NF 24 Diagnostic Tests and Specimen Collection PDF

ch a p te r Diagnostic Tests and Specimen Collection 24 http://evolve.elsevier.com/Williams/fundamental Objectives Upon completing this chapter, you should be able to do the following: Theory 1. Discuss appropriate psychosocial care and education for patients undergoing diagnostic tests or proce...

ch a p te r Diagnostic Tests and Specimen Collection 24 http://evolve.elsevier.com/Williams/fundamental Objectives Upon completing this chapter, you should be able to do the following: Theory 1. Discuss appropriate psychosocial care and education for patients undergoing diagnostic tests or procedures. 2. Prepare to perform a capillary glucose test, a venipuncture, a throat culture, an electrocardiogram, a urine dipstick test, and a stool for occult blood test. 3. Describe each of the categories of tests that are commonly performed. 4. Explain factors to be considered when an older adult is to undergo diagnostic testing. Clinical Practice 1. Provide pretest and posttest nursing care, including appropriate education, for patients undergoing diagnostic tests and procedures. 2. Attend to psychosocial concerns of patients undergoing various diagnostic tests. 3. Perform a random blood glucose test using capillary blood and a glucometer. 4. Perform patient education for magnetic resonance imaging (MRI). 5. Describe how to prepare a patient for and assist with aspiration procedures such as lumbar puncture, thoracentesis, paracentesis, bone marrow aspiration, and liver biopsy. 6. Correctly use Standard Precautions whenever obtaining or handling specimens for diagnostic tests. 7. List the steps for assisting with a pelvic examination and Pap test. 8. Correctly ill out laboratory and test requisition forms. Skills & Steps Skills Phlebotomy and Obtaining Blood Samples with a Vacutainer System 412 Skill 24.2 Performing a Capillary Blood Test: Blood Glucose 414 Skill 24.3 Performing a Urine Dipstick Test 417 Skill 24.4 Obtaining a Stool Specimen for Occult Blood, Culture, or Ova and Parasites 419 Skill 24.5 Obtaining Culture Specimens: Throat and Wound Skill 24.1 431 Skill 24.6 Assisting with a Pelvic Examination and Papanicolaou Test (Smear) 432 Steps Steps 24.1 Obtaining an Electrocardiogram Tracing Steps 24.2 Assisting with a Flexible Sigmoidoscopy 424 426 Key Terms anemias (ă-nē-mē-ăz, p. 409) aspiration (ăs-pĕr-ā-shŭn, p. 416) biopsy (bī-ŏp-sē, p. 416) colonoscopy (KŌ-lŏn-Ŏ-skō-pē, p. 426) culture (cŭl-chŭr, p. 408) cystoscopy (sĭst-Ŏ-skō-pē, p. 427) electroencephalogram (EEG) (ē-LĔK-trō-ĕn-SĔ-fă-lō-grăm, p. 428) endoscope (ĔN-dō-skōp, p. 425) gastroscopy (găs-TRŎ-skō-pē, p. 425) hematoma (hē-mă-TŌ-mă, p. 425) jaundice (JĂWN-dĭs, p. 427) panel (p. 411) polyps (PŎL-ĭps, p. 426) smears (p. 430) transducer (trăns-DŪ-sĕr, p. 416) venipuncture (VĔN-ĭ-pŭnk-chŭr, p. 411) 407 408 UNIT V Basic Nursing Skills Concepts Covered in This Chapter • • • • • • • • Anxiety Fluid and electrolyte balance Glucose regulation Infection Inlammation Patient education Perfusion Safety DIAGNOSTIC TESTS AND PROCEDURES Diagnostic tests and procedures provide important information about complex chemical reactions that affect the body’s function. Laboratory examinations of blood, urine, and other body luids and tissues provide accurate information about the function of various organs and physiologic mechanisms. The information is helpful in making or conirming a diagnosis or in evaluating the effectiveness of a treatment. It is necessary to check the instructions from the particular department of the facility in which the test is to be performed for the speciics of patient preparation because this may vary somewhat from facility to facility. Box 24.1 provides terms with deinitions speciic to diagnostic testing. APPLICATION OF THE NURSING PROCESS ASSESSMENT (DATA COLLECTION) When a diagnostic test or procedure is ordered, determine what the patient knows about the test to establish what patient education is needed. Inquire about concerns the patient may have about the test. Determine if any special nursing measures are needed to protect the patient’s safety. Inspect wounds each shift for signs of infection so that the primary care provider can be alerted to the need for a culture (the growing of microorganisms in or on a medium designed for their growth). Assess the patient for allergies to medication and to iodine and other procedure skin-prep solutions used for diagnostic testing. NURSING DIAGNOSIS Nursing diagnoses are those pertinent to the problems for which a diagnostic test or procedure is ordered. “Deicient knowledge” related to the type of diagnostic test is appropriate if the patient is unfamiliar with the test. A few examples of nursing diagnoses for which diagnostic tests might be part of the treatment plan include: • Impaired urinary elimination related to dysuria and foul-smelling urine. • Acute pain related to raw, sore throat. • Acute pain related to inlammation and swelling at wound site. PLANNING Check to see that pretest medications and supplies are available on the unit 1 to 2 hours before the scheduled test time. Plan when to do any patient education about the test or procedure. Include the pretest and posttest care in your work schedule. A test involving the colon requires the administration of enemas, which can be time consuming. Many diagnostic tests require frequent vital sign measurement when the patient returns to the nursing unit. Expected outcomes are written for the particular nursing diagnosis associated with the problem for which the test is being performed. Assignment Considerations Posttest Assessments Carefully consider before assigning vital sign measurements to the unlicensed personnel (UAPs) after invasive diagnostic tests. Vital signs are not the only parameters that are usually needed to assess a patient. The patient may need to be monitored for bleeding, neurologic abnormalities, decreases in sensation or function, increasing pain, and general changes in condition. The licensed nurse’s assessment should encompass all considerations for the patient. IMPLEMENTATION Make certain that the patient has received adequate education about the test or procedure to be performed and that their concerns have been addressed. Carry out the pretest and posttest actions for the particular test or procedure, including the signed consent for any invasive procedure requiring one. Remind the patient that test results often are not available the same day and often take up to a week or more to be reported. Patient Education Patient Education DIAGNOSTIC TESTS You should also consider the instructions for the preparation for the speciic test available from the department performing the test. Teach the patient: • Τhe purpose of the test. • What will be experienced during the test. • Whether it is necessary to refrain from eating or drinking before the test and for how many hours. • Whether the test requires special preparation (medications, special diet, laxatives, enemas, or the need to drink a lot of water). • Whether routine medications may be taken before the test. • When the result will probably be available. • Any posttest measures such as drinking more water, taking a laxative, or remaining on bed rest for a certain number of hours. • Whether it is necessary to arrange for someone to drive the patient home after the test. • About how long the test usually takes. • Any after effects of the