AANA Journal Course 1

Update for Nurse Anesthetists 6 CE Credits*

Anesthesia Case Management for Thyroidectomy

Sass Elisha, CRNA, EdD
Michael Boytim, CRNA, EdD
Sandy Bordi, CRNA, MSN
Jeremy Heiner, CRNA, MSN
John Nagelhout, CRNA, PhD, FAAN
Ed Waters, CRNA, MN

An intimate knowledge of the anatomy, physiology, essential that all patients having an elective thyroidec-
pathophysiology, pharmacology, and specific issues tomy be in a euthyroid state before surgery. There are
related to anesthesia case management for thyroidec- multiple preoperative antithyroid medication regimens
tomy is essential to provide high-quality care. Airway that effectively treat thyroid hormone hypersecretion.
management may be difficult despite a normal airway However, although a rare event, thyroid storm can still
examination due to impingement of a thyroid mass on occur during the perioperative period. Anesthetic con-
the laryngeal and tracheal structures. Anesthetists must siderations and surgical complications are presented.
be prepared to use emergency airway adjuncts in case
a patient cannot be ventilated or intubated. Because Keywords: Antithyroid medications, nerve integrity
sympathetic nervous system hyperactivity is associ- monitor endotracheal tube, recurrent laryngeal nerve
ated with increased amounts of thyroid hormone, it is injury, thyroidectomy, thyroid storm.

Objectives ough knowledge of the pathophysiology and potential

At the completion of this course the reader should be able complications associated with thyroidectomy is neces-
to: sary for competent patient care. A nerve integrity
1. Explain the signs and symptoms that result from re- monitor (NIM) endotracheal tube (Medtronic Xomed,
current laryngeal nerve injury and the emergency in- Jacksonville, Florida) may be inserted to help the
terventions necessitated by such injury. surgeon assess the potential for recurrent laryngeal
2. Discuss the proper placement of a nerve integrity nerve (RLN) injury.
monitor endotracheal tube.
3. List the most common causes of hyperthyroidism. Anatomy and Physiology Associated With
4. Identify a preoperative antithyroid drug regimen for Thyroid Gland Structure and Function
patients with hyperthyroidism. The thyroid gland is butterfly-shaped and composed of 2
5. Describe the signs, symptoms, and treatment of thy- lobes that are connected by a median tissue mass named
roid storm. the thyroid isthmus.1 It is located on the anterior and an-
terolateral aspect of the trachea immediately inferior to
Introduction the larynx. The thyroid gland is the largest endocrine
The anatomic and physiologic effects associated with hy- gland in the body, weighing 20 g in a healthy adult. Its
perthyroidism can cause end-organ damage, hyperdy- major blood supply arises from the superior thyroid ar-
namic effects causing extreme cardiovascular lability, teries, which originate from the external carotid artery
and tracheal distortion causing difficult airway manage- and inferior thyroid arteries, a branch of the thyrocervi-
ment. Creating a euthyroid state by administering a pre- cal trunk. Blood flow is approximately 5 times the
operative antithyroid drug regimen is essential. A thor- weight of the gland, and, therefore, the thyroid receives

* AANA Journal Course No. 30 (Part 1): The American Association of Nurse Anesthetists is accredited as a provider of continuing edu-
cation in nursing by the American Nurses Credentialing Center Commission on Accreditation. The AANA Journal course will consist of
6 successive articles, each with objectives for the reader and sources for additional reading. At the conclusion of the 6 -part series, a
final examination will be published on the AANA website. Successful completion will yield the participant 6 CE credits (6 contact hours),
code number: 33539, expiration date: July 31, 2011.

