1. Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
2. Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
3. Section of Palliative Care and Medical Ethics, Division of General Internal Medicine, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
4. Departments of Psychiatry, Psychology, Epidemiology, Biostatistics, and Clinical and Translational Science, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
5. Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Loyola, Chicago, Illinois, USA.
6. Division of Respirology and Division of Palliative Medicine, University of Toronto, Toronto, Ontario, Canada.
7. Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
8. Division of Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA.
9. Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of California, San Francisco, San Francisco, California, USA.
10. Division of Pulmonary and Critical Care Medicine, Department of Medicine, Washington University in St Louis, St. Louis, Missouri, USA.
11. Department of Medicine, Division of Pulmonary Critical Care, and Sleep Medicine, University of Washington, Seattle, Washington, USA.
12. Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, Duke University, Durham, North Carolina, USA.