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Introduction

  1. Know the patient’s age and health status. Children and older people, especially those with medical problems, may be especially sensitive to contrast agents. This sensitivity may increase the chance for side effects.

  2. The presence of other medical problems may increase the risk for side effects.

    1. Individuals with asthma or hay fever are at a greater risk for having an allergic reaction to the contrast agent.

    2. Patients with diabetes have a greater risk for developing kidney problems.

    3. Patients with severe hypertension may experience a dangerous rise in blood pressure and tachycardia.

    4. Patients with kidney and liver disease may experience exacerbation of their disease.

    5. Individuals with multiple myeloma may develop severe kidney problems.

    6. Patients with overactive thyroid may experience a sudden increase in symptoms or thyroid storm.

    7. Patients with sickle cell disease may experience the formation of abnormal blood cells.

    8. Patients using beta-blockers may have a higher risk for developing anaphylactoid reactions.

    9. Patients with chronic obstructive pulmonary disease (COPD) have an increased risk for postinjection dyspnea.

  3. Patients who are allergic to iodine contrast media must have this information documented in their healthcare records. The risk for subsequent reactions increases three to four times after the first reaction; however, subsequent reactions will not necessarily be more severe than the first. The patient must be made aware of the implications of the situation. Assess for and document allergies to iodine-containing substances (e.g., seafood, cabbage, kale, raw leafy vegetables, turnips, iodized salt). Also, determine each person’s reaction to penicillin or skin test for allergies because these patients have a greater chance of having a reaction.

  4. Check the patient’s fasting status before the x-ray procedure has begun. Except in an extreme emergency, iodine contrast media should never be administered intravenously sooner than 90 minutes after the patient has eaten. In most instances, the patient should fast the night before undergoing any x-ray procedure using an iodine contrast agent.

  5. Death from an allergic reaction can occur if severe symptoms go untreated. Staff in attendance must be qualified to administer cardiopulmonary resuscitation if necessary. Emergency equipment and supplies must be readily available.

  6. Promptly administer antihistamines per healthcare provider’s order if mild to moderate reactions to iodine contrast substances occur (see Table 10.1).

  7. When coordinating x-ray testing with a contrast agent, keep in mind that studies using iodine and those using barium should be scheduled at different times.

  8. Some physiologic change can be expected when an iodine contrast substance is injected, as during an intravenous pyelogram (IVP). Physiologic responses to iodine given intravenously include hypotension, tachycardia, and arrhythmias. For this reason, always check blood pressure, pulse, and respirations before and after these tests are performed.

  9. If appropriate for the patient, encourage intake of large amounts of oral fluids after the test to promote frequent urination to assist with flushing the iodine out of the body.

  10. Possible contraindications to the administration of iodine contrast substances include the following conditions:

    1. Hypersensitivity to iodine

    2. Sickle cell anemia (iodine use may increase sickling effect)

    3. Syphilis (iodine use may lead to nephrotic syndrome)

    4. Long-term steroid therapy (iodine substances may render part of the drug inactive)

    5. Pheochromocytoma (iodine use may produce sudden, potentially fatal rise in blood pressure)

    6. Hyperthyroidism

    7. COPD

    8. Multiple myeloma

    9. Acute asthma

    10. History of kidney disease

    11. Pregnancy

    12. Diabetes

    13. Severe dehydration

    14. Heart failure

    15. Drug therapy known to be nephrotoxic (e.g., cisplatin)

  11. Nonionic contrast agents tend to produce fewer side effects than do ionic materials.

  12. Patients with chronic kidney disease may develop acidosis when iodine contrast is administered.

Clinical Alert

  1. Careful patient preparation considers patient safety, prevents complications, and can avoid the necessity of repeat procedures. Assess for the following risk factors associated with a higher incidence of undesirable contrast agent reactions:

    1. Allergy

    2. Asthma

    3. Previous reactions to contrast media

    4. Repeat and high dosages administered

    5. Diabetes

    6. Kidney disease (preexisting); many laboratories require preprocedural assessment of 
creatinine levels in older adults

    7. Liver insufficiency

    8. Multiple myeloma

    9. Dehydration

    10. Older adult (older than 65 years)

    11. Newborns

    12. History of seizures

    13. Pheochromocytoma

  2. No contrast agent is without risk for causing reactions. Benefit versus risk must be considered. For example, in a workup to detect cancer, the benefits of early detection far outweigh the dangers of cumulative radiation exposure. The patient must be informed of the risk-to-benefit ratio; the patient has a legal right to this knowledge. In instances in which contrast must be delivered to high-risk patients, prophylactic premedication with prednisone may be ordered. Consult the radiology department for further information.

  3. Never inject iodized oils or barium into the bloodstream.

  4. Contrast agent–induced acute renal insufficiency is a rare and dangerous complication that occurs 1–5 day following IV injection of a contrast medium. Dehydrated patients and those with serum creatinine levels greater than 1.4 mg/dL (greater than 123.8 μmol/L) are at greatest risk.

  5. Intravascular iodinated contrast may interact with certain IV medications. These interactions produce insoluble precipitates that may lead to embolism. For that reason, an existing IV line should be flushed with saline before using this line as the mechanism for delivering contrast.

  6. Special attention is necessary for patients with diabetes because of their increased potential for kidney disease and development of lactic acidosis. Persons with diabetes taking oral hypoglycemic metformin should have this drug withheld the day of and 48 hours following the injection of iodinated contrast. In addition, advise the patient that a serum creatinine level should be rechecked 24–48 hours after receiving parenteral contrast. Examinations requiring extremely small volumes of contrast (myelography, arthrography) may not require such stringent precautions. Check with the radiology department for specific instructions.

  7. Tests for thyroid function (serum tests as well as nuclear medicine studies) are adversely affected for several weeks to months following iodinated contrast injection.

  8. Late reactions (2–3 days after procedure) most often occur with the use of agents such as iotrolan and iodohexane for intravascular procedures such as angiography.