[1] Norwegian Air Ambulance Fdn, Dept Res & Dev, N-1441 Drobak, Norway
[2] Viborg Reg Hosp, Prehosp Crit Care Team, Dept Anaesthesiol, DK-8800 Viborg, Denmark
[3] Aarhus Univ Hosp, Prehosp Crit Care Team, DK-8100 Aarhus C, Denmark
[4] Cent Denmark Reg, Dept Prehosp Med Serv, DK-8200 Aarhus N, Denmark
[5] Aarhus Univ Hosp, Ctr Emergency Med Res, DK-8200 Aarhus N, Denmark
[6] Aarhus Univ Hosp, Dept Anaesthesiol, DK-8000 Aarhus, Denmark