Materials and methods: this study will include patients with aneurysmal SAH requiring external ventricular drainage. The investigators will perform a pragmatic randomized controlled trial: compare the standard of care, i.e. the EVD alone, to the experimental treatment, i.e. IVF, with an open design. After exclusion of the aneurysm, patients will be randomly allocated to receive either EVD alone or EVD+IVF (72 hours, 9 doses). The primary outcome will be the proportion of patients without severe disability 6 months after the aneurysm rupture, as evaluated by the modified Rankin Scale (mRS). The investigators plan to include 440 patients, to show an increase of the rate of good functional outcome of 10% in the EVD+IVF group compared to the EVD alone group (α=0.05 and β=0.8). To obtain such sample, a multicenter trial is mandatory, and to date 16 centers accepted to participate. Each center will include one patient per month, and the inclusion period is to last 48 months.