[1] Univ Hosp Zurich, Inst Anaesthesiol, CH-8091 Zurich, Switzerland
[2] Univ Zurich, Epidemiol Biostat & Prevent Inst, Dept Epidemiol, CH-8001 Zurich, Switzerland
[3] Univ Zurich, Epidemiol Biostat & Prevent Inst, Dept Biostat, CH-8001 Zurich, Switzerland
[4] Clin Hirslanden Zurich, Inst Anaesthesiol & Intens Care Med, CH-8032 Zurich, Switzerland
[5] Univ Wurzburg, Univ Hosp Wuerzburg, Dept Anaesthesiol Intens Care Emergency & Pain Me, D-97080 Wurzburg, Germany
[6] Goethe Univ Frankfurt, Univ Hosp Frankfurt, Dept Anaesthesiol Intens Care Med & Pain Therapy, D-60323 Frankfurt, Germany
[7] Univ Barcelona, Hosp Clin Barcelona, Dept Anaesthesiol Intens Care Med & Pain Therapy, Barcelona 08036, Spain