Abstract
Adequate preoperative assessment, recognition of the compromised airway, optimal preparation, achieving euthyroid status, and intraoperative recurrent laryngeal nerve monitoring minimize the complications of thyroidectomy. We present a case of a hyperthyroid patient with possible tracheal compression, then review the assessment, preparation, and management of such patients, including an approach to the patient with hyperthyroid crisis. We also discuss a postoperative scenario of an evolving airway obstruction and discuss the management.
Keywords
airway obstruction, anesthesia, complications, thyroidectomy, thyroid surgery
Case Synopsis 1
A 55-year-old woman with a 5-year history of swelling in the front of the neck presented for subtotal thyroidectomy. She has a history of palpitations on minimal exertion. She gives a history of shortness of breath on lying supine and prefers to sleep on her side. She also has an altered voice. A prominent thyroid gland is palpated on physical examination. The chest radiograph demonstrates moderate displacement of the trachea to the right from the midline. Indirect laryngoscopy revealed bilateral normal vocal cord function.
Case Synopsis 2
The same patient underwent uneventful subtotal thyroidectomy for multinodular goiter. The patient complains of difficulty in breathing 3 hours after surgery. On examination the patient is slightly restless, and mild inspiratory stridor is noted. Pulse oximetry reveals an arterial oxygen saturation of 94% on 2 L/min of nasal O 2 and other vital signs are stable.
Acknowledgment
The authors wish to thank Dr. Samuel A. Irefin for his contribution to the previous edition of this chapter.
Problem Analysis: Case Synopsis 1
Thyroid surgery may range from lobectomy to total thyroidectomy ( Table 51.1 ). Solitary thyroid nodule may be removed by lobectomy or hemithyroidectomy. The most common cause of hyperthyroidism is Graves disease. Toxic adenoma and toxic multinodular goiter (MNG) are other causes of hyperthyroidism. Surgical management of Graves disease involves near-total thyroidectomy. However, aggressive thyroid malignancy may require extensive neck dissection in addition to total thyroidectomy.
| Thyroid Disease | Type of Surgery | Potential for Complication |
|---|---|---|
| Small solitary nodule | Hemithyroidectomy | Low risk of injury to laryngeal nerves |
| Solitary toxic adenoma | Ipsilateral lobectomy | Hyperthyroidism |
| Retrosternal goiter | Subtotal thyroidectomy | Risk of severe bleeding, airway obstruction May require a sternotomy approach |
| Graves disease | Total thyroidectomy | Hyperthyroid crisis |
| Aggressive malignancy | Total thyroidectomy with neck dissection | Injury to the laryngeal nerves May require tracheostomy |
| Thyroglossal duct cyst excision | Sistrunk procedure | Inadvertent damage to thyroid cartilage causing severe airway obstruction |
Preoperative Assessment
Adequate preoperative assessment with optimal preparation of the patient minimizes the postoperative complications of thyroidectomy. Preoperative assessment involves history, examination, thyroid function tests, imaging, and evaluation of vocal cord function ( Table 51.2 ). Preoperatively it is important to ensure euthyroid status. Graves disease is a common cause of hyperthyroidism, followed by MNG and toxic adenomas.
| History | To assess airway compromise (dyspnea on lying supine) To assess symptoms of hyperthyroidism/hypothyroidism Medication history including antiplatelet agents/anticoagulants Remember: association of pheochromocytoma with medullary carcinoma of thyroid |
| Examination | For retrosternal extension of goiter Look for SVC obstruction—facial plethora—Pemberton sign |
| Blood tests | Full blood count (methimazole may cause agranulocytosis) Blood grouping and typing Thyroid function tests |
| Imaging | Chest x-ray—tracheal deviation CT scan—anatomic level and extent of tracheal narrowing |
| Nasendoscopy | Assessment of vocal cord function |
| ECG (e.g., in AF) | Assess rhythm, presence of LVH, ischemic changes |
| Lung function tests Flow-volume loop | In extrathoracic airway obstruction (goiter) the inspiratory airflow is reduced This distinguishes local pressure effects caused by the goiter from underlying asthma |
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