[1] Harvard Univ, Sch Med, Childrens Hosp, Div Emergency Med, Boston, MA 02115 USA
[2] Stanford Univ, Sch Med, Lucile Salter Packard Childrens Hosp, Palo Alto, CA 94304 USA
[3] Univ Penn, Sch Med, Childrens Hosp Philadelphia, Div Neurosurg, Philadelphia, PA 19104 USA
[4] Harvard Univ, Sch Med, Childrens Hosp, Div Gen Pediat, Boston, MA USA
[5] Washington Univ, Sch Med, St Louis Childrens Hosp, Div Emergency Med, St Louis, MO USA
[6] Univ Calif Los Angeles, Sch Med, Harbor UCLA Med Ctr, Dept Emergency Med, Torrance, CA 90509 USA
[7] Indiana Univ, Sch Med, James Whitcomb Riley Hosp Children, Div Neurosurg, Indianapolis, IN USA
[8] Univ Utah, Sch Med, Primary Childrens Med Ctr, Div Emergency Med, Salt Lake City, UT USA