for orientation, there were no significant differences between the early and late orientation recovery groups.

CONCLUSIONS

Our data shows that the predicted blood propofol levels and the total dose influences memory impairment after the ECT.

Propofol and thiopental as anesthetic agents in electroconvulsive therapy: a retrospective study in major depression

OBJECTIVE

To determine the influence of propofol and thiopental as anesthetics in electroconvulsive therapy (ECT), as regards, seizure duration, electrical charge, clinical efficacy, cardiovascular profile, and presence of adverse cognitive effects.

METHODS

A retrospective design including 127 patients who received bilateral ECT for the treatment of a major depressive episode.

RESULTS

The mean seizure duration in the propofol group was significantly shorter than in the thiopental group (21.23±6.09 versus 28.24±6.6 7s, P<.001). The mean stimulus charge was 348.22 mC in the propofol group, and 238 mC in the thiopental group (P<.001). Propofol was associated with a lower increase in blood pressure. There were no differences between groups in treatment response or presence of adverse effects.

CONCLUSIONS

The anesthetic agent used in ECT might determine differences in parameters such as seizure duration or electrical charge. However, this does not seem to be translated into differences in clinical efficacy or the pattern of adverse effects observed.

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.

Cognitive impairment following electroconvulsive therapy--does the choice of anesthetic agent make a difference?

The range of drugs available to provide anesthesia for patients undergoing electroconvulsive therapy (ECT) is ever increasing. Initially, anesthetic agents were selected on the basis of their capacity not to antagonize the induced seizure. This was not always a simple task because almost all general anesthetic agents have "in built" antiepileptic activity. Nonbarbiturate agents such as propofol have been successfully used as alternatives to thiopental and methohexitone, but this drug too has antiepileptic properties. Most recently, opioid-like drugs such as remifentanil have been used, and there has been renewed interest in ketamine, a phencyclidine derivative. Attention has also focused on whether the anesthetic agent selected may affect the cognitive impairment seen after ECT. Studies in this area are limited, but early results suggest that agents such as ketamine may have particular benefit. This article reviews the current literature dealing with anesthesia and postoperative cognitive impairment in general and with regard to ECT in particular.

Propofol and methohexital as anesthetic agents for electroconvulsive therapy: a randomized, double-blind comparison of electroconvulsive therapy seizure quality, therapeutic efficacy, and cognitive performance

BACKGROUND

Propofol is often used as an anesthetic agent for electroconvulsive therapy (ECT). Whether the relatively short seizure duration, resulting from the medication, deteriorates the seizure quality and therapeutic outcomes, or whether propofol might be associated with small but significant post-ECT cognitive impairments, is still a subject of controversy. The purpose of our study was to test these hypotheses in comparison with methohexital.

MATERIALS AND METHODS

In a double-blind, controlled study, 50 patients with severe major depression who were to be treated with ECT were randomly assigned to anesthesia with propofol (120.9 +/- 50.0 mg) or methohexital (83 +/- 26.3 mg) and were observed for 2 months. The 2 drugs were compared on the basis of electroencephalography-registered seizure duration, mean blood pressure, as well as pulse frequency, seizure efficacy index, and postictal suppression. Systolic and diastolic blood pressure, and seizure duration and quality were recorded consecutively during ECT treatments. Changes in depressive symptoms and cognitive functions were measured at 5 time points, pre-ECT, after the third to fifth ECT, post-ECT treatment, and at a follow-up examination 2 and 8 weeks after the last ECT treatment.

RESULTS

Patients on propofol showed a significantly lower increase in blood pressure post-ECT (P < 0.001), their seizure duration was comparable to patients on methohexital (P = 0.072), and seizure quality was significantly superior, as was measured by the Postictal Suppression Index (P = 0.020), and comparable to the methohexital group as measured by the Seizure Efficacy Index (P = 0.160). The improvement of depressive symptoms and the improvement in cognitive functions were similar in both groups (with the exception of the results from 2 cognition tests).

