Infection Associated with Global Cerebral Edema and Delayed Cerebral Ischemia in Patients with Aneurysmal Subarachnoid Hemorrhage

<b>Background/Objectives:</b> Patients with aneurysmal subarachnoid hemorrhage (SAH) experience functional impairment due to early brain injury and delayed complications. We aimed to clarify the association between cerebral edema and post-SAH infection. We investigated whether this association leads to delayed cerebral ischemia (DCI) and poor clinical outcomes. <b>Methods:</b> We included 189 patients diagnosed with aneurysmal SAH at our institution. Demographic data and data on World Federation of Neurological Surgeons (WFNS) grade, modified Fisher grade, aneurysm location, treatment methods, global cerebral edema (GCE) assessed according to Subarachnoid Hemorrhage Early Brain Edema Score (SEBES), DCI, infection, duration of hospital stay, and modified Rankin Scale at 3 months were collected. <b>Results:</b> Overall, 88 patients (46.6%) developed GCE ([SEBES] 3 or 4), while 101 patients (53.4%) did not. DCI was observed in 58 (30.7%) patients. Infectious complications occurred in 80 (42.3%) patients. Kaplan-Meier analysis results suggested a higher frequency of DCI among patients with GCE and infection than those without (<i>p</i> < 0.01). Logistic regression analysis identified GCE (<i>p</i> < 0.001, odds ratio [OR] 3.3, 95% confidence interval [CI] [1.3-8.6]), older age (<i>p</i> = 0.02, OR 2.5, 95%CI [1.2-4.9]), higher WFNS grade (<i>p</i> = 0.01, OR 3.9, 95%CI [1.5-9.5]), and mechanical ventilation use (<i>p</i> = 0.04, OR 1.4, 95%CI [1.1-3.9]) as risk factors for infection, while age (<i>p</i> = 0.03, OR 2.3, 95%CI [1.1-4.6]), WFNS grade (<i>p</i> < 0.001, OR 4.5, 95%CI [1.5-9.2]), and GCE + infection (<i>p</i> < 0.001, OR 4.1, 95%CI [1.3-8.9]) were independent risk factors for DCI. <b>Conclusions:</b> GCE-infection linkage is associated with DCI, poor clinical outcomes, and longer hospital stays in patients with aneurysmal SAH. Therefore, the EBI-DCI chain plays an important role in the postsurgical management of these patients.