1 Department of Neurosurgery, Olympion General Hospital and Rehabilitation Center, Patras, Greece, karamanakosp@gmail.com.
2 Department of Pharmacology, Faculty of Medicine, School of Health Sciences, University of Ioannina, Ioannina, Greece.
3 Department of Anesthesiology and Critical Care Medicine, University Hospital of Patras, School of Medicine, University of Patras, Rion-Patras, Greece.