1. Facultad de Medicina, Universidad San Sebastian, Concepcion, Chile
2. Complejo Asistencial Dr. Victor Rios Ruiz, Los Angeles, Región del Bío Bío, Chile
3. Department of Pneumology and Critical Care Medicine, Thoraxklinik, Translational Lung Research Center Heidelberg, University of Heidelberg, Heidelberg, Germany
4. Division of Pulmonary and Critical Care Medicine, Mayo Clinic, Jacksonville, Florida