Inclusion Criteria:  Patients undergoing craniotomy who are at an increased risk for developing post- operative brain swelling or increased intracranial pressure from a malignant stroke Patients undergoing craniotomy who are at an increased risk for developing post- operative brain swelling or increased intracranial pressure from traumatic brain injury Patients undergoing craniotomy who are at an increased risk for developing post- operative brain swelling or increased intracranial pressure from brain tumors.  Exclusion Criteria:  Patients with blown pupil (cerebral herniation), Massive brain swelling Dismal outcome not expected to survive more than 1-2 weeks.