Propofol is one of the most commonly used anesthetics in the world. However, the dose-response of propofol was remarkable variety. Herein, this study aims to investigate the possible association of gene polymorphism and propofol susceptibility, and to research more precise infusion model of this drug.

Patients undergoing gastrointestinal endoscopy will be recruited. Anesthesia is induced with propofol via TCI at 1.5µg/ml, and increases 0.5µg/ml for every 3min until OAA/S score 0. During this period, OAA/S score will be evaluated every 1min until OAA/S score 0. At this moment, the blood concentration of propofol, the doses of propofol, the onset time and BIS are recorded, and blood sample for gene polymorphism detection were required.

Inclusion Criteria:

1. patients who undergoing gastrointestinal endoscopy with anesthesia
2. age ≥18 years

Exclusion Criteria:

1. hepatic or kidney function injured;
2. received hypnotic sedative drug regularly;
3. Pregnancy, excessive drinking, or current smoker;
4. be allergic to propofol
5. patients who with difficulty communication

patients who will undergo gastrointestinal endoscopy with propofol