[1] Univ Missouri, Dept Emergency Med, Div Pediat Emergency Med, Sch Med, Columbia, MO 65203 USA
[2] Washington Univ, Dept Pediat, Div Pediat Emergency Med, Sch Med, St Louis, MO USA
[3] Washington Univ, Div Biostat, Sch Med, St Louis, MO USA
[4] St Louis Childrens Hosp, Trauma Serv, St Louis, MO USA
[5] Univ Missouri, Dept Emergency Med, Sch Med, 1 Hosp Dr, Suite M562, Columbia, MO 65203 USA