1. Division of Pulmonary, Critical Care, and Sleep Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma;
2. Quantitative Sciences Unit and
3. Division of Pulmonary and Critical Care Medicine, Stanford University School of Medicine, Stanford, California;
4. Vera Moulton Wall Center for Pulmonary Disease at Stanford University, Stanford, California;
5. Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania;
6. Division of Pulmonary and Critical Care Medicine, University of Colorado, Denver, Colorado;
7. Division of Cardiology, University of California San Francisco, San Francisco, California;
8. Division of Pulmonary and Critical Care Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina;
9. Division of Pulmonary and Critical Care Medicine, Virginia Commonwealth University Medical Center, Richmond, Virginia;
10. Division of Pulmonary and Critical Care Medicine, Brown University, Providence, Rhode Island;
11. Kentuckiana Pulmonary Associates, Louisville, Kentucky;
12. Department of Pediatrics, Columbia University, New York, New York; and
13. Inova Fairfax Hospital, Falls Church, Virginia