1. Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Kentucky College of Medicine, Lexington, Kentucky;
2. Division of Pulmonary, Critical Care, and Sleep Medicine, University of Kansas, Lawrence, Kansas;
3. Division of Pulmonary and Critical Care Medicine, University of California San Francisco, San Francisco, California;
4. Division of Pulmonary and Critical Care Medicine, Indiana University, Bloomington, Indiana;
5. Section of Pulmonary, Critical Care, and Environmental Medicine, Tulane University, New Orleans, Louisiana; and
6. Department of Pulmonary and Critical Care Medicine, University of Pennsylvania, Philadelphia, Pennsylvania