[1] Univ Toronto, Dept Surg, Toronto, ON, Canada
[2] Sunnybrook Res Inst, Clin Evaluat Sci, Toronto, ON, Canada
[3] ICES, Toronto, ON, Canada
[4] Univ Toronto, Inst Hlth Policy Measurement & Evaluat, Toronto, ON, Canada
[5] Univ Toronto, Dept Anesthesiol & Pain Med, Toronto, ON, Canada
[6] Univ Laval, Div Crit Care Med, Dept Anesthesiol & Crit Care Med, Quebec City, PQ, Canada
[7] Univ Laval, Laval Res Ctr, Populat Hlth & Optimal Hlth Practices Res Unit, Trauma Emergency Crit Care Med,CHU Quebec Univ, Quebec City, PQ, Canada
[8] Univ Ottawa, Dept Anesthesiol, Ottawa, ON, Canada
[9] Univ Toronto, Dept Otolaryngol Head & Neck Surg, Toronto, ON, Canada