COMMON DIAGNOSTIC PROCEDURES

  1. Noninvasive diagnostic procedures are those procedures that provide an indirect assessment of organ size, shape, and/or function; these procedures are considered safe, are easily reproducible, require less complex equipment for recording, and generally do not require the written consent of patient or guardian.
    1. General nursing responsibilities:
      1. Reduce patient’s anxieties and provide emotional support by:
        1. Explaining purpose and procedure of test.
        2. Answering questions regarding safety of the procedure, as indicated.
        3. Remaining with patient during procedure when possible.
      2. Use procedures in the collection of specimens that avoid contamination and facilitate diagnosis-clean-catch urine and sputum specimens after deep breathing and coughing, for example.
    2. General nursing responsibilities:
      1. Electrocardiogram (ECG)-graphic record of electrical activity generated by the heart during depolarization and repolarization; used to diagnose abnormal cardiac rhythms and coronary heart disease.
      2. Echocardiography (ultrasound cardiography)-graphic record of motions produced by cardiac structures as high-frequency sound vibrations are echoed through chest wall into the heart; transesophageal echocardiography produces a clearer image, particularly in obese, barrel-chested, or patients with chronic obstructive pulmonary disease (COPD); used to demonstrate valvular or other structural deformities, detect pericardial effusion, diagnose tumors and cardiomegaly, or evaluate prosthetic valve function.
      3. Phonocardiogram-graphic record of heart sounds; used to keep a permanent record of patient’s heart sounds before and after cardiac surgery.
      4. Electroencephalogram (EEG)-graphic record of the electrical potentials generated by the physiological activity of the brain; used to detect surface lesions or tumors of the brain and presence of epilepsy.
      5. Echoencephalogram-beam of pulsed ultrasound is passed through the head, and returning echoes are graphically recorded; used to detect shifts in cerebral midline structures caused by: subdural hematomas, intracerebral hemorrhage, or tumors.
    3. Roentgenological studies (x-ray)
      1. Chest-used to determine size, contour, and position of the heart; size, location, and nature of pulmonary lesions; disorders of thoracic bones or soft tissue; diaphragmatic contour and excursion; pleural thickening or effusions; and gross changes in the caliber or distribution of pulmonary vasculature.
      2. Kidney, ureter, and bladder (KUB)-used to determine size, shape, and position of kidneys, ureters, and bladder.
      3. Mammography-examination of the breast with or without the injection of radiopaque substance into the ducts of the mammary gland; used to determine the presence of tumors or cysts. Patient preparation: no deodorant, perfume, powders, or ointment in underarm area on day of x-ray. May be uncomfortable due to pressure on the breast.
      4. Skull-outline configuration and density of brain tissues and vascular markings; used to determine the size and location of: intracranial calcifications, tumors, abscesses, or vascular lesions.
    4. Roentgenological studies (fluoroscopy)-require the ingestion or injection of a radiopaque substance to visualize the target organ.
      1. Additional nursing responsibilities may include:
        1. Administration of enemas or cathartics before the procedure and a laxative after.
        2. Keeping the patient NPO 6-12 hours before examination; check with MD regarding oral medications.
        3. Ascertaining patient’s history of allergies or allergic reactions (iodine, seafood).
        4. Observing for allergic reactions to contrast medium following procedure.
        5. Providing fluid and food following procedure, to counteract dehydration.
        6. Observing stool for color and consistency until barium passes.
      2. Common fluoroscopic examinations:
        1. Upper GI-ingestion of barium sulfate or meglumine diatrizoate (Gastrografin, a white, chalky, radiopaque substance), followed by fluoroscopic and x-ray examination; used to determine:
          1. Patency and caliber of esophagus; may also detect esophageal varices.
          2. Mobility and thickness of gastric walls, presence of ulcer craters, filling defects due to tumors, pressures from outside the stomach, and patency of pyloric valve.
          3. Rate of passage in small bowel and presence of structural abnormalities.
        2. Lower GI-rectal instillation of barium sulfate followed by fluoroscopic and x-ray examination; used to determine contour and mobility of colon and presence of any space-occupying tumors; perform before upper GI. Patient preparation: explain purpose; no food after evening meal the evening before test; stool softeners, laxatives enemas, and suppositories to cleanse the bowel before the test; NPO after midnight before test; oral medications not permitted day of test. After completion of exam: food, increased liquid intake, and rest; laxatives for at least 2 days or until stools are normal in color and consistency.
