The Effect of Circadian Rhythms on Norctrend Index in Anesthesia

The purpose of this study is to determine whether the Circadian Rhythms effects on the Norctrend Index in Anesthesia.

It has been reported that circadian rhythm has many aspects of influence on human body. But little is knew about the circadian rhythm affect on Narcotrend index (made in Germany) in total intravenous anesthesia .The investigators' study is to find the relationship between them.

Inclusion Criteria:

• American Society of Anesthesiologists（ASA） Ⅰ - Ⅱ;
• ability to compliance the research plan;
• volunteered and signed for the study ;
• receive surgery and general anesthesia

Exclusion Criteria:

• ASA>Ⅱ;
• Head or facial surgery
• can't collaborate;