1. Postanesthesia Care Unit, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, P.R. China.
2. Nursing Department, and Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, P.R. China.
3. Intensive Care Unit, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, P.R. China.