        3. Cholecystogram (done if gallbladder not seen with ultrasound)-ingestion of organic iodine contrast medium Telepaque (iopanoic acid), or Oragrafin (preparation of calcium or sodium salt of ipodate) followed in 12 hours by x-ray visualization; gallbladder disease is indicated with poor or no visualization of the bladder; accurate only if GI and liver function is intact; perform before barium enema or upper GI. Patient preparation: explain purpose; administer large amount of water with Wil contrast capsules; low-fat meal evening before x-ray; oral laxative or stool softener after meal; no food allowed after contrast capsules; water, tea, or coffee, with no cream or sugar, usually allowed. After completion of exam: fluids, food, and rest; observe for any signs of allergy to contrast medium.
        4. Cholangiogram-intravenous injection of a radiopaque contrast substance, followed by fluoroscopic and x-ray examination of the bile ducts; failure of the contrast medium to pass certain points in the bile duct pinpoints obstruction.
        5. Intravenous urography (IVU) or pyelography (IVP)-injection of a radiopaque contrast medium, followed by fluoroscopic and x-ray films of kidneys and urinary tract; used to identify lesions in kidneys and ureters and provide a rough estimate of kidney function.
        6. Cystogram-installation of radiopaque medium through a catheter into the bladder; used to visualize bladder wall and evaluate ureterovesical valves for reflux.
        7. Phlebography (lower limb venography)-determines patency of the tibial-popliteal, superficial femoral, common femoral, and saphenous veins. A contrast medium is injected into the superficial and/or deep veins of the involved extremity, followed by x-rays, while the leg is placed in a variety of positions; used to detect deep-vein thrombosis and to select a vein for use in arterial bypass grafting; localized clotting may result.
    5. Computed tomography (CT)-an x-ray beam sweeps around the body, allowing measurement of various tissue densities; provides clear radiographic definition of structures that are not visible by other techniques, permitting earlier diagnosis and treatment and more effective and efficient follow-up. Initial scan may be followed. by “contrast enhancement” using an injection of an intravenous contrast agent (iodine), followed by a repeat scan. Patient preparation: instructions for eating before test vary. Clear liquids up to 2 hours before are usually permitted.
    6. Magnetic resonance imaging (MRI)-noninvasive, nonionic technique produces cross-sectional images by exposure to magnetic energy sources. Provides superior contrast of soft tissue, including healthy, benign, and malignant tissue, along with veins and arteries; uses no contrast medium; takes 30-90 minutes to complete; patient must stay still for periods of 5-20 minutes at a time-equipment often very noisy. Patient preparation: patient can take food and medications except for low abdominal and pelvic studies (food/fluids withheld 4-6 hours to decrease peristalsis). Restrictions: patients who have metal implants, permanent pacemakers, or implanted medication pumps such as insulin, or who are pregnant or on life support systems. Patients who are obese may not be able to have full-body MRI because they may not fit in the scanner tunnel. Patients who are claustrophobic may need distraction (music) or may be referred to a facility that has an MRI chamber that is more open.
    7. Multiple-gated acquisition scan (MUGA)-also known as blood pool imaging. Red blood cells are tagged with a radioactive isotope. A computer-operated camera takes sequential pictures of actual heart wall motion; complement to cardiac catheterization; used to determine valvular effectiveness, follow progress of heart disease, diagnose cardiac aneurysms, detect coronary artery disease, determine effects of cardiovascular drug therapy. No special preparation. Painless, except for injections. Wear gloves if contact with patient urine occurs within 24 hours after scan.
    8. Ultrasound (sonogram)-scanning by ultrasound is used to diagnose disorders of the thyroid, kidney, liver, uterus, gallbladder, and fetus and the intracranial structures in the neonate. It is not useful when visualization through air or bone is required (lung studies). In some agencies the sonogram has taken the place of the oral cholecystogram in diagnosing gallbladder disease, bile duct distention, and calculi. Patient preparation is minimal, NPO for at least 8 hours for gallbladder studies. No x-rays. Thirty-two ounces of water PO 30 minutes before studies of lower abdomen or uterus.
    9. Pulmonary function studies:
      1. Ventilatory studies-utilization of a spirometer to determine how well the lung is ventilating.
        1. Vital capacity (VC)-largest amount of air that can be expelled after maximal inspiration.
          1. Normally 4000-5000 ml.
          2. Decreased in restrictive lung disease.
          3. May be normal, slightly increased, or decreased in chronic obstructive lung disease.
        2. Forced expiratory volume (FEVr)-percentage of vital capacity that can be forcibly expired in 1, 2, or 3 seconds.
          1. Normally 81-83% in 1 second, 90-94% in 2 seconds, and 95-97% in 3 seconds.
          2. Decreased values indicate expiratory airway obstruction.
        3. Maximum breathing capacity (MBC)-maximum amount of air that can be breathed in and out in 1 minute with maximal rate and depth of respiration.
