1 Institute of Anesthesiology, University and University Hospital Zurich, Zurich, Switzerland. kurt.ruetzler@meduniwien.ac.at.
2 Division of Cardiothoracic and Vascular Anaesthesia and Intensive Care Medicine, Medical University of Vienna, Vienna, Austria. kurt.ruetzler@meduniwien.ac.at.
3 Department of Outcomes Research, Cleveland Clinic, Cleveland, OH, USA.