[1] North York Gen Hosp, Toronto, ON, Canada
[2] Ohio State Univ, Columbus, OH 43210 USA
[3] McGill Univ, Montreal, PQ, Canada
[4] Bystander Partner, Beijing, Peoples R China
[5] Johns Hopkins Univ, Sch Med, Baltimore, MD 21218 USA
[6] Univ Toronto, Toronto, ON, Canada
[7] Ctr Resuscitat Sci, Philadelphia, PA USA
[8] Virginia Commonwealth Univ Hlth Syst, Richmond, VA USA
[9] William Beaumont Hosp, Southfield, MI USA