1. Department of Neonatology and Neonatal Intensive Care, Faculty of Medicine, School of Health Sciences, Aristotle University of Thessaloniki, Ippokrateion General Hospital, 54642 Thessaloniki, Greece
2. Department of Neonatology, University of Vermont, Burlington, VT 05405, USA
3. Department of Anesthesia and Intensive Care, Faculty of Medicine, School of Health Sciences, Aristotle University of Thessaloniki, AHEPA University General Hospital of Thessaloniki, 54621 Thessaloniki, Greece