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Figure 1. Thyroid Gland and Surrounding Anatomic Structures

one of the greatest blood supplies per gram of tissue in

the body.2 Venous drainage from the thyroid gland
passes into the superior thyroid veins to the internal
jugular veins and the inferior thyroid veins into the left
brachiocephalic vein.
The primary motor function associated with move-
ment of the intrinsic muscles of the larynx and vocal
cords is supplied by the RLN. The RLN controls abduc-
tion and adduction of the vocal cords via the posterior
cricoarytenoid muscles and the lateral cricoarytenoid
muscles, respectively. The external branch of the superi-
or laryngeal nerve innervates the pharyngeal constrictors
and the cricothyroid muscle, which enhances vocal cord
tension.3 These nerves lie in proximity to the lateral lobes
of the thyroid gland. During surgical resection, if these
nerves are temporarily or permanently damaged, vocal
cord movement can be adversely affected, which may
result in airway compromise after extubation. Anatomic
representation of the thyroid gland and its associated Figure 2. Thyroid Follicles
structures is shown in Figure 1. A more thorough expla-
nation of the results associated with RLN damage is given • Thyroid Hormone. Thyroid hormone, which has a
later in this course. dramatic effect on increasing the basal metabolic rate,
The thyroid gland is composed of spherical structures consists of thyroxine (T4) and triiodothyronine (T3). The
called follicles. The walls of the follicles are formed by major hormone secreted by the thyroid gland is T4,
cuboidal epithelial cells that produce the glycoprotein whereas most of the T3 is formed by the conversion of T4
thyroglobulin, which is essential for thyroid hormone to T3 at the target tissues. Despite the fact that the
synthesis.4 Colloid is stored in the central cavity of the fol- amounts of T4 and T3 in circulation are 90% and 10%, re-
licle, which is where the thyroglobulin is created (Figure spectively, the high potency of T3 results in production of
2). The creation of thyroid hormone is a complex process. 80% of the metabolic activity.

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Figure 3. Iodide Trapping and Organification of Thyroglobulin
I- indicates iodide; I, iodine.

• Synthesis. After iodide is ingested and absorbed by tion of thyroid-stimulating hormone (TSH) by the ante-
the gastrointestinal tract into the blood, thyroid hormone rior pituitary gland. Thyroid-stimulating hormone is
synthesis begins when iodide is actively transported from transported to the thyroid gland, which stimulates the
the plasma into the colloid of the follicle. Once inside the production of T4 and T3 by the thyroid gland. The home-
follicle, iodide is converted to iodine by thyroid peroxi- ostatic regulation of thyroid hormone production is
dase. This process is known as iodide trapping. maintained by a negative feedback loop. When normal or
The organification of thyroglobulin occurs when increased amounts of thyroid hormone are present, T4
iodine molecules attach to the amino acid tyrosine on the and T3 primarily inhibit further TSH secretion from the
thyroglobulin molecule.5 Thyroxine is formed when 2 di- anterior pituitary and secondarily by decreasing thy-
iodotyrosine compounds are linked, and T3 is composed rotropin-releasing hormone formation and release from
of diiodotyrosine and monoiodotyrosine (Figure 3). the hypothalamus (Figure 4).
• Transport. When released, the majority of T4 and T3 • Physiologic Effects. It is likely that all cells in the
are immediately bound to thyroxine-binding globulins and body are targets for thyroid hormones. Although not
albumin that are produced by the liver.6 Both hormones strictly necessary for life, thyroid hormones have pro-
bind to target tissue receptors; however, T3 has a higher found effects on many physiologic processes such as de-
affinity for binding and is 10 times more metabolically velopment, growth, and metabolism.7
active than T4. Despite the high degree of protein binding,
it is the unbound or free T3 that provides the majority of Pathophysiology
the metabolic effects. Most peripheral tissues contain the Thyroid dysfunction can be treated medically or surgically.
enzymes needed to convert T4 to T3; however, the majori- A thyroidectomy is performed as definitive treatment for
ty of deiodination occurs in the liver and kidneys. thyrotoxicosis and for malignancy. Thyrotoxicosis is a con-
• Regulation. Thyrotropin-releasing hormone is secret- dition in which excessive amounts of thyroid hormone are
ed by the hypothalamus, which stimulates the produc- present in a patient’s system; hyperthyroidism (the most

