[1] Univ Copenhagen, Rigshosp, Ctr Head & Orthopaed, Dept Anaesthesia, Inge Lehmanns Vej 6, DK-2100 Copenhagen, Denmark
[2] Odense Univ Hosp, Dept Anaesthesiol & Intens Care, J B Winslows Vej 4, DK-5000 Odense C, Denmark
[3] Odense Univ Hosp, Prehosp Res Unit, Kildemosevej 15, DK-5000 Odense C, Denmark
[4] Aarhus Univ Hosp, Dept Anaesthesia, Palle Juul Jensens Blvd 165, DK-8200 Aarhus N, Denmark
[5] Danish Air Ambulance, Brendstrupgardsvej 7, DK-8200 Aarhus N, Denmark
[6] Erasmus MC, Dept Anaesthesiol, Dr Molewaterplein 40, NL-3015 GD Rotterdam, Netherlands
[7] Univ Hosp Bern, Dept Emergency Med, Freiburgstr 20, CH-3010 Bern, Switzerland
[8] Antwerp Univ Hosp, Dept Gastroenterol & Hepatol, Drie Eikenstr 655, Antwerp, Belgium
[9] Univ Antwerp, Fac Med & Hlth Sci, Univ Pl 1, B-2610 Antwerp, Belgium
[10] Danish Minist Def Personnel Agcy, HC Sneedorffs 3, DK-1439 Copenhagen, Denmark
[11] Univ Copenhagen, Inst Clin Med, Blegdamsvej 3B, DK-2200 Copenhagen, Denmark
[12] Aarhus Univ, Fac Hlth, Vennelyst Blvd 4, DK-8000 Aarhus, Denmark