Siri van der Meijden1,2, Peter Somhorst3, Abraham Schoe4. 1. Department of Intensive Care, Leiden University Medical Centre, Leiden, The Netherlands. 2. Faculty of Mechanical Engineering, Delft University of Technology, Delft, The Netherlands. 3. Department of Intensive Care, Erasmus MC, University Medical Center, Rotterdam, The Netherlands. 4. Department of Intensive Care, Leiden University Medical Centre, Leiden, The Netherlands. a.schoe@lumc.nl.