Effect of Dexmedetomidine After Thyroidectomy

Anesthesia is maintained with desflurane

Remifentanil is infused for the maintenance of anesthesia during surgery and discontinued 15 min before end of surgery

The aim of this study is evaluation of effect of dexmedetomidine on emergence response and postoperative outcome after thyroidectomy

"Systolic blood pressure, diastolic blood pressure, mean arterial pressure, and heart rate are measured before infusion of testing drugs, after infusion of them (5 min, 10 min, and 15 min), during extubation (0 min and 5 min after extubation), and at recovery room.~And the complications such as hypotension, hypertension, bradycardia, tachycardia, and desaturation after infusion of testing drugs are observed."

During recovery from anesthesia at operation room, cough reflex is measured and rated. \[Grade 0, no cough; Grade 1, single cough with mild severity; Grade 2, cough persistence less than 5 s with moderate severity; Grade 3, severe, persistent cough for more than 5 s (bucking)\]

"When the patient has fully awaken and transferred to the recovery room, Ramsay Sedation Scale is measured.~1. Awake Patient anxious and agitated or restless or both!~2. Patient cooperative, oriented and tranquil!~3. Patient responds to commands only!~4. Asleep A brisk response to a light glabellar tap or loud auditory stimulus!~5. A sluggish response to a light glabellar tap or loud auditory stimulus!~6. No response to a light glabellar tap or loud auditory stimulus"

"The time from discontinuing anesthetic gas to endotracheal extubation is measured.~And the time from the discontinuing of anesthetic gas to transferring to the recovery room is also measured."

The severity of pain after surgery is measured by VAS (at recovery room, POD 1, POD 2, and POD 3)

The amount of postoperative bleeding which is collected in the barovac is measured.

Postoperative complications after thyroidectomy such as hoarseness and hematoma, and reoperation due to such complication is observed.

The time from the end of surgery to remove drainage is measured. And the duration of hospital staying is measured.

Dexmedetomidine has started infusion for 15 min (rate of 0.6 ug/kg/hr) before end of surgery as experimental intervention

Normal saline has started infusion for 15 min (as same rate of dexmedetomidine) before end of surgery as control intervention