T | Nurse Key

Tau, phosphorylated (p-tau)

See Lumbar Puncture and Spinal Fluid Analysis on pp. 423-424.

Testosterone, total, free

Specimen or type of test:

NURSING CARE

Nursing measures include care of the venipuncture or capillary puncture site as described in Chapter 2, with the following additional measures.

Pretest

• The nurse schedules this test before or 7 days after any radioisotope scan because radioisotopes can interfere with the laboratory method of analysis.

Posttest

• The patient often has symptoms that he or she may find embarrassing or difficult to accept because they involve changes in the physical appearance and a disturbance in body image. For the female, manifestations may include male pattern baldness, acne, and hirsutism. For the male, infertility may exist. For the child with precocious puberty, both physical and sexual organs are developed beyond the age-related norms. The nurse can help the patient by using an open and calm approach in interactions and using listening skills if the patient verbalizes his or her feelings.

Thoracentesis, pleural fluid analysis, and pleural biopsy

Also called: Pleural tap, Pleural fluid aspiration

Specimen or type of test:

Pleural Fluid; Possible Pleural Biopsy Tissue

Purpose of the test

Thoracentesis is performed to remove fluid from the pleural space for diagnostic or therapeutic reasons. Examination of pleural fluid identifies or confirms diagnoses of cancer, infection, or severe fluid overload (congestive heart failure, liver failure, and systemic or pulmonary hypertension). The biopsy tissue and/or fluid is used to identify cancer or other pathologic change in the pleural tissue.

Basics the nurse needs to know

An accumulation of fluid in the pleural space is abnormal. Thoracentesis is an invasive procedure used to remove fluid from the pleural space. It is indicated for new or large effusions. It may be performed for diagnostic or therapeutic reasons, or both. During thoracentesis, pleural fluid is removed. In addition, a percutaneous needle biopsy of the pleura may be performed.

Pleural fluid analysis

Pleural effusions (accumulation of fluid in the pleural space) may be a result of neoplastic or infectious processes or of leakage of fluid from the vascular system. If the effusion is due to neoplasm or infection, the fluid is usually called an exudate. If the fluid is due to leakage from the blood vessels, it is called a transudate. To distinguish between exudates and transudates, pleural fluid is evaluated for protein, specific gravity, glucose, and a blood cell count with differential. Pleural fluid is also obtained for cultures to identify tuberculosis, fungal, and various bacterial infections. Cytologic examination of the pleural fluid is performed to rule out malignancy. For a diagnostic thoracentesis usually 5 to 100 mL of fluid are removed.

Pleural biopsy

If tissue samples are removed from the pleura during the thoracentesis, they will be examined microscopically to identify the cell types. Malignancy of the pleura can be detected.

REFERENCE VALUES

Normal pleural fluid

No pathogens or malignant cells are present

How the test is done

Thoracentesis and pleural fluid collection

After the patient is positioned in a seated, upright position with arms folded and their head resting on a pillow on the overhead table, the lower posterior chest is exposed and prepared, and a local anesthetic is given. A needle is inserted into the pleural space guided by ultrasound and the fluid is aspirated. The fluid is placed in a sterile container. The nurse affixes the label containing the patient’s identification data, date, and the type of fluid. The container is sent to the laboratory immediately. If pleural fluid is to be drained, a catheter is inserted using the needle as guide.

If the patient is on a mechanical ventilator or is unable to sit up, they can be placed in supine or recumbent position with the head of the bed elevated to 30 to 40 degrees on their unaffected side. The arm of the affected side is raised above the patient’s head.

Pleural biopsy

A pleural biopsy may be performed at this time. If a pleural biopsy is planned, a special biopsy needle is used with a hooked biopsy trocar. Usually, three tissue specimens are obtained from three pleural sites. Specimens are placed in a sterile container with fixative and labeled with the patient’s identification data, date, and the source of the tissue specimen. The container is sent to the lab immediately.

Significance of test results

Bacterial, viral, or fungal infection

Malignancy

Collagen disease

Lymphoma

Systemic lupus erythematosus

Interfering factors

• Uncooperative patient

NURSING CARE

Pretest

• Explain the procedure and the purpose of the test to the patient. Inform patient the procedure usually takes about 30 minutes. If a catheter is inserted to maintain drainage, explain the purpose to the patient and the need not to pull on it.

• No food or fluid restrictions are necessary.

• Ensure that a signed consent form has been obtained.

• Perform and document a baseline assessment. A blood pressure cuff is left in place to permit easy monitoring of the blood pressure during the procedure.

• Check the patient’s recent laboratory values of the prothrombin time (PT), partial thromboplastin time (PTT), and platelet count to identify the potential for bleeding problems.

• Observe for any local cutaneous infection.

• Check for allergy to local anesthetic.

• If prescribed, initiate supplemental O₂.

