1. Division of Hospital Medicine, Department of Internal Medicine, Northcentral Baptist Medical Center, San Antonio, TX, USA
2. Section of Vascular Surgery and Endovascular Therapy, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, México
3. Department of Pulmonary and Critical Care Medicine, Respiratory Institute, Cleveland Clinic, Cleveland, OH, USA
4. Division of Pulmonary and Critical Care Medicine; University of Pittsburgh Medical Center, Pittsburgh, PA, USA