1. University Hospital of Alexandroupolis, Democritus University of Thrace, Alexandroupolis, Greece
2. Department of Medical Statistics, Medical School, Democritus University of Thrace, Alexandroupolis, Greece
3. Faculty of Nursing, National and Kapodistrian University of Athens, Athens, Greece
4. Department of Paediatric Surgery, Atikkon University General Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
5. Department of Anesthesiology, Medical School, Democritus University of Thrace, Alexandroupolis, Greece
6. Department of Anesthesiology, University Hospital of Alexandroupolis, Alexandroupoli, Greece