Care of the Patient Undergoing Surgical Excision of a Carotid Body Chemodectoma

Article Outline

• Abstract
• Anatomy
• Diagnosis
• Treatment Options
• Preoperative Assessment
• Intraoperative Care
• Surgical Resection
• Postoperative Care
• Case Studies
• Conclusions
• Acknowledgement
• Examination. Continuing Education Program
  • 2.9
    • Care of the Patient Undergoing Surgical Excision of a Carotid Body Chemodectoma
      • Questions
• Learner Evaluation. Continuing Education Program
  • 2.9
    • Care of the Patient Undergoing Surgical Excision of a Carotid Body Chemodectoma
      • Objectives
      • Content
• References
• Biography
• Copyright

Abstract 

The carotid body is a small mass of tissue inside the carotid bifurcation that reacts to the body's level of oxygen. In rare cases, the carotid body may develop a tumor known as a chemodectoma or paraganglioma. These tumors can vary in size and, typically, they are benign. Although carotid body tumors usually are painless and slow growing, they may cause a compression syndrome that results in symptoms such as dysphagia.

The treatment of choice for many carotid body tumors is surgical removal, but there are risks involved with resecting these tumors because of their close location to the carotid vessels and cranial nerves. The use of newer imaging modalities to allow earlier detection of carotid body tumors and careful surgical technique can decrease the complications associated with this challenging surgical procedure.

Key words: chemodectoma, carotid body tumor, paraganglioma, carotid body, Shamblin's classification

A chemodectoma or paraganglioma is a rare, usually benign tumor of the chemoreceptor system.¹ Carotid body tumors are among the most common paragangliomas.² These hard, solid, usually painless tumors are slow growing and can cause compression syndrome problems, such as dysphagia and hoarseness.³ These tumors occur primarily in women, followed by men aged 40 to 60 years.³ In 1891, Felix Jacob Marchand, a German pathologist, provided a report on carotid body tumors that indicated how infrequently they occur, and only approximately 100 cases were reported during the following century.⁴

Carotid body tumors can be confused with other conditions, such as enlarged lymph nodes, brachial cysts, salivary glands, carotid aneurysms, or neurofibromas.⁴ A useful clinical sign for distinguishing between a carotid body tumor and these other conditions is Fontaine's sign, in which the tumor usually can be moved laterally but not vertically.⁴ Although these tumors are usually benign, Kopfstein reported the first case of lymph node involvement in 1894 and Sapegno reported a case of distant metastases in 1913.⁵ Usually, these tumors are treated with careful surgical excision, which sometimes requires arterial resection. To optimize patient outcomes, perioperative nurses need to be aware of the intraoperative and postoperative risks and the potential for life-threatening complications associated with surgical excision of carotid body chemodectomas.

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Anatomy 

The anterior cervical region of the neck contains the common carotid artery, which produces the pulse palpated at the side of the neck (Figure 1). The common carotid artery divides into two smaller vessels—the internal and external carotid—forming a structure known as the carotid triangle.⁶ In the carotid triangle are two important structures: the carotid sinus and the carotid body.⁶ The carotid sinus is located inside the proximal internal carotid artery. It is a baroreceptor that responds to fluctuations in arterial blood pressure.⁶ The carotid body is a small mass of tissue (ie, approximately 3 mm by 5 mm in diameter) inside the common carotid artery bifurcation, close to the carotid sinus. It was first identified in 1743 by Albrecht von Haller, a Swiss anatomist and physiologist.⁷ The carotid body is a chemoreceptor that responds to low blood oxygen levels by increasing respiration, heart rate, and blood pressure.⁶ Carotid body tumors are vascular tumors that develop at the bifurcation of the common carotid artery, where it branches into the internal and external carotid arteries.⁸

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• Figure 1. 

  Diagram showing a left-sided view of the anatomy of the carotid structures.

