1 Department of Pneumology, Respiratory Intensive and Intermediate Care Unit, Respiratory Institute, Hospital Clinic, University of Barcelona, Barcelona, Spain.
2 Institute for Biomedical Research August Pi i Sunyer (Institut d'Investigacions Biomediques August Pi I Sunyer, IDIBAPS), Institut Català de Recerca i Estudis Avançats, Barcelona, Spain.
3 Network for Biomedical Research in Respiratory Disease (Centro de Investigación Biomedica En Red, Enfermedades Respiratorias, CibeRes, CB06/06/0028)-Carlos III Health Institute (Instituto de Salud Carlos III, ISCiii), Spanish Ministry of Science and Innovation, Madrid, Spain.