[1] UCL, Dept Med, London, England
[2] Hadassah Hebrew Univ Med Ctr, Dept Anesthesiol & Crit Care Med, Jerusalem, Israel
[3] Orebro Univ Hosp, Dept Anesthesiol, Orebro, Sweden
[4] Herlev Univ Hosp, Dept Anesthesiol, DK-2730 Herlev, Denmark
[5] Hop Cantonal Univ Geneva, Geneva, Switzerland
[6] Hebrew Univ Jerusalem, Hadassah Sch Publ Hlth, Jerusalem, Israel
[7] S Karelia Cent Hosp, Dept Anesthesiol, Lappeenranta, Finland
[8] Hosp Geral Santo Antonio, Dept Intens Care, Oporto, Portugal
[9] Mater Hosp Univ Coll, Dept Intens Care, Dublin, Ireland
[10] Univ Hosp Jena, Dept Anesthesiol & Intens Care Med, Jena, Germany
[11] Univ Halle Wittenberg, Halle An Der Saale, Germany
[12] Univ Hosp Glostrup, Dept Anesthesiol, Glostrup, Denmark
[13] Southampton Univ Hosp NHS Trust, Crit Care Directorate, Southampton, Hants, England