[1] Univ Calif Davis, Sch Med, Dept Emergency Med, Sacramento, CA 95817 USA
[2] Boston Childrens Hosp, Div Pediat Emergency Med, Boston, MA USA
[3] Harvard Univ, Sch Med, Boston, MA USA
[4] Boston Childrens Hosp, Dept Anesthesiol Perioperat & Pain Med, Boston, MA USA
[5] Univ Calif Davis, Sch Med, Dept Surg, Div Trauma & Emergency Surg, Sacramento, CA 95817 USA
[6] Univ Calif Davis, Sch Med, Dept Pediat, Sacramento, CA 95817 USA