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 Symptoms
Heat intolerance
Palpitations
Fatigue and weakness
Anxiety and restlessness
Insomnia
Increased appetite
Signs
Weight loss
Warm, pink, moist skin
Tachycardia
Dysrhythmias (supraventricular tachycardia, atrial fibrillation)
Irregular menstruation
Reduced fertility
Goiter
Retraction or lag of eyelids
Ophthalmopathy (including exophthalmos)a
Pretibial myxedemaa

Table 1. Clinical Manifestations of Thyrotoxicosis

aSpecific to Graves disease.
(Adapted from Davies and Larsen.9 )

Figure 4. Neurologic Regulation of Thyroid Hormone adenoma does not usually manifest with clinical fea-
Secretion tures typical of other causes of thyrotoxicosis. The au-
tonomy of a toxic adenoma has been linked to a muta-
common cause of thyrotoxicosis) describes states in which tion that leads to altered function of the TSH receptor
the excessive thyroid levels are due to a hyperactive pathway.11
thyroid gland.8,9 When hyperthyroidism occurs, the follic- Graves disease accounts for 68% to 80% of cases and
ular cells of the thyroid produce 5 to 15 times the normal is the most common cause of thyrotoxicosis.11 This
amount of thyroid hormone.2 Hyperthyroidism occurs in pathologic process is most common among women
1% to 2% of women and in approximately 0.1% to 0.2% of between the ages of 20 and 40 years. Graves disease is the
men.9 Hyperthyroidism is most frequently caused by 1 of 3 result of an autoimmune process in which autoantibodies
pathologic processes: Graves disease, toxic multinodular stimulate TSH receptors to produce excessive amounts of
goiter, and toxic adenoma. thyroid hormones.10
Thyroid hormone has an essential role in metabolism; An unusual exacerbation of thyrotoxicosis, thyrotoxic
therefore, the signs and symptoms of thyrotoxicosis crisis (thyroid storm), manifests as severe hypermetabo-
reflect a generalized hypermetabolism (Table 1).9 A hy- lism with signs such as fever, tachycardia, ectopy, and
perfunctioning thyroid gland may enlarge to 2 to 3 times delirium.11 Thyrotoxicosis can be precipitated by infec-
the normal size and is termed a toxic goiter.2 Another type tion, surgery, and trauma and is more often associated
of goiter is commonly due to deficient thyroid hormone with Graves disease than with toxic multinodular goiter
synthesis or iodine deficiency. Nontoxic (or simple) or toxic adenoma.9
goiters are usually treated medically, and surgical resec- Malignancies of the thyroid gland are the most
tion is reserved for cases in which the goiter produces common malignancies of the endocrine system and have
compression of the trachea or major vessels or is unre- been associated with exposure to radiation.9,11
sponsive to medical treatment.10 Thyrotoxicosis is a rare occurrence (2%) in thyroid ma-
Toxic multinodular goiter is a condition in which mul- lignancies. Surgery is the principal treatment used to
tiple nodules within the thyroid gland assume functional treat thyroid malignancies and is used for excision of the
autonomy and secrete thyroid hormones independent of tumor and for staging. Most thyroid malignancies
the action of TSH. The cause of autonomy in toxic (>90%) are considered well differentiated and catego-
multinodular goiter is not well understood.9 rized as papillary thyroid carcinoma or follicular thyroid
Toxic adenoma (also called Plummer disease and hy- carcinoma. Papillary thyroid carcinoma accounts for
perfunctioning solitary nodule) is the result of a single 70% to 80% of thyroid malignancies and usually is dis-
thyroid nodule assuming functional autonomy. Toxic covered at an early stage and has an excellent prognosis

