FA(redirected from FAH)
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flip angle (see there)
To assist in detecting vascular changes in the eyes affecting vision related to diseases such as diabetic retinopathy and macular degeneration.
Area of applicationEyes.
Fluorescein angiography (FA) involves the color radiographic examination of the retinal vasculature following rapid IV injection of a sodium fluorescein contrast medium. A special camera allows images to be taken in sequence and manipulated by a computer to provide views of the retinal vessels during filling and emptying of the dye. The camera allows only light waves in the blue range to strike the fundus of the eye. When the fluorescein reaches the blood vessels in the eye, blue light excites the dye molecules to a higher state of activity and causes them to emit a greenish-yellow fluorescence that is recorded.
This procedure is contraindicated for
- Patients with a past history of hypersensitivity to radiographic dyes. Address concerns about nausea and vomiting, as appropriate.
- Patients with narrow-angle glaucoma if pupil dilation is performed; dilation can initiate a severe and sight-threatening open-angle attack.
- Patients with allergies to mydriatics if pupil dilation using mydriatics is performed.
- Detect arterial or venous occlusion evidenced by the reduced, delayed, or absent flow of the contrast medium through the vessels or possible vessel leakage of the medium
- Detect possible vascular disorders affecting visual acuity
- Detect presence of microaneurysms caused by hypertensive retinopathy
- Detect the presence of tumors, retinal edema, or inflammation, as evidenced by abnormal patterns or degree of fluorescence
- Diagnose and manage diabetic retinopathy
- Diagnose past reduced flow or patency of the vascular circulation of the retina, as evidenced by neovascularization
- Diagnose presence of macular degeneration and any other degeneration and any associated hemorrhaging
- Observe ocular effects resulting from the long-term use of high-risk medications
- No leakage of dye from retinal blood vessels
- Normal retina and retinal and choroidal vessels
- No evidence of vascular abnormalities, such as hemorrhage, retinopathy, aneurysms, or obstructions caused by stenosis and resulting in collateral circulation
Abnormal findings related to
- Arteriovenous shunts
- Diabetic retinopathy
- Macular degeneration
- Obstructive disorders of the arteries or veins that lead to collateral circulation
- Ocular histoplasmosis
- Retinal vascular occlusion
Factors that may impair the results of the examination
- Inability of the patient to cooperate or remain still during the test because of age, significant pain, or mental status may interfere with the test results.
- Presence of cataracts may interfere with fundal view.
- Ineffective dilation of the pupils may impair clear imaging.
- Allergic reaction to radiographic dye, including nausea and vomiting, may interrupt the procedure.
- Failure to follow medication restrictions before the procedure may cause the procedure to be canceled or repeated.
Nursing Implications and Procedure
- Positively identify the patient using at least two unique identifiers before providing care, treatment, or services.
- Patient Teaching: Inform the patient this procedure can assist in detecting changes in the eye that affect vision. It may also be used as a preoperative assessment tool prior to retinal laser procedures.
- Obtain a history of the patient’s complaints, including a list of known allergens, especially allergies or sensitivities to latex or radiographic dyes.
- Obtain a history of the patient’s known or suspected vision loss; changes in visual acuity, including type and cause; use of glasses or contact lenses; and eye conditions with treatment regimens.
- Obtain a history of the patient’s symptoms and results of previously performed laboratory tests and diagnostic and surgical procedures.
- Obtain a list of the patient’s current medications, including herbs, nutritional supplements, and nutraceuticals (see Effects of Natural Products on Laboratory Values online at DavisPlus).
- Instruct the patient to remove contact lenses or glasses, as appropriate. Instruct the patient regarding the importance of keeping the eyes open for the test.
- Review the procedure with the patient. Explain that the patient will be requested to fixate the eyes during the procedure. Address concerns about pain and explain that mydriatics, if used, may cause blurred vision and sensitivity to light. There may also be a brief stinging sensation when the drop is put in the eye. Explain to the patient that some discomfort may be experienced during the insertion of the IV. Inform the patient that when fluorescein dye is injected, it may cause facial flushing or nausea and vomiting. Inform the patient that a health-care provider (HCP) performs the test, in a quiet, darkened room, and that to dilate and evaluate both eyes, the test can take up 60 min.
- Sensitivity to social and cultural issues, as well as concern for modesty, is important in providing psychological support before, during, and after the procedure.
- Explain that an IV line will be inserted to allow intermittent infusion of dye.
- Note that there are no food or fluid restrictions unless by medical direction.
- Instruct the patient to avoid eye medications (particularly miotic eye drops which may constrict the pupil preventing a clear view of the fundus and mydriatic eyedrops in order to avoid instigation of an acute open angle attack in patients with narrow angle glaucoma) for at least 1 day prior to the test.
- Ensure that the patient understands that he or she must refrain from driving until the pupils return to normal (about 4 hr) after the test and has made arrangements to have someone else be responsible for transportation after the test.
- Make sure a written and informed consent has been signed prior to the procedure and before administering any medications.
- Potential complications:
- Dilation can initiate a severe and sight-threatening open-angle attack in patients with narrow-angle glaucoma if pupil dilation is performed.
