INTRODUCTION: Ever since its discovery, Electroconvulsive Therapy (ECT) has continued to occupy a central place in the armamentarium of psychiatrists inspite of advances in psychopharmaco therapy.¹ Despite both medical and legal opposition it is still widely practiced as one of the cheapest, safest and yet one of the most effective therapeutic technique in the whole of medical sciences.² Due to trauma caused to the patient physically and psychologically with unmodified direct electroconvulsive therapy in the past it has now been modified with anaesthesia. The aim of ECT is to produce a grand mal seizure. It is the seizure rather than the electrical stimulus, which is responsible for the therapeutic effect.

Electroconvulsive therapy can produce severe disturbances in the cardiovascular system, most commonly a transient period of hypertension and changes in the heart rate.³ These cardiovascular changes may be altered by using various anaesthetic drugs and the violent muscular contractions occurring during the convulsions can be reduced by the usage of muscle relaxants.

METHODOLOGY: After obtaining clearance from the institutional ethics committee, patients of either gender scheduled for modified electroconvulsive therapy (MECT) were selected for the study.

Patients with ASA physical status 1 or 2 and age between 16-60 years are included in the study. Patients in whom thiopentone sodium, propofol or succinylcholine were contraindicated and with renal, hepatic or neuromuscular disorders were excluded.

Forty patients who presented for a minimum of two ECT treatments consecutively were studied. Patients were randomly allocated to receive either 1% propofol or 2.5% thiopentone for their first treatment and the other drug was administered on the second occasion. Heart rate was monitored by palpating pulse beats (Radiation pulsation) and blood pressure was measured using a mercury sphygmomanometer at time intervals that have been indicated. Isolation of a limb was done in the upper limb at the level of the arm by using a blood pressure cuff that was inflated 50mmHg above systolic blood pressure.

Anaesthesia was induced by using either 1% propofol (1.5mg/kg) or 2.5% thiopentone (3mg/kg), given over 20 seconds through a 20 G or 22 G I.V. cannulae.

The induction dose was considered adequate if the eyelash reflex was lost after 30seconds, following thiopentone or there was no response to call following propofol.

Additional dose of the appropriate agent was titrated as necessary. Following the onset of anaesthetic effect, depolarizing muscle relaxant succinyl choline (0.5mg/kg) was administered. Muscle fasiculations or fine twitching movements inhibited its action.

The disappearance of these movements indicated that the maximal relaxation has occurred. The electrical stimulus was delivered by the attending psychiatrist using bifrontal electrodes.

The duration of motor seizure was recorded as the time taken from the administration of the electrical stimulus to the cessation of the tonic–clonic activity in the isolated limb. Arterial blood pressure and heart rate were recorded before and immediately after the injection of anaesthetic and then every one minute for the first five minutes following the electro shock. The time taken to follow simple commands (i.e., mentioning name on command or moving limbs to command) was recorded.

RESULTS: In this study, modified ECT was given to 40 patients who received alternately either propofol (1.5mg/kg) or thiopentone (3mg/kg) and the results evaluated. The dose of the drugs were titrated according to requirements. The mean dose of thiopentone (Group–I) used was 3.15mg/kg and that for propofol (Group – II) was 1.56mg/kg.

ECT was given to patients with different age groups, weight and different psychiatric illness.

The percentage changes in Systolic blood pressure, Diastolic blood pressure and Heart rate from the baseline were calculated at various time intervals following delivery of shock.

Non-parametric ANOVA for repeated measures. ‘F’ value = 61.153, p<0.0001 multiple comparison test, p< 0.0001.

This analysis shows that there is a highly significant change (p<0.0001) in the systolic blood pressure post ECT between the two groups.

Non parametric ANOVA for repeated measures ‘F’ value = 203.119, p<0.0001 Multiple comparison test, p<0.0001.

This analysis shows that there is a highly significant change (p<0.0001) in the diastolic blood pressure post ECT between the two groups.

Non-parametric ANOVA for repeated measures ‘F’ value=150.4358, p<0.0001 Multiple comparison test, p<0.0001.

This analysis shows that there is a highly significant change (p<0.0001) in the heart rate post ECT between the two groups.

The differences between the two groups for duration of motor seizure, time for eye opening and time to follow simple commands were analysed using the students ‘T‘ test for paired observations.

SEIZURE DURATION: The seizure duration in the thiopentone–succinylcholine group was 45.4+/-13.20 seconds while in the propofol–succinylcholine group it was 37.56+/-10.53 seconds. The comparison between paired data indicated a difference of 7.84+/-15.64 seconds, which was statistically significant (p < 0.05).

TIME TO EYE OPENING: The time to eye opening in the thiopentone–succinylcholine group was 376.56+/-113.08 seconds, while in the propofol–succinylcholine group it was 331.32+/-106.26 seconds. The comparison between paired data indicated a difference of 41.36 +/-152.49 seconds, which was not stastically significant.

RESPONSE TO SIMPLE COMMANDS: The time to response to simple commands in the thiopentone-succinylcholine group was 519.64+/-144.81 seconds, while in the propofol–succinylcholine group it was 442.16+/-126.07 seconds. The comparison between paired data indicated a difference of 99.12+/-200.17 seconds, which was statistically significant (p<0.05).

TS- thiopentone–succinylcholine group, PS–propofol–succinylcholine group