[1] Washington Univ, Sch Med, Dept Neurol, St Louis, MO 63110 USA
[2] Barnes Jewish Hosp, Neurol Neurosurg Intens Care Unit, St Louis, MO 63110 USA
[3] Washington Univ, Sch Med, Sect Neurol Intens Care, St Louis, MO 63110 USA
[4] Washington Univ, Sch Med, Dept Neurol Surg, St Louis, MO 63110 USA
[5] Washington Univ, Sch Med, Dept Anesthesiol, St Louis, MO 63110 USA