1. Department of Surgery, Hualien Tzu-Chi Hospital, Buddhist Tzu Chi Medical Foundation and School of Medicine, Tzu-Chi University, Hualien 970, Taiwan
2. Department of Anesthesia, Hualien Tzu-Chi Hospital, Hualien 970, Taiwan
3. Bio-Math Laboratory, Department of Financial Engineering, Providence University, Taichung 433719, Taiwan
4. Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02115, USA
5. Division of Otolaryngology—Head and Neck Surgery, LifeBridge Sinai Hospital, Baltimore, MD 21040, USA
6. Division of Otolaryngology—Head and Neck Surgery, MedStar Union Memorial Hospital, Baltimore, MD 21218, USA