The purpose of this study is to determine if giving blood transfusions to anemic patients with subarachnoid hemorrhage will reduce their chances of having a stroke from vasospasm.
Inclusion Criteria: 1. Aneurysmal SAH confirmed by angiography 2. Hemoglobin \< 12.5 gm/dl 3. One of the following: * Considered at increased risk for vasospasm by care team * Angiographic vasospasm * Delayed ischemic deficit 4. Able to be studied within 2 weeks after subarachnoid hemorrhage Exclusion Criteria: 1. Active Coronary Artery Disease 2. Severe congestive heart failure 3. Jehovah's witness 4. Unable to obtain appropriately matched blood 5. Other contraindications for transfusion 6. Pregnancy