Modern electroconvulsive therapy (ECT) is a remarkably safe and effective antidepressant treatment. It remains a critical option for urgently ill patients, many of whom do not adequately respond to antidepressant medications.1,2
Advances in anesthesia technique are a major part of the safety and comfort profile of ECT today. In this article, we briefly review important aspects of the anesthesia used in ECT. While we do not believe that all psychiatrists need to be expert in the details, knowledge of the basics is necessary to adequately inform patients about ECT during the referral process.
ECT is performed under full general anesthesia and muscle relaxation. Blood pressure, pulse, ECG, and blood oxygen saturation are monitored to ensure patient safety. Supplemental oxygen is provided throughout the procedure by the anesthesiologist, who ventilates the patient using a mask and bag. Patients are not intubated for ECT, except under extremely rare circumstances.
An intravenous line is inserted in the patient’s arm, through which the anesthetic and muscle relaxant medications are administered. The sequence of administration is to give the anesthetic induction agent first, followed by the muscle relaxant, only after the patient has lost consciousness. The patient is ventilated with oxygen while the muscle relaxant takes effect (1 to 2 minutes). A foam or rubber protective device is then inserted into the patient’s mouth, and the electrical stimulus is delivered. A seizure occurs (typically 30 to 60 seconds), and the patient awakens in a few minutes as the medications wear off. The total procedure takes less than 10 minutes.
The anesthesiologist will consult with the patient before the treatment. For medically complex patients, this should be done in advance; for younger, medically healthy patients, it may be done the morning of the first treatment. Some patients who present for ECT may be poor historians or completely nonverbal; it may therefore be necessary to rely on supplemental sources of information, such as consults with other treating physicians, discussion with family members, and laboratory or other diagnostic tests.
Although ECT is generally a low-risk procedure, many ECT patients fall into the high-risk category. The pre-anesthetic assessment should therefore focus on identifying conditions that increase the risk of morbidity or mortality during treatment.3 The ECT psychiatrist and the anesthesiologist must decide which laboratory tests will need to be done before ECT. At a minimum, each patient referred for ECT should have an ECG to evaluate potential cardiac problems and to establish a baseline; a complete blood cell count to detect anemia or infection; and a basic metabolic panel to look for electrolyte imbalances, especially potassium and sodium levels.
When evaluating a potential candidate for ECT, it is particularly important to pay close attention to the patient’s cardiovascular and pulmonary status.4 The release of endogenous catecholamines associated with the therapeutic seizure typically causes transient hypertension and tachycardia. Patients with a significant cardiac history who may be at risk for myocardial ischemia under these conditions need a careful cardiac evaluation. It is also important to evaluate the patient’s pretreatment pulmonary function. Particularly close attention needs to be paid to any signs of deteriorating respiratory status or infection, such as shortness of breath, cough, fever, or low oxygen saturation on room air.
Potential interactions between psychiatric medications the patient is taking and the medications used during anesthesia need to be assessed. The patient’s current medication list needs to be reviewed and decisions made in advance about which medications to taper or stop before the procedure, which medications to continue during the course of ECT (but held until after each treatment), and which medications can safely be given with a minimum amount of water early in the morning of the ECT.
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