1. Respiratory Department; Txagorritxu Hospital; Vitoria Spain
2. Department of Pulmonary, Critical Care, and Sleep Medicine; Walter Reed National Military Medical Center; Bethesda MD USA
3. Division of Pulmonary and Critical Care Medicine; Duke University Medical Center; Durham NC USA
4. F. Edward Hebert School of Medicine; Uniformed Services University; Bethesda MD USA
5. Respiratory Department; Galdakao Hospital; Galdakao Spain
6. Respiratory Department; San Pedro Hospital; Logroño Spain
7. Respiratory Department; Virgen del Rocío Hospital; Sevilla Spain
8. Respiratory Department; La Fe Hospital; Valencia Spain
9. Medicine Department; Hospital Sierrallana; Cantabria Spain
10. Medicine Department; Germans Trias I Pujol Hospital; Badalona Spain
11. Divisions of Pulmonary and Critical Care Medicine and General Medical Sciences; Washington University School of Medicine; St Louis MO USA
12. Respiratory Department; Ramón y Cajal Hospital; IRYCIS; Madrid Spain