 When a cerebral aneurysm ruptures, the surface of the brain and its blood vessels are covered with clotted blood. This condition is called subarachnoid hemorrhage SAH. Subarachnoid hemorrhage secondary to rupture of a cerebral aneurysm is a medical condition associated with a high morbidity and mortality; approximately 10-15 of patients die before reaching medical care, and overall mortality is approximately 45. Of those that survive, 30 suffer permanent disability graded as moderate to severe, and two-thirds of survivors never return to the same quality of life as they had prior to their hemorrhage. A large number of patients 30-70 who are able to make it to the hospital and have successful treatment of their aneurysm will develop delayed cerebral vasospasm that is related to the blood clot from their initial aneurysm rupture. Of patients that survive their initial aneurysm rupture, vasospasm results in an additional 7 mortality and another 7 of severe disabilities secondary to ischemic strokes from severe spasm of cerebral arteries. 