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Diagnosis 

Preoperative diagnostic imaging studies are valuable for demonstrating the relationship between the tumor and the adjoining carotid vessels and for determining the adequacy of cerebral blood flow when the carotid artery is clamped during tumor excision.⁷ Diagnosis of a carotid body tumor or chemodectoma usually begins with a color flow duplex scan.⁵ Magnetic resonance imaging and magnetic resonance angiography also are useful, especially to evaluate bilateral disease.⁵ Arteriography is valuable, especially in larger tumors, and is regarded as the best practice for diagnosis.⁵

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Treatment Options 

Typically carotid body tumors are slow growing and asymptomatic; therefore, conservative options, such as observation and radiation, may be chosen. Although observation is a nontraumatic treatment, there are still risks involved with this option. The tumor may continue to enlarge, compressing surrounding nerves and structures. This can lead to symptoms such as dysphagia, bradycardia, or dizziness. Radiation also has risks, including redness and soreness of the radiated tissue, dry mouth, dysphagia, changes in taste, or nausea. Radiation therapy usually is recommended only

The treatment of choice for many carotid body tumors is surgical removal.⁷ There are major risks involved with resecting these tumors because of their close location to the carotid vessels and cranial nerves; these risks increase as the tumor increases in size. Tumors smaller than 5 cm in diameter are associated with a complication rate of 15%; however, tumors with a diameter greater than 5 cm have a 67% complication rate. Thus, tumor size is an important predictor of possible complications.⁷ Shamblin's classification system is used to categorize carotid body tumors based on their size and the difficulty of surgical resection, and this system is often used in the plan of care for patients with a carotid body tumor (Table 1).⁷ Although surgical resection is usually safe and produces good results, stroke, blood loss, and nerve damage, particularly to those nerves that control the movement of the tongue and vocal cords, are possible risks with this surgery. There is also a risk of recurrence, and follow-up x-rays may be used to screen for this.⁹

TABLE 1. Shamblin's Tumor Classification^1,2

There is some discussion of the use of angiographic embolization to reduce the vascularity of the tumor, thus decreasing blood loss during surgical resections.⁴ Some researchers, however, discourage this approach because it seems to cause an inflammatory phase that makes the subadventitial dissection more difficult.⁴ “The routine use of preoperative tumor embolization has [also] been questioned because of the potential neurological complications associated with the accidental reflux of particulate matter into the ophthalmic and cerebral circulation.”^4(p90)

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Preoperative Assessment 

In addition to a radiological workup, patients undergoing surgical carotid body tumor resection also need baseline laboratory tests, such as a complete blood count, comprehensive metabolic panel, prothrombin time, partial thromboplastin time, and an international normalized ratio (Table 2). These blood tests are important preoperatively because many patients with a carotid body tumor may also have other vascular diseases that require the use of anticoagulant therapies and could exacerbate the bleeding risks already associated with carotid body tumor resection.⁷ Urinary catecholamine levels are also important because some of these tumors produce catecholamines. An increase in catecholamine levels may cause ventricular arrhythmias and require perioperative alpha- and beta-adrenergic blocker medications (Table 3).⁷ Carotid body tumors are highly vascular in nature; therefore, typing and crossing for blood products also may be deemed necessary.

TABLE 2. Normal Laboratory Test Values¹, ², ³

TABLE 3. Normal Catecholamine Laboratory Test Values¹

The surgeon or anesthesia care provider may determine that the patient should have a medical cardiac clearance. This is particularly important if the patient has cardiac-related comorbidities (eg, coronary artery disease), which could be exacerbated by general anesthetic agents.

Before surgery, the preoperative nurse assesses the patient for potential risks and lack of knowledge regarding the procedure and postoperative complications. The nurse educates the patient and family members about the surgical procedure and what to expect during the patient's recovery. The nurse identifies factors that may lead to increased intraoperative bleeding, such as the use of anticoagulation medications, and ensures that all team members are aware of these factors.

