1. Department of Pulmonary and Critical Care Medicine, The General Hospital of Western Theater Command, Chengdu, Sichuan, P.R. China
2. Department of Urology, The General Hospital of Western Theater Command, Chengdu, Sichuan, P.R. China
3. Department of Burn, The General Hospital of Western Theater Command, Chengdu, Sichuan, P.R. China
4. Department of Geriatrics, The General Hospital of Western Theater Command, Chengdu, Sichuan, P.R. China