1. Department of Surgery, Helsingborg Hospital, 25187 Helsingborg, Sweden
2. Department of Anaesthesiology and Intensive Care, Landspitali University Hospital, 101 Reykjavik, Iceland
3. Department of Surgery, Landspitali University Hospital, 101 Reykjavik, Iceland
4. Faculty of Medicine, University of Iceland, 101 Reykjavik, Iceland
5. Department of Gastroenterology, Landspitali University Hospital, 101 Reykjavik, Iceland