1. Elective Surgery Centre; Silkeborg Regional Hospital; Silkeborg Denmark
2. Department of Clinical Medicine, Health; Aarhus University; Aarhus Denmark
3. Department of Anaesthesiology; Aarhus University Hospital; Aarhus Denmark
4. Department of Anaesthesiology, Intensive Care and Pain Therapy; Sacred Heart of Jesus Hospital; Vienna Austria
5. Division of Clinical and Functional Anatomy; Medical University of Innsbruck (MUI); Innsbruck Austria
6. Department of Anaesthesiology and Intensive Care Medicine; Zealand University Hospital; University of Copenhagen; Roskilde Denmark