[1] Univ Florida, Coll Med, Dept Emergency Med, Gainesville, FL 32610 USA
[2] Baylor Coll Med, Texas Childrens Hosp, Div Emergency Med, Houston, TX USA
[3] Univ Washington, Seattle Childrens Res Inst, Sch Med, Dept Pediat, Seattle, WA USA
[4] Seattle Childrens Res Inst, Ctr Child Hlth Behav & Dev, Seattle, WA USA