[1] Massachusetts Gen Hosp, Gen Med Unit, Dept Med, Sect Gen Med, Boston, MA 02114 USA
[2] Harvard Univ, Sch Med, Boston, MA USA
[3] Massachusetts Gen Hosp, Dept Med, Pulm & Crit Care Unit, Boston, MA 02114 USA
[4] Massachusetts Gen Hosp, Ctr Canc, Boston, MA 02114 USA
[5] Brigham & Womens Hosp, Div Trauma Burns & Crit Care, Boston, MA 02115 USA
[6] Boston Univ, Sch Med, Dept Med, Ctr Pulm, Boston, MA 02118 USA
[7] ENRM VA Hosp, Ctr Hlth Qual Outcomes & Econ Res, Bedford, MA USA