test or procedure. Diagnostic Tests and Specimen Collection CHAPTER 24 Box 24.1 409 Terminology for Diagnostic Testing Angiography: A method of injecting a dye into an artery and obtaining an x-ray study of blood vessels, tumors, and lesions. Arteriography: Radiography of an artery or arterial system after injection of a contrast medium into the bloodstream. Bronchoscopy: Inspection of the interior of the tracheobronchial tree through a bronchoscope. Cardiac catheterization: Introduction of a catheter into the heart chambers to conirm a diagnosis or to evaluate the extent of the disease process. Colposcopy: A gynecologic examination that uses the colposcope to examine the walls of the vagina and the cervix. Complete blood count (CBC): Includes type and number of red blood cells, white blood cells, platelets, and hemoglobin. Computed tomography (CT) scan: Through use of a computer, cathode ray tubes emit radiation at different depths to show the density of tissues and organs, indicating malformations, tumors, or other irregularities; also called computed axial tomography (CAT) scan. Conization: Coring or removal of the mucous lining of the cervical canal and its glands by means of cutting with a high-frequency current; performed when a Pap smear indicates abnormal cells. Cytology: The study of the structure, function, and pathology of cells. Endoscopic retrograde cholangiopancreatography (ERCP): Examination of the biliary system done through a lexible endoscope and instillation of contrast medium into the ampulla of Vater of the pancreas. Esophagogastroduodenoscopy (EGD): Endoscopic examination of the esophagus, stomach, and duodenum. Fluoroscopy: Examination by means of luoroscope using x-ray studies displayed on a luorescent screen. Glucometer: A small machine used to measure glucose content of capillary blood. Hematology: The study of blood and its components. Histology: The branch of anatomy dealing with the structure, composition, and function of tissues. Intravenous pyelography (IVP): Injection of a dye into a vein to show urine low through the renal pelvis, ureters, and bladder on x-ray examination. KUB x-ray: X-ray study of the kidneys, ureters, and bladder. Liquid-based cytology (LBC): This type of Pap smear performed in approximately 90% of Pap smears in Laboratory Tests Tests can be performed on body luid or tissue to detect changes from the normal state. Because blood bathes and nourishes all body tissues and collects waste products for elimination, chemical changes in the blood can be signs of disease. Analysis of urine also provides a rich source of information about cellular activity. Hematology tests. Hematology is the study of blood and its components. The complete blood count (CBC) the United States. In contrast to the traditional Pap, it produces a sample that has improved clarity and quality. Instead of cells being directly placed onto a microscope slide, they are deposited into a small bottle of preservative liquid. Lumbar puncture: Insertion of a hollow needle into the subarachnoid space between the third and fourth lumbar vertebrae to withdraw samples of cerebrospinal luid for analysis and to measure the pressure; also called spinal puncture and spinal tap. Magnetic resonance imaging (MRI): A noninvasive method, based on magnetic ields, of visualizing soft tissue without the use of contrast media or ionizing radiation. Papanicolaou (Pap) smear: A laboratory test to detect cancer, especially cervical, vaginal, or uterine cancer; use began in the 1950s. Later the test was improved by use of LBC. Paracentesis: A needle puncture of the abdomen to remove ascites luid, to perform a lavage, or to initiate peritoneal dialysis. Proctosigmoidoscopy: Examination of the rectum and sigmoid colon with a sigmoidoscope. Radiography: The making of ilm records of internal structures of the body by exposure of ilm sensitized to x-rays. Radioimmunoassay (RIA): Use of radionuclides, following principles of immunology, to measure materials present in blood in minute amounts. Radionuclides: Radioactive substances that disintegrate with the emission of electromagnetic radiation. Radiopharmaceutical: A radioactive pharmaceutical substance used for diagnostic or therapeutic purposes. Sequential multiple assay (SMA): A series of assay tests for a variety of chemical substances performed one after another on one blood or serum sample by a chemical analyzer. Thoracentesis: Insertion of a needle through the chest wall to the pleural space to drain luid or air or to instill medication. Treadmill stress test: A test that measures heart rate and blood pressure response to clinically controlled active exercise on a treadmill (a machine with a moving belt on which one walks while staying in one place). Ultrasonography: A technique in which deep structures of the body are visualized by recording the relections (echoes) of ultrasonic waves directed into the tissues. provides information about the state of health or presence of illness (Table 24.1). Changes in the number, size, or appearance of red blood cells (erythrocytes) occur in diseases associated with types of anemia. The hematocrit refers to the separation of blood and is the amount of blood cells in relation to the amount of plasma. It is decreased in severe anemias (low red blood cell count) and massive blood losses but is higher than normal in dehydration and shock. During infections, the type and number of white blood cells (leukocytes) increase (leukocytosis). The 410 UNIT V Table 24.1 Basic Nursing Skills Example of a Complete Blood Count (Adult) Table 24.2 Blood Chemistry Tests and Their Purpose COMPONENT WBC TEST VALUE 6.8 k/μL NORMAL RANGE 5.0-10.0/mm3 TEST Glucose ORGAN CHECKED OR PURPOSE Diabetes or hypoglycemia RBC 4.59 M/μL 4.2-6.1/mm3 14.0 g/dL 12.0-18.0 g/dL Bilirubin, ALT, ALP, and albumin Liver Hgb HCT 40.8 mL/dL 37.0-52.0 mL/dL AST Liver or coronary artery disease BUN and creatinine Kidney MCV 89.0 fL 80.0-95.0 fL MCH 30.6 pg/cell 27.0-31.0 pg/cell LDH, CK, and troponins Heart Parathyroid and calcium metabolism RDW 11.3% 11.6-14.6% Calcium PLT 252,000/mm3 150,000-400, 000/mm3 Cholesterol Segmented neutrophils 50% 54%-62% Potential for atherosclerotic heart disease Phosphate Lymphocyte 36% 28%-33% Renal failure, bone metastasis, and hypercalcemia Monocyte 12% 3%-7% Total protein Malnutrition, liver disease Eosinophil 2% 1%-3% Uric acid Gout Basophil 0% 0%-1% RBC morphology Normal Normal Hgb, Hemoglobin; HCT, hematocrit; MCH, mean corpuscular hemoglobin; MCV, mean corpuscular volume; PLT, platelet; RBC, red blood cell; RDW, red cell distribution width; WBC, white blood cell. neutrophil count, in particular, can be signiicant. When infection is severe, the bone marrow releases more granulocytes as a compensatory measure; many young, immature polymorphonuclear neutrophils called “bands” are released into the bloodstream. Clinical Cues Most laboratories report the cells on the differential white blood cell (WBC) count by order of maturity, with the less mature cell forms being on the left side of the report. Therefore, a “shift to the left” in the number of cells, or an increase in bands, may indicate infection. Life-Span Considerations Older Adults Because of normal changes with aging, older adults may not be able to mount a signiicant leukocytosis; therefore, even a moderate rise in WBCs can indicate infection. ALT, Alanine aminotransferase; ALP, alkaline