Cerebral vasospasm following subarachnoid haemorrhage (SAH) is the leading potentially treatable cause of morbidity and mortality in patients who experience the rupture of an intracranial aneurysm.1,2 A significant predictor of outcome in patients with aneurysmal SAH, cerebral vasospasm

Cerebral vasospasm following subarachnoid haemorrhage (SAH) is the leading potentially treatable cause of morbidity and mortality in patients who experience the rupture of an intracranial aneurysm.1,2 A significant predictor of outcome in patients with aneurysmal SAH, cerebral vasospasm is radiographically present in up to 70% of patients and is clinically evident in 20–30%.1,3 Annually, between seven and 20 people per 100,000 will experience a ruptured intracranial aneurysm.4–6 Fifty per cent of these patients will eventually die, while 15% will be rendered severely disabled. Only one-fifth to one-third of patients who experience a ruptured intracranial aneurysm will go on to have a moderate or good recovery.7,8 In large part, this poor prognosis is due to the significant death and disability associated with vasospasm. Approximately 50% of patients with symptomatic vasospasm will develop infarctions, and 15–20% will develop a disabling stroke or die of ischaemia.9,10