5 Organisation and delivery of psychiatric services5.3 Provision of specific treatments
5.3.3 Practical administration of ECT
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Written by Resident Doctor Committee · Published
Medication before a course
Benzodiazepines are anticonvulsant: they raise the seizure threshold and shorten seizures, so they are withdrawn or tapered before a course of electroconvulsive therapy (ECT) where possible.
Lithium raises the risk of prolonged seizures, delirium, toxicity and prolonged neuromuscular blockade (delayed recovery from suxamethonium), so it is adjusted around ECT.
Other psychotropics are usually continued, and anticonvulsants are adjusted only after weighing why they are prescribed.
Anaesthesia and muscle relaxation
Suxamethonium is a rapid, short-acting muscle relaxant broken down by plasma cholinesterase, and it prevents the fractures of unmodified ECT.
An inflated limb cuff keeps relaxant out of one limb so the motor seizure can be seen.
Electrode placement and dose
Placement | Efficacy and dose | Cognitive cost |
|---|---|---|
Bitemporal | Reliable at about 1.5 times threshold | Greatest memory burden |
Right unilateral | Needs a substantially higher multiple of threshold | Less verbal and autobiographical memory loss |
Bifrontal | Less consistent evidence | Benefit uncertain |
Seizure threshold varies between people and rises during a course, and the first dose is set by titration or by age (half the age as a percentage of device output).
Judging the seizure
Conventional guides are 15 to 20 seconds of motor activity and at least 25 seconds on electroencephalogram (EEG).
In modified ECT the EEG seizure commonly outlasts the observed motor seizure, because the muscle relaxant masks the convulsion.
A well-generalised seizure passes from fast activity to slower polyspike and wave activity, then post-ictal suppression, and organisation matters more than length.
Frequency and course length
UK guidance caps routine acute ECT at two treatments a week, because closer spacing causes cumulative cognitive impairment.
Thrice-weekly ECT is practice abroad, mainly in North America, and maintenance ECT is spaced further apart.
A course for depression usually runs 6 to 12 treatments, catatonia often 3 to 6, and resistant mania or psychosis sometimes 20 or more.
Recovery
Donepezil, an acetylcholinesterase inhibitor, has trial evidence for shortening post-ictal disorientation and recovery time after ECT.