1. Department of Anesthesiology and Reanimation, Koc University Hospital, Istanbul, Turkey
2. Department of Anesthesiology and Perioperative Medicine, Penn State University, Milton S Hershey Medical Center, Pennsylvania, USA
3. Department of Biostatistics, Faculty of Medicine, Ataturk University, Erzurum, Turkey
4. Department of Anesthesiology and Reanimation, Ataturk University Hospital, Erzurum, Turkey.