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Intraoperative Care 

After reviewing the patient's medical record and assessing the patient in the preoperative holding area, the circulating nurse develops a care plan specific to the patient undergoing carotid body chemodectoma resection (Table 4). The nurse then transports the patient to the OR and helps the patient move onto the OR bed in a supine position. The nurse secures the patient's arms at his or her sides with the palms facing upward and pads bony prominences appropriately to prevent pressure injury. After inducing general anesthesia, the anesthesia care provider carefully rotates the patient's head and neck to the nonsurgical side to expose the surgical site. The anesthesia care provider, surgeon, and circulating nurse may place a padded roll horizontally under the patient's shoulders to extend the patient's neck.

TABLE 4. Nursing Care Plan for Patients Undergoing Surgical Excision of a Carotid Body Tumor

Diagnosis	Nursing Interventions	Outcome Indicator	Outcome Statement
Ineffective protection	■Assesses current physiological status and reports variances to appropriate members of the health care team. ■Assesses baseline neurological status. ■Implements protective measures by ■reviewing/establishing neurological nursing assessment; ■obtaining previous diagnostic tests for comparison during the surgical procedure (eg, x-rays, computed tomography scans, magnetic resonance imaging scans, angiograms); ■monitoring cognition, level of consciousness, orientation to person, place, and time, and the presence of restlessness or agitation; ■providing hemostatic agents to minimize bleeding; and ■ensuring the Doppler probe and unit are available and functioning. ■Protects the patient from harm caused by equipment, supplies, or positioning specific to neurosurgical procedures. ■Evaluates postoperative neurological status throughout the postoperative phase of care.	■The patient flexes and extends all extremities at discharge from the OR. ■The patient's sensory responses are within expected ranges at discharge from the OR. ■The patient's peripheral pulses and Doppler readings are present and equal bilaterally at discharge from the OR.	■The patient's neurological status is consistent with or improved from baseline levels established preoperatively.
Acute pain	■Assesses pain control using a validated pain scale. ■Implements pain guidelines by ■providing care consistent with clinical practice guidelines related to pain assessment and management; ■reviewing patient assessment for type of pain being treated, medical condition, and health status; and ■administering medications as prescribed.	■The patient verbalizes control of pain. ■The patient's vital signs at discharge from the OR are equal to or improved from preoperative values.	■The patient demonstrates and/or reports adequate pain control throughout the perioperative period.
	■Implements alternative methods of pain control by using diversified activities, therapeutic touch, meditation, breathing, and positioning to augment pain control methods. ■Assesses the patient's responses to pain management interventions, including physiological parameters and subjective and objective findings.
Risk for fluid volume imbalance	■Identifies factors associated with an increased risk for hemorrhage or fluid and electrolyte loss by ■verifying the patient's preoperative hydration status, height, weight, skin turgor, and pulses; ■conferring with the physician and/or anesthesia care provider if there are unusual assessment data or if signs or symptoms of fluid, electrolyte, or acid-base imbalances are noted. ■Monitors physiological parameters, such as ■measuring intake and output, ■evaluating serum blood counts and electrolyte levels; ■evaluating laboratory results specific to fluid balance (eg, hematocrit, blood urea nitrogen, albumin, total protein, serum osmolality, specific gravity); ■estimating blood and fluid loss by weighing sponges, measuring suctioned output, and summing fluid amounts from drainage devices (wound drains, chest tubes). ■Obtaining peripheral blood specimen as ordered for monitoring of fluid and electrolyte levels (eg, hematocrit, blood urea nitrogen, protein, sodium, potassium, glucose levels).	■The patient's blood cell count is within normal limits at discharge from the OR. ■The patient's blood pressure and pulse are within the expected range and remain stable with position change at the time of transfer to the postanesthesia care unit. ■The patient's urinary output is within the expected range at discharge from the OR.	■The patient's fluid, electrolyte, and acid-base balances are consistent with or improved from baseline levels established preoperatively.
	■Implements hemostasis techniques by ■ensuring an adequate supply of warm intravenous fluids; ■providing supplies (eg, sponges, suction containers, suture, hemostatic agents); instrumentation (eg, hemostats); and appropriate surgical techniques (eg, electrosurgery) as needed to control hemorrhage; and ■applying pressure to bleeding sites as directed. ■Establishes IV access and maintains peripheral IV access to administer IV fluids, medications, and blood products per physician order. ■Administers blood product therapy as prescribed by ■identifying and verifying availability of blood/plasma replacement; and ■collaborating with the blood bank to ensure the supply of blood/plasma replacement. ■Evaluates response to administration of fluids and electrolytes.

