[1] Univ Penn, Perelman Sch Med, Dept Neurol, 3400 Spruce St, Philadelphia, PA 19104 USA
[2] Univ Penn, Perelman Sch Med, 3400 Spruce St, Philadelphia, PA 19104 USA
[3] Univ Penn, Ctr Resuscitat Sci, Perelman Sch Med, Dept Emergency Med, 3400 Spruce St, Philadelphia, PA 19104 USA
[4] Univ Penn, Perelman Sch Med, Dept Neurol, Div Neurocrit Care, 3400 Spruce St, Philadelphia, PA 19104 USA