[1] Univ Ottawa, Ottawa Hlth Res Inst, Dept Emergency Med, Ottawa, ON, Canada
[2] Medtron Emergency Response Syst, Redmond, WA USA
[3] Univ Ottawa, Ottawa Hlth Res Inst, Clin Epidemiol Program, Ottawa, ON, Canada
[4] Univ British Columbia, Vancouver, BC V5Z 1M9, Canada
[5] Windsor Base Hosp, Windsor, ON, Canada
[6] Emergency Med Serv, Edmonton, AB, Canada
[7] Vancouver Fire Dept, Vancouver, BC, Canada
[8] Univ Ottawa, Ottawa Hlth Res Inst, Dept Epidemiol & Community Med, Ottawa, ON, Canada