phosphatase; AST, aspartate aminotransferase; BUN, blood urea nitrogen; CK, creatine kinase; LDH, lactate dehydrogenase. diseases of the liver and in certain blood disorders. PT is widely used to adjust dosages of anticoagulant drugs such as sodium warfarin (Coumadin). This test is reported using International Normalized Ratio (INR) numbers. The partial thromboplastin time is used for monitoring clotting time during heparin therapy. Safety Alert Bleeding Danger A normal platelet count is 150 to 400/mm3 of blood. Platelet activity is essential to blood clotting. Spontaneous bleeding is a serious danger when the platelet count falls below 20,000/mm3 of blood. Observe for bleeding gums, blood in the urine, and oozing from needle sticks. The erythrocyte sedimentation rate (ESR or “sed rate”) measures the rate at which the red blood cells settle out of unclotted blood in 1 hour. Inlammatory conditions cause the cells to settle more rapidly: the more rapid the settling, the higher the ESR. Think Critically Certain drugs may cause a sharp fall in leukocytes (leukopenia), making the individual less able to ight off infection. Hemoglobin testing shows the blood’s capacity to transport oxygen from the lungs to the tissues. Hemoglobin levels drop when there is bleeding within the body. In addition to the CBC, tests of bleeding and clotting time of the blood may be done. Knowledge about the length of bleeding time is essential before most surgeries or extensive dental extractions are performed. Common tests for clotting time are the prothrombin time (PT) and activated partial thromboplastin time (APTT). PT is prolonged in certain The patient’s hemoglobin level when she was admitted was 13.8 g/dL. Two days later, the level is 13.2 g/dL. Is this signiicant? What could it mean? Blood chemistry tests. Blood chemistries are commonly obtained to detect changes in biochemical reactions in the body and to determine a diagnosis. They provide information about the electrolyte balance, the body’s ability to metabolize nutrients, the function of organs, and the presence or accumulation of toxic substances (Table 24.2). Most laboratory reports list the normal values (reference range) for each test with the results of the test. Diagnostic Tests and Specimen Collection CHAPTER 24 Food and drink are usually withheld for 8 to 12 hours before blood chemistry tests. The blood specimen for a CBC, chemistry, or serology test is obtained by venipuncture (puncture of the vein with a needle). Wear gloves and implement Standard Precautions; take steps to prevent continued bleeding from the puncture site. The blood specimens are collected in tubes with color-coded stoppers, which indicate the type of anticoagulant or preservative, if any, the tubes contain (Skill 24.1). Blood glucose tests are essential in the diagnosis and control of diabetes. They are also commonly ordered when a patient is receiving total parenteral nutrition (TPN, described in Chapter 27). Testing the amount of blood glucose can be done outside the laboratory using capillary blood from a inger stick, test strips, and a machine called a glucometer (Skill 24.2). Other tests are used to determine toxic levels of substances such as barbiturates, lead, arsenic, and medications. Most laboratories are equipped with automated and computerized instruments that carry out multiple tests on a single specimen. One model is the sequential multiple assay (SMA) unit, which can be programmed to run a battery of screening tests on one blood sample. Table 24.3 shows a typical SMA-12 panel (group of tests) with normal values for each component. Think Critically The patient was admitted with malaise and fever. The ESR was 27 mm/h on admission. Today it is 34 mm/h. What does this indicate? Serology tests. Serology tests are based on the analysis of blood serum. They are important in diagnosing many diseases stemming from bacterial and viral infections. Diseases such as dysentery, rheumatic fever, typhoid, inluenza, rubella, and syphilis produce positive reactions related to antigen antibodies. Radio immunoassays (RIAs), which are based on principles of immunity, use radionuclides (radioactive material; formerly called radioisotopes), such as iodine-125 and iodine-131, to detect minute particles of protein in the blood. Blood typing and identiication of blood factors may also be carried out in the serology section of the laboratory. Examples of common serology tests are listed in Box 24.2. Most serology tests can be done without restricting the patient’s food or luid intake. However, some of the RIAs may require the administration of the radionuclide drug at a certain time before drawing blood for the test. For viral infections, two separate specimens are needed to show a rise in titer during the illness. Urinalysis. Analysis of urine provides valuable information about the kidney function and other biologic processes within the body. Organic compounds found in the urine include urea, uric acid, creatinine, and hippuric acid. Inorganic substances found are sodium, chloride, phosphate, potassium, and ammonia. Urine 411 composition varies according to luid intake and diet; therefore, the time the specimen is obtained may inluence the results. Clinical Cues Urine deteriorates rapidly, so specimens should be analyzed soon after collection. Send the specimen to the laboratory quickly or refrigerate it. Urine specimens can be classiied as: • Single, catheterized, or random specimens that can be collected at any time, with no special preparation required (a specimen of the irst voiding in the morning is preferred because it is more concentrated). • Midstream specimens, in which the external genitalia are cleansed, a small amount of urine is passed, and then a midportion of the voiding is collected in a sterile container and used for a culture. • Timed, long-period specimens, in which all urine is collected over a 12- or 24-hour period and placed in a container containing some type of preservative. No special instructions are required for the single, random specimen. Often a urine dipstick test is performed to screen the specimen for abnormalities. Urine dips are performed using test strips or sticks that have various chemicals impregnated in them (Skill 24.3). The Patient Education box in Chapter 29 provides instructions for the midstream specimen. The method for obtaining a specimen from an indwelling urinary catheter is listed in Steps 29.1, in Chapter 29. Consult a laboratory manual for instructions on special types of urine tests. Some tests require restriction of luid intake; others require that set amounts of luids be given and urine specimens obtained at speciied times. A normal urinalysis is presented in Table 24.4. Patient Education Collection of a 24-Hour Urine Specimen Give the patient a 24-hour urine collection container. Provide the following instructions: • Empty the bladder into the toilet and begin timing the collection of the specimen. • For the next 24 hours, add all urine to the collection container. • Keep the container on ice or refrigerated if instructed to do so (depends on the laboratory and the type of test ordered). • When the 24 hours is up, empty the bladder and add the urine to the collection container. • Seal the collection container and return it to the laboratory or the primary care provider’s ofice as directed. Other laboratory tests. Other laboratory tests performed are