A patient with known phaeochromocytoma is under pre-operative alpha-blockade with phenoxybenzamine for 2 weeks. During intraoperative tumour manipulation, the anaesthetist notes a sudden blood pressure rise to 240/130 mmHg. What is the FIRST-LINE agent to control this hypertensive crisis?
- A IV labetalol 20 mg
- B IV esmolol infusion
- C IV hydralazine 10 mg
- D IV phentolamine 2–5 mg boluses ✓
Explanation
Phentolamine is a short-acting, competitive, non-selective alpha-adrenergic antagonist and is the agent of choice for intraoperative hypertensive crises during phaeochromocytoma resection. It rapidly counteracts the massive catecholamine surge from tumour manipulation. Labetalol (alpha+beta blocker) is an alternative, but giving a beta-blocker before adequate alpha-blockade is established risks paradoxical severe hypertension from unopposed alpha stimulation. Esmolol (pure beta-blocker) would be inappropriate as first-line because the crisis is alpha-mediated. Nitroprusside infusion is an effective alternative when phentolamine is not available.
Reference: Morgan & Mikhail's Clinical Anesthesiology, 6th ed.
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