The purpose of this study is to determine the effect of desflurane on postoperative cognitive dysfunction

Postoperative cognitive dysfunction is a common complication during postoperative period，especially in elderly patients. It is characterized by cognitive decline, inattention and abnormal mental status following surgery. The presence of postoperative cognitive dysfunction is independently associated with poor recovery, increased hospital length of stay and increased mortality.

Desflurane is a widely used volatile anesthetic, associated with shorter emergence times than other volatile anesthetics. This study aims to access the effect of desflurane in preventing postoperative cognitive dysfunction.

Inclusion Criteria:

• 1. Written consent given
• 2. Scheduled to undergo elective non-cardiac surgeries under general anesthesia
• 3. ASA Physical Score I-III

Exclusion Criteria:

• 1. Patients with a history of neurological disease, such as Alzheimer disease.
• 2. Patients with a history of psychiatric disease
• 3. Patients with a medication history of antipsychotic drugs.
• 4. Unable to complete neuropsychological testing including patients with severe visual or hearing impairment.
• 5. Patients with preoperative delirium.
• 6. Patients who have severe adverse events, such as cardiac arrest.
• 7. Patients who preoperative MMSE score are below 20;
• 8. Patients who undergo second operation in a short period.