This positioning is very similar to the positioning for a carotid endarterectomy, but the need for carotid artery resection cannot always be predicted. Therefore, one of the patient's legs is also prepped in all procedures in case the saphenous vein should be needed for arterial repair.⁴ The circulating nurse may insert a urinary drainage catheter and the anesthesia care provider may insert an arterial line according to the surgeon's request. The circulating nurse may place an underbody or lower body thermoregulating blanket over the nonsurgical leg to help prevent hypothermia intraoperatively. Intraoperative electroencephalographic monitoring may also be used during the surgery to help assess cerebral circulation if carotid clamping or vessel replacement is needed.⁸

Many of the supplies and instruments used are similar for both carotid body tumor excision and carotid endarterectomy. Depending on the location in the neck, some carotid body tumor procedures may require a partial dislocation, or subluxation, of the mandible to fully reach the area. Should this need arise, additional otorhinolaryngological supplies and orthopedic instruments may be required based on the surgeon's request (Table 5).

TABLE 5. Carotid Body Tumor Resection Preference Card¹

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Surgical Resection 

The surgeon obtains surgical exposure via an oblique incision along the anterior border of the sternocleidomastoid muscle, although larger tumors may require a Y-shaped incision.⁸ The surgeon uses vessel loops to control the common, internal, and external carotid arteries and then identifies the hypoglossal nerve (ie, cranial nerve 12) and vagus nerve (ie, cranial nerve 10).⁴ The hypoglossal nerve controls tongue movement.⁶ Injury to the right hypoglossal nerve causes paralysis to the left side of the tongue and vice versa, causing difficulty with word articulation.⁶ The vagus nerve controls movement of the voluntary muscles of the larynx, including the vocal cords and superior esophagus. Injury to the vagus nerve causes difficulty with swallowing and speaking.⁶ Depending on the severity of the injury, complete paralysis of the vocal cords can occur.⁶ In addition to damage to involved cranial nerves, risk of stroke from embolization of loose plaque in the carotid as well as hypovolemia as a result of potential blood loss are possible risks during the surgical procedure. The perioperative nurse should pay close attention to the patient's intraoperative temperature and input and output.

The approach to the carotid bifurcation is similar to that used for a carotid endarterectomy, and the surgeon may chose to insert a shunt device if vessel resection or replacement is necessary.¹⁰ The surgeon then carefully dissects the tumor from the common carotid, often following the subadventitial plane.⁷ If the tumor encompasses the internal carotid artery, the involved portion may be removed and replaced with a saphenous interposition vein graft.⁴ When the tumor has been removed, the circulating nurse sends it to the pathology department to be evaluated by a pathologist. The surgeon then closes the surgical incision.

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Postoperative Care 

After surgery, the patient is transferred to the postanesthesia care unit and may spend the first postoperative night in the surgical intensive care unit. Later, the patient may need to have a radiological follow-up scan to ensure that the tumor has not recurred; follow-up scanning is performed at one year or earlier, as ordered by the surgeon.

