[1] Wilford Hall USAF Med Ctr, MCCP, Lackland AFB, TX 78236 USA
[2] Univ Toronto, Mt Sinai Hosp, Sunnybrook & Womens Coll,Hlth Sci Ctr, Dept Med, Toronto, ON, Canada
[3] Univ Toronto, Mt Sinai Hosp, Sunnybrook & Womens Coll,Hlth Sci Ctr, Dept Anaesthesia, Toronto, ON, Canada
[4] Univ Toronto, Mt Sinai Hosp, Sunnybrook & Womens Coll,Hlth Sci Ctr, Dept Crit Care Med, Toronto, ON, Canada
[5] Univ Toronto, Mt Sinai Hosp, Sunnybrook & Womens Coll,Hlth Sci Ctr, Dept Trauma, Toronto, ON, Canada
[6] Univ Toronto, Hlth Network, Toronto, ON, Canada
[7] Loma Linda Univ, Med Ctr, Dept Crit Care Med, Loma Linda, CA USA
[8] Loma Linda Univ, Med Ctr, Dept Resp Care, Loma Linda, CA USA
[9] Barnes Jewish Hosp, Div Surg, St Louis, MO 63110 USA
[10] Allegheny Gen Hosp, Dept Pulm Crit Care Med, Pittsburgh, PA 15212 USA
[11] Univ Virginia, Med Ctr, Dept Anesthesia, Charlottesville, VA USA
[12] Univ Virginia, Med Ctr, Dept Crit Care Med, Charlottesville, VA USA