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