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Case Studies 

Carotid body chemodectomas are rare, so it was an unusual coincidence that two patients with this condition were seen at the same facility within a three-month period. The first was a 59-year-old white man who presented with a 4-cm Shamblin II right carotid body tumor verified by magnetic resonance imaging and angiography. The patient had no other health problems noted and was a nonsmoker. He reported hoarseness and a large mass in his neck but no other neurological symptoms. A previous attempt by an otorhinolaryngologist to remove the tumor had failed, so the patient was subsequently referred to a vascular surgeon for treatment. During this second surgery, the tumor was completely freed from the carotid arteries without need for artery resection or replacement. Frozen section was performed in the OR suite and revealed no evidence of malignancy. The surgery lasted approximately four hours with an estimated blood loss of 200 mL.

The second patient was a 73-year-old Hispanic woman who presented with a 3.5-cm Shamblin III right carotid body tumor verified by angiography (Figure 2). The patient had no other health problems and was a nonsmoker. She had undergone two previous abdominal surgeries. The patient's major symptom was dizziness. The standard preoperative workup was performed.

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• Figure 2. 

  Angiogram denoting a high carotid body tumor on the right side of the patient's neck.

The circulating nurse identified the patient using two identifiers and performed a preoperative assessment to evaluate the patient's medical history, including other medical conditions. This patient's body mass index was 30.1 kg/m², but she had no other comorbidities. The nurse reviewed the patient's current medication list for any medications that might pose additional risk for surgical complications, such as anticoagulant use. The patient's only medication was a nonsteroidal anti-inflammatory drug.

All of the patient's laboratory test results were within normal limits with the exception of the electrocardiogram, which showed sinus bradycardia rhythm from stimulation of the affected carotid body. The patient confirmed the surgery and the correct side, and the surgeon marked the site. The patient was alert and oriented, denied having pain, and expressed understanding of the surgery with no additional questions. The circulating nurse transported the patient from the preoperative holding area to the OR suite via a stretcher.

With assistance of OR staff members, the patient moved herself from the transport stretcher to the OR bed. The circulating nurse placed her in a supine position with arms padded and tucked to her sides. After intubation, the surgeon, anesthesia care provider, and circulating nurse placed a shoulder roll. The anesthesia care provider turned the patient's head to her left side, exposing the surgical site. The circulating nurse inserted a urinary drainage catheter, and the anesthesia care provider inserted a radial arterial line. All team members participated in a surgical time-out to verify the patient's identify, position, type of surgery to be performed, surgical site, antibiotic administration, and availability of all necessary equipment and images.

The surgeon dissected down to the carotid body tumor (Figure 3). Using bipolar cautery, the surgeon completely freed the tumor from the internal carotid artery (Figure 4); arterial resection or replacement was not required. The surgeon did, however, have to ligate some branches of the external carotid artery because they were embedded in the tumor (Figure 5). The circulating nurse sent the tumor to the OR laboratory for frozen section, which revealed no evidence of malignancy (Figure 6). The surgery lasted approximately three-and-a-half hours with an estimated blood loss of 100 mL. No evidence of stroke or damage to the surrounding nerves was noted. After the initial recovery, the patient was transferred to the surgical intensive care unit and discharged home the next day. The patient was seen in the surgeon's office for follow-up one week after surgery. The patient was stable with her bradycardia resolved and no signs of postoperative stroke or nerve damage.

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• Figure 3. 

  Dissection of the soft tissue, exposing the carotid body tumor.

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• Figure 4. 

  The tumor after it is released from the internal carotid but is still encompassing the external carotid.

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• Figure 5. 

  The carotid structures after the tumor is removed and the external carotid branch is ligated.

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• Figure 6. 

  After the blood supply is removed, the tumor shrinks in size. It is then evaluated by the pathology laboratory for malignancy status.

