[1] Med Univ Salzburg, Dept Anesthesia & Intens Care Med, Salzburg, Austria
[2] Cent Hosp Bolzano, Dept Anesthesia & Intens Care Med, Lorenz Bohlerstr 5, I-39100 Bolzano, Italy
[3] Cairns Base Hosp, Dept Anaesthesia & Intens Care, The Esplanade, Cairns, Australia
[4] Schulthess Klin, Dept Anaesthesia, Zurich, Switzerland