[1] Univ Hlth Network UHN, Toronto, ON, Canada
[2] Rush Univ, Dept Emergency Med, Med Ctr, Chicago, IL USA
[3] Advocate Christ Med Ctr, Dept Emergency Med, Oak Lawn, IL USA
[4] Univ Illinois, Dept Emergency Med, Chicago, IL USA
[5] Univ Manitoba, Winnipeg, MB, Canada