1. Department of Anaesthesiology, Kolding Hospital, a part of Lillebaelt Hospital University Hospital of Southern Denmark Denmark
2. Department of Anaesthesiology, Vejle Hospital, a part of Lillebaelt Hospital University Hospital of Southern Denmark Denmark
3. Institute of Clinical Medicine, Health Aarhus University Aarhus Denmark
4. Department of Orthopaedic Surgery, Kolding Hospital, a part of Lillebaelt Hospital University Hospital of Southern Denmark Denmark
5. Department of Anaesthesiology Horsens Hospital Denmark
6. Department of Anaesthesiology Aarhus University Hospital Aarhus Denmark