[1] Sunnybrook Ctr Prehosp Med, 77 Browns Line,Suite 100, Toronto, ON M8W 3S2, Canada
[2] Univ Toronto, Div Emergency Med, Dept Family & Community Med, Toronto, ON, Canada
[3] St Michaels Hosp, Li Ka Shing Knowledge Inst, Toronto, ON, Canada
[4] Univ Ottawa, Ottawa Hosp Res Inst, Dept Emergency Med, Ottawa, ON, Canada