[1] Univ Gottingen, Dept Anesthesiol Emergency & Intens Care Med, Gottingen, Germany
[2] Reg Hosp, Pulm & Crit Care Med, St Paul, MN USA
[3] Univ Minnesota, St Paul, MN 55108 USA
[4] San Paolo Univ Hosp, ASST Santi Paolo & Carlo, Dept Anesthesia & Intens Care, Milan, Italy
[5] Guys & St Thomas NHS Fdn Trust, Dept Adult Crit Care, London, England
[6] Kings Coll London, Ctr Human Appl Physiol Sci, London, England