1. Department of Anesthesiology; University Hospital of North Norway and UiT-The Arctic University of Norway; Tromsø Norway
2. Department of Anesthesiology; Sykehuset Sørlandet; Kristiansand Norway
3. Department of Orthopedic Surgery; University Hospital of North Norway and UiT-The Arctic University of Norway; Tromsø Norway
4. Department of Community Medicine; UiT-The Arctic University of Norway; Tromsø Norway