[1] St Michaels Hosp, 30 Bond St, Toronto, ON M5B 2Y9, Canada
[2] Univ Ottawa, Dept Emergency Med, Ottawa Hosp Res Inst, Ottawa, ON, Canada
[3] Univ Western Ontario, Dept Pediat & Med, Pediat Emergency Med, London, ON, Canada
[4] Univ Alberta, Dept Emergency Med, Edmonton, AB, Canada
[5] Univ Saskatchewan, Dept Emergency Med, Saskatoon, SK, Canada
[6] Univ Toronto, Dept Family & Community Med, Div Emergency Med, Toronto, ON M5S 1A1, Canada
[7] North York Gen Hosp, Toronto, ON, Canada
[8] Dalhousie Univ, Fac Med, Clin Res Ctr, Halifax, NS, Canada
[9] Univ Ottawa, Childrens Hosp Eastern Ontario, Dept Pediat Med Educ, Ottawa, ON, Canada
[10] Ornge, Mississauga, ON, Canada
[11] Vancouver Isl Hlth Author, Victoria, BC, Canada
[12] Coll Phys & Surg Ontario, Toronto, ON, Canada
[13] Canadian Assoc Emergency Phys, Ottawa, ON, Canada
[14] Univ British Columbia, Vancouver Gen Hosp, Dept Emergency Med, JPPN, Vancouver, BC V5Z 1M9, Canada