1. Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine,
2. Division of Cardiovascular Surgery, and
3. Department of Medicine and Anesthesia, University of California, San Francisco, San Francisco, California;
4. Division of Pulmonary, Allergy, and Critical Care Medicine, Columbia University School of Medicine, New York, New York;
5. Division of Pulmonary and Critical Care Medicine and
6. Division of Cardiovascular and Thoracic Surgery, Department of Surgery, Duke University Medical Center, Durham, North Carolina;
7. Division of Pulmonary and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, Alabama;
8. Division of Pulmonary, Allergy, and Critical Care, University of Pittsburgh, Pittsburgh, Pennsylvania;
9. Division of Pulmonary and Critical Care Medicine, Johns Hopkins University Medical Center, Baltimore, Maryland;
10. Division of Pulmonary and Critical Care Medicine, Stanford University Medical Center, Palo Alto, California;
11. Division of Pulmonary and Critical Care Medicine, University of Michigan Medical Center, Ann Arbor, Michigan; and
12. Division of Pulmonary and Critical Care Medicine, Indiana University School of Medicine, Indianapolis, Indiana
13. Division of Biostatistics, Department of Biostatistics, Epidemiology, and Informatics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania;