[1] Northwestern Univ, Ann & Robert H Lurie Childrens Hosp Chicago, Feinberg Sch Med, Div Emergency Med, Chicago, IL USA
[2] Osaka Univ, Grad Sch Med, Dept Integrated Med, Div Biomed Stat, Osaka, Japan
[3] UPMC Childrens Hosp Pittsburgh, Div Emergency Med, Pittsburgh, PA USA
[4] ESO, Austin, TX USA
[5] Univ Pittsburgh, Sch Med, Dept Emergency Med, Pittsburgh, PA USA
[6] Ann & Robert H Lurie Childrens Hosp Chicago, Dept Pediat, Div Pediat Emergency Med, 225 E Chicago Ave,Box 62, Chicago, IL 60611 USA