[1] St Michaels Hosp, Dept Med, Toronto, ON M5B 1W8, Canada
[2] St Michaels Hosp, Dept Anesthesia & Crit Care Med, Toronto, ON M5B 1W8, Canada
[3] St Michaels Hosp, Keenan Res Ctr, Li Ka Shing Knowledge Inst, Toronto, ON M5B 1W8, Canada
[4] Univ Toronto, Dept Med, Div Emergency Med, Toronto, ON, Canada
[5] Univ Toronto, Div Gen Med, Toronto, ON, Canada
[6] Univ Toronto, Div Cardiol, Toronto, ON, Canada
[7] Univ Toronto, Fac Med, Dept Anesthesia, Toronto, ON, Canada
[8] Univ Toronto, Fac Med, Dept Physiol, Toronto, ON, Canada
[9] Univ Toronto, Fac Med, Dalla Lana Sch Publ Hlth, Toronto, ON, Canada
[10] Univ Toronto, Fac Med, Dept Hlth Policy Management & Evaluat, Toronto, ON, Canada
[11] Harvard Univ, Sch Med, Dept Med, Boston, MA USA
[12] Massachusetts Gen Hosp, Dept Med, Boston, MA 02114 USA