[1] Univ Toronto, Temerty Fac Med, Toronto, ON, Canada
[2] Univ Toronto, Dalla Lana Sch Publ Hlth, Toronto, ON, Canada
[3] Mackenzie Hlth, Dept Emergency Med, Richmond Hill, ON, Canada
[4] Univ Toronto, Dept Med, Div Emengency Med, Toronto, ON, Canada
[5] Univ Hlth Network, Dept Emergency Med, Toronto, ON, Canada
[6] McMaster Univ, Dept Family Med, Hamilton, ON, Canada