The goal of this study is to assess the efficacy of milrinone as an agent to treat cerebral vasospasm by adding it to standard therapy. This will take the form of a randomized, controlled trial in which patients will receive either standard hyperdynamic therapy or hyperdynamic therapy + milrinone. The hypothesis of this study is that good outcomes will be 25% more common in the experimental (milrinone) group than the control (standard therapy) group.