bacteriologic, histologic, and cytologic tests. Specimens of blood, urine, feces, and wound drainage, and samples of other body luids or tissues, may be cultured to identify the disease-causing organism. To obtain a stool specimen, ask the patient to catch some stool in a container suspended in the Continues on page 416 412 UNIT V Skill 24.1 Basic Nursing Skills Phlebotomy and Obtaining Blood Samples with a Vacutainer System Blood tests are the most commonly ordered diagnostic procedure. Every time a venipuncture is performed for blood sampling, two patient identiiers must be used to verify that the procedure is being performed on the correct patient. The room number cannot be one of the identiiers. Patient name and patient number or birth date are valid identiiers. When there is not a laboratory with a phlebotomist on the premises, the nurse is usually responsible for obtaining the needed blood samples. The Vacutainer system is the most common method used to obtain blood samples. Blood can be drawn using a syringe and needle with the same venipuncture technique. The correct tube, indicated by the color of its top, must be used for the test ordered. SUPPLIES • Tube labels • Pen • Tape • Blood-impervious gloves • Vacutainer tubes • Vacutainer holder • Vacutainer needle with needle guard • Towel, paper towel, or underpad • Tourniquet • Alcohol swabs • 2 × 2 gauze squares • Bandage • Cotton balls • Biohazard sharps container • Biohazard plastic bag • Requisition slip Review and carry out the Standard Steps in Appendix A. ACTION (RATIONALE) Assessment (Data Collection) 1. Check the medical order for tests to be done. (Determines the type of tube to be used.) 2. Ask the patient’s name and date of birth or check the wristband. (Veriies that the right patient will have blood drawn.) Planning 3. Check to see that the needed tubes and materials are on hand. (Prevents having to stop and obtain supplies.) Implementation 4. Fill out a label for each tube. (Ensures that tubes will be correctly labeled.) 5. Explain the procedure and have patient sit with arm on a table or have patient lie down with the arm stretched out at the side. (Explaining procedure decreases fear of the unknown. Positioning provides stable access to venipuncture site.) 6. Perform hand hygiene and don clean gloves. (Reduces transfer of microorganisms.) 7. Select an appropriate venipuncture site, avoiding scars, lesions, or a vessel in which intravenous (IV) luids are infusing. (Scar tissue is dificult to puncture; a puncture over a lesion may introduce microorganisms into the blood; IV luids may alter the test results.) Cephalic vein Basilic vein Accessory cephalic vein Median cubital vein Median antebrachial vein Cephalic vein Basilic vein Dorsal venous network Step 7 8. Place the Vacutainer tube inside the holder, but do not push it onto the needle; position the Vacutainer holder and tubes within easy reach. (Preparing the system for use allows you to pick up the equipment with one hand after you have stabilized the vessel.) Diagnostic Tests and Specimen Collection CHAPTER 24 9. Lower the extremity so the site is below the heart. (A dependent position enhances blood low to the site.) 10. Apply a tourniquet to the extremity 2 to 4 inches above the venipuncture site. It should be moderately tight. Ask the patient to make a ist (unless a potassium level specimen is being drawn). (The tourniquet obstructs blood low out of the vessel and causes the vein to ill with blood. A distended vein is easier to palpate and puncture. Making a ist aids in vein distention, but elevates the reading for potassium by forcing potassium out of cells.) 11. Cleanse the site with 70% alcohol in a circular motion outward; allow the area to dry. (Alcohol decreases the number of microorganisms on the skin, preventing their transfer to the blood.) 12. Pick up the Vacutainer holder and tube in your dominant hand and remove the needle cover. (Prepares the unit for venipuncture.) 13. Anchor the vein with the thumb of your nondominant hand, far enough below the site so that the needle will not touch the thumb as it enters the vessel. (Stabilizes the vein so that it does not roll when venipuncture is performed.) 14. Hold the Vacutainer unit with the needle bevel facing up and position it at a 30-degree angle over the desired venipuncture site. (Positions the needle for entry into the vessel.) 18. 19. 20. 21. 22. 23. 24. 413 before removing needle prevents introducing air into the tube.) Loosen the tourniquet then withdraw the needle from the vein and secure the needle guard. (Loosening tourniquet before withdrawing the needle decreases the amount of bleeding that occurs.) Immediately apply a dry gauze pad with pressure to the vein to stop the bleeding. (A dry pad aids coagulation of the blood, and pressure constricts the vessel, decreasing bleeding.) Apply a small adhesive bandage over the puncture site. (Decreases entrance of microorganisms at the site and helps prevent further bleeding.) Carefully remove and dispose of the Vacutainer needle in a biohazard sharps container. (Prevents accidental needle sticks.) Remove and label the tube(s) of blood, and place in a biohazard bag. (Labeling tube(s) correctly identiies the patient’s blood. A biohazard bag prevents blood contamination should the tube[s] become broken.) Fill out the laboratory requisition slip, and attach to the blood samples; send to the laboratory. (Identiies the correct test to be done for the right patient.) Remove gloves and perform hand hygiene. (Reduces transfer of microorganisms.) Evaluation 25. Check to be certain the correct tubes were used and all samples have been obtained with adequate blood in each tube. (Ensures that patient will not have to return for another venipuncture.) Documentation 26. Note the procedure and samples obtained on the patient’s medical record; include how they were sent to the laboratory. (Veriies that the ordered blood samples were drawn and sent to the laboratory.) Step 14 15. Puncture the site, and, while stabilizing the Vacutainer unit, press the tube stopper onto the needle; blood running into the tube indicates successful venipuncture. (Stabilizing the unit prevents pushing the needle through the vein when pressing the tube stopper onto the Vacutainer needle.) 16. Allow tube to ill completely. (Ensures a suficient quantity of blood to perform the test.) 17. If further specimens are needed, stabilize the holder and remove illed tube and set safely aside. Place next tube carefully on needle and allow to ill. Repeat until all required tubes are illed. Remove inal tube. (Obtains suficient blood for all ordered tests. Stabilizing holder prevents pushing needle through vessel wall. Removing last tube Documentation Example 1/8 0700 Successful venipuncture; three tubes drawn and sent to lab for CBC, SMA-12, and VDRL. No hematoma at site; bleeding stopped and bandage applied. Patient tolerated procedure without problems. (Nurse’s electronic signature) Critical Thinking Questions 1. An older adult tells you that technicians and nurses always have dificulty drawing her blood samples because she has tiny veins. What would you do to ensure a successful venipuncture? 