[1] Univ Pittsburgh, Sch Med, Div Gen Internal Med, Dept Med, Pittsburgh, PA 15261 USA
[2] Univ Pittsburgh, Sch Med, Dept Crit Care Med,Program Eth & Decis Making Cri, Clin Res Invest & Syst Modeling Acute Illness Ctr, Pittsburgh, PA 15261 USA
[3] Univ Pittsburgh, Sch Med, Div Pulm Allergy & Crit Care Med, Dept Med, Pittsburgh, PA 15261 USA
[4] Univ Pittsburgh, Palliat & Support Inst, Med Ctr, Pittsburgh, PA 15261 USA
[5] Carnegie Mellon Univ, Sch Comp Sci, Human Comp Interact Inst, Pittsburgh, PA 15213 USA
[6] Univ Laval, Dept Family & Emergency Med, Quebec City, PQ, Canada
[7] Duke Univ, Sch Med, Dept Med, Div Pulm & Crit Care Med, Durham, NC 27706 USA