[1] McMaster Univ, Div Emergency Med, Dept Med, Hamilton, ON, Canada
[2] McMaster Educ Res Innovat & Theory Program, Hamilton, ON, Canada
[3] Univ Toronto, Sch Med, Toronto, ON, Canada
[4] Univ Saskatchewan, Dept Emergency Med, Saskatoon, SK, Canada
[5] Northwestern Univ, Dept Emergency Med, Chicago, IL 60611 USA
[6] Univ Calif Los Angeles, David Geffen Sch Med, Greater Los Angeles VA Healthcare Syst, Div Emergency Med, Los Angeles, CA 90095 USA
[7] Univ Calif Los Angeles, David Geffen Sch Med, Dept Emergency Med, Los Angeles, CA 90095 USA