1. Division for Health Services, Norwegian Institute of Public Health, Oslo, Norway (U.H.L., A.S.-S., B.R.).
2. The Norwegian Air Ambulance Foundation, Oslo, Norway (K.L., K.G.B.).
3. Institute of Basic Medical Sciences, University of Oslo, Norway (K.L., K.G.B.).
4. Research and Dissemination, Østfold University College, Halden, Norway (K.G.B.).
5. Department of Global Public Health and Primary Care, University of Bergen, Norway (B.R.).