[1] Brown Univ, Dept Emergency Med, Warren Alpert Med Sch, Providence, RI 02912 USA
[2] Oregon Hlth & Sci Univ, Dept Emergency Med, Portland, OR 97201 USA
[3] Boston Univ, Sch Med, Dept Emergency Med, Boston, MA 02118 USA
[4] Yale Univ, Sch Med, Dept Emergency Med, New Haven, CT USA
[5] Univ Colorado, Sch Med, Dept Emergency Med, Denver Hlth, Denver, CO USA
[6] Univ S Florida, Morsani Coll Med, Lehigh Valley Hosp, Dept Emergency Med, Allentown, PA USA
[7] Univ Penn, Sch Med, Dept Emergency Med, Philadelphia, PA 19104 USA
[8] Texas Tech Univ, Hlth Sci Ctr, Dept Emergency Med, El Paso, TX USA
[9] Univ Massachusetts, Sch Med, Dept Emergency Med, Worcester, MA USA
[10] Boston Univ, Sch Publ Hlth, Dept Community Hlth Sci, Boston, MA USA
[11] Univ Massachusetts, Sch Med, Dept Med, Worcester, MA USA