2. If you have done three “sticks” on a patient for blood samples and have not been successful, what would you do? 414 UNIT V Basic Nursing Skills Skill 24.2 Performing a Capillary Blood Test: Blood Glucose Random blood glucose tests are performed for known diabetic patients and for patients who are showing signs and symptoms of hyperglycemia or hypoglycemia. SUPPLIES • Gloves • Cotton ball • Fingerstick device holder • Bandage • Lancet • Alcohol swabs • Glucometer (Accu-Chek) • Glucometer strips Review and carry out the Standard Steps in Appendix A. ACTION (RATIONALE) Assessment (Data Collection) 1. Gather equipment and assess whether all supplies are on hand. (Prevents having to stop procedure to retrieve needed items.) 2. Identify the patient and determine what is known about the procedure. (Identiies what information needs to be given to patient.) Planning 3. Plan which inger to use and ask patient to allow hand to hang downward. If hand is cold, have patient warm it under running warm water, or warm it with your hands. (Holding hand down and warming it brings blood to the ingertips.) Implementation 4. Perform hand hygiene and don gloves. Cleanse the chosen ingertip thoroughly with an alcohol swab. Ask the patient to hold the inger separated from the others and not to touch anything as the alcohol dries. (Removes bacteria from the inger, preparing it for the puncture. Alcohol will dry while machine is set up, saving time.) 5. Turn on the machine, place the lancet in the holder, and remove the lancet cover. Cock the lancet device. Check the control number that appears on the screen with the control number on the bottle of test strips. (Prepares the equipment to puncture the skin. Checking control number ensures that the correct setting is used for the machine because it must match the strip number.) Step 5 6. Remove a test strip from the bottle and insert the end with the metal strips into the machine. (For machines that have intervening steps, check the manufacturer’s directions. Some machines require that the specimen be obtained and a certain time period elapse before the strip is placed in the machine.) (Prepares the machine to read the amount of glucose in the blood.) 7. Place the ingerstick device irmly on the skin and push the release button, causing the lancet to pierce the skin. (With the device at a right angle to the ingerprint lines, the needle should pierce the skin deeply enough to provide free blood low with little pressure.) Step 7 8. If machine directions indicate it, wipe away the irst drop of blood with a clean cotton ball. (First drop often contains a large portion of serous luid that dilutes the specimen, causing a false result.) 9. Lightly squeeze the inger, gently milking down the inger toward the tip until an appropriate drop of blood has formed on the tip. (Provides an adequate amount of blood for the specimen.) Diagnostic Tests and Specimen Collection CHAPTER 24 10. Lightly apply the drop of blood to the pad on the test strip and apply a clean cotton ball to the puncture wound with pressure. Ask patient to hold the cotton ball tightly in place. (Applying blood to test strip begins the test. Pad must be completely covered with blood for accurate results. Pressure and dry cotton ball stop the bleeding.) Step 10 11. For alternate type of glucometer, start the timer and place the test strip on a paper towel beside the timer. At 60 seconds, place the test strip into the machine. See the manufacturer’s directions. (Some machines require different procedures for an accurate result.) Evaluation 12. Note the reading on the screen of the machine and record it. Turn the machine off. Share the result with the patient. (Machine will provide a reading. If “error” appears, turn off the machine and start the procedure over from the beginning. Too much or too little blood on the test strip may cause an error. The patient must know the reading to participate in care.) 415 13. Assess whether the patient’s inger is still bleeding. Stop the bleeding and apply an adhesive bandage if patient desires one. (Prevents blood from continuing to low; prevents transmission of possible blood-borne pathogens.) 14. Dispose of test strip, lancet, and blood-tinged supplies in the appropriate hazardous materials waste receptacles. Remove gloves and perform hand hygiene. (Prevents transmission of blood-borne pathogens.) Documentation 15. Document the procedure and the reading on the patient’s medical record. In the inpatient facility, record the reading on the appropriate medication administration record (MAR) or electronic medication administration record (eMAR). (Provides a record of the reading; patients on insulin have a place on the MAR or eMAR to record blood glucose readings.) Documentation Example 1/6 1030 Fingerstick glucose 126. (Nurse’s electronic signature) Special Considerations • Warming the patient’s hand before attempting the inger stick provides a greater chance of a successful specimen on the irst attempt. • Small children need to be held by the parent or another nurse. • Children should be told that they will feel “a tiny sting” and that they will see blood. Do not lie to children. • Having children use a inger puppet on the other hand sometimes will distract them suficiently from the procedure, and they will hold still. • Older adults bleed more easily than younger people do and may not need as deep a puncture. • The puncture depth of the lancet needle can be adjusted by pushing the lancet further in or pulling it out a little from the holder. • This procedure should never be performed without the use of gloves because of the risk of contamination with blood. Critical Thinking Question 1. If you get an error message when performing a inger stick for blood glucose, what would you do? Step 12 416 UNIT V Table 24.3 Basic Nursing Skills Sequential Multiple Assay Panel (SMA-12) TESTS INCLUDED Albumin NORMAL RANGEA 3.5-5.0 g/dL ALP 30-120 units/L AST 0-35 units/L Bilirubin, total 0.3-1.1 mg/dL Calcium, serum 8.4-10.6 mg/dL Cholesterol less than 200 mg/dL Glucose 70-100 mg/dL LDH 140-280 units/L Phosphate 2.5-4.5 mg/dL Total protein 6.0-8.0 g/dL BUN 11-23 mg/dL Uric acid 2.2-8.0 mg/dL aNormal range may vary among laboratories depending on the type of test performed and the reagents used. (The SMA-6, SMA-7, and SMA-20 are different panels containing tests for 6, 7, and 20 substances, respectively.) ALP, Alkaline phosphatase; AST, aspartate aminotransferase; BUN, blood urea nitrogen; LDH, lactate dehydrogenase; SMA, sequential multiple assay. Box 24.2 Examples of Serology Tests Many different types of serology tests may be ordered. Common examples are: • Agglutination tests for speciic organisms • Antistreptolysin-O titer • Blood typing: ABO groups and Rh • Carcinoembryonic antigen (CEA) assay • Coombs test • C-reactive protein antiserum • Heterophil antibody titer • Immunoelectrophoresis • Immunoglobulin (Ig) types: IgG, IgA, IgM, IgE, and IgD • Radioimmunoassays (RIAs) • Tests for syphilis • Treponema pallidum–microhemagglutination (TP-MHA) • Venereal Disease Research Laboratory (VDRL) • Fluorescent treponemal antibody (FTA) • Enzyme-linked immunosorbent assay (ELISA) antibody test for human immunodeiciency virus (HIV) • Western blot toilet bowl, in a bedpan, or in plastic wrap draped on the rim of the toilet bowl. Transfer a small amount of stool to the appropriate container for a culture or a test for ova and parasites (O & P) or onto cards for the occult blood test (Skill 24.4). Maintain aseptic technique when collecting specimens for culture and sensitivity. In sensitivity tests, the identiied organism is subjected to various antibiotic drugs to see which