The Effect of Esketamine on Cough Reflex During Tracheal Extubation in Patients Undergoing Open Thyroid Surgery

This study intends to conduct a prospective randomized controlled trial to implement esketamine-assisted anesthesia in patients undergoing open thyroidectomy, in order to observe the effect of esketamine on coughing during extubation in thyroidectomy patients.

Inclusion Criteria: * Patients scheduled for elective open thyroid surgery * ASA class I-II * Voluntarily participate in the study and sign the informed consent form Exclusion Criteria: * Body Mass Index \> 30 kg/m² * Patients with unstable ischemic cardiomyopathy, pulmonary hypertension, poorly controlled or untreated hypertension (arterial hypertension, resting systolic/diastolic blood pressure \>180/100 mmHg) * Hepatic or renal dysfunction * History of oral, maxillofacial, neck, or airway surgery, or pathological structural alterations * Respiratory diseases (COPD, asthma, inflammation, chronic cough) * Patients with elevated intracranial pressure * Patients undergoing repeat surgery * History of allergy to the investigational drug used in the study * Patients with psychiatric disorders or alcohol abuse (daily ethanol intake ≥40 g, or having experienced alcohol withdrawal within the past 6 months, or unable to control alcohol consumption)