[1] Univ Ottawa, Dept Med, Ottawa, ON, Canada
[2] Univ Ottawa, Dept Emergency Med, Ottawa, ON, Canada
[3] Univ Ottawa, Ottawa Hlth Res Inst, Ottawa, ON, Canada
[4] Queens Univ, Dept Emergency Med, Kingston, ON, Canada
[5] Univ Alberta, Div Emergency Med, Edmonton, AB, Canada
[6] London Hlth Sci Ctr, Dept Emergency Med, London, ON, Canada
[7] St Michaels Hosp, Toronto, ON M5B 1W8, Canada