During the laparoscopic cholecystectomy, Pneumoperitoneum could affect to the regional oxygen saturation of brain. positive end expiratory pressure (PEEP)could improve the respiratory parameters include oxygenation. So applying PEEP could improve the regional brain oxygen saturation (rSO2)

During the laparoscopic cholecystectomy, Pneumoperitoneum could affect to the regional oxygen saturation of brain due to increased intracranial pressure, central venous pressure and make worse to respiratory parameters. Positive end expiratory pressure could improve the respiratory parameters include oxygenation. So applying PEEP could improve the regional oxygen saturation of brain during the pneumoperitoneum during the laparoscopic cholecystectomy.

Inclusion Criteria:

• ASA I or II,
• 20-65 year,
• patient who undergoing laparoscopic cholecystectomy

Exclusion Criteria:

• cerebrovascular disease,
• coronary artery disease,
• morbid obesity (BMI > 30)
• propofol allergy,
• addictive