Initial loss of consciousness and risk of delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage

Background and Purpose-Delayed cerebral ischemia (DCI) is a major cause of death and disability in patients with aneurysmal subarachnoid hemorrhage. W e studied the prognostic value for DCI of 2 factors: the duration of uncons ciousness after the hemorrhage and the presence of risk factors for atheros clerosis, Methods-In 125 consecutive patients admitted within 4 days after hemorrhage , we assessed the presence and duration of unconsciousness after the hemorr hage, the neurological condition on admission, the amount of subarachnoid b lood, the size of the ventricles, and a history of smoking, hypertension, s troke, or myocardial infarction. The relationship between these variables a nd the development of DCI was analyzed by means of the Cox proportional haz ards model. Results-The univariate hazard ratio (HR) for the development of DCI in pati ents who had lost consciousness for >1 hour was 6.0 (95% CI 3.0 to 12.0) co mpared with patients who had no loss or a <1-hour loss of consciousness. Th e presence of any risk factor for atherosclerosis yielded an HR of 1.4 (95% CI 0.6 to 3.5), The HR for unconsciousness remained essentially the same a fter adjustment for other risk factors for DCI, The HR for a poor World Fed eration of Neurological Surgeons score (grade IV or V) on admission was 2.9 (95% CI 1.5 to 5.5); that for a large amount of subarachnoid blood on CT w as 3.4 (95% CI 1.6 to 7.3). Conclusions-The duration of unconsciousness after subarachnoid hemorrhage i s a strong predictor for the occurrence of DCI. This observation may contri bute to a better understanding of the pathogenesis of DCI and increased att ention for patients at risk.