Anaesthesia for cerebrovascular surgery

Abstract

Cerebrovascular surgery includes clipping of aneurysms, excision of arteriovenous malformations (AVM), carotid endarterectomy and extracranial-intracranial anastomosis. Anaesthesia for clipping of cerebral aneurysms aims to minimise the chances of rupture of the aneurysm whilst maintaining adequate cerebral perfusion. Ischaemic deficits occurring postoperatively should be actively treated by raising the cerebral perfusion pressure which may require hypervolaemic, hypertensive haemodilution. Induced hypotension is now generally avoided and profound hypothermia only used in the management of giant aneurysms. In patients with arteriovenous malformations cerebral vasospasm is not a problem so controlled hypotension can usefully be employed to reduce blood loss, which may be considerable, and prevent or treat hyperperfusion and oedema of the surrounding brain following obliteration of the AVM. Carotid endarterectomy is usually performed on patients with significant intercurrent disease, and manoeuvres aimed at optimising cerebral perfusion may have detrimental effects on a diseased heart, so compromise is required. Various methods are used to monitor cerebral perfusion during cross-clamping and the procedure may be performed under local anaesthesia to allow continuous monitoring of neurological function. Extracranial-intracranial anastomosis requires careful anaesthetic management but the operation is presently out of favour.