[1] Washington Univ, Sch Med St Louis, Dept Emergency Med, One Brookings Dr, St Louis, MO 63130 USA
[2] Univ Western Australia, Dept Emergency Med, Perth, WA, Australia
[3] Harry Perkins Inst Med Res, Ctr Clin Res Emergency Med, Perth, WA, Australia
[4] John Hunter Hosp, Emergency Dept, Newcastle, NSW, Australia
[5] Univ Newcastle, Fac Hlth & Med, Dept Emergency Med, Newcastle, NSW, Australia
[6] Liverpool Hosp, Dept Emergency Med, Liverpool, NSW, Australia
[7] Univ Sydney, Sch Med, Dept Emergency Med, Sydney, NSW, Australia
[8] Harvard Univ, Brigham & Womens Hosp, Sch Med, Dept Surg, Boston, MA 02115 USA
[9] Princess Alexandra Hosp, Brisbane, Qld, Australia
[10] Univ Queensland, Sch Med, Dept Emergency Med, Brisbane, Qld, Australia