Feasibility study to derive a clinical decision rule for the investigation of alert patients suspected of having a non-traumatic subarachnoid haemorrhage.

Context. Subarachnoid haemorrhage is a type of haemorrhagic stroke with an annual incidence of 1 per 10,000 people and accounts for 1% of emergency department visits for acute headache. Objectives. (1) Phase 0: To determine patient characteristics, association of predictor variables with subarachnoid haemorrhage, mean length of stay determined by investigation(s) performed, and an estimate of the incidence of subarachnoid haemorrhage in alert patients with headache and normal neurological examination at the Ottawa Hospital. (2) Phase 1: To develop and pre-test standardized clinical assessments in alert patients with possible subarachnoid haemorrhage and apply these standardized clinical assessments to alert patients with possible subarachnoid haemorrhage. With these clinical assessments, determine the statistical association between the clinical findings and the diagnosis of subarachnoid haemorrhage, and develop a preliminary decision rule to determine which patients require investigation to rule out subarachnoid haemorrhage. (Abstract shortened by UMI.