[1] Univ Maryland, Sch Med, Dept Emergency Med, Baltimore, MD 21201 USA
[2] Univ Maryland, Sch Med, Program Trauma, R Adams Cowley Shock Trauma Ctr, Baltimore, MD 21201 USA
[3] Univ Maryland, Sch Med, Dept Emergency Med, Res Associate Program Emergency Med & Crit Care, Baltimore, MD 21201 USA
[4] George Washington Univ, Sch Med & Hlth Sci, Dept Emergency Med, 2120 L St, Washington, DC 20037 USA