[1] Rush Univ, Med Ctr, Dept Emergency Med, 1750 West Harrison St,Suite 108 Kellogg, Chicago, IL 60612 USA
[2] Univ Iowa, Carver Coll Med, Iowa City, IA USA
[3] Univ Michigan, Sch Med, Dept Emergency Med, Ann Arbor, MI USA
[4] Allegheny Hlth Network, Dept Emergency Med, Erie, PA USA
[5] Ohio State Univ, Wexner Med Ctr, Dept Emergency Med, Columbus, OH 43210 USA
[6] Yale Sch Med, Dept Emergency Med, New Haven, CT USA
[7] Virginia Commonwealth Univ, Sch Med, Dept Emergency Med, Richmond, VA USA