Anesthesia for Thyroid Parathyroid Procedures Flashcards
What is an example of indications for Thyroid Disease?
Grave’s Disease
Thyroid Nodule
Multinodular Goiter
Thyroid Cancer
What is an example of indications for Parathyroid Disease?
Primary Hyperparathyroidism (Only1 gland involved 80% cases)
Hypercalcemia
Parathyroid Adenoma
Parathyroid Cancer
Describe Thyroid Arterial Blood Supply.
Superior thyroid artery (branch of external carotid artery)
Inferior thyroid artery (branch of the thyrocervical trunk)
Anatomical variant the thyroid internal mammery artery (which has a variable origin/ex. aorta)
4-6cc/min/gram
Thyroid Venous Drainage is carried out by which veins?
Venous drainage is carried out by the superior, middle and inferior thyroid veins, which form a venous plexus
Which Nerve is of greatest concern for injury during thyroid or parathyroid surgery?
Where does this nerves name originate?
Clinical Relevance: Recurrent Laryngeal Nerve gets its name from the fact that it loops below the aorta on its way to the intrinsic muscles of the larynx. The RLN arise from their respective vagus nerves, and descend into the chest.
The left recurrent laryngeal nerve passes under and around the aorta on its way to the larynx, whereas the right recurrent laryngeal nerve passes under and around the subclavian artery.
During surgery on the thyroid gland, care must be taken not to ligate or damage the recurrent laryngeal nerves.
Describe the Anatomy & Physiology of the Thyroid Gland.
The thyroid is a highly vascular gland located anterior to the trachea in the lower neck (just below cricoid cartilage), extending from the level of the 5th cervical vertebra down to the 1st thoracic. Shaped from an H to a U and has 2 elongated lateral lobes with superior and inferior poles connected by a median isthmus, overlying the second to fourth tracheal rings.
What is the Primary Goal for patients with Thyroid Disease?
Ensure Euthyroid state prior to procedure if possible.
Assessment & Patient History
Elicitation of symptoms r/t thyroid disease & co-morbid medical diseases
Voice Change?
History of difficulties encountered during normal breathing
Dyspnea
Orthopnea (is patient propped up with pillows or need for sleeping?)
Dysphagia
Stidor or breathlessness with supine position
Risk of MEN syndrome with above symptoms (MEN Multiple Endocrine Neoplasia Syndrome) is a rare genetic disorder of abnormal growth of endocrine tumors or enlarged gland growth
Pre-operative Ultrasound of neck (lymph nodes) if malignancy suspected
Which multi-disciplinary care providers would be included in a multidisciplinary approach for a patient with thyroid / parathyroid disease?
Endocrinologist Surgeon Cardiologist Radiologist Anesthesiologist
What are extreme examples of thyroid dysfunction?
Hyperthyroidism
Watch for Thyroid Storm (Thyrotoxicosis)
Hypothyroidism
Watch for Myxedema Coma
What are some areas to look into when assessing for co-morbid diseases?
Cardiac disease
Respiratory disease
Other endocrine disorders
How can you identify Signs of tracheal compression and vocal cords palsy?
Examination of Goiter
Size
Consistency
Duration and extent of enlargement
Fixed and hardness of gland (malignancy?)
Inability to feel lower border of thyroid gland consider retrosternal extension
Retrosternal extension may cause Superior Venocaval Obstruction Syndrome (SVC Syndrome)
May see pleural and pericardial effusion
May see Horner’s syndrome (Classic Triad: Miosis, Partial Ptosis & Anhidrosis)
What is Horner’s syndrome
results from an interruption of the sympathetic nerve supply to the eye and is characterized by the classic triad.
Classic Triad: Miosis, Partial Ptosis & Anhidrosis
Transient Horner syndrome is a well-known side effect of stellate ganglion block, interscalene block of the brachial plexus, and occasionally epidural analgesia.
May also be caused by Lesions of the Pontine, lesions thalamus &/or hypothalamus, such as tumor or hemorrhage.
In Airway Evaluation, what are predictors of Impossible Mask Ventilation?
Male Beard Obstructive sleep apnea (moderate to severe, requiring PAP treatment) Mallampati III or IV H/of neck radiation
In Airway Evaluation, what are Predictors of Difficult Face Mask Ventilation?
Age > 57 y.o. Body Mass Index ≥ 30 kg/m2 Beard Snoring or OSA Lack of teeth Mallampati III or IV Limited mandibular protrusion
A potential difficult airway with planned DVL should include at least two clearly defined backup airway management plans READILY AVAILABLE. What are some backup plans?
Video laryngoscopy (e.g., Glidescope) will often improve airway visualization
LMA-Fastrach™ provides rescue ventilation with a 95-100% success rate in difficult airway situations.
Optimize patient position
Have intubating aids readily available Bougie, Stylettes
Which Thyroid and Parathyroid disease factors surround Airway Evaluations & History / Physical Findings?
Anatomic characteristics (e.g., ↓ C-spine ROM, large tongue, receding jaw, etc.)
Hx of stridor and hoarseness (airway narrowing and possible vocal cord (VC) dysfunction)
Previous Hx of neck surgery, trauma, or XRT (↓ compliance of the tissues, ↓ neck ROM, ↓ mouth opening)
Previous Hx of difficult intubation
Infections (e.g., epiglottitis, retropharyngeal abscess, Ludwig’s angina)
Why would an indirect laryngoscopy be performed prior to a thyroid or parathyroid procedure?
To assess vocal cord movement prior to procedure (and sometimes after procedure)
Consider an indirect laryngoscopy prior to thyroid surgery by ENT specialist
3-5% of population has unilateral paralysis of vocal cords
ENT may assist in surgical airway if needed
What type of Radiological investigations should be considered for thyroid/parathyroid procedures?
Large thyroid gland?
X Rays of Chest & Neck should be reviewed
Large thyroid gland and retrosternal extension, computed tomography (CT) scan or magnetic resonance imaging (MRI) is preferable to delineate the exact location and extension
May obtain diagnosis of Tracheal Stenosis with spiral CT scan
