What is the recommended anesthesia regimen for a hemithyroidectomy (partial thyroid removal)?

Anesthesia Management for Hemithyroidectomy

General anesthesia with endotracheal intubation is the recommended anesthesia regimen for hemithyroidectomy, with special consideration for potential airway challenges and nerve monitoring requirements. 1, 2

Pre-anesthetic Assessment

• Thorough airway assessment is essential before hemithyroidectomy, including evaluation of neck mobility, mouth opening, thyromental distance, and any signs of tracheal deviation or compression 1
• Review thyroid anatomy and physiology to assess for potential difficult airway due to enlarged thyroid gland, abnormal laryngeal structures, or presence of goiter 2
• Evaluate thyroid function tests (TSH, FT4, T3) to determine thyroid status 2
• Communicate with the surgical team about any special monitoring requirements, particularly if recurrent laryngeal nerve monitoring will be used, as this will affect choice of muscle relaxants 1, 2

Anesthesia Induction and Airway Management

• Position the patient supine with neck extended to ensure optimal surgical exposure 1
• Apply cricoid pressure during induction to reduce aspiration risk 1
• If nerve monitoring is planned, avoid long-acting neuromuscular blocking agents as they are absolutely contraindicated 1, 2
• Consider videolaryngoscopy for first intubation attempt, especially if any predictors of difficult airway are present 1
• Routine use of an intubating bougie is recommended to optimize first-pass intubation success 1
• Confirm correct tube placement with clinical assessment and waveform capnography 1
• Have difficult airway equipment readily available, as thyroid pathology may cause tracheal deviation or compression 1, 2

Anesthetic Maintenance

• Sevoflurane is preferred over desflurane for maintenance of anesthesia, as desflurane has been associated with worse emergence agitation in adult patients undergoing thyroid surgery 3
• Consider administering dexamethasone (0.15-1.0 mg/kg, maximum 8-25 mg) to reduce post-operative laryngeal edema 1
• For patients on corticosteroids, provide stress-dose steroids, including hydrocortisone 100 mg IV at induction, followed by continuous infusion of 200 mg/24h 2

Special Considerations

• Accurate endotracheal tube placement is critical when nerve monitoring is used; improper electrode placement can lead to false monitoring security 1
• Avoid excessive neck manipulation during intubation to prevent disruption of thyroid pathology 1
• Be cautious with endotracheal tube cuff pressure, as placement adjacent to the recurrent laryngeal nerve may cause temporary voice dysfunction 1
• While local anesthesia has been reported as an alternative approach for thyroidectomy in selected patients, general anesthesia remains the standard of care for most cases 4, 5

Post-operative Management and Potential Complications

• Monitor for signs of post-thyroidectomy hematoma using the DESATS approach: difficulty swallowing/discomfort, elevated early warning score, swelling, anxiety, tachypnea/difficulty breathing, stridor 1, 6
• Perform routine observations at least hourly for the first 6 hours postoperatively, as hemorrhage and subsequent hematoma most frequently occur within the first 24 hours 6
• Position patient in head-up position to optimize airway patency if there are concerns about hemorrhage or hematoma 6
• Assess voice function immediately postoperatively and be prepared for possible airway compromise requiring re-intubation 2
• Have emergency front-of-neck airway equipment immediately available in case of post-operative airway compromise 1, 6
• If hematoma with airway compromise occurs, follow the SCOOP approach: skin exposure, cut sutures, open skin, open muscles, pack wound 1, 6

Pitfalls to Avoid

• Stridor may be a late sign of airway compromise and warrants immediate management 6
• Drains do not prevent hematoma formation in routine thyroid surgery, and clot formation may prevent free drainage, providing false reassurance 6
• Do not remove cricoid pressure prematurely, but be prepared to release it if laryngoscopic view is difficult 1
• Dizziness may be related to anesthesia effects, pain medication, or positional changes - these should be considered after excluding more serious causes 6