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 Drug Daily oral adult dosage Comments
Thionamides Starting: 10 - 40 mg once or in divided doses Methimazole preferred due to ease of dosing and a
Methimazole Maintenance: 5- 15 mg once or in divided doses better side effect profile; continue up to the
morning of surgery
Propylthiouracil Starting: 100 - 450 mg divided 2 or 3 times per day;
maintenance: 100 - 150 mg divided 2 or 3 times per
day
Iodide 1- 3 drops 3 times per day Iodide therapy added 1 wk before surgery and
Saturated solution of 5 drops 3 times per day continued through the day of surgery; decreases
potassium iodide; (dissolve in a full glass of water) production and release of thyroid hormone and
Lugol solution reduces thyroid vascularity
β-Blockers 20 - 40 mg 4 times per day β-Blockers without intrinsic sympathomimetic activ-
Propranolol ity are preferred; also used in emergency thyroid
(Inderal long acting) 80 - 160 mg once daily surgery for adrenergic suppression
Atenolol (Tenormin) 25- 100 mg once or twice daily
Metoprolol (Lopressor) 50 - 200 mg divided 2 or 3 times per day

Table 2. Oral Drugs Used to Treat Hyperthyroidism

(Adapted from Treatment guidelines from the Medical Letter: drugs for thyroid disorders. Med Lett Drugs Ther. 2009;84(7):57- 64.)

(>95% 10-year survival).8 Follicular thyroid carcinoma gias, and gastric intolerance. The onset of action is ap-
accounts for 10% of thyroid malignancies and tends to proximately 2 weeks and is noted by decreased nervous-
be discovered at a later stage than papillary thyroid car- ness, fewer palpitations, and less tachycardia. A euthy-
cinoma.10,11 The 10-year survival rate for follicular roid state is usually achieved within 4 to 6 weeks. At that
thyroid carcinoma is 85%.10 time, the dosage may be substantially reduced to main-
Medullary thyroid cancer arises from the parafollicu- tain a normal metabolic state. At 7 to 10 days before
lar cells of the thyroid and accounts for 5% to 10% of surgery, after the metabolic state has returned to normal,
thyroid malignancies. Medullary thyroid cancer can iodine therapy is generally started with saturated solution
occur as part of the syndrome of multiple endocrine neo- of potassium iodide or Lugol solution. Therapy with
plasia.12 Medullary thyroid cancer regularly invades iodine should not be started until a euthyroid state has
tissues distant from the thyroid gland. The prognosis been achieved. Antithyroid drugs should not be discon-
depends on the subtype of the tumor and its stage at the tinued when iodine therapy is started but are continued
time of diagnosis. until the morning of surgery.14
Many of the effects of hyperthyroidism are mediated
Preoperative Medication Regimens through adrenergic receptors, specifically, β receptors.
The preoperative use of antithyroid drugs has greatly de- The β-blocking drugs are widely used as an adjunct to
creased the morbidity from thyroid surgery and made thionamides for symptomatic control. They help decrease
thyroid storm a rare event. The aim of preoperative man- the palpitations, anxiety, heat intolerance, tremors,
agement is to restore a normal metabolic state before sur- profuse sweating, and tachycardia produced by high
gical intervention. Patients with hyperthyroidism have thyroid hormone levels. Propranolol has been traditional-
increased T3 and T4 values and decreased or normal TSH ly used; however, atenolol and metoprolol are both β1 se-
levels. The primary agents used to treat hyperthyroidism lective and may be substituted for propranolol. For pa-
are the thionamide class of drugs, including methimazole tients with a contraindication to β-blockers, diltiazem has
and propylthiouracil. Both drugs inhibit the synthesis of been successfully substituted. The β-blockers are general-
thyroid hormone by preventing the oxidation and ly continued throughout the surgical period and may be
organic binding of thyroid iodide, preventing the organi- incrementally withdrawn postoperatively.15 Drugs that are
fication of thyroglobulin. An intrathyroidal iodine defi- used to treat hyperthyroidism are listed in Table 2.
ciency is created that further increases the ratio of T3 to
T4. Because T3 is more potent than T4, a high T3 to T4 Preoperative Anesthetic Management
ratio results in a greater metabolic rate. Propylthiouracil The primary goals of the preoperative assessment are en-
also further inhibits the conversion of T4 to T3.13 suring that the patient is euthyroid, assessing the degree
Methimazole is preferred to propylthiouracil because of end-organ complications, and determining the extent
it can be given once per day and is effective at low of airway involvement.1,3,16 Patients who have not been
dosages. Major side effects are rare; however, agranulocy- medically managed for hyperthyroidism are at increased
tosis and hepatitis may occur. Minor side effects occur in risk for severe perioperative hemodynamic complica-
5% of patients and usually include nausea, rash, arthral- tions. In addition, thyroid tumors and large goiters can

