James M Walter1, Lewis Satterwhite2, Kenneth E Lyn-Kew3. 1. Department of Medicine, Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL. Electronic address: james.walter@northwestern.edu. 2. Department of Medicine, Division of Pulmonary and Critical Care Medicine, University of Kansas Medical Center, Kansas City, KS. 3. Department of Medicine, Division of Pulmonary, Critical Care, and Sleep Medicine, National Jewish Health, Denver, CO.