1. Department of Anaesthesiology; Telemark Hospital; Skien Norway
2. Department of Circulation and Medical Imaging; Faculty of Medicine; Norwegian University of Science and Technology; Trondheim Norway
3. Centre of Palliative Medicine, Surgical Division; Akershus University Hospital; Lørenskog Norway
4. National Competence Centre for Complex Symptom Disorders; Department of Pain and Complex Disorders; Trondheim Norway
5. Research and Development; Vestfold Hospital Trust; Tønsberg Norway
6. Institute of Clinical Medicine; Medical Faculty; University of Oslo; Oslo Norway
7. Department of Anaesthesiology; St. Olav University Hospital; Trondheim Norway
8. Department of Anaesthesiology; Oslo University Hospital; Oslo Norway