1 Department of Neurosurgery, Oslo University Hospital, Oslo, Norway. dagnet@ous-hf.no.
2 Faculty of Medicine, University of Oslo, Oslo, Norway. dagnet@ous-hf.no.
3 Department of Neurosurgery, Oslo University Hospital, Oslo, Norway.
4 Department of Neurology, Oslo University Hospital, Oslo, Norway.
5 The Norwegian Air Ambulance Foundation, Oslo, Norway.
6 Department of Neurosurgery, School of Medicine, Faculty of Health Sciences, University of Pretoria, Steve Biko Academic Hospital, Pretoria, South Africa.
7 Faculty of Medicine, University of Oslo, Oslo, Norway.
8 Department of Health Research, Medical Technology, SINTEF, Trondheim, Norway.