on Outcome Global Cerebral Edema After Subarachnoid Hemorrhage: Frequency, Predictors, and

Background and Purpose —Cerebral edema visualized by CT is often seen after subarachnoid hemorrhage (SAH). Inflammatory or circulatory mechanisms have been postulated to explain this radiographic observation after SAH. We sought to determine the frequency, causes, and impact on outcome of early and delayed global cerebral edema after SAH. Methods —We evaluated the presence of global edema on admission and follow-up CT scans in 374 SAH patients admitted within 5 days of onset to our Neurological Intensive Care Unit between July 1996 and February 2001. Using multivariate analysis, we identified predictors of global cerebral edema and evaluated the impact of global edema on outcome 3 months after onset with the modified Rankin Scale. Results —Global edema was present on admission CT scans in 8% (n (cid:1) 29) and developed secondarily in 12% (n (cid:1) 44) of the patients. Global edema on admission was predicted by loss of consciousness at ictus and increasing Hunt-Hess grade. Delayed global edema was predicted by aneurysm size (cid:2) 10 mm, loss of consciousness at ictus, use of vasopressors, and increased SAH sum scores. Thirty-seven percent (n (cid:1) 137) of the patients were dead or severely disabled (modified Rankin Scale 4 to 6) at 3 months. Death or severe disability was predicted by any global edema, aneurysm size (cid:2) 10 mm, loss of consciousness at ictus, increased National Institutes of Health Stroke Scale scores, and older age. Conclusions —Global edema is an independent risk factor for mortality and poor outcome after SAH. Loss of consciousness, which may reflect ictal cerebral circulatory arrest, is a risk factor for admission global edema, and vasopressor-induced hypertension is associated with the development of delayed global edema. Critical care management strategies that minimize edema formation after SAH may improve outcome. ( Stroke and chronic health We whether patients were during hospitalization and documented on We identified patients We also recorded and TCD findings, mode treatment (clipping versus whether any vasopres- sors were used after surgery, and whether vasopressors were used specifically to treat symptomatic vasospasm (HHT). t tests for normally distributed continuous variables, and Mann-Whitney U tests for nonnormally distributed continuous variables. Among similar variables that were highly intercorrelated (ie, clinical scales), only the variable with the highest odds ratio (OR) and smallest P value in the binary logistic regression analysis was used as a candidate variable in the final multivariate model. Independent predictors of admission global edema, delayed global edema, any global edema, death at 3 months, and death or severe disability at 3 months were identified with backward stepwise multiple logistic regression analysis. We ex-plored 2-way interaction terms among all variables with independent predictive value. When significant 2-way interactions were identified, we reanalyzed the predictive value of each factor after strati- fying the analysis between the 2 levels of the other factor. Because of the large number of statistical tests performed, significance was judged at P (cid:3) 0.01.