ones are most effective in killing it. With culture media that contain chromogens that interact with bacterial and fungal enzymes, organisms can be identiied after only 24 hours of incubation. Histologic and cytologic tests involve the study of tissues and cells. Conirmation of a diagnosis often depends on viewing tissues under a microscope to see the effects of the disease. Organs and tissues removed at biopsy (surgical excision of a small amount of tissue) are studied closely, and a pathology report is prepared. Studies of tissues and cells are performed to detect carcinogenic, metabolic, vascular, and other changes. A variety of procedures may be used to obtain specimens for bacteriologic or cytologic examinations. Venipuncture and bone marrow aspiration (withdrawal of luid or cells) yield specimens for culture or cytologic studies; urine specimens can be obtained from catheters and by clean-catch procedures. Lumbar puncture is used to obtain spinal luid for culture. Standard Precautions must be employed and aseptic technique followed to guard against infection or contamination of specimens. Ultrasonography Ultrasonography (sonography) is a noninvasive method of visualizing soft tissue structures of the body. The sonogram is a recording of the relection of the ultrasonic waves directed into the tissues. The procedure is used to diagnose many pathologic conditions of female reproductive organs, prostate, heart, kidney, pancreas, gallbladder, lymph nodes, liver, spleen, thyroid, eye, and peripheral blood vessels. It is often used in conjunction with radiography or nuclear medicine scans. The procedure is quick and does not usually produce much discomfort. Sonograms are produced with high-frequency sound waves that pass through the body. Echoes vary with tissue density, and the tracing produced is an echo-relection map. Patient preparation depends on the type of sonogram desired. For an abdominal sonogram, the patient is asked to drink a liter of water before the procedure. A gel or lubricant is applied to the skin over the area to be examined. The technician moves the transducer (wand emitting the sound waves) over the area with slight pressure. The echo-relection pattern is displayed on a monitor, and pictures may be recorded or printed. The test takes approximately 35 to 45 minutes. No particular aftercare is needed. Radiology Procedures X-ray studies, fluoroscopy, and cineradiography. Different types of radiation are used for diagnosis and treatment of disease: alpha rays, beta rays, gamma rays, and x-rays. The most widely used radiologic diagnostic technique, irradiation by x-ray beams, produces an image of the denser tissues of the body by passing rays through the part to expose a ilm. The denser tissues block the x-rays and prevent them from exposing the ilm; therefore, tissues appear as black, gray, or white images depending on the degree of density. X-ray studies of the bony skeleton are examples of this process. Radiopaque solutions and materials can be used in various organs to form shadows on the ilm Diagnostic Tests and Specimen Collection CHAPTER 24 417 Skill 24.3 Performing a Urine Dipstick Test Urine dipsticks are manufactured to test for several substances in the urine. They provide a quick and easy way to screen for abnormalities in the urine in the primary care provider’s ofice, at home, in the clinic, in the long-term care facility, or on the hospital nursing unit. A random or midstream urine specimen is used for the test. SUPPLIES • Multistix for urine testing • Gloves • Timer or watch • Urine specimen Review and carry out the Standard Steps in Appendix A. ACTION (RATIONALE) Assessment (Data Collection) 1. Assess whether patient can produce urine specimen. (If patient has recently emptied the bladder, it may be necessary for them to drink some water and wait a while before producing specimen.) Planning 2. Determine that gloves and Multistix are available. (Prevents hunting for supplies when ready to test specimen.) Implementation 3. Fill in a laboratory report form with the patient’s name, the primary care provider’s name, the date, and your initials. (The sheet is ready for recording of test results.) 4. Obtain the specimen, don gloves, and wet the dipstick with urine, making certain that each colored square is moistened. Remove the stick from the urine quickly and gently tap it on the side of the container to remove excess urine. (The stick can be dipped into the urine or a small amount of urine can be poured down the stick while holding it over the toilet or a workroom sink.) Step 4 5. Start timing the tests immediately after wetting the stick. (Exact timing is necessary for the accuracy of the test results. Some portions of the test require 30 seconds before reading; others are read at 40 seconds, 45 seconds, or 60 seconds.) Evaluation 6. Hold the stick horizontally and compare the color chart on the side of the Multistix bottle with the color on the strip at the correct time interval. (Allows for close comparison of the colors for each square on the stick with the color chart on the bottle.) Step 6 418 UNIT V Basic Nursing Skills 7. Document the result for each component of the test on the laboratory report form. (Records the test results.) 8. Dispose of urine, container, and used Multistix correctly in the biohazard waste receptacle. Remove gloves and perform hand hygiene. (Reduces transfer of microorganisms.) 9. Share results with patient or give the report to the primary care provider. (Participation of patient in testing and care improves understanding of treatment. Documentation is the completed laboratory slip.) Special Considerations • Certain medications and vitamins may discolor the urine and interfere with accurate reading of the test results. Table 24.4 Normal Urinalysis CHARACTERISTIC Color NORMAL VALUE Yellow, straw, dark yellow, amber Character Clear Speciic gravity (sp gr) 1.003-1.030 Acetone, ketones Negative Glucose (gluc) Negative Protein (Alb) 0-0.8 mg/dL Nitrite Negative Occult blood Negative pH 4.6-8.0 Odor Faint (not fruity, musty, ishy, or fetid) Urobilinogen Negative or 0.1-1 Ehrlich units/dL Cells Erythrocytes Leukocytes Less than or equal to 2 cells/ high-power ield Less than or equal to 4 cells/ high-power ield Casts None Crystals None Bacteria or fungi None Parasites None Epithelium Less than or equal to 10 cells/ high-power ield that show the size, location, and structure of less dense tissues (Fig. 24.1). Fluoroscopy is used to examine movement. X-rays are passed through the body part and are projected on a luorescent screen. The dense tissues produce dark shadows on the ilm, whereas soft tissues appear whiter. To examine movement through organs or soft tissues, the room is made dark, and a radiopaque substance is introduced into the body. For example, to observe movement and structure of the throat, esophagus, and stomach, barium is swallowed. Cineradiography is the • Urine specimens must be tested while they are fresh for the result to be accurate. • If the patient produces the specimen at home, ask that it be refrigerated until it can be brought in for testing. Critical Thinking Questions 1. If some of the test-strip squares turn an odd color after exposure to urine, what would you do? 2. If a patient’s specimen was obtained 2 hours ago and brought to the ofice, will the test results of a urine dip be accurate? method of adding a video camera to the luoroscope