1. Department of Maxillofacial Surgery, Oslo University Hospital Ullevål, Oslo, Norway
2. Finance Department, Oslo University Hospital, Oslo, Norway
3. Department of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway
4. Oslo Centre for Biostatistics and Epidemiology, Research Support Services, University of Oslo, Oslo, Norway
5. Division of Emergencies and Critical Care, Department of Anesthesiology, Oslo University Hospital Ullevål, Oslo, Norway