1 Institute of Clinical Medicine, University of Oslo, Post Box 1072, Blindern, N-0316, Oslo, Norway; Department of Anaesthesiology, Division of Emergencies and Critical Care, Oslo University Hospital, Post Box 4956, Nydalen, N-0424, Oslo, Norway. Electronic address: sigrid.beitland@medisin.uio.no.
2 Institute of Clinical Medicine, University of Oslo, Post Box 1072, Blindern, N-0316, Oslo, Norway; Department of Anaesthesiology, Division of Emergencies and Critical Care, Oslo University Hospital, Post Box 4956, Nydalen, N-0424, Oslo, Norway.