[1] Univ Oslo, Inst Clin Med, Fac Med, PB 1171 Blindern, N-0318 Oslo, Norway
[2] Oslo Univ Hosp, Norwegian Natl Advisory Unit Prehosp Emergency Me, PB 4956 Nydalen, N-0424 Oslo, Norway
[3] Oslo Univ Hosp, Dept Anaesthesiol, Div Emergencies & Crit Care, PB 4956 Nydalen, N-0424 Oslo, Norway
[4] Ostfold Univ Coll, Dept Hlth & Social Studies, PB 700, N-1757 Halden, Norway
[5] Vestfold Hosp Trust, Prehosp Clin, Vestfold & Telemark Emergency Med Commun Ctr, NO-3103 Tensberg, Norway
[6] Oslo Univ Hosp, Oslo Emergency Med Commun Ctr, Prehosp Clin, PB 4956 Nydalen, N-0424 Oslo, Norway
[7] Ostfold HF Hosp Trust, Prehosp Clin, PB 300, NO-1714 Sarpsborg, Norway
[8] Oslo Univ Hosp, Prehosp Clin, PB 4956 Nydalen, N-0424 Oslo, Norway