1. Clinic of Respiratory Failure, General Hospital of Thessaloniki ‘Georgios Papanikolaou’ Aristotle University of Thessaloniki Thessaloniki Greece
2. Department of Pulmonary Medicine, General Hospital of Thessaloniki ‘Georgios Papanikolaou’ Aristotle University of Thessaloniki Thessaloniki Greece
3. 1st ICU ‘Evangelismos Hospital’ School of Medicine National and Kapodistrian University of Athens Athens Greece
4. Clinic of Pulmonary Medicine of National Healthcare System General Hospital of Thessaloniki ‘Georgios Papanikolaou’ Thessaloniki Greece