ECT Anesthesia — Methohexital, Sux, Lithium, Hemodynamic Surge

Electroconvulsive therapy (ECT) delivers a brief electrical stimulus (0.5-8 s) via bilateral or right unilateral electrodes to induce a generalized tonic-clonic seizure lasting 25-90 s.

Typical course: 6-12 treatments over 3-4 weeks, then maintenance.

Each session is ~10-15 min from induction to recovery.

Methohexital 0.75-1 mg/kg IV is the historical and still-preferred induction agent because it raises seizure threshold less than other agents (allows lower stimulus charge → fewer cognitive side effects).

Modern practice when methohexital unavailable: propofol 0.75-1 mg/kg with acceptance of slightly shorter seizure, or etomidate 0.15-0.3 mg/kg if seizures have been inadequate.

Avoid benzodiazepines (raise threshold + shorten seizure).

Sux 0.5-1 mg/kg IV attenuates the motor convulsion enough to prevent musculoskeletal injury (long-bone fracture historically reported pre-NMB era) while still permitting some visible activity.

Onset 30-60 s; ideal for the brief duration.

To monitor seizure duration when sux is given, inflate a BP cuff or tourniquet on one limb (foot or forearm) to suprasystolic 50 mmHg ABOVE SBP BEFORE giving sux — the limb is excluded from circulation, sux does not reach the muscle, and overt motor seizure activity is visible there.

Deflate when stimulus ends.

EEG monitoring is the alternative + complementary monitor — EEG seizure typically lasts longer than motor seizure.

Glycopyrrolate 0.2 mg IV or atropine 0.4-0.6 mg IV pretreatment if history of significant bradycardia, vagal pause >6 s, or in patients on beta-blockers.

Phase 2 (sympathetic, during + immediately after seizure): tachycardia to 130-150, BP rise 30-40%, increased myocardial O2 demand.

In CAD or aneurysm patients, attenuate with esmolol 0.5-1 mg/kg or labetalol 0.1-0.3 mg/kg or remifentanil 1 mcg/kg pre-stimulus.

Avoid excessive blunting — sustained hypotension shortens seizure.

Nitroglycerin paste pretreatment is a simple low-tech option for chronic HTN.

Lithium prolongs the duration of both succinylcholine and nondepolarizing NMB paralysis (mechanism: inhibits presynaptic ACh release + alters Na/K flux at NMJ) and prolongs seizure duration.

Many anesthesiologists hold lithium for 24-48 h before ECT or reduce sux dose by ~50% (0.3-0.5 mg/kg).

Document timing of last dose.

ICDs: deactivate tachy detection with magnet before stimulus (myopotentials from seizure can trigger inappropriate shock); reactivate after.

Pregnancy: ECT is safe in all trimesters and often preferred over medications in severe depression; left-lateral tilt after 20 wk, aspiration prophylaxis (sodium citrate 30 mL PO + ranitidine), continuous FHR monitoring during/after, tocolysis if uterine activity.

Patients with intracranial aneurysm or recent stroke: relative contraindication; aggressive BP control essential.