Effect of cerebrospinal fluid drainage on clinical outcomes following aneurysmal subarachnoid hemorrhage

We study the relationship between external ventricular drainage (EVD) of cerebrospinal fluid output and functional outcomes in patients with aneurysmal subarachnoid hemorrhage (aSAH).A retrospective chart review of patients presenting to a single center with aSAH was performed. The primary outcome was good functional outcomes assessed by a composite of the modified Rankin scale (mRS 0-2) at last follow-up. Secondary outcomes were clinical and radiographic vasospasm. For data analysis, multivariable generalized estimating equations adjusting for potential confounders were used.A total of 119 patients were included; 91 (75.6%) presented with a modified Fisher grade 4 and 76 (63.9%) had hydrocephalus. The median EVD duration was 13 days. On average, most EVDs were set at 15 cmH2O (50, 42%). Follow-up was available in 109 patients; median time was 10.7 months; 69 (63.3%) had good outcomes. Multivariable analysis showed that EVDs set at 10 cmH2O had increased odds of good outcomes for every ml increase in the EVD output (OR = 1.02; 95% CI 1.01-1.03; p = 0.001). Post estimation analyses show that EVDs at 10 cmH2O with output close to 200 ml predicted a 50% probability of good outcomes.Increased EVD outputs were associated with favorable outcomes at the last follow-up.