This prospective observational study aims to evaluate the association between perioperative hypothermia and sevoflurane consumption in elderly patients undergoing hip arthroplasty under general anesthesia. Patients aged 65 years and older will be included. Perioperative body temperature and anesthetic consumption will be recorded, and the relationship between hypothermia and anesthetic requirements will be analyzed. The findings may help clarify whether hypothermia influences anesthetic depth monitoring and anesthetic consumption in elderly surgical patients.

Inclusion Criteria:

• Age ≥ 65 years
• Elective hip arthroplasty under general anesthesia
• ASA physical status I-III

Exclusion Criteria:

• Preoperative Mini-Cog score ≤ 2
• Neurological or psychiatric disorders affecting cognitive function
• Endocrine or metabolic disorders affecting thermoregulation
• Excessive intraoperative blood loss
• Emergency surgery

Patients aged 65 years and older undergoing elective hip arthroplasty under general anesthesia.