1. Department of Anaesthesia and Intensive Care Medicine; Philipps-University of Marburg; Marburg Germany
2. Department of Anaesthesia and Intensive Care Medicine; Clinique Bénigne Joly; Talant France
3. Department of Anaesthesia; Krankenhaus St. Joseph-Stift; Dresden Germany
4. Institute of Medical Biometry and Epidemiology; Philipps-University of Marburg; Marburg Germany
5. Department of Anaesthesiology; Diakonie-Klinikum; Schwäbisch Hall Germany
6. Department of Anaesthesia, Intensive Care Medicine and Pain Therapy; Kreisklinikum; Siegen Germany
7. Department of Anaesthesia and Intensive Care Medicine; Ilmtalklinik Pfaffenhofen; Pfaffenhofen Germany