[1] Stanford Univ, Sch Med, Dept Surg, Div Emergency Med, Stanford, CA 94305 USA
[2] Univ Utah, Sch Med, Dept Surg, Div Emergency Med, Salt Lake City, UT USA
[3] Univ Texas Southwestern, Div Emergency Med, Dept Surg, Galveston, TX USA
[4] Univ Calif San Francisco, Dept Emergency Med, Fresno, CA USA
[5] Harvard Univ, Massachusetts Gen Hosp, Sch Med, Dept Emergency Med,Div Wilderness Med, Boston, MA USA
[6] Univ Colorado Hosp, Dept Emergency Med, Denver Hlth Med Ctr, Denver, CO USA
[7] Georgia Regents Univ, Dept Emergency Med, Med Coll Georgia, Augusta, GA USA
[8] Univ New Mexico, Dept Emergency Med, Albuquerque, NM 87131 USA
[9] Spartanburg Reg Med Ctr, Dept Emergency Med, Spartanburg, SC USA
[10] Alaska Reg Hosp, Dept Emergency Med, Anchorage, AK USA
[11] Wake Forest Baptist Hlth, Dept Emergency Med, Winston Salem, NC USA
[12] Columbia Univ Coll Phys & Surg, Dept Med, New York, NY 10032 USA
[13] Vet Adm Med Ctr, Div Emergency Med, Las Vegas, NV USA