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 Respiratory Chest radiograph, computed tomography scan of neck and chest, pulmonary function tests
Cardiovascular Electrocardiogram, echocardiography
Neurological Neurology consult if findings of history and physical examination indicate
Musculoskeletal Creatinine kinase, urine myoglobin
Endocrine Thyroid functions (thyroid-stimulating hormone, thyroxine, triiodothyronine) and glucose level
Hematologic Complete blood cell count, prothrombin time, international normalized ratio
Laboratory Metabolic panel and calcium, magnesium, phosphate, and alkaline phosphatase levels

Table 3. Preoperative Laboratory and Diagnostic Tests

(Adapted from Koransky et al.16 )

impinge on the tracheal cartilage and esophageal tissues, tions exist, an echocardiogram and a consultation with a
resulting in tracheomalacia and airway compromise.1 cardiologist should be obtained to evaluate myocardial
Preoperatively, the patient will be taking a combina- function. Patients with hyperthyroidism have a higher in-
tion of antithyroid medications to decrease the synthesis cidence of myasthenia gravis and may have skeletal muscle
and release of thyroid hormone and to treat the hyperdy- weakness. Care should be exercised because patients with
namic state associated with hyperthyroidism. The patient myasthenia gravis may have an increased sensitivity to
may have taken or be currently taking glucocorticoids muscle relaxants.1,3,16 If emergency surgery is necessary for
and, thus, require the administration of a steroid stress a patient with hyperthyroidism, the usual treatment
dose preoperatively or intraoperatively. In addition, a modality will be ineffective because achieving a euthyroid
single dose of steroids can be given to reduce the inci- state usually takes 6 to 7 weeks. Therefore, surgery should
dence of postoperative nausea and vomiting.17 Patients proceed only if a life-threatening situation exists.1 If time
should continue their regimen of antithyroid medications permits, oral potassium iodide can be given 6 hours pre-
and β-blockade through the morning of surgery.1,3 operatively to block hormone synthesis and release. A β-
A euthyroid state is associated with a normal temper- blocker such as metoprolol or esmolol should be titrated to
ature, a normal resting heart rate, and a normal blood decrease the heart rate, blood pressure, and sympathetic
pressure.16 Lack of patient fatigue, intolerance to heat, nervous system activation.1,16
and weight loss will further aid in determining the effica-
cy of the preoperative antithyroid medication regimen. Intraoperative Anesthetic Management
A thorough airway assessment is vital for patients with Intraoperative anesthetic management should focus on
hyperthyroidism, including visualization and palpation the prevention of sympathetic nervous system stimula-
of the patient’s neck to determine if a thyroid goiter tion, proper positioning, and adequate hemodynamic
exists. Thyroid gland enlargement can cause tracheal and monitoring.1,3 An adequate depth of anesthesia should be
esophageal deviation and compression. Therefore, it is established and maintained to prevent sympathetic
imperative to assess the patient’s ability to breathe while nervous system stimulation.1,16
in the supine position. Tracheomalacia can occur from General endotracheal anesthesia is the anesthetic tech-
chronic pressure on the tracheal cartilage, indicating the nique of choice for thyroidectomy. Infrequently, local
possibility for prolonged intubation. Signs and symptoms anesthesia such as a cervical plexus block can be consid-
of tracheoesophageal compression include stridor, ered; however, this technique is reserved for patients in
hoarseness, sore throat, a feeling of pressure in the neck, poor health in whom a general anesthetic is not indicat-
coughing, dysphagia, and/or dyspnea. The anesthetist ed.1,3 Thiopental administered for induction has been
should consider an awake fiberoptic intubation under shown to have antithyroid activity; however, it is doubt-
topical anesthesia for any patient who is perceived as ful that significant antithyroid activity would result after
having a difficult airway, has a large goiter, or has altered a single dose.1 Muscle relaxation can be provided to assist
airway anatomy.1,16 with tracheal intubation as long as the airway is not com-
Preoperative testing should be guided by the patient’s promised by a tumor or goiter.1,3 Paralysis is not routine-
health status and coexisting disease processes. Table 3 lists ly maintained because it will inhibit the surgeon’s ability
suggested preoperative tests for patients having a thyroid to assess the integrity of the RLN.
resection. If there is any indication for the potential for The Medtronic NIM electromyographic (EMG) endo-
airway compromise, a chest radiograph and a computed tracheal tube (Medtronic Xomed) is constructed of a
tomography scan of the neck and chest should be per- flexible silicone elastomer and has a distal inflatable cuff.
formed. Patients with hyperthyroidism commonly experi- The tube is fitted with 4 stainless steel wire electrodes (2
ence palpitations, increased heart rate, congestive heart pairs) that are embedded in the silicone of the main shaft
failure, and/or atrial fibrillation.16 If any of these complica- of the endotracheal tube and exposed only for a short

