[1] Univ South China, Affiliated Hosp 2, Hengyang Med Sch, Dept Urol Surg,Gastroenterol Sect, Hengyang 422300, Hunan, Peoples R China
[2] Cent Hosp Shaoyang, Dept Anesthesiol, 36 Qianyuan Lane, Hongqi Rd, Shaoyang 422300, Hunan, Peoples R China
[3] Cent Hosp Shaoyang, Dept Gastrointestinal Surg, 36 Qianyuan Lane, Hongqi Rd, Shaoyang 422300, Hunan, Peoples R China