equipment and making a video recording of the procedure so the results can be examined in further detail. The low intensities of diagnostic x-rays make them safe to use because the exposure is of short duration and the rays do not penetrate deeply into the tissues. Higher intensity doses of radiation are harmful to the cells and are used therapeutically to bombard and kill cancer cells in the body. Commonly performed radiologic procedures include: • Chest x-ray (CXR) studies • Barium swallow and upper gastrointestinal (GI) series • Barium enema and small bowel series • Kidneys, ureters, and bladder (KUB) x-ray studies • Gallbladder series and cholangiogram • Intravenous pyelogram (IVP) • X-ray studies of the bony skeleton: arthrogram and myelogram • Radionuclide scans • Computed tomography scans (CT scans) Think Critically The patient asks how a sonogram works. Can you explain the process in easy-to-understand terms? Radionuclide scans. Radionuclide scans are based on the fact that various organs and soft tissues of the body attract and concentrate certain radionuclides. These studies are carried out in the nuclear medicine department, which is often a division of the radiology department. A radioactive substance is injected into a vein and then, after allowing time for the organ being scanned to absorb the substance, a radioactivity scanner (scintillator) is passed over the area where the organ is located. Serial pictures are then produced at intervals. The radioactive substance is typically passed from the body, in the urine, quickly, depending on the patient’s renal function. Only a small amount of radia- Diagnostic Tests and Specimen Collection CHAPTER 24 419 Skill 24.4 Obtaining a Stool Specimen for Occult Blood, Culture, or Ova and Parasites Nurses frequently need to obtain a stool specimen from a patient and test it for occult blood indicating GI tract bleeding. Specimens may also be sent for culture or for tests for ova and parasites or other substances when a GI complaint needs to be diagnosed. Stool for ova and parasites must be sent to the laboratory immediately. In some states, stool testing is permitted only in the laboratory. SUPPLIES • “Hat” collection container to place in the toilet • Bedpan • Toilet tissue • Gloves • Container with culture preservative • Sterile swab(s) • Specimen container for ova and parasites • Test cards for stool for occult blood • Wooden sticks • Tongue blades Review and carry out the Standard Steps in Appendix A. ACTION (RATIONALE) Assessment (Data Collection) 1. Determine whether the patient understands why the specimen is needed. (Understanding helps patient accept need for specimen.) 2. Determine whether patient will need to use a bedpan or can use the toilet to deposit the specimen. (Identiies equipment needed.) Planning 3. Determine when patient usually has a bowel movement. (Allows nurse to be available to collect the specimen.) 4. Instruct patient about need for stool specimen. (Understanding makes patient more cooperative.) Implementation 5. Place collection container by toilet or position patient on bedpan. Ask patient to use call button when specimen is ready. (Container will be at hand when needed. Alerts nurse to collect specimen.) 6. Instruct patient to void and use tissue before placing the stool collection container in toilet to catch stool specimen; or clean and replace bedpan after voiding. (Stool specimen should be free of urine or tissue.) 7. Don gloves; assist patient with cleansing of rectal area if needed. Assist to perform hand hygiene. (Keeps patient clean and prevents spread of microorganisms.) 8. Perform hand hygiene and don fresh gloves. (Protects hands from fecal contamination.) 9. Take specimen in covered bedpan to bathroom or utility room if bedpan was used. (Provides a private area in which to transfer the specimen to the laboratory container or onto the stool cards.) Stool Culture 10. Open specimen jar containing culture medium, placing lid upside down on the counter. Withdraw sterile swab from culture tube or package and place it into the stool to obtain a stool sample the size of a bean. Place stool into the stool culture container with the culture medium. Taking care not to contaminate the inside of the jar lid, replace it on the container. (Placing lid upside down prevents contamination of the lid. Prepares stool for laboratory culture.) Test for Ova and Parasites 11. Using wooden tongue blade(s), transfer a portion (1 inch [2.5 cm]) from the middle of the stool to the container for the ova and parasite specimen. If the stool is liquid, transfer about 15 mL of liquid stool to the container. Place container in a biohazard bag and seal. (Readies the specimen for the laboratory.) 12. Send specimen to the laboratory immediately with a completed requisition slip. Be certain specimen container is properly labeled with the patient’s name and room number, the date, and the primary care provider’s name. (Identiies specimen as belonging to the patient; routes laboratory result to the correct care provider.) Test for Occult Blood 13. Open the front window(s) of the specimen card. (Readies the card for receipt of the specimen.) 14. With wooden stick, obtain a small amount of stool from the middle, interior portion of the specimen. Smear it on the area within the window of the stool card. Repeat if more than one window is to be illed for the test. (Places specimen within the testing area of the card. Only a small amount of stool is required.) 420 UNIT V Basic Nursing Skills the stool. Careful timing is essential for test accuracy.) 18. Dispose of the test card in a biohazard waste container. Cleanse the bedpan or “hat” stoolcollection container. Remove gloves and perform hand hygiene. (Reduces transfer of microorganisms.) Evaluation 19. If the test result is positive, be certain that the patient adhered to the diet restrictions before reporting. Determine whether the patient took any medications that could have produced a false-positive test result. (Ensures accuracy of test result.) Step 14 15. Open the occult blood specimen card back window. (Provides access to the specimen for testing.) 16. Place two drops of the occult blood specimen reagent on the stool smear and one drop on the control; repeat for each window on the card. (Check test instructions for the number of drops of the reagent; some test instructions differ.) (Begins the test.) Documentation 20. Complete the laboratory test form with the patient’s name, date, the primary care provider’s name, type of test, and the result, or enter the result in the patient’s medical record. (Ensures that the test result is recorded.) Documentation Example 1/04 0915 Stool for occult blood negative ×2. (Nurse’s electronic signature) Special Considerations • False-positive and false-negative results for occult blood tests are prevented by the patient following the recommendations for diet and medication cessation for several days before the test. See the particular test manufacturer’s recommendation sheet. • Stool cultures are often done in a series of three on specimens taken from different bowel movements. • Newer fecal immunochemical tests can be performed without dietary and medication restrictions (check the manufacturer’s product information). Step 16 17. Wait 30 seconds. Read the test, looking for blue discoloration in or around the stool smear. Check that the control turned blue. (Blue color within 30 seconds indicates that blood is present in tion is given, and the patient is not considered radioactive. Radionuclides are used in scanning the thyroid gland, kidneys, the brain, the liver, lungs, bones, and pericardium and in determining blood volume. The time required for the scan depends on the organ being scanned. Critical Thinking Questions 1. Why do you think a stool specimen for ova and parasites needs to be fresh when it reaches the laboratory? 