1

What is electroconvulsive therapy?

ECT is the application of electrical stimuli to the brain to induce a therapeutic seizure. ECT is an effective treatment for major depressive disorder, bipolar disorder, catatonia, and schizophrenia. Most patients referred for ECT are seriously depressed, often suicidal or psychotic and unable to function because of their psychiatric illness. These patients have typically failed medical treatment. ECT has been a safe and effective therapy for refractory depression and other mental illnesses since its introduction. Most treatment-associated morbidity and mortality have been attributed to cardiovascular sequelae related to the physiologic response to treatment.

ECT can be administered with either bilateral or unilateral electrode placement. Bilateral electrode placement is associated with more rapid improvement but also portends increased risk of short-term and long-term memory impairment. Unilateral electrode placement is associated with less risk for memory-associated problems, but the clinical response may be slower and the patient may require a greater number of treatments. In addition, the period of asystole during stimulus application is typically longer with unilateral electrode placement. For patients who are at increased risk for a cardiovascular event during treatment, the risks associated with an increased number of treatments needs to be evaluated if unilateral electrode placement is considered.

2

Do you have enough information to proceed with general anesthesia?

The tasks of the anesthesiologist are to determine if the patient is an acceptable anesthetic candidate for ECT, to create a humane and safe anesthetic without suppressing the therapeutic seizure, to mitigate or manage the physiologic effects of the treatment, and to manage the transient effects of the anesthetics including management of the airway. General anesthesia is required, and patients receiving ECT should have the same quality of anesthetic evaluation as patients undergoing anesthesia for a surgical procedure. A thorough history should be taken.

A complete list of current medications should be obtained because some medications are known to interact with either the treatment or the anesthetic ( Box 17-1 ). Patients presenting for ECT are usually taking multiple psychotropic medications. These medications may include tricyclic antidepressants (TCAs), lithium carbonate, monoamine oxidase inhibitors (MAOIs), selective serotonin reuptake inhibitors (SSRIs), antipsychotics, benzodiazepines, and miscellaneous second-generation antidepressants such as bupropion.

TCAs block the reuptake of norepinephrine at the postganglionic sympathetic nerve endings, resulting in increased baseline sympathetic tone. In these patients, direct-acting sympathetic agents are preferred to indirect-acting agents that increase the release of norepinephrine. Several categories of drugs must be used cautiously with TCAs, antihypertensives, potent volatile agents, and anticholinergics.

MAOIs block the metabolism of catecholamines, increasing baseline sympathetic tone as well. The interaction between MAOIs and meperidine or indirect-acting sympathomimetic agents has been shown to lead to hypertensive crises, seizures, and hyperpyrexia.

Patients who have a history of pseudocholinesterase deficiency or who are at risk for malignant hyperthermia present special problems. Both of these issues relate to succinylcholine, a depolarizing muscle relaxant. Patients with pseudocholinesterase deficiency are at risk for prolonged neuromuscular blockade if given succinylcholine, so an alternative agent such as rocuronium should be administered. Succinylcholine is contraindicated in patients with malignant hyperthermia because it is a known trigger for the disease.

In the present case, none of the medications the patient is taking appears to present a problem, but his blood pressure is elevated. Because ECT is associated with acute but transient elevations in blood pressure, one needs to confirm that the patient has received his antihypertensive medications according to schedule and that his blood pressure is within the expected range given his history before proceeding. Additional antihypertensive medications may be administered immediately before the procedure or on an “as-needed” basis to keep the systolic pressure less than 200 mm Hg. The patient’s blood pressure should be measured frequently throughout the perioperative period (every 1 to 2 minutes).