1. Department of Anesthesiology; University Hospital Regensburg; 93053 Regensburg Germany
2. Department of Anesthesiology; Klinikum Frankfurt (Oder); Frankfurt (Oder) Germany
3. Department of Anesthesiology; University Hospital Würzburg; Würzburg Germany
4. Department of Anesthesiology; Krankenhaus Landshut Achdorf; Landshut Germany