• A pulse oximeter is attached.

• Patient teaching.

Warn the patient not to cough or move during the procedure.

• Obtain a thoracentesis tray and place at the bedside.

During the test

• The nurse continuously monitors the patient’s response to the procedure.

• The nurse monitors the pulse oximeter readings for changes in O₂ sat.

• If the patient is mildly anxious, a mild sedative may be ordered. The nurse may also use guided imagery to comfort the patient.

• The patient is positioned in an upright position, seated on the side of the bed with the legs resting on a footstool. The patient’s arms should be supported on a padded overbed table (Figure 90). If the patient is on a mechanical ventilator or is unable to sit up, he or she may lie on the unaffected side with the back flush with the edge of the bed. The head of the bed may be elevated 30 to 40 degrees.

• The nurse provides emotional support to the patient because pressure pain may be experienced even though local anesthetic is given.

• After the physician inserts a thoracentesis needle with a stopcock attached, fluid is drawn off for analysis. Be sure the stopcock is turned to prevent opening to the atmosphere. A catheter may be inserted at this point if a large amount of fluid is to be drained.

• Pleural fluid is drained slowly and limited to 1.5 L/24 hr to prevent reexpansion pulmonary edema and hypotension.

• When the physician performs a biopsy, the nurse instructs the patient to exhale fully and perform the Valsalva maneuver. This prevents air from entering the pleural space when the tissue sample is taken.

• Procedure may be stopped if the patient experiences chest pain, shortness of breath, or coughing. Pleuritic pain may occur. Listen for a pleural friction rub.

• The needle/catheter is removed on exhalation.

Figure 90. Thoracentesis. A, Thoracentesis position. Arms are raised and crossed. Head rests on folded arms. This position allows the chest wall to be pulled outward in an expanded position. If an overbed table is not available, the arms may be left down but positioned forward of the hips or crossed in front of the chest. B, The usual site for the insertion of a thoracentesis needle for a right-sided effusion. The actual site varies with each patient, depending on the location and volume of the effusion. The physician tries to keep the needle as far away from the diaphragm as possible, while at the same time inserting the needle close to the base of the effusion so that gravity can help with drainage.

Posttest

• The nurse checks vital signs every 15 minutes until they are stable and assesses bilateral breath sounds.

• Pressure is applied to the insertion site for 5 minutes to control bleeding.

• Apply dry sterile dressing to site.

• The nurse documents the amount, color, and character of the fluid obtained and a notation of how the patient tolerated the procedure. Normal pericardial fluid is clear and colorless to straw color.

• If it is ordered, the nurse schedules a chest x-ray that would assess for potential pneumothorax.

• The nurse encourages the patient to lie on the uninvolved side for 1 hour to improve oxygenation.

• The nurse continues assessments by observation of the small dressing over the site for bleeding or drainage and palpates around the site for subcutaneous emphysema.

• As the lungs reexpand, the patient may develop a cough. Reassure patient this is normal.

• Patient teaching.

Nurse instructs the patient and family that the dressing may be removed after 24 hours. The nurse instructs the patient and family to check the site for bleeding and signs of infection (redness, swelling, and drainage).

• If the procedure is done as an outpatient, ensure the patient has another person drive them home.

♦ Nursing response to complications

The major complication after thoracentesis is a pneumothorax. Another complication the nurse needs to observe for is reexpansion pulmonary edema. It occurs when large amounts of pleural fluid are removed, causing an increase in negative intrapleural pressure. If the lungs do not reexpand to fill the space, edema can result. Bleeding is a rare complication. Because thoracentesis is an invasive procedure, infection is possible, but extremely rare because thoracentesis is performed using sterile technique. Another rare complication is the accidental puncture of the liver or spleen.

Pulmonary edema.

The nurse will assess for pulmonary edema by checking bilateral breath sounds and observing for indications of hypoxia. The nurse will report crackles and hypoxia immediately. The nurse will anticipate the physician’s orders for oxygen, diuresis, intubation, and mechanical ventilation.

Bleeding.

The nurse assesses for indications of bleeding: tachycardia, restlessness, hypotension, and bloody drainage. The nurse reports indications of bleeding immediately.

Pneumothorax.

Anxiety, restlessness, dyspnea, tachypnea, pallor, and decreased breath sounds are indications of a pneumothorax. If a tension pneumothorax has occurred, there will be a mediastinal shift to the unaffected side. Notify the physician immediately and anticipate an order for a chest radiograph to evaluate the size of the pneumothorax. If a tension pneumothorax is present, the nurse needs to assess the patency of any chest tube that has been inserted.

Thyrocalcitonin

See Calcitonin on pp. 157.

Thyroglobulin autoantibodies

Also called: Antithyroid Antibodies

Specimen or type of test:

Serum

Purpose of the test

Thyroglobulin antibodies are evaluated to detect autoimmune-based thyroid disease.

