[1] UCLA, Dept Emergency Med, David Geffen Sch Med, Los Angeles, CA 90095 USA
[2] Rush Univ, Dept Emergency Med, Med Ctr, Chicago, IL USA
[3] Univ Massachusetts, Med Sch Baystate, Inst Healthcare Delivery & Populat Sci, Dept Emergency Med, Springfield, MA USA
[4] Weill Cornell Med Sch, Dept Emergency Med, New York, NY USA
[5] George Washington Univ, Dept Emergency Med, Washington, DC USA
[6] Georgetown Univ, Washington, DC USA