A patient with hypertrophic obstructive cardiomyopathy (HOCM) requires appendicectomy under general anaesthesia. During induction, sudden severe hypotension occurs. Which combination of management steps is MOST appropriate?

• A Increase IV fluid bolus + dobutamine infusion + Trendelenburg positioning
• B Glyceryl trinitrate infusion + tachycardia induction + reduce anaesthetic depth
• C IV fluid bolus + phenylephrine (pure alpha agonist) + increase anaesthetic depth ✓
• D Adrenaline 0.5 mg IM + atropine 0.6 mg IV + defibrillation standby

Explanation

HOCM has dynamic LVOT obstruction that worsens with decreased preload, decreased afterload, increased contractility, and tachycardia. For hypotension in HOCM: increase preload (IV fluids), increase afterload with pure vasopressors (phenylephrine is ideal — no beta-agonist activity avoids tachycardia/increased contractility), and maintain bradycardia. Deepening anaesthesia reduces sympathetic drive. Dobutamine is absolutely contraindicated — its positive inotropic and chronotropic effects worsen LVOT obstruction catastrophically. GTN reduces afterload and preload, both harmful. Adrenaline's beta-agonism worsens obstruction.

Reference: Morgan & Mikhail's Clinical Anesthesiology, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.