Thyroid surgery requires smooth emergence from anesthesia to minimize coughing, hemodynamic fluctuations, and agitation during extubation, which may contribute to postoperative complications such as bleeding or cervical hematoma. Dexmedetomidine, a selective α2-adrenergic receptor agonist, has sedative, analgesic-sparing, and sympatholytic properties that may improve anesthetic stability and recovery quality.

This randomized controlled trial aims to evaluate the effectiveness of a continuous perioperative dexmedetomidine regimen initiated at induction of anesthesia and maintained during thyroid surgery.

The study will compare dexmedetomidine combined with standard balanced anesthesia versus standard anesthesia alone in terms of anesthetic requirements and emergence quality.

The primary hypothesis is that perioperative dexmedetomidine administration reduces anesthetic and opioid requirements and improves emergence quality by decreasing coughing during extubation and hemodynamic responses.

Dexmedetomidine has been widely studied as an anesthetic adjunct due to its sedative and analgesic-sparing effects without significant respiratory depression. Previous randomized trials have demonstrated its ability to reduce coughing during extubation, attenuate sympathetic responses, and improve recovery quality after thyroid surgery. However, most studies have administered dexmedetomidine only during emergence or intraoperatively.

This study investigates a comprehensive perioperative dexmedetomidine protocol consisting of:

• A loading dose immediately before induction of anesthesia
• Continuous infusion during surgery The aim is to assess whether this regimen improves intraoperative anesthetic efficiency and postoperative recovery quality.

Patients scheduled for thyroid surgery under general anesthesia will be randomized to receive dexmedetomidine or standard anesthesia without dexmedetomidine. Standardized anesthetic techniques will be used for induction, maintenance, and postoperative care.

Outcome measures include anesthetic requirements, opioid consumption, coughing at extubation, emergence agitation, hemodynamic responses, postoperative nausea and vomiting (PONV), and postoperative bleeding complications.

Inclusion Criteria:

• Age 18-65 years.
• American Society of Anesthesiologists (ASA) physical status I-III.
• Scheduled for elective thyroid surgery (thyroidectomy) under general anesthesia with endotracheal intubation.
• Able to understand the study procedures and provide written informed consent.

Exclusion Criteria:

• Known hypersensitivity or contraindication to dexmedetomidine or study-related medications.
• Clinically significant cardiac conduction abnormality or arrhythmia (e.g., second- or third-degree atrioventricular block without a pacemaker), severe bradyarrhythmia, or unstable cardiovascular disease.
• Severe hepatic dysfunction or severe renal failure.
• Pregnancy or breastfeeding.
• Planned postoperative ICU admission or postoperative deterioration requiring ICU admission.
• Major intraoperative complications (e.g., major bleeding requiring urgent hemostatic intervention, tracheal or esophageal injury, or recurrent laryngeal nerve injury identified intraoperatively).
• Any condition that, in the investigator's judgment, would interfere with outcome assessment or increase risk (e.g., inability to reliably report pain scores or complete QoR-15).

De-identified individual participant data (IPD) underlying the published results, along with the study protocol and statistical analysis plan, will be available upon reasonable request.

Beginning 6 months after publication and ending 24 months after publication.

Requests will be reviewed by the study investigators. Data will be shared for non-commercial research purposes following approval and execution of a data use agreement.

Double-blind (Participant, Outcome Assessor)