What are the steps and medication doses involved in administering anesthesia for Electroconvulsive Therapy (ECT)?

Anesthesia Protocol for Electroconvulsive Therapy (ECT)

Administer methohexital 1.0 mg/kg IV as the primary anesthetic agent, succinylcholine 0.9 mg/kg IV for muscle relaxation, and atropine or glycopyrrolate IV for anticholinergic prophylaxis, followed by 100% oxygen ventilation before delivering the electrical stimulus. 1, 2

Pre-Procedure Requirements

Patient Preparation

• Ensure the patient has fasted for approximately 12 hours before the procedure 3, 4
• Verify that an anesthesiologist experienced in treating the patient population is present 3
• Confirm emergency airway equipment is immediately available 5

Medication Review and Discontinuation

• Discontinue lithium when clinically possible due to risk of acute brain syndrome 4, 6
• Stop benzodiazepines as they increase seizure threshold 3, 6
• Discontinue trazodone due to risk of prolonged seizures 4, 6
• Stop carbamazepine as it may prevent seizure induction 4, 6
• Discontinue theophylline as it prolongs seizure duration at all levels 3, 6
• If medications cannot be stopped due to clinical necessity, continue with appropriate monitoring 3, 4

Anesthetic Medication Protocol

Step 1: Anticholinergic Premedication

Administer atropine or glycopyrrolate IV immediately before ECT to prevent vagally-induced bradycardia, arrhythmias, and potential cardiac asystole 3, 4

• This is mandatory before seizure threshold determination and before the first treatment with right unilateral electrode placement 3, 4
• Protects the cardiovascular system from vagal discharge during incomplete or missed seizures 3

Step 2: Primary Anesthetic Agent

Administer methohexital 1.0 mg/kg IV slowly over 60 seconds 1, 2, 7

• Methohexital is the preferred anesthetic agent recommended by the American Academy of Child and Adolescent Psychiatry 1
• Rapid administration may result in respiratory depression and enhanced vasopressor response 5
• The 100 mg/mL concentration must be diluted with an equal volume of Sterile Water, Normal Saline, or 5% Dextrose before IV administration 5

Alternative Anesthetic Agents (if methohexital unavailable)

• Etomidate 0.15-0.3 mg/kg IV: Produces longer seizure durations than methohexital and is advantageous in seizure-resistant patients 3, 1, 8, 9
• Ketamine 1-4.5 mg/kg IV administered slowly over 60 seconds: Alternative agent, though less commonly used 3, 5
• Thiopental sodium: Acceptable alternative but may increase seizure threshold 3, 1
• Propofol 0.75-1.5 mg/kg IV: Associated with shortest seizure durations but does not compromise antidepressant efficacy; use lowest effective dose 1, 10, 9

Step 3: Muscle Relaxation

Administer succinylcholine 0.9 mg/kg IV 1, 2, 7

• Succinylcholine is the standard muscle relaxant recommended by the American Academy of Child and Adolescent Psychiatry 1
• There is considerable variability in patient response to this drug 2

Alternative Muscle Relaxants

• Atracurium or mivacurium: Acceptable alternatives if succinylcholine is contraindicated 3, 1

Step 4: Oxygenation

Ventilate the patient with 100% oxygen before administration of the electrical stimulus 3, 1, 4

• This step is critical to prevent hypoxia-related complications during the seizure 3

During ECT Administration

Monitoring Requirements

• Continuously monitor vital signs, airway patency, seizure duration, and adverse effects 3
• Monitor for both motor and EEG seizure activity using an ECT device with EEG recording capacity 3
• Observe for purposeless and tonic-clonic movements of extremities, which do not indicate need for additional anesthetic 3

Management of Prolonged Seizures

If seizure duration exceeds 180 seconds, terminate with additional methohexital, diazepam, or lorazepam 3, 6

• Prolonged seizures are associated with greater postictal confusion, amnesia, and increased hypoxia-related risks 3
• Obtain neurology consultation if recurrent prolonged seizures or tardive seizures occur 3, 6

Post-Procedure Recovery

Immediate Recovery

• Recover the patient in a specially designated area with expert nursing care 3
• Continue monitoring until fully recovered from anesthesia 3

Extended Monitoring

• Monitor for at least 24 hours for tardive seizures that may occur after the ECT session 3, 6
• Tardive seizures are rare but potentially serious, usually occurring in patients with normal pre-treatment EEG who are not receiving seizure-lowering medications 3

Maintenance Anesthesia for Repeated Treatments

Repeat Dosing

• Administer increments of one-half to the full induction dose as needed for maintenance 3
• Adjust dose based on anesthetic needs and whether additional anesthetic agents are employed 3

Continuous Infusion Option

• Methohexital 0.1-0.5 mg/minute by slow microdrip infusion maintains general anesthesia 3
• For dilute solution: Add 10 mL of 50 mg/mL vial or 5 mL of 100 mg/mL vial to 500 mL of 5% Dextrose or Normal Saline to achieve 1 mg/mL concentration 5

Critical Pitfalls to Avoid

• Never withhold anticholinergic premedication during seizure threshold determination or first unilateral treatment, as this leaves patients vulnerable to vagally-induced cardiac complications 4
• Never administer the 100 mg/mL concentration of ketamine IV without proper dilution 5
• Never rapidly administer methohexital or ketamine, as this causes respiratory depression and enhanced vasopressor response 5
• Avoid propofol in seizure-resistant patients, as it produces the shortest seizure durations among anesthetic agents 10, 9
• Do not co-administer theophylline or aminophylline with ketamine, as this lowers seizure threshold 5

Special Population Considerations

Adolescents

• Adolescents may have lower seizure thresholds and more prolonged seizures than adults, requiring adjusted anesthetic dosing 1, 4, 6
• Consider propofol for management of prolonged seizures in this population 1
• ECT should only be administered on an inpatient basis for adolescents to better monitor treatment response and recovery 3