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Figure 5. Nerve Integrity Monitor (NIM) Endotracheal Tube
A. Refers to proper placement of the NIM endotracheal tube in relation to the thyroid gland.
B. Depicts the 4 electrode contact points in relation to the vocal cords.
LU indicates left upper; LL, left lower; RU, right upper; and RL, right lower.

distance, slightly superior to the cuff. The electrodes are frequent monitoring of neuromuscular function with a
designed to make contact with the patient’s vocal cords nerve stimulator are prudent.3 A combined deep and su-
to facilitate EMG monitoring of the RLN when connect- perficial cervical plexus block can be considered for in-
ed to a multichannel EMG monitoring device. If moni- traoperative and postoperative pain management.21
toring correctly, the EMG monitor should show a con- The patient should be constantly monitored for an in-
sistent sound signal and an action potential tracing.18 crease in core body temperature and a hyperdynamic re-
The red wire pair of the NIM tube should contact the an- sponse.1,3 If hypotension occurs, it is best treated with a
terior and posterior portions of the right true vocal cord, direct acting vasopressor (phenylephrine) rather than an
and the blue wire pair should contact the anterior and indirect acting vasopressor (ephedrine) that stimulates
posterior portions of the left true vocal cord (Figure 5). the release of catecholamines.3 Hypercarbia and hypoxia
Paralysis and laryngeal tracheal anesthesia administra- are potent stimulators of the sympathoadrenal axis;
tion with lidocaine inhibit accurate EMG readings. therefore, adequate inspired oxygen concentrations and
Research is ongoing regarding the efficacy of EMG; minute ventilations should be maintained.1
however, some studies have shown no statistically sig- The patient is positioned supine with the head elevated
nificant difference in outcome between a standard endo- 30° and the neck extended by using a roll behind the neck
tracheal tube and an NIM tube.19,20 and shoulders (Rose position).16 The arms are tucked at
At various institutions, the NIM tube is inserted by patient’s sides with the ulnar nerves padded and protected.
using a GlideScope (Verathon, Bothell, Washington), that Hyperextension of the neck should be avoided in patients
allows the surgeon and the anesthetist to visualize the with atlantoaxial joint instability and in patients with
vocal cords for correct placement. limited range of motion. Due to the limited access to the
Maintenance of anesthesia can be provided by inhala- face, special care should be taken to protect the eyes from
tional anesthetics such as sevoflurane and isoflurane with injury, especially in patients with exophthalmos.
or without nitrous oxide. The inhalation agents have an • Surgical Procedure. Removal of the thyroid gland can
inhibitory effect on the sympathetic nervous system, be accomplished via open surgical excision or by en-
which is especially important for patients with hyperthy- doscopy. Surgical excision requires a transverse neck inci-
roidism.1,16 Care should be taken when providing muscle sion approximately 6 to 8 cm long. It involves resection of
relaxation for patients with underlying myasthenia the total thyroid gland (total thyroidectomy); partial exci-
gravis. If muscle relaxation is used, cautious titration and sion of the gland, including the affected lobe, isthmus,

