1. Department of Otorhinolaryngology, Head and Neck Surgery, The Second Affiliated Hospital of Harbin Medical University, Harbin, China
2. Department of Intensive Care Unit, The Affiliated Hongqi Hospital of Mudanjiang Medical University, Mudanjiang, China
3. Department of Otorhinolaryngology, Hegang People's Hospital, Hegang, China
4. Department of Otorhinolaryngology, The Affiliated Hospital of Northeast Agriculture University, Harbin, China