Abstract TP422: Prevalence and Outcome of Post-Admission Global Brain Edema in Patients with Subarachnoid Hemorrhage

Abstract

Introduction: Global cerebral edema (GCE) has been recognized in patients with aneurysmal subarachnoid hemorrhage (SAH). The pathophysiology and time course of GCE is not fully understood due to difficulties in quantitating GCE. Objective: To quantitate GCE using advanced image analysis software on serial computed tomographic (CT) scans and to determine the temporal evolution in patients with SAH. Methods: Thirty two consecutive SAH patients were identified and all the brain CT scans (n=96) which had been performed during the first week of admission were collected. Using Analyze software (AnalyzeDirect, Overland Park, KS), total brain volume was calculated in each CT scan after subtracting ventricular, gyral, and blood volumes. The difference of total brain volume between follow up and baseline CT scans calculated as GCE. The associations between GCE and patients’ demographic and clinical characteristics and hospital outcome were analyzed. Results: A total of 12 (38%) of 32 patients had GCE at 24 hour CT scan. The number increased to 14 (44%) and 17 (53%) in 48 hour and one week follow up CT scans, respectively. Mean volume of GCE was 30 ml (95% CI: 0.9-59), 39 ml (95% CI: 24-54), and 33 ml (95% CI: 22-44) in 24 hour, 48 hour, and one week follow up CT scans, respectively. Although the mean age of patients with GCE at 24 hours was higher than patients without edema, the difference was not statistically significant (56 versus 49; p=0.2). Gender, race, Fisher, Hunt and Hess scores, and in-hospital mortality were not different between patients who developed or did not develop GCE. Patients with favorable outcome (modified Rankin Scale<3) had significantly higher volume of GCE in 24 hour follow up CT scan in comparison to patients with poor outcome (mean; 95% CI: 15.6 ml; -15.6-46.8 versus 7.5 ml; 1.7-13.3, p<.0001). The volumes of GCE in 48 hour and one week follow up were also higher in patients with favorable outcomes but the difference was not significant. Conclusions: Our study demonstrated that GCE can occur in more than 50% of SAH patient during the first week with the rate of occurrence depending upon the time interval elapsed from admission.