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Conclusions 

Although it was said as early as 1917 that “these curious little tumors have been dissected, studied, and described … ,”^5(p823) there is more to learn. In the past, many physicians believed carotid body tumors to be malignant, so they recommended aggressive surgical resection.⁴ As these tumors were studied more, it was determined that they were slow growing and usually benign, but because of the high risk of damage to the surrounding nerves, it was recommended that these tumors be carefully observed rather than surgically removed.⁴ Currently, many surgeons believe that carotid body tumors should be removed in all patients for whom the surgery is deemed appropriate and safe.⁴ “The increasing use of newer imaging modalities, particularly duplex scanning, may allow earlier detection of carotid body tumors and hence safer operations.”^4(p91) These techniques, paired with the use of electroencephalographic monitoring, careful surgical technique, and possibly perioperative embolization, have greatly decreased the complications of this challenging surgical procedure.¹⁰ Now, these patients have risks similar to those of patients undergoing carotid endarterectomy. Most patients with a carotid body tumor have a short hospital stay and few complications. Yearly follow-up may be necessary for early identification of recurrence, but because of the slow growth of these tumors, additional surgical interventions should be few.

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Acknowledgement 

The author thanks Harvey A. Nurick, MD, and his staff members, Riverside, CA, for their assistance in the preparation of this manuscript.

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Examination. Continuing Education Program 

2.9 

PURPOSE/GOAL

To educate perioperative nurses about caring for patients undergoing surgical excision of a carotid body chemodectoma.

OBJECTIVES

The Examination and Learner Evaluation are printed here for your convenience. To receive continuing education credit, you must complete the Examination and Learner Evaluation online at http://www.aorn.org/CE.

Questions 

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Learner Evaluation. Continuing Education Program 

2.9 

This evaluation is used to determine the extent to which this continuing education program met your learning needs. Rate the items as described below.

Objectives 

To what extent were the following objectives of this continuing education program achieved?

Content 

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References 

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2. Patlola R, Ingraldi A, Walker C, Allie D, Khan I. Carotid body tumor. Int J Cardiol. 2009;Epub ahead of print http://www.internationaljournalofcardiology.com/article/S0167-5273(08)01397-1/abstractAccessed October 8, 2009
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3. Durdik S, Malinovsky P. Chemodectoma—carotid body tumor surgical treatment. Bratisl Lek Listy. 2002;103(11):422–423
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4. Westerband A, Hunter GC, Cintora I, et al. Current trends in the detection and management of carotid body tumors. J Vasc Surg. 1998;28(1):84–93
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5. Dias Da Silva A, O'Donnell S, Gillespie D, Goff J, Shriver C, Rich N. Malignant carotid body tumor: a case report. J Vasc Surg. 2000;32(4):821–823
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6. Moore KL, Dalley AF. Clinically Oriented Anatomy. In: 5th ed.. Philadelphia, PA: Lippincott Williams and Wilkins; 2006;p. 1065–10681151-1154
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7. Stevens R, Rassekh CH, Quinn FB. Carotid body paraganglioma. Department of Otolaryngology, UTMB, Grand Rounds http://www.utmb.edu/otoref/Grnds/carotidbody.htmAccessed October 9, 2009
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8. LaMuraglia GM, Fabian RL, Brewster DC, et al. The current surgical management of carotid body paragangliomas. J Vasc Surg. 1992;15(6):1038–1045
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9. Managing the side effects of treatment to certain parts of the body. American Cancer Society; December 23, 2008;http://www.cancer.org/docroot/ETO/content/ETO_1_7x_Managing_Side_Effects_of_Treatment.aspAccessed October 15, 2009
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10. Hallett J, Mills JL, Earnshaw JJ, Reekers JA. Comprehensive Vascular and Endovascular Surgery. In: 2nd ed.. Philadelphia, PA: Mosby; 2005;p. 565–567
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• 1 Carotid body tumors. The Cleveland Clinic. http://my.clevelandclinic.org/heart/disorders/vascular/carotid_body_tumors.aspx. Accessed October 2, 2009.