Anesthesia for Electroconvulsive Therapy

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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.

EEG waveform during ECT seizure phases

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_._

Practice Questions: Anesthesia for Electroconvulsive Therapy

Test your understanding with these related questions

A 72 year old lady is severely depressed. For the past 2 days she has suicidal thoughts with an actual intent to die. Which of the following is best suitable to alleviate the symptoms?

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Flashcards: Anesthesia for Electroconvulsive Therapy

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Symptoms such as metallic taste, perioral numbness, visual changes, twitching, and seizures in a patient on local anesthesia point towards _____

TAP TO REVEAL ANSWER

Symptoms such as metallic taste, perioral numbness, visual changes, twitching, and seizures in a patient on local anesthesia point towards _____

local anesthetic systemic toxicity (LAST)

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