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 Ensure adequate oxygenation Hypocalcemia-hypoparathyroidism
Administer glucose-containing intravenous fluids Recurrent laryngeal nerve injury, unilateral or bilateral

Administer β-adrenergic blockers Neck hematoma

Thyroid storm
Administer sodium iodide
Superior laryngeal nerve injury
Administer propylthiouracil or methimazole
Infection
Administer glucocorticoids
Pneumothorax
Correct electrolyte imbalances
Tracheolmalacia
Correct acid-base imbalances Sympathetic trunk nerve injury (rare) resulting in Horner
Administer acetaminophen syndrome
Apply cooling blankets Thoracic duct injury (rare), chylous fistula

Table 4. Management of Thyroid Storm Table 5. Complications Associated With Thyroidectomy

(Adapted from Schwartz et al.3) (Adapted from Koransky et al.16 )

and, possibly, the remaining lobe (subtotal/partial thy- be avoided to prevent complications such as a hematoma
roidectomy); or excision of the affected lobe of the gland at the surgical site. The surgeon should be encouraged to
(lobar). During surgical excision, hemostasis is crucial; inject local anesthesia at the surgical incision to decrease
the 2 anterior jugular veins must be avoided, and ligation postoperative pain. Vocal cord function may need to be vi-
of the middle thyroid arteries is crucial. In addition, the sually assessed before extubation due to the possibility of
right and left RLNs, which lie along the tracheal RLN damage, tracheomalacia, or hematoma.1,16 The
esophageal grooves, need to be identified to avoid injury. patient should be monitored closely for postoperative res-
The estimated blood loss is approximately 50 to 75 mL.16 piratory distress.
In an effort to improve cosmetic results by minimizing
scarring of the neck, minimally invasive techniques for Postoperative Management
thyroid removal have been developed, including video- The most common postoperative complications include
assisted thyroidectomy and total endoscopic thyroidecto- hypocalcemia, RLN damage, and hematoma at the surgi-
my. Total endoscopic thyroidectomy can be performed by cal site. A comprehensive list of the potential postopera-
accessing the neck, chest wall (subclavicular or breast), tive complications is given in Table 5.
or axilla. Insufflation of carbon dioxide is used to aid Postoperative hypocalcemia can result from hy-
with surgical visualization and excision.22 Minimally in- poparathyroidism. The 4 parathyroid glands (2 superior
vasive techniques for removal of the thyroid gland remain and 2 inferior) are located on the posterior aspect of the
controversial because the gland must be removed intact thyroid gland and produce parathyroid hormone, which
for adequate histologic analysis.16 increases the serum calcium level.1,3,16,24 Inadequate
• Thyroid Storm. Any patient undergoing a thyroidec- release of parathyroid hormone is due to the inadvertent
tomy is at risk for thyroid storm throughout the perioper- removal of the parathyroid glands during a total thy-
ative period, even if the patient is in a euthyroid state pre- roidectomy. It can also occur secondary to parathyroid
operatively. Thyroid storm is most frequently caused by gland devascularization, injury, or “stunning” from dis-
physiologic stress.22 Thyroid storm is a life-threatening section.23,25
emergency, and its manifestations include tachycardia, hy- Hypocalcemia causes neuronal excitability in sensory
perpyrexia, hypertension, tremor, sweating, widened and motor nerves. Patients most commonly experience
pulse pressure, agitation, confusion, dysrhythmias, my- signs and symptoms associated with hypocalcemia 24 to
ocardial ischemia, and congestive heart failure. Prompt 96 hours postoperatively.3 The degree of hypocalcemia
recognition and diagnosis are essential to decrease mor- coincides with the severity of the symptoms, which
bidity and mortality because similarities exist in the symp- include perioral numbness and tingling, abdominal
toms of thyroid storm, pheochromocytoma, malignant pain, paresthesias of the extremities, carpopedal spasm,
hyperthermia, neuroleptic malignant syndrome, sepsis, tetany, laryngospasm, mental status changes, seizures,
anaphylaxis, and light anesthesia.1,23 Q-T prolongation on the electrocardiogram, and cardiac
Treatment of thyroid storm involves restoring intravas- arrest.1,3,24,26 Neuromuscular irritability can also be
cular volume, providing hemodynamic support, and con- confirmed by assessing for the Chvostek sign (facial
trolling hyperthermia. Table 4 lists the interventions used contractions elicited by tapping the facial nerve in the
to manage thyroid storm. Invasive hemodynamic moni- periauricular area) and the Trousseau sign (carpal
toring and vasodilating medications may be necessary to spasm after inflation of a blood pressure cuff).24,26 In
treat hypertension and cardiovascular instability.1,23 addition, monitoring postoperative ionized calcium
Excessively forceful coughing during emergence should levels is recommended because these values are reflec-

