1 Department of Cardiothoracic and Vascular Anesthesia, General Hospital "G. Papanikolaou", Thessaloniki, Greece.
2 Department of Anesthetics, Guy's and St Thomas' NHS Foundation Trust, London, UK.
3 Department of Respiratory Medicine, G. Papanikolaou Hospital, Thessaloniki, Greece.
4 Department of Anesthesiology and Intensive Care, Intensive Care Unit, AHEPA University Hospital of Thessaloniki, Aristotle University of Thessaloniki, Thessaloniki, Greece.