CONCLUSIONS

Propofol, as compared with methohexital, results in a more moderate increase in blood pressure and shorter seizure duration. The seizure quality did not differ significantly between the 2 groups. We detected a tendency toward improved cognitive performance after anesthesia with propofol as compared with methohexital, but with statistical significance in only 2 cognition trials. Therefore, propofol is a safe and efficacious anesthetic for ECT treatment.

Landiolol attenuates acute hemodynamic responses but does not reduce seizure duration during maintenance electroconvulsive therapy

Maintenance electroconvulsive therapy (mECT) is an outpatient procedure that requires further consideration in terms of management of ambulatory anesthesia. Although many adjunctive drugs for stabilizing hemodynamic changes during ECT have been reported, side-effects of these drugs may delay recovery and discharge from hospital. The effects of landiolol, a novel ultra-short-acting beta-adrenergic blocker, have been measured on seizure duration, hemodynamic changes, recovery from anesthesia, and cognitive function during mECT under propofol anesthesia. A total of 10 patients with depression in the remission phase, were studied in a randomized, double-blind, placebo-controlled, crossover manner. Administration of 0.1 mg/kg of landiolol immediately before anesthesia significantly blunted the increase in heart rate and blood pressure during convulsions compared with placebo; landiolol was not associated with excessive hypotension or bradycardia. Landiolol did not affect seizure duration, recovery from anesthesia, or cognitive function before or after ECT. These results suggest that landiolol can be used effectively and safely during mECT.

Propofol reduces cognitive impairment after electroconvulsive therapy

BACKGROUND

Cognitive impairments are the main complication after electroconvulsive therapy (ECT). Modification of treatment parameters has been shown to affect the magnitude of these impairments, but the role of anesthetic type remains unclear. This study tested whether there is a difference in cognitive impairments immediately after ECT with propofol compared to thiopental anesthesia.

METHODS

This randomized, double-blind, crossover study included 15 patients receiving right unilateral ECT for depression. Patients received propofol or thiopental on alternating ECTs up to 6 treatments. Immediate and delayed verbal memory, motor speed, reaction speed, visuospatial, and executive functions were assessed 45 minutes after each ECT. Differences were assessed with repeated measures analysis of variance.

RESULTS

Cognitive impairments were reduced after ECT with propofol compared to thiopental. Time to emergence was quicker and EEG seizure duration was shorter after propofol treatments. There was no significant correlation between seizure duration and neuropsychological test performance.

CONCLUSIONS

Our results indicate that cognitive impairments in the early recovery period after ECT are reduced with propofol compared to thiopental anesthesia. We suggest that, in addition to ECT parameters, the type of anesthetic agent should be considered to reduce cognitive impairments after ECT.

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.

Asystole during electroconvulsive therapy: a case report

OBJECTIVE

The objective of the report is to describe a case of asystole lasting for 18 s, which developed after a subconvulsive stimulus during electroconvulsive therapy (ECT) in a patient without pre-existing cardiovascular abnormality. A brief review of the relevant literature is also provided.

CLINICAL PICTURE

The patient was a 65-year-old Chinese man with a 2-year history of depression and good past medical health. Earlier he had responded well to a course of ECT without adverse effects. This time he presented with low mood, anhedonia, poor appetite and constipation. He did not respond to adequate trials with several antidepressant medications. When a subconvulsive stimulus was administered to determine the seizure threshold, no seizure activity was detected. However, immediately after the stimulus the patient developed an 18-s asystole, followed by bradycardia of 40 beats per minute for 10 s. The bradycardia resolved spontaneously before therapeutic intervention was effected.

TREATMENT

Intravenous atropine was employed as premedication and suprathreshold stimulus was used in further ECT sessions.

OUTCOME

Asystole did not recur in the subsequent six ECT sessions.

CONCLUSION

When proper precautions are taken, asystole does not necessitate the suspension of further ECT sessions but intravenous atropine should be considered as premedication in such cases. Inducing anaesthesia with methohexital, avoiding excessive amounts of succinylcholine and employing suprathreshold stimulus and unilateral electrode placement may further lessen the likelihood of asystole in susceptible cases.