[1] McMaster Univ, Dept Med, Div Emergency Med, 1280 Main St West, Hamilton, ON L8S 4L8, Canada
[2] Univ British Columbia, Dept Emergency Med, Kelowna, BC, Canada
[3] Queens Univ, Dept Emergency Med, Kingston, ON, Canada
[4] Univ Ottawa, Dept Emergency Med, Ottawa, ON, Canada
[5] Univ Saskatchewan, Dept Med, Dept Emergency Med, Saskatoon, SK, Canada
[6] Univ British Columbia, Dept Emergency Med, Vancouver, BC, Canada
[7] Oregon Hlth & Sci Univ, Dept Emergency Med, Portland, OR USA