1. Department of Anaesthesiology, Intensive Care Medicine and Pain Therapy, Klinikum Hanau GmbH, Leimenstrasse 20, Hanau D-63450, Germany
2. Department of Anaesthesiology, Heidelberg University Hospital, Im Neuenheimer Feld 110, Heidelberg D-69120, Germany
3. Department of Medical Informatics, University Hospital RWTH Aachen, Aachen, Germany