1. Department of Thoracic Surgery, Center for Pneumology and Thoracic Surgery, Chest Hospital Schillerhoehe, Robert-Bosch-Krankenhaus, Teaching Hospital of the University of Tuebingen, Stuttgart, Germany
2. Institue of Stochastics and Applications, Department of Mathematics, University Stuttgart, Stuttgart, Germany
3. Department of Anesthesia, Chest Hospital Schillerhoehe, Robert-Bosch-Krankenhaus, Teaching Hospital of the University of Tuebingen, Stuttgart, Germany