1. Sleep Disorders Center, Department of Respiratory Medicine, University of Crete School of Medicine, Crete, Greece
2. Department of Pulmonology, University Hospital Zurich and University of Zurich, University of Zurich Faculty of Medicine, Zurich, Switzerland
3. Division of Respiratory Medicine, PROMISE Department, University of Palermo Faculty of Medicine and Surgery, Palermo, Italy
4. Department of Respiratory and Sleep Medicine, St Vincent’s Hospital Group, University College Dublin, Dublin, Ireland
5. Respiratory Failure Unit, G Papanikolaou Hospital, Medical School, Aristoteleio Panepistemio Thessalonikes Schole Epistemon Ygeias, Thessaloniki, Greece