2. Why is it contraindicated to take aspirin for 5 days before obtaining a stool sample for an occult blood test? Safety Alert NUCLEAR SCANS AND PREGNANCY Radionuclide tests are contraindicated for pregnant or nursing women. Always verify whether a woman is pregnant, could be pregnant, or is nursing before sending her for a nuclear scan. Diagnostic Tests and Specimen Collection CHAPTER 24 421 A FIGURE 24.1 Chest x-ray ilm showing a tumor. (From Grainger, R. G., Allison, D. J., Adam, A., & Dixon, A. K. [2002]. Grainger & Allison’s Diagnostic Radiology [4th ed.]. Philadelphia, PA: Churchill Livingstone.) Nursing care involves proper disposal of linens, waste materials, and body secretions that have been exposed to radioactive materials. The patient is asked to empty the bladder when imaging is complete to reduce radiation exposure time. Part of patient education is to assure patients that they are not radioactive or a danger to others in the vicinity. Computed tomography. CT scans of various organs and parts of the body are used to conirm a diagnosis, plan treatment, evaluate the effects of treatment, and guide needle placement for biopsy or aspiration. A computer enhances x-ray images and allows examination of horizontal sections of the body at various angles to deine tissue density. Blood low is assessed with CT angiography. A contrast medium in used for the procedure. The test is used for suspected pulmonary embolism and arteriovenous malformation, to determine patency of coronary arteries, and to detect blood low patterns to tumors. Clinical Cues If a patient who has diabetes is to have a CT scan with an iodine-based contrast medium and is taking a medication containing metformin, that medication must be discontinued before the test and another means used to control blood glucose, because metformin can signiicantly alter renal function. Most CT scans are noninvasive, but consent may be required for scans using any contrast medium. Preparation of the patient depends on the organ or part to be examined. The CT scan requires that the patient be in one position for 10 to 45 minutes. The patient is positioned on a table inside the scanner. The B FIGURE 24.2 (A) MRI machine. (B) Midline sagittal view of the brain using MRI. (From Lewis, S. L., Heitkemper, M. M., Dirksen, S. R., O’Brien, P. G., & Bucher, P. [2007]. Medical-Surgical Nursing: Assessment and Management of Clinical Problems [7th ed.]. St. Louis, MO: Mosby.) scanning machinery revolves around the body part being scanned. Data are fed into the computer, which produces images in shades of gray that indicate the different densities of the organ. Think Critically If your patient expresses fear at receiving a radionuclide for a particular diagnostic test, how could you reassure them? Magnetic resonance imaging. Magnetic resonance imaging (MRI) is a noninvasive method of differentiating normal from abnormal tissue in the body. MRI is commonly used for the brain, knee joint, spine and spinal cord, and abdominal organs. The patient must lie lat and very still. The patient is placed on a table and then slid inside the large cylinder-shaped machine; the cylinder may be of open or closed design (Fig. 24.2). 422 UNIT V Basic Nursing Skills As scanning takes place, loud clicks can be heard. The procedure takes up to 1½ hours. The patient can talk through an intercom system to the MRI staff. This may help relieve feelings of claustrophobia. Patients with metal devices implanted in the body, such as cardiac pacemakers, automatic implantable cardiac deibrillators, metal hip prostheses, artiicial cardiac valves, vascular clips, or staples from recent surgery, cannot undergo this procedure because the machine emits a strong magnetic ield. Patients with tattoos occasionally report burning or swelling of the tattooed area because some inks contain traces of metal. The patient must inform the MRI technician of any tattoos, and if they experience any burning feeling during the procedure. Magnetic resonance angiography (MRA) is used to visualize arteries, veins, and the heart chambers, using the same technology as MRI. MRA is useful in detecting aneurysm of the aorta and atherosclerotic disease in the arterial system. MRA may be used to assess the arteries that supply a tumor before tumor removal. It is particularly useful in identifying arteriovenous malformations in the brain and alterations of blood low in the circle of Willis that could contribute to stroke. Clinical Cues For patients undergoing MRI, remove any transdermal medication patch, including a nicotine patch because the metal backing may cause a burn from this procedure. Inquire about any internal prosthetic device that contains metal. Many patients become anxious about being placed in an MRI scanner. Obtain an order for sedation, if needed, before the procedure. Describe the machine and procedure to the patient. The underlying concept is one of changing magnetic ields, and information is translated into images of different densities of tissue in the body. Nursing care involves obtaining consent and making certain that all surface metal (e.g., rings and watch) is removed from the patient’s body. Instruct the patient to lie very still during the procedure and to keep the eyes closed to decrease feelings of claustrophobia. Music of the patient’s choice may be provided. Teach the patient deepbreathing and rhythmic breathing relaxation techniques. Think Critically The patient scheduled for an abdominal MRI says she does not think she can stand to hold still in a restricted position for more than 10 minutes. What would you do? Positron emission tomography scans. Positron emission tomography (PET) scans are used to diagnose cancer, heart disease, and some brain disorders. The scan produces digital pictures that show abnormal cells in the body. The scan shows differences in blood low and oxygen uptake in cells. Problems can be identiied earlier with PET than with CT or MRI. The test takes about 2 hours and is noninvasive and painless. Tell patients not to exercise for 24 hours and not to eat or drink anything for several hours before the scan. Metal should be eliminated from clothing, and no jewelry should be worn because it can interfere with the scan. An intravenous (IV) radiotracer is injected before beginning the scan. About 45 minutes later, the scan will be performed. The scanner is a large donut-shaped machine with a table that slides into the opening. The machine makes whirring and clicking sounds. The patient must lie still during the scan. Cardiopulmonary Studies and Procedures A battery of tests that range from simple to complex is used to diagnose heart or lung disease (Box 24.3). Electrocardiogram. The electrocardiogram (ECG or EKG) was one of the irst diagnostic tests of heart activity. It remains important because it is quick and easy and it provides an immediate visual record. The ECG consists of waves and lines that represent the electrical activity during the c