          1. Best overall measurement of ventilatory ability.
          2. Reduced in restrictive and chronic obstructive lung disease.
      2. Diffusion studies-measure the rate of exchange of gases across alveolar membrane. Carbon monoxide single-breath, rebreathing, and steady-state techniques-used because of special affinity of hemoglobin for carbon monoxide; decreased when fluid is present in alveoli or when alveolar membranes are thick or fibrosed.
    10. Sputum studies:
      1. Gross sputum evaluations-collection of sputum samples to ascertain quantity, consistency, color, and odor.
      2. Sputum smear-sputum is smeared thinly on a slide so that it can be studied microscopically; used to determine cytological changes (malignant cell) or presence of pathogenic bacteria, tubercle bacilli.
      3. Sputum culture-sputum samples are implanted or inoculated into special media; used to diagnose pulmonary infections.
      4. Gastric lavage or analysis-insertion of a nasogastric tube into the stomach to siphon out swallowed pulmonary secretions; used to detect organisms causing pulmonary infections; especially useful for detecting tubercle bacilli in children.
    11. Examination of gastric contents:
      1. Gastric analysis-aspiration of the contents of the fasting stomach for analysis of free and total acid.
        1. Gastric acidity is generally increased in presence of duodenal ulcer.
        2. Gastric acidity is usually decreased in pernicious anemia, cancer of the stomach.
      2. Stool specimens-examined for: amount, consistency, color, character, and melena; used to determine presence of: urobilinogen, fat, nitrogen, parasites, and other substances.
    12. Thermography-a picture of the surface temperature of the skin using infrared photography (non-ionizing radiation) detects the circulation pattern of areas in the breasts. Tumors produce more heat than normal breast tissue. Useful with large tumors, but may not detect small or deep lesions. Requires expensive equipment and is difficult to interpret accurately.
    13. Doppler ultrasonography-used to measure blood flow in the major veins and arteries. The transducer of the test instrument is placed on the skin, sending out bursts of ultra-highfrequency sound. The ratio of ankle to brachial systolic pressure (API ≥ 1) provides information about vascular insufficiency. Sound varies with respiration and the Valsalva maneuver. No discomfort to the patient.
    14. Caloric stimulation test-used to evaluate the vestibular portion of the eighth cranial nerve, identify the impairment or loss of thermally induced nystagmus. Reflex eye movements (nystagmus) result in response to cold or warm irrigations of the external auditory canal if the nerve is intact. A diminished or absent response occurs with Meniere’s or acoustic neuroma. Nausea, vomiting, or dizziness can be precipitated by the test.
    15. 24-hour urine collection-a true and accurate evaluation of kidney function, primarily glomerular filtration. Substances excreted by the kidney are excreted at different rates, amounts, and times of day or night. Timed urine collection is done for protein, creatinine, electrolytes, urinary steroids. A large container is used with or without preservative. Label with patient name, type of test, and exact time test starts and ends. Not usually necessary to measure urine. Have patient void, discard urine; test starts at this time. Have patient void as close to the end of the 24 hours period as possible. If refrigeration is required, urine may be stored in iced container.
    16. Glucose testing-to detect disorder of glucose metabolism, such as diabetes.
      1. Fasting (FBS): blood sample is drawn after a 12 hours fast (usually overnight). Water is allowed. If diabetes is present, value will be 126 mg/dL.
      2. 2 hours postprandial (PPBS): blood is taken after a meal. For best results, patient should be on a high-carbohydrate diet for 2 to 4 days before testing. Patient fasts overnight, eats a highcarbohydrate breakfast; blood sample is drawn 2 hours after eating. Patient should rest during 2 hours interval. Smoking and coffee may increase glucose level.
      3. Glucose tolerance test (GTT): done when sugar in urine, or FBS or 2 hours PPBS is not conclusive. A timed test, usually 2 hours. High-carbohydrate diet is eaten 3 days before test.Blood is drawn after overnight fast. Patient drinks a very sweet glucose liquid. All of the solution must be taken. Blood and urine sample usually taken at 30 minutes, 1 hour, 2 hours, and sometimes 3 hours after drinking solution. Blood glucose peaks in 30 to 60 minutes, and returns to normal, usually within 3 hours.