[1] Dalhousie Univ, Div Crit Care Med, Dept Emergency Med, Nova Scotia Trauma Program,QEH Hlth Sci Ctr, Halifax, NS, Canada
[2] Dalhousie Univ, Div Crit Care Med, Dept Anesthesia, Nova Scotia Trauma Program,QEH Hlth Sci Ctr, Halifax, NS, Canada
[3] Univ Ottawa, Dept Med, Ottawa Hosp Res Inst, Div Clin Epidemiol, Ottawa, ON, Canada
[4] Univ Laval, CHU Quebec Res Ctr, Hop Enfant Jesus, Dept Anesthesiol,Div Crit Care Med, Quebec City, PQ, Canada
[5] Univ Ottawa, Ottawa Hosp Res Inst, Div Crit Care Med, Dept Med, Ottawa, ON, Canada
[6] Dalhousie Univ, Dept Emergency Med, Halifax, NS, Canada
[7] Univ British Columbia, Vancouver Gen Hosp, Dept Anesthesia Pharmacol & Therapeut, Dept Med,Div Crit Care Med, Vancouver, BC V5Z 1M9, Canada
[8] Dalhousie Univ, Div Crit Care Med, Dept Anesthesia, Halifax, NS, Canada