The Incidence and Impact of Secondary Cerebral Insults on Outcome After Aneurysmal Subarachnoid Hemorrhage

INTRODUCTION: Secondary cerebral insults can adversely affect patients with traumatic brain injury. By contrast, the incidence of secondary cerebral insults after aneurysmal subarachnoid hemorrhage (SAH) and their impact on outcome have been less well studied. METHODS: Four hundred and twenty-one patients with SAH who underwent surgical occlusion of their ruptured aneurysm and who received intensive care unit care for >= 48 hours were retrospectively identified from a prospective observational database. Patients were managed according to standard recommendations for SAH. Three secondary cerebral insults were examined: hypotension (<90 mmHg systolic), hypoxia (PaO2 < 60 mm Hg), and hyperglycemia (>200 mg/dL). RESULTS: A secondary cerebral insult was observed in 309 (73.4%) patients including 135 (32.1%) who had multiple insults. There was an association between worse clinical grade and development of secondary insults (P = 0.0002), particularly multiple insults (P < 0.0001). When stratified by clinical grade, single (adjusted odds ratio [OR], 2.23; 95% confidence interval [CI], 1.10-4.51; P = 0.026) and multiple (adjusted OR, 4.37; 95% CI, 2.14-8.93; P < 0.0001) secondary cerebral insults were associated with worse outcome. In multivariate analysis and controlling for age, admission clinical grade, severity of SAH on computed tomography, intracerebral hematoma, increased intracranial pressure (>20 mm Hg), rebleed, intraoperative rupture, and hydrocephalus, secondary cerebral insults were independently associated with poor outcome (adjusted OR, 2.45; 95% CI, 1.20-5.02; P = 0.014). CONCLUSIONS: Secondary cerebral insults (hypoxia, hypotension, and hyperglycemia) are common after SAH, including among patients with a good clinical grade. These insults after SAH are associated with worse outcome. These data suggest that prevention of secondary cerebral insults may provide an opportunity to improve patient outcome after SAH.