Short- and long-term prognosis of patients with a subarachnoid haemorrhage in relation to intra-operative period of hypotension.

112 patients operated on for an intracranial aneurysm were surveyed. The immediate (up to 3 days from surgery) and late (from 3 days onwards and up to 2 years) outcome was examined in relation to the level and duration of per-operative hypotension as well as technical difficulties. The risk of both immediate and late post-operative neurological deficit was increased when the systolic blood pressure was pharmacologically reduced below the level of 60 mm Hg. The duration of such hypotension had a similar influence. A proportion of patients, following subarachnoid haemorrhage, respond poorly to hypotension and identification of these "vulnerable perfusers" by bedside cerebral blood flow or other monitoring procedures may be useful.