[1] Univ Amsterdam, Acad Med Ctr, Dept Intens Care Med, NL-1105 AZ Amsterdam, Netherlands
[2] Univ Amsterdam, Acad Med Ctr, Lab Expt Intens Care & Anaesthesiol, NL-1105 AZ Amsterdam, Netherlands
[3] John Radcliffe Hosp, Intens Care Unit, Oxford OX3 9DU, England