Disordered cerebro-vascular physiology in aneurysmal subarachnoid haemorrhage.

The technical problems of surgery for anterior circle aneurysm have in large measure been solved. The problem of reduced perfusion to the brain which characterises the patient with aneurysmal subarachnoid haemorrhage in a poor clinical condition demands more subtle physiological handling. It appears likely that maintenance of an intact cell membrane and blood brain barrier may be aided by the exhibition of pre and post-operative steriods, and that concentration on regional perfusion should be the main aim in post-operative management of such cases. This demands maintenance of adequate blood volume, avoidance of platelet stickiness, and utilisation of the pathological paralysis of autoregulation to improve flow to ischaemic zones by hypertensive agents if necessary. The possibility that early operation with evacuation of blood from the basal cisterns may in the end prevent the vascular damage and disordered vaso-reactivity which encourages the development of transient ischaemic deficits, is a concept which has to be actively pursued. The problem is a continuing one which has bedevilled aneurysm surgery for 25 years, but the omens suggest that a solution is appreciably nearer at hand.