1. Department of Anesthesiology and Intensive Care, Institution for Clinical Medicine, University Hospital, Örebro
2. University of Linköping, Sweden
3. Department of Anesthesiology and Intensive Care, Institution for Clinical Medicine, University Hospital, Örebro, Sweden
4. Statistical and Epidemiology Unit, Institution for Clinical Medicine, University Hospital, Örebro, Sweden
5. Department of Hand Surgery, Institution for Clinical Medicine, University Hospital, Örebro, Sweden