Effect of Dexmedetomidine After Thyroidectomy

Smooth emergence from general anaesthesia after surgery is important to prevent potentially dangerous effects such as hypertension, tachycardia, myocardial ischaemia, arrhythmias and increased intracranial and intra-abdominal pressure. After thyroidectomy, activities during emergence such as agitation or coughing, signs of hypertension or tachycardia, or etc. may lead to postoperative bleeding, resulting in acute airway obstruction or reoperation.

The purpose of the present study was to compare the effect of dexmedetomidine which is administered during emergence in adult patients undergoing elective thyroidectomy on smooth emergence form general anesthesia and postoperative outcome.

• Desflurane (Drug), also known as Anesthetic gas: Anesthesia is maintained with desflurane
• Remifentanil (Drug), also known as Opioid: Remifentanil is infused for the maintenance of anesthesia during surgery and discontinued 15 min before end of surgery
• Thyroidectomy (Procedure), also known as Surgery: The aim of this study is evaluation of effect of dexmedetomidine on emergence response and postoperative outcome after thyroidectomy
• Vital signs (Other), also known as Hemodynamics: 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.
• Cough reflex (Behavioral): During recovery from anesthesia at operation room, cough reflex is measured and rated. \[Grade 0, no cough; Grade 1, single cough with mild severity; Grade 2, cough persistence less than 5 s with moderate severity; Grade 3, severe, persistent cough for more than 5 s (bucking)\]
• Ramsay Sedation Scale (Behavioral), also known as RSS: 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
• Extubation time and Recovery time (Other): 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.
• Visual analogue scale (Behavioral), also known as VAS: The severity of pain after surgery is measured by VAS (at recovery room, POD 1, POD 2, and POD 3)
• Postoperative bleeding (Other): The amount of postoperative bleeding which is collected in the barovac is measured.
• Postoperative complications (Other): Postoperative complications after thyroidectomy such as hoarseness and hematoma, and reoperation due to such complication is observed.
• Time to remove drainage and duration of hospital staying (Other): The time from the end of surgery to remove drainage is measured. And the duration of hospital staying is measured.
• Dexmedetomidine (Drug), also known as Precedex: Dexmedetomidine has started infusion for 15 min (rate of 0.6 ug/kg/hr) before end of surgery as experimental intervention
• Normal saline (Drug), also known as NS: Normal saline has started infusion for 15 min (as same rate of dexmedetomidine) before end of surgery as control intervention

Primary outcomes

• Postoperative bleeding [From the end of surgery to the 3rd postoperative day (an expected average of 3 days)]: Postoperative bleeding: Sum of bleeding via barovac

Secondary outcomes

• Ramsay Sedation scale [During the recovery time of anesthesia, an expected average of 20 min]: Ramsay Sedation scale at recovery room
• Extubation time [During the recovery time of anesthesia, an expected average of 20 min]: time to extubation from the end of surgery
• Recovery time of anesthesia [During the recovery time of anesthesia, an expected average of 20 min]: time to transfer to recovery room from the end of surgery
• Duration of hospital stay [Participants will be followed for the duration of hospital stay, an expected average of 1 week]: Duration of hospital stay
• Pain score [From the end of surgery to the 3rd postoperative day (an expected average of 3 days)]: Pain score: NRS
• Incidence of postoperative complications [Participants will be followed for the duration of hospital stay, an expected average of 1 week]: Hoarseness, hematoma, and reoperation
• Coughing Response [During the recovery time of anesthesia, an expected average of 20 min]: Coughing Response during recovery from anesthesia

Other outcomes

• Vital signs [From 15 min before the end of surgery to the time when the patient has transferred to the recovery room, an expected average of 40 min]: Systolic blood pressure, diastolic blood pressure, mean arterial pressure, and heart rate
• Complications of testing drug [During infusion of testing drug (15 min)]: Hypertension, hypotension, bradycardia, tachycardia, and desaturation after infusion of dexmedetomidine or normal saline

Sex: Female, ages: 20 Years to 60 Years

Inclusion Criteria:

* Female patient,
* Aged 20-60 yr,
* ASA physical status 1-2,
* Patients undergoing elective thyroidectomy under general anesthesia

Exclusion Criteria:

* Sighs of difficult airway,
* History of respiratory disease or chronic cough,
* Cardiovascular disease,
* Pregnant or breast-feeding woman

• Patel A, Davidson M, Tran MC, Quraishi H, Schoenberg C, Sant M, Lin A, Sun X. Dexmedetomidine infusion for analgesia and prevention of emergence agitation in children with obstructive sleep apnea syndrome undergoing tonsillectomy and adenoidectomy. Anesth Analg. 2010 Oct;111(4):1004-10. doi: 10.1213/ANE.0b013e3181ee82fa. Epub 2010 Aug 12. PMID 20705788
• Reeve T, Thompson NW. Complications of thyroid surgery: how to avoid them, how to manage them, and observations on their possible effect on the whole patient. World J Surg. 2000 Aug;24(8):971-5. doi: 10.1007/s002680010160. PMID 10865043
• Results publication: Lee B, Lee JR, Na S. Targeting smooth emergence: the effect site concentration of remifentanil for preventing cough during emergence during propofol-remifentanil anaesthesia for thyroid surgery. Br J Anaesth. 2009 Jun;102(6):775-8. doi: 10.1093/bja/aep090. Epub 2009 May 2. PMID 19411668
• Results publication: Kim SH, Kim YS, Kim S, Jung KT. Dexmedetomidine decreased the post-thyroidectomy bleeding by reducing cough and emergence agitation - a randomized, double-blind, controlled study. BMC Anesthesiol. 2021 Apr 12;21(1):113. doi: 10.1186/s12871-021-01325-6. PMID 33845761

• Ki Tae Jung, M.D., Study chair, Chosun University Hospital