Medical management

Preoperative medication and fluid management is an important aspect of SAH care. We initially attempt to normalise the patient's intravascular volume status and do not prophylactically induce hypervolaemia since its institution has been shown to be potentially hazardous and offers no clear benefit.159 Administered medications include anticonvulsants, corticosteroids, calcium channel blockers, antihypertensives, and analgesics. Strict attention to blood pressure control prior to aneurysm surgery has been shown to reduce the rate of aneurysm rebleeding.160 For patients who are hypertensive and have risk factors for coronary artery disease, the addition of a beta-blocker perioperatively will significantly reduce the risk of perioperative cardiac complications. The effect of calcium channel blockers on outcome is less clear. Reports show that prophylactic use of these agents does not prevent angiographic vasospasm but may decrease the overall management morbidity following SAH.161-163 In light of the referenced reports on calcium channel blocking agents, we place all patients on this drug immediately upon admission to the hospital. Further studies need to be performed on this important issue.

The administration of antifibrinolytics designed to minimise clot lysis is controversial.164-167 Epsilon-aminocaproic acid (AMICAR) is one of the more widely used medications which primarily inhibits the conversion of plasminogen into plasmin, the main function of which is to digest fibrin and aid in clot lysis. Intravenous injection of AMICAR provides a peak plasma level within 20 minutes. The drug crosses the blood-brain barrier and achieves maximal antifibrinolytic activity within the CSF 48 hours after therapy is initiated.167 Patients are given 2 g per hour intravenously for 48 hours, then 15 g per hour for the duration of therapy or until surgery is performed. Review of the 1966 Cooperative Study found a reduction in rehaemorrhage and death at 14 days from 21% to 10% with the use of antifibrinolytics.168 Although antifibrinolytic therapy decreases rebleeding by 50% during the first two weeks following SAH, there is an increase in associated medical complications, the most frequent of which is diarrhoea, occurring in 24% of patients. Communicating hydrocephalus is 25% more frequent with antifibrinolytic therapy.169 The greatest concern over use of antifibrinolytic agents is the associated increase in ischaemic neurological deficits that has negated its benefits in some studies.164 Our feeling is that antifibrinolytics have little role in acute aneurysmal SAH if surgery is anticipated within two days of admission. These agents may be of value if an operative procedure is delayed longer than 48 hours. Their efficacy when used in conjunction with calcium channel blockers has yet to be studied.

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