[1] Univ Michigan, Med Sch, Dept Emergency Med, Ann Arbor, MI 48109 USA
[2] Wake Forest Sch Med, Dept Emergency Med, Winston Salem, NC USA
[3] North Shore Univ Hosp, Dept Emergency Med, Manhasset, NY USA
[4] Virginia Commonwealth Univ, Sch Med, Dept Emergency Med, Richmond, VA USA