Placido Argüelles-Delgado1, Gerhard Schwarz2. 1. Department of Anaesthesiology and Intensive Care Medicine, Medical University of Graz, Auenbruggerplatz 5, A-8036, Graz, Austria. placido.delgado@medunigraz.at. 2. Department of Anaesthesiology and Intensive Care Medicine, Medical University of Graz, Auenbruggerplatz 5, A-8036, Graz, Austria.