[1] Norwegian Air Ambulance Fdn, Dept Res & Dev, Drobak, Norway
[2] St Olavs Univ Hosp, Dept Anaesthesia & Emergency Med, Trondheim, Norway
[3] Norwegian Univ Sci & Technol NTNU, Fac Med, Dept Circulat & Med Imaging, Trondheim, Norway
[4] N Bristol NHS Trust, Bristol, Avon, England
[5] Kuopio Univ Hosp, Ctr Prehosp Care, Div Prehosp Emergency Care Emergency & Intens Car, Kuopio, Finland
[6] Anaesthesia & ICU SMM Hosp, Udine Reg Hlth Agcy Emilia Romagna, Bologna, Italy
[7] Karolinska Inst, Dept Clin Sci & Educ, Sodersjukhuset & Sect Emergency Med, Stockholm, Sweden
[8] Odense Univ Hosp, Dept Anaesthesia & Intens Care Med, Mobile Emergency Care Unit, Odense, Denmark
[9] Univ Bergen, Dept Surg Sci, Bergen, Norway