Anesthesia for Electroconvulsive Therapy

ECT Overview & Pre-Op - Shocking Start

• ECT: Therapeutic induction of generalized seizure for psychiatric conditions.
• Key Indications:
  • Major Depressive Disorder (severe, treatment-resistant, psychotic features).
  • Catatonia.
  • Acute Mania, Schizophrenia (selected cases).
• Absolute Contraindications:
  • Pheochromocytoma.
  • Recent Myocardial Infarction (<4-6 weeks).
  • Recent Cerebrovascular Accident (<3 months).
  • Intracranial mass lesion or significantly ↑ Intracranial Pressure (ICP).
• Pre-Anesthetic Check:
  • Informed consent, ASA status.
  • History: CVS, CNS, medications (e.g., Lithium, MAOIs, Theophylline - ⚠️ interactions).
  • Airway assessment.
  • NPO: 6-8 hours for solids, 2 hours for clear fluids.
  • Premedication: Glycopyrrolate (↓secretions, ↓bradycardia).

⭐ Classic cardiovascular response to ECT: Initial brief bradycardia/asystole, then marked sympathetic surge (↑HR, ↑BP, ↑myocardial oxygen demand).

Anesthetic Goals & ECT Physiology - Balancing Act

• Anesthetic Goals:
  • Rapid induction & emergence
  • Profound amnesia
  • Muscle relaxation (prevent injury)
  • Attenuate CV responses
  • Adequate seizure duration (typically >25s)
  • Minimize agitation
• ECT Physiology: Biphasic autonomic surge:
  • Initial Parasympathetic Phase (<1 min):
    • Bradycardia, hypotension, salivation.
    • Rarely asystole.
  • Subsequent Sympathetic Phase (several mins):
    • Tachycardia, hypertension.
    • ↑HR, ↑BP, ↑CBF, ↑ICP, ↑IOP, ↑CMRO2.
• Balancing Act: Anesthetic choice critical.
  • Facilitate therapeutic seizure.
  • Protect patient: manage hemodynamics, prevent injury.

⭐ The hallmark physiological response to ECT is an initial brief parasympathetic discharge (bradycardia, asystole risk) followed by a significant sympathetic surge (tachycardia, hypertension).

ECT Pharmacology - Potion Protocol

• Anticholinergics (Premedication): ↓ secretions, prevent bradycardia.
  • Glycopyrrolate: 0.2-0.4 mg IV. Peripheral action.
  • Atropine: 0.4-0.6 mg IV. Crosses BBB.
• Induction Agents: Rapid onset, short duration.
  • Methohexital: 0.75-1.5 mg/kg IV. Gold standard, pro-convulsant.
  • Propofol: 0.5-1.5 mg/kg IV. Antiemetic; ↑ seizure threshold, hypotension.
  • Etomidate: 0.15-0.3 mg/kg IV. Hemodynamic stability; myoclonus.
  • Thiopentone: 2-4 mg/kg IV. Rapid; anticonvulsant.
  • Ketamine: 0.5-1 mg/kg IV. Analgesic; ↑ secretions, psychomimetic.
• Muscle Relaxants: Attenuate motor response.
  • Succinylcholine: 0.5-1.0 mg/kg IV. Standard; rapid, short. Risks: fasciculations, ↑K+.
  • Rocuronium: 0.3-0.6 mg/kg IV. If succinylcholine C/I. Longer duration.

⭐ Methohexital is favored for ECT: enhances seizure quality/duration; propofol significantly ↑ seizure threshold.

ECT Technique & Recovery - Smooth Sailing

• Pre-Procedure: NPO 6-8h, consent, IV access. Glycopyrrolate (0.2-0.4mg IV) for secretions/bradycardia.
• Anesthesia:
  • Preoxygenate: 100% O2, 3-5 min.
  • Induction: Methohexital (0.75-1mg/kg IV) preferred; Propofol (0.5-1mg/kg IV) alternative.
  • Muscle Relaxant: Succinylcholine (0.5-1mg/kg IV).
  • Airway: Bite block, bag-mask ventilation.
• Monitoring:
  • Standard ASA: ECG, NIBP, SpO2, (EtCO2).
  • EEG: Seizure duration goal 25-120s.

  ⭐ EEG seizure duration (25-120s) is the primary measure of ECT adequacy. Motor seizure (>15s) can be assessed via cuff technique if relaxants used.

• Recovery:
  • Oxygen, vital signs monitoring.
  • Manage headache, myalgia, nausea.
  • Orientation assessment.

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High‑Yield Points - ⚡ Biggest Takeaways

• ECT induces a generalized seizure; anesthesia provides amnesia, muscle relaxation, and hemodynamic stability.
• Induction agents: Methohexital (classic), propofol (common, may ↓ seizure duration), etomidate (CV stable).
• Succinylcholine is standard for muscle relaxation to prevent injury.
• Biphasic CV response: Initial parasympathetic (bradycardia) then sympathetic surge (tachycardia, hypertension).
• Manage CV changes: Glycopyrrolate for bradycardia, β-blockers (esmolol) for tachycardia/hypertension.
• EEG monitoring confirms adequate seizure duration (>25s).
• Raised ICP is an absolute contraindication_._