[1] Univ Penn, Perelman Sch Med, Palliat & Adv Illness Res Ctr, Philadelphia, PA 19104 USA
[2] Sinai Hlth Syst, Toronto, ON, Canada
[3] Univ Toronto, Dept Med, Toronto, ON, Canada
[4] Univ Toronto, Interdept Div Crit Care, Toronto, ON, Canada
[5] Univ Penn, Dept Biostat & Epidemiol, Perelman Sch Med, Philadelphia, PA 19104 USA
[6] Univ Penn, Leonard Davis Inst Hlth Econ, Philadelphia, PA 19104 USA
[7] Pulm & Crit Care Atlanta, Atlanta, GA USA
[8] Wayne State Univ, Sch Med, Detroit, MI USA
[9] Univ Calif San Diego, Sch Med, San Diego, CA 92103 USA
[10] Univ Kentucky, Coll Med, Lexington, KY USA
[11] Univ Penn, Dept Med, Perelman Sch Med, Div Pulm Allergy & Crit Care Med, Philadelphia, PA 19104 USA
[12] Univ Penn, Dept Med Eth & Hlth Policy, Philadelphia, PA 19104 USA