1. Department of Anaesthesiology Lillebaelt Hospital Kolding Denmark
2. Department of Anaesthesiology Centre of Head and Orthopedics, Rigshospitalet University Hospital of Copenhagen Copenhagen Denmark
3. Department of Anaesthesiology Horsens Hospital Horsens Denmark
4. Department of Clinical Medicine Faculty of Health Aarhus University Aarhus Denmark
5. Department of Anaesthesiology and Intensive Care Aarhus University Hospital Aarhus Denmark