Bradycardia and Asystole：Anesthetic Complications of Modified Electroconvulsive Therapy

Abstract

Anesthesia management of patients undergoing modified electroconvulsive therapy（m-ECT）is preferably performed by an anesthesiologist. The effects on the autonomic nervous system are：1. Sympathetic nerve activity decreases with the induction of anesthesia；2. Parasympathetic nerve activity increases immediately after the energization；3. Sympathetic nerve activity increases during the clonic convulsions and parasympathetic nerve activity increases after the convulsions；and 4. Sympathetic nerve activity returns to its original state upon the patient emerging from the anesthesia.

Parasympathetic nerve activity remains high for longer when convulsions do not occur. Convulsions are more likely to occur due to irritation at a small depth of anesthesia, in the event of use of the bispectral index（BIS）, in the event of hyperventilation, and with reduced sedative use. Use of ketamine, which lowers the seizure threshold, and remifentanil, which can reduce the amount of sedative needed, is also effective.

ECT is a short-term treatment but is associated with major changes in hemodynamics. Cardiac arrest during ECT anesthesia is often caused by a hyperactive parasympathetic nervous system. Cardiac motion can be safely restored by precordial thumping, atropine administration, and/or cardiac massage, and it is important to deal with it in a calm manner.