[1] Triemli City Hosp, Inst Anaesthesiol & Intens Care Med, Dept Transversal Med, CH-8063 Zurich, Switzerland
[2] St George Hosp, Dept Intens Care, London, England
[3] Rhein Westfal TH Aachen, Univ Hosp Aachen, Dept Intens Care, Aachen, Germany
[4] Univ Udine, Azienda Osped Univ Udine, Dept Anaesthesia & Intens Care, I-33100 Udine, Italy