1. Department of Pulmonary Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland;
2. Department of Pulmonary Medicine, University Hospital of Zürich, Zürich, Switzerland;
3. Department of Pulmonary Medicine, Kantonsspital St. Gallen, St. Gallen, Switzerland; and
4. Clinics of Respiratory Medicine, University Hospital of Basel, Basel, Switzerland