[1] Foothills Med Ctr, Calgary, AB, Canada
[2] Univ Calgary, Calgary, AB, Canada
[3] Natl & Gulf Ctr Evidence Based Hlth Practice, Riyadh, Saudi Arabia
[4] King Saud Bin Abdulaziz Univ Hlth Sci, Riyadh, Saudi Arabia
[5] McMaster Univ, Dept Clin Epidemiol & Biostat, Hamilton, ON, Canada
[6] Univ S Carolina, Sch Med, St Francis Hosp, Med,Dept Emergency, Columbus, GA USA
[7] Eastern Virginia Med Sch, Div Pulm & Crit Care Med, Norfolk, VA 23501 USA
[8] Virginia Commonwealth Univ, Dept Emergency Med, Sch Med, Richmond, VA USA
[9] Mayo Clin, Aerosp & Crit Care Med, Rochester, MN USA
[10] Renown Hlth, Reno, NV USA
[11] Univ Hosp Sarrland, Dept Anesthesiol, Homburg, Germany
[12] Hosp Goethe Univ, Clin Anesthesiol Intens Care & Pain Therapy, Frankfurt, Germany
[13] Royal Brompton Hosp, London SW3 6LY, England
[14] Eastern Virginia Med Sch, Norfolk, VA 23501 USA
[15] Harvard Univ, Sch Med, Beth Israel Deaconess Med Ctr, Dept Anesthesia Crit Care & Pain Med, Boston, MA USA