1. ICU, General Hospital of Thessaloniki “Hippokration”, 49th Kostantinoupoleos Street, 57642 Thessaloniki, Greece
2. Pulmonary Clinic of Aristotle University of Thessaloniki, General Hospital of Thessaloniki “Georgios Papanikolaou”, Leoforos Papanikolaou, Exohi, 57010 Thessaloniki, Greece
3. Laboratory of Histology-Embryology, Medical School, Aristotle University of Thessaloniki, Leoforos Agiou Dimitriou, 54124 Thessaloniki, Greece
4. 2nd University Department of Respiratory Medicine, Attikon Hospital, 1st Rimini Street, Haidari,12462 Athens, Greece
5. Respiratory Failure Clinic of Aristotle University of Thessaloniki, General Hospital of Thessaloniki “Georgios Papanikolaou”, Leoforos Papanikolaou, Exohi, 57010 Thessaloniki, Greece