1. Division of Pulmonary and Critical Care Medicine, University of Tennessee College of Medicine at Chattanooga, Chattanooga, Tennessee;
2. Division of Pulmonary and Critical Care Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina;
3. Respiratory Institute, Cleveland Clinic, Cleveland, Ohio;
4. School of Nursing, Indiana University, Indianapolis, Indiana; and
5. Mel and Enid Zuckerman College of Public Health, University of Arizona, Tucson, Arizona