Following a subarachnoid haemorrhage, cerebral vasospasm is MOST likely to occur during which time window after the initial bleed?

• A Immediately (0–24 hours)
• B 2–4 weeks post-bleed
• C Days 4–14 post-bleed ✓
• D After 4 weeks, as a late complication

Explanation

Cerebral vasospasm after aneurysmal subarachnoid haemorrhage typically occurs between days 4 and 14, with a peak incidence around days 6–8. The pathophysiology involves haemoglobin degradation products (oxyhaemoglobin) inducing endothelial dysfunction, release of endothelin-1 and free radicals, causing arterial smooth muscle contraction. Anaesthetic management during this window requires maintenance of adequate cerebral perfusion pressure; the 'triple-H' therapy (hypertension, hypervolaemia, haemodilution) was traditionally used, though current practice favours euvolaemia with induced hypertension if vasospasm is symptomatic.

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

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Written and medically reviewed by the StethoPrep medical team.