[1] Boston Childrens Hosp, Div Emergency Med, Boston, MA USA
[2] Univ Penn, Perelman Sch Med, Philadelphia, PA USA
[3] Vot ER, Boston, MA USA
[4] Univ Calif San Francisco, Dept Emergency Med, San Francisco, CA USA
[5] Univ Calif San Francisco, Dept Emergency Med, San Francisco, CA USA
[6] Harvard Med Sch, Dept Pediat, Boston, MA USA
[7] Childrens Hosp Philadelphia, Dept Pediat, Philadelphia, PA USA
[8] Harvard Med Sch, Dept Emergency Med, Boston, MA USA
[9] Boston Childrens Hosp, Div Emergency Med, 300 Longwood Ave,BCH 3066, Boston, MA 02115 USA