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 5. Larsen P, Davies T, Schlumberger M, Hay I. Thyroid physiology and
tive of the physiologically active form of calcium. diagnostic evaluation of patients with thyroid disorders. In: Kronen-
Treatment for severe symptomatic hypocalcemia in- berg H, Melmed S, Polonsky K, Larsen P, eds. Williams Textbook of
cludes the administration of calcium gluconate or calcium Endocrinology. 11th ed. Philadelphia, PA: Elsevier; 2008:299-326.
chloride (10 mL of 10% solution) intravenously during 6. John A, Sieber F. Evaluation of the patient with endocrine disease or dia-
betes mellitus. In: Longnecker D, Brown D, Newman M, Zapol W, eds.
several minutes and followed by a continuous infusion (1- Anesthesiology. New York, NY: McGraw Hill Medical; 2008:173-190.
2 mg/kg per hour) until calcium levels normalize.3,26 7. Dillmann W. The thyroid. In: Goldman L, Ausiello D, eds. Textbook of
Damage to the RLN during thyroidectomy is rare and Medicine. 22nd ed. Philadelphia, PA: Saunders; 2004:1391-1412.
estimated to occur in up to 14% of cases. The surgical iden- 8. Hanks JB, Salomone LJ. Thyroid. In: Beauchamp RD, Evers BM,
tification and preservation of the RLN is essential to avoid Mattox KL, eds. Sabiston Textbook of Surgery. 18th ed. Philadelphia,
PA: Saunders; 2008:917-954.
injury. A study by Canbaz et al27 supports the practice of
9. Davies TF, Larsen PR. Thyrotoxicosis. In: Kronenberg HM, Melmed S,
identification and exposure of the RLN and its branches Polonsky KS, Larsen PR, eds. Williams Textbook of Endocrinology. 11th
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26. Fewins J, Simpson C, Miller F. Complications of thyroid and parathy- Michael Boytim, CRNA, EdD, is assistant director, Kaiser Permanente
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John Nagelhout, CRNA, PhD, FAAN, is director, Kaiser Permanente
AUTHORS School of Anesthesia.
Sass Elisha, CRNA, EdD, is assistant director, Kaiser Permanente School of Ed Waters, CRNA, MN, is academic and clinical educator, Kaiser Per-
Anesthesia, Pasadena, California. manente School of Anesthesia.

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