Electroconvulsive Therapy - Administration

Administration

Prior to treatment, a patient is given a short-acting anesthetic such as methohexital, etomidate, or thiopental, a muscle relaxant such as suxamethonium (succinylcholine), and occasionally atropine to inhibit salivation.

Both electrodes can be placed on the same side of the patient's head. This is known as unilateral ECT. Unilateral ECT is used first to minimize side effects (memory loss). When electrodes are placed on both sides of the head, this is known as bilateral ECT. In bifrontal ECT, an uncommon variation, the electrode position is somewhere between bilateral and unilateral. Unilateral is thought to cause fewer cognitive effects than bilateral but is considered less effective. In the USA most patients receive bilateral ECT. In the UK almost all patients receive bilateral ECT.

The electrodes deliver an electrical stimulus. The stimulus levels recommended for ECT are in excess of an individual's seizure threshold: about one and a half times seizure threshold for bilateral ECT and up to 12 times for unilateral ECT. Below these levels treatment may not be effective in spite of a seizure, while doses massively above threshold level, especially with bilateral ECT, expose patients to the risk of more severe cognitive impairment without additional therapeutic gains. Seizure threshold is determined by trial and error ("dose titration"). Some psychiatrists use dose titration, some still use "fixed dose" (that is, all patients are given the same dose) and others compromise by roughly estimating a patient's threshold according to age and sex. Older men tend to have higher thresholds than younger women, but it is not a hard and fast rule, and other factors, for example drugs, affect seizure threshold.