[1] Univ Ottawa, Ottawa Hosp, Dept Surg, Ottawa, ON, Canada
[2] Ottawa Hosp, Res Inst, Clin Epidemiol Program, Ottawa, ON, Canada
[3] Univ Ottawa, Fac Med, Ottawa, ON, Canada
[4] Univ Laval, CHU Quebec, Dept Anesthesia, Quebec City, PQ, Canada
[5] Univ Ottawa, Ottawa Hosp, Dept Anesthesiol, Ottawa, ON, Canada
[6] Univ Ottawa, Ottawa Hosp, Dept Pain Med, Ottawa, ON, Canada
[7] Univ Ottawa, Ottawa Hosp, Dept Med, Ottawa, ON, Canada
[8] Canadian Blood Serv, Ottawa, ON, Canada
[9] Univ Toronto, Dept Surg, Toronto, ON, Canada
[10] Sunnybrook Hlth Sci Ctr, Odette Canc Ctr, Div Surg Oncol, Toronto, ON, Canada