Anesthesia for ECT: lidocaine effect

Electroconvulsive therapy (ECT) is a procedure where a generalized epileptic seizure is purposely induced for the treatment of psychiatric disorders (including acute and chronic depression/mania) that are resistant to medical management. The initial reaction following application of the electric current is a parasympathetic response resulting in bradydysrhythmias and possibly sinus pause (1,2). The parasympathetic response is followed by a sympathetic response associated with tachycardia and hypertension. During the sympathetic response, systolic blood pressure may increase by 30-40% and heart rate may increase by 20% (or more). The typical effective seizure should have a duration of 20 to 50 seconds. The treatment includes a series of ECT performed 3 times a week for a period of 6 to 8 weeks.

Anesthesia for ECT includes the use of a induction agent and short acting muscle relaxant such as succinylcholine to minimize the amount of muscle contraction that occurs with the seizure. Selection of the induction agent or other medications used during the procedure should consider its effect on the seizure duration.

Many different medications, including lidocaine, have been studied in hopes of attenuating the sympathetic response to ECT. Lidocaine, an amide local anesthetic, has been shown to be ineffective in ameliorating the robust sympathetic response associated with ECT. In addition, pre-treatment with lidocaine is also associated with decreased seizure duration and a higher likelihood of patients requiring multiple applications of electric current during a single ECT session to achieve a therapeutic seizure.

ANESTHETIC DRUGS

Increases duration: Etomidate

NO change in duration:

• Methohexital (Induction agent of choice)
•  Ketamine

Decreases duration:

• Thiopental
• Midazolam
• Propofol

CARDIOVASCULAR DRUGS

Increases duration:

• Aminophylline
• Caffeine (often given pre-procedure to increase duration)

NO change in duration:

• Clonidine
• Esmolol
• Labetalol
• Dexmedetomidine
• Nifedipine
• Nicardipine
• Nitroglycerin
• Nitroprusside

Decreases duration:

• Diltiazem
• Lidocaine (While lidocaine has been shown to reduce the HR changes associated with ECT, lidocaine significantly reduces seizure duration.)