All adult subjects who have a subarachnoid hemorrhage from a ruptured aneurysm and require high levels of sedation, or a poor neurologic exam and mechanical ventilation will be eligible for the study. Hunt and Hess Grade 4 and 5(worst grades; highest mortality; highest level of dependence if survived) subarachnoid hemorrhage subjects by definition have a severely depressed exam, and will require intubation and mechanical ventilation. Those subjects whose respiratory status deteriorates necessitating intubation and high levels of sedation will also qualify.