Pulmonary Angiography

Also called pulmonary arteriography, pulmonary angiography is the radiographic examination of the pulmonary circulation following injection of a radiopaque iodine contrast agent into the pulmonary artery or one of its branches.

Possible complications include arterial occlusion, myocardial perforation or rupture, ventricular arrhythmias from myocardial irritation, and acute renal failure from hypersensitivity to the contrast agent.

Purpose

• To detect pulmonary embolism in a patient who is symptomatic but whose lung scan is indeterminate or normal, especially before anticoagulant therapy or in patients in whom anticoagulant therapy is contraindicated
• To evaluate pulmonary circulation preoperatively in the patient with congenital heart disease

Patient preparation

• Describe the procedure to the patient. Explain that this test permits evaluation of the blood vessels to help identify the cause of his symptoms.
• Instruct him to fast for 8 hours before the test or as prescribed. Tell him who will perform the test and where and that it will take approximately 1 hour.
• Tell the patient a small incision will be made in the right arm where blood samples are usually drawn, or in the right groin, and that a local anesthetic will be used to numb the area. Inform him that a small catheter will then be inserted into the blood vessel and passed into the right side of the heart and then to the pulmonary artery.
• Tell him the contrast agent will then be injected into this artery. Warn him that he may experience an urge to cough, a flushed feeling, nausea, or a salty or metallic taste for approximately 5 minutes after the injection.
• Inform him that his heart rate will be monitored continuously during the procedure.
• Make sure the patient or a responsible family member has signed a consent form. Check the patient's history for hypersensitivity to anesthetics, iodine, seafood, or radiographic contrast agents.

Equipment

50 ml of 60% meglumine diatrizoate or of 45% diatrizoate; 60 ml of thimerosal; 60 ml of 70% alcohol; 500 ml of physiologic saline solution; epinephrine for emergency administration; 30 ml of 2% procaine; 3-ml, 6-ml, and 20-ml syringes; two 2½" 18G needles; polyethylene catheter; extension tubing (Venotube) with stopcock; two sterile graduated cups; knife blade and handle; mechanical contrast agent injector; radiographic equipment

Procedure and posttest care

• After the patient is placed in a supine position, the local anesthetic is injected and the cardiac monitor is attached to the patient.
• An incision is made, and a catheter is introduced into the antecubital or femoral vein. As the catheter passes through the right atrium, the right ventricle, and the pulmonary artery, pressures are measured and blood samples are drawn from various regions of the pulmonary circulatory system.
• The contrast agent is injected and circulates through the pulmonary artery and lung capillaries while X-rays are taken.
• Apply a pressure dressing over the catheter insertion site, and note any bleeding.
• Maintain bed rest for about 6 hours.
• Observe for signs of myocardial perforation or rupture by monitoring vital signs.
• Be alert for signs of acute renal failure, such as sudden onset of oliguria, nausea, and vomiting.
• Check the catheter insertion site for inflammation or hematoma formation and report symptoms of a delayed hypersensitivity response to the contrast agent or to the local anesthetic (dyspnea, itching, tachycardia, palpitations, hypotension or hypertension, excitation, or euphoria).
• Advise the patient about any restriction of activity. Tell him that he may resume his usual diet after the test, and encourage him to drink lots of fluids.

Precautions

Clinical Alert Pulmonary an giography is contraindicated during pregnancy and in patients who are hypersensitive to iodine, seafood, or radiographic contrast agents.

• Monitor for ventricular arrhythmias due to myocardial irritation from passage of the catheter through the heart chambers.
• Observe for signs of hypersensitivity to the contrast agent, such as dyspnea, nausea, vomiting, sweating, increased heart rate, and numbness of extremities.
• Keep emergency equipment available in case of a hypersensitivity reaction to the contrast agent.

Normal Findings

Normally, the contrast agent flows symmetrically and without interruption through the pulmonary circulatory system.

Abnormal findings

Interruption of blood flow may result from emboli and from other types of pulmonary vascular abnormalities.

Interfering factors

• None significant