1. First Intensive Care Unit (ICU) Department Evaggelismos Hospital, National and Kapodistrian University of Athens Athens Greece
2. Sleep Laboratory First ICU Clinic, Evaggelismos Hospital Athens Greece
3. 4th Pulmonary Department Sotiria General Hospital of Chest Diseases of Athens Athens Greece
4. Department of Critical Care O Agios Dimitrios, General Hospital of Thessaloniki Thessaloniki Greece
5. Sleep Laboratory Sismanogleio Amalia Phlemink General Hospital Athens Greece
6. Immunology‐Histocompatibility Department Evaggelismos General Hospital Athens Greece
7. Respiratory Failure Unit Aristotle University of Thessaloniki George Papanikolaou Hospital Thessaloniki Greece
8. Pulmonary Department‐Oncology Unit George Papanikolaou General Hospital, Aristotle University of Thessaloniki Thessaloniki Greece
9. Pulmonary Department Aristotle University of Thessaloniki, George Papanikolaou General Hospital Thessaloniki Greece
10. 1st Intensive Care Unit George Papanikolaou General Hospital, Aristotle University of Thessaloniki Thessaloniki Greece
11. Department of Immunology – Histocompatibility George Papanikolaou Hospital Thessaloniki Greece
12. Intensive Care Unit University Hospital of Heraklion Crete Greece
13. Primary Health Care Center of Kastelli Sleep Disorders Center, Department Of Thoracic Medicine, University Of Crete Heraklion Greece
14. Virology Laboratory University Hospital of Heraklion Crete Greece
15. Pulmonary Department General Hospital Of Trikala Greece
16. Pulmonary Department General Oncologic Hospital Of Athens Athens Greece
17. Intensive Care Unit Sotiria General Hospital of Chest Diseases of Athens Athens Greece
18. Intensive Care Unit General Hospital of Nikaia – Peiraia Agios Panteleimon Athens Greece