the Research of the Cerebral Protection Effects of Electroencephalogram (SedLine) During Carotid Endarterectomy

Inclusion Criteria: 1. Patients undergoing elective carotid endarterectomy; 2. All those who agree to join the trial and sign the informed consent form; 3. ASAI to III. Exclusion Criteria: 1. Those who refuse to sign the informed consent form; 2. ASA Level IV and above; 3. Unstable angina or acute myocardial infarction within 4 to 6 weeks before surgery, and heart function NYHA III to IV; 4. Those with severe liver and kidney function diseases; 5. Preoperative combined cognitive impairment; \[MMSE reference demarcation value: illiterate (uneducated) group ≤ 19 points, primary school (education years ≤ 6 years) group ≤ 22 points, secondary school or above (education years) 6 years) group ≤26 points; MoCA reference demarcation value: illiterate ≤13, primary school ≤19, middle school and above ≤24. \] 6. Preoperative combined anxiety and depression; (SDS or SAS\>41 points) 7. Patients with an endotracheal intubation returning to the ICU; 8. severe allergic reactions, major bleeding, etc. during surgery, causing severe fluctuations in hemodynamics; 9. The subject actively requested to withdraw from the study or to be lost to follow-up.