[1] McMaster Univ, Dept Med, Dept Clin Epidemiol & Biostat, Hamilton, ON, Canada
[2] Univ Toronto, Interdept Div Crit Care Med, Toronto, ON, Canada
[3] St Michaels Hosp, Keenan Res Ctr, Toronto, ON, Canada
[4] St Michaels Hosp, Li Ka Shing Knowledge Inst, Toronto, ON, Canada
[5] St James Univ Hosp, Dept Resp Med, Leeds, W Yorkshire, England
[6] Harvard Med Sch, Massachusetts Gen Hosp, Resp Care Dept, Boston, MA USA
[7] Harvard Med Sch, Dept Anesthesia, Boston, MA USA
[8] Tufts Med Ctr, Div Pulm Crit Care & Sleep Med, Boston, MA USA
[9] Univ Bologna, St Orsola Malpighi Hosp, Dept Specialist Diagnost & Expt Med, Resp & Crit Care, Via Zamboni 33, I-40126 Bologna, Italy
[10] Magna Graecia Univ Catanzaro, Dept Med & Surg Sci, Anesthesia & Intens Care, Catanzaro, Italy
[11] Univ Cattolica Sacro Cuore, A Gemelli Univ Hosp, Dept Anesthesiol, Rome, Italy
[12] Univ Cattolica Sacro Cuore, A Gemelli Univ Hosp, Intens Care Med, Rome, Italy
[13] Univ Barcelona, IDIBAPS, Hosp Clin, Dept Pneumol,Resp Inst, Barcelona, Spain
[14] CIBERES, Barcelona, Spain
[15] Baylor Coll Med, Dept Pulm, Houston, TX 77030 USA
[16] Baylor Coll Med, Dept Crit Care Med, Houston, TX 77030 USA
[17] St Eloi Univ Hosp, Res Unit INSERM U1046, Dept Crit Care Med & Anesthesiol DAR B, Montpellier, France
[18] Montpellier Sch Med, Montpellier, France
[19] Univ British Columbia, Div Crit Care Med, Vancouver, BC, Canada
[20] Royal Columbian Hosp, Dept Crit Care Med, New Westminster, BC, Canada
[21] Hosp Santa Creu & Sant Pau, Serv Med Intens, Barcelona, Spain
[22] Univ Toronto, Mt Sinai Hosp, Toronto, ON, Canada
[23] Univ Toronto, Interdept Div Crit Care Med, Toronto, ON, Canada
[24] Lenox Hill Hosp, Pulm & Crit Care Med, New York, NY 10021 USA
[25] Hofstra Northwell Sch Med, Hempstead, NY USA