[1] Univ Vermont, Div Emergency Med, Med Ctr, Burlington, VT 05405 USA
[2] Univ Utah, Sch Med, Div Emergency Med, Salt Lake City, UT USA
[3] Harvard Med Sch, Harvard Affiliated Emergency Med Residency, Dept Emergency Med, Massachusetts Gen Hosp,Brigham & Womens Hosp, Boston, MA 02115 USA
[4] Columbia Univ, Dept Emergency Med, Valegos Coll Phys & Surg, New York, NY USA
[5] Univ Florida, Coll Med Jacksonville, Dept Emergency Med, Jacksonville, FL USA
[6] Northwestern Univ, Dept Emergency Med, Chicago, IL 60611 USA
[7] Univ Calif San Francisco Fresno, Dept Emergency Med, Fresno, CA USA
[8] Rush Univ, Dept Emergency Med, Med Ctr, Chicago, IL 60612 USA