[1] Univ Aberdeen, Hlth Serv Res Unit, Aberdeen AB25 2ZD, Scotland
[2] Hadassah Hebrew Univ, Med Ctr, Dept Anesthesiol & Crit Care Med, Jerusalem, Israel
[3] Univ Versailles, Raymond Poincare Hosp, AP HP, Gen Intens Care Unit,SQY, Garches, France
[4] St Louis Hosp, Dept Biostat, Paris, France
[5] Ipswich Hosp NHS Trust, Intens Care Unit, Ipswich, Suffolk, England
[6] UCL, St Luc Univ Hosp, Dept Crit Care Med, Brussels, Belgium
[7] Erasme Univ Hosp, Intens Care Unit, B-1070 Brussels, Belgium
[8] Analyt Int GmbH, Lorrach, Germany
[9] Univ Jena, Dept Anaesthesiol & Intens Care Med, Jena, Germany
[10] UCL, Wolfson Inst Biomed Res, Dept Med, London, England
[11] Hop Lariboisiere, F-75475 Paris, France