[1] Yale Sch Med, Dept Emergency Med, New Haven, CT 06520 USA
[2] Yale Sch Med, Ctr Outcomes Res & Evaluat, New Haven, CT USA
[3] Harvard Med Sch, Massachusetts Gen Hosp, Dept Emergency Med, Boston, MA USA
[4] Stanford Univ, Sch Med, Dept Emergency Med, Stanford, CA USA
[5] Univ Texas Southwestern Med Ctr, Dept Emergency Med, Dallas, TX USA
[6] UCLA, Dept Emergency Med, David Geffen Sch Med, Torrance, CA USA
[7] Univ Cincinnati, Dept Emergency Med, Cincinnati, OH USA
[8] Univ Washington, Dept Emergency Med, Seattle, WA USA
[9] Rutgers New Jersey Med Sch, Dept Emergency Med, Newark, NJ USA
[10] Washington Univ, Dept Emergency Med, Sch Med St Louis, St Louis, MO USA