[1] Univ Warwick, Warwick Med Sch, Coventry CV4 7AL, W Midlands, England
[2] Heart England NHS Fdn Trust, Crit Care Unit, Birmingham, W Midlands, England
[3] Univ Amsterdam, Acad Med Ctr, Dept Cardiol, NL-1105 AZ Amsterdam, Netherlands
[4] Helsinki Univ Hosp, Dept Emergency Med & Serv, Helsinki, Finland
[5] Univ Helsinki, FIN-00014 Helsinki, Finland
[6] West Midlands Ambulance Serv NHS Fdn Trust, Dudley, England
[7] Oslo Univ Hosp, Norwegian Natl Advisory Unit Prehosp Emergency Me, Oslo, Norway
[8] Oslo Univ Hosp, Dept Anesthesiol, Oslo, Norway
[9] Univ Antwerp, Fac Med & Hlth Sci, B-2020 Antwerp, Belgium
[10] Univ Ghent, Fac Med & Hlth Sci, B-9000 Ghent, Belgium
[11] Municipal Inst Emergency Med Novi Sad, Novi Sad, Serbia
[12] Univ Med Ctr Schleswig Holstein, Dept Anaesthesia & Intens Care Med, Kiel, Germany
[13] Med Univ Innsbruck, Dept Anesthesiol & Crit Care Med, A-6020 Innsbruck, Austria
[14] IRCCS Ist Ric Farmacol Mario Negri, Dept Cardiovasc Res, Milan, Italy
[15] Southmead Hosp, Anaesthesia & Intens Care Med, Bristol, Avon, England