Basics the nurse needs to know

Some thyroid disorders may be autoimmune in origin. To evaluate this potential cause, antithyroid antibodies are measured. One of these antibodies is thyroglobulin autoantibody. The thyroglobulin autoantibodies act on the antigen thyroglobulin, the storage form of thyroid hormones. The presence of these antibodies helps confirm the diagnosis of autoimmune disease; however, their absence does not rule out the potential diagnosis.

REFERENCE VALUES

Immunofluorescence method: Titer less than 1:100

Hemagglutination method: Negative

How the test is done

Venipuncture is performed.

Interfering factors

• Oral contraceptives

NURSING CARE

The nursing actions are similar to those of other venipuncture techniques presented in Chapter 2.

Thyroid scan

Also called: Radionuclide Thyroid Scanning

Specimen or type of test:

Nuclear Imaging

Purpose of the test

A thyroid scan is done to differentiate causes of hyperthyroidism, to locate ectopic tissue, evaluate whether a nodule is functional, and to assess for congenital hypothyroidism.

A thyroid scan may be done with ¹³¹I or ¹²³I to determine the ability of the gland to take up iodine. This is called a radioactive iodine uptake study (RAIU). This may be ordered before initiating iodine therapy for thyroid cancer.

A whole body scan may be performed to assess for metastasis of thyroid cancer after therapy with radioactive iodine.

Basics the nurse needs to know

To produce its hormones, the thyroid gland must extract iodide from the extracellular fluid. Once it has taken up enough iodide to meet its needs, the iodide left in the extracellular fluid is excreted in urine. The thyroid gland cannot distinguish between dietary iodine and radioactive iodine. Thus it will take up the radioactive iodide, which can be scanned by a gamma camera. The functioning of the thyroid gland can be evaluated by the amount of radioactive iodide it takes up. In thyrotoxic states, more iodide is needed and the uptake is increased, whereas in hypothyroid states, less than normal amounts of iodide are needed, thus less is taken up by the thyroid gland.

In addition to an increase or decrease in uptake by the thyroid gland, scanning may also identify “hot” or “cold” spots. Cold nodules are areas of the gland that take up less or no radioactive iodine. Hot nodules are areas that take up more radioactive iodine than does the surrounding tissue. Cold spots may indicate cancer, whereas hot spots are usually not malignant. An echogram (sonogram) may be obtained to distinguish if the cold spot is a solid or semicystic lesion or a pure cyst. Pure cysts are rarely cancerous.

Additional information on nuclear scans is presented on p. 455.

REFERENCE VALUES

Normal anatomic position and size, with homogenous (equally distributed) uptake of the isotopes throughout the glandular tissue (Figure 91)

Figure 91. Thyroid scan. Appearance of (A) normal and (B-D) abnormal thyroid scans following an injection of technetiuim-99m.

(From Mettler FA, Guiberteau MJ: Essentials of nuclear medicine imaging, ed 5, Philadelphia, 2006, Saunders.)

How the test is done

Radionuclide agents used in a thyroid scan are ¹²³I and technetium (Tc 99m). These agents are given intravenously, which allows scanning to be done by the gamma camera within 20 minutes. ¹²³I may also be given orally and the thyroid is scanned after 24 hours.

Interfering factors

• Dietary intake of iodized foods (e.g., salt, bread)

• Iodine-deficient diet

• Previous radiographic studies with iodine-based dye

• Severe diarrhea

• Renal failure

• Noncompliance with dietary restrictions

• Medications such as anticoagulants, antihistamines, antithyroid medications, corticosteroids, lithium, multivitamins, penicillin, phenothiazines, phenylbutazone, salicylates, and thyroid hormones

NURSING CARE

Pretest

• The nurse obtains a medication history to determine if any interfering drugs were taken.

• Assess for allergy to iodine and seafood.

• Schedule any x-ray studies requiring dyes after the radioactive iodine uptake study.

• Check patient’s renal status. Report elevations in patient’s BUN and serum creatinine.

• Patient teaching.

Instruct the patient not to eat or drink for 4 hours before the test.

• Patient teaching.

Describe the scanning equipment to the patient. The probe is placed over the anterior portion of the neck. Emphasize that no discomfort is involved but that the patient must lie absolutely still while the scan is performed. The nurse informs the patient that the oral radioactive iodine, if being used, has little or no taste. It comes in capsule or liquid form. Explain to the patient the need for two scans because the uptake of the radioactive iodine is usually maximized at 24 hours but some thyroid conditions may cause the peak uptake to occur earlier.

• Remove all metal objects and jewelry from the neck.

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Tags: Saunders Nursing Guide to Diagnostic and Laboratory Tests

Feb 18, 2017 | Posted by admin in NURSING | Comments Off

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