1. Department of Medicine University of Utah Salt Lake City Utah USA
2. Department of Medicine, College of Medicine Northern Border University Arar Saudi Arabia
3. Division of Allergy, Pulmonary, and Critical Care Medicine Vanderbilt University Medical Center Nashville Tennessee USA
4. Department of Medicine, Division of Pulmonary and Critical Care Medicine University of Utah Salt Lake City Utah USA
5. Division of Cardiovascular Medicine Vanderbilt University Medical Center Nashville Tennessee USA