1. Faculty of Health Sciences, University of Stavanger, Stavanger, Norway
2. Department of Surgery, Haugesund Hospital, Haugesund, Norway
3. Department of Gastrointestinal Surgery, Stavanger University Hospital, Stavanger, Norway
4. Critical Care and Anaesthesiology Research Group, Stavanger University Hospital, Stavanger, Norway
5. Department of Clinical Medicine, University of Bergen, Bergen, Norway