1. From the Department of Otorhinolaryngology–Head and Neck Surgery
2. University of Greifswald, Greifswald, Germany; and the Departments of Otorhinolaryngology–Head and Neck Surgery
3. Anesthesia
4. University Hospital Regensburg, Regensburg, Germany and Institute of Clinical Chemistry and Laboratory Medicine, Universtiy of Mainz, Mainz, Germany. Greifswald, Mainz, Regensburg, Germany