- There are a number of complications associated with venipuncture. Pain is commonly associated with needles and while pain experienced during venipuncture is usually mild, on a rare occasion the needle may strike a nerve causing severe and lasting pain. Hematoma results when blood leaks into the tissue during or after a venipuncture as evidenced by pain, bruising, and/or swelling at the venipuncture site. The swelling can cause temporary or permanent injury by compressing the surrounding nerves. Hematomas occur more often in elderly or frail patients, or those with difficult veins to access. Prolonged bleeding is a complication that occurs with patients who are taking blood thinners such as aspirin or warfarin, or who have coagulopathies such as hemophilia. Bleeding or bruising can be prevented by applying direct pressure to the site, once the needle has been removed, with gauze for a minute or two. The site should then be observed/assessed for bleeding or bruising. If no further action is required, the site can be covered by the gauze and an adhesive bandage or paper tape. Some patients experience a vasovagal reaction during the venipuncture procedure, evidenced by sweating (diaphoresis), low blood pressure (hypotension), fainting (syncope), or near fainting (near syncope). The potential for a fall injury is a significant concern related to vasovagal reactions. Other more unusual complications of venipuncture include cellulitis, phlebitis, seizures, inadvertent arterial puncture, and sepsis. Sepsis can be caused by introduction of bacteria from the surface of the skin into the blood as the result of improper cleansing of the venipuncture site. Immunocompromised patients are at higher risk for developing this complication.
- Anaphylaxis, bronchospasm, cardiac arrest, laryngeal edema, myocardial infarction, nausea, pruritus, urticaria, or vomiting can occur in response to the dye and extravasation of the dye can occur during injection.
- Observe standard precautions, and follow the general guidelines in Patient Preparation and Specimen Collection. Positively identify the patient.
- Ensure that the patient has complied with medication restrictions; ensure that eye medications, especially miotics and mydriatics, have been withheld for at least 1 day prior to the test.
- Avoid the use of equipment containing latex if the patient has a history of allergic reaction to latex.
- Have emergency equipment readily available.
- Instruct the patient to cooperate fully and to follow directions. Instruct the patient to remain still during the procedure because movement produces unreliable results.
- Seat the patient in a chair that faces the camera. Instruct the patient to look at a directed target while the eyes are examined.
- Administer the ordered mydriatic to each eye and repeat in 5 to 15 min, if dilation is to be performed. Drops are placed in the eye with the patient looking up and the solution directed at the six o’clock position of the sclera (white of the eye) near the limbus (gray, semitransparent area of the eyeball where the cornea and sclera meet). Neither dropper nor bottle should touch the eyelashes.
- Insert an intermittent infusion device, as ordered, for subsequent injection of the contrast media or emergency medications.
- After the eyedrops are administered but before the dye is injected, color fundus photographs are taken.
- Instruct the patient to place the chin in the chin rest and gently press the forehead against the support bar. Instruct the patient to open his or her eyes wide and look at the desired target.
- Fluorescein dye is injected into the brachial vein using the intermittent infusion device, and a rapid sequence of photographs are taken and repeated after the dye has reached the retinal vascular system. Follow-up photographs are taken in 20 to 30 min.
- At the conclusion of the procedure, remove the IV needle and apply direct pressure with dry gauze to stop bleeding. Observe venipuncture site for bleeding or hematoma formation and secure gauze with adhesive bandage.
- Observe for hypersensitive reaction to the dye. The patient may become nauseous and vomit.
- Inform the patient that a report of the results will be made available to the requesting HCP, who will discuss the results with the patient.
- Instruct the patient to resume usual medications, as directed by the HCP.
- Nutritional Considerations: Increased glucose levels may be associated with diabetes. There is no “diabetic diet”; however, many meal-planning approaches with nutritional goals are endorsed by the American Dietetic Association. Patients who adhere to dietary recommendations report a better general feeling of health, better weight management, greater control of glucose and lipid values, and improved use of insulin. Instruct the patient, as appropriate, in nutritional management of diabetes. The 2013 Guideline on Lifestyle Management to Reduce Cardiovascular Risk published by the American College of Cardiology (ACC) and the American Heart Association (AHA) in conjunction with the National Heart, Lung, and Blood Institute (NHLBI) recommends a “Mediterranean”-style diet rather than a low-fat diet. The new guideline emphasizes inclusion of vegetables, whole grains, fruits, low-fat dairy, nuts, legumes, and nontropical vegetable oils (e.g., olive, canola, peanut, sunflower, flaxseed) along with fish and lean poultry. A similar dietary pattern known as the Dietary Approaches to Stop Hypertension (DASH) diet makes additional recommendations for the reduction of dietary sodium. Both dietary styles emphasize a reduction in consumption of red meats, which are high in saturated fats and cholesterol, and other foods containing sugar, saturated fats, trans fats, and sodium. If triglycerides also are elevated, the patient should be advised to eliminate or reduce alcohol. The nutritional needs of each diabetic patient need to be determined individually (especially during pregnancy) with the appropriate HCPs, particularly professionals trained in nutrition.
- Recognize anxiety related to test results, and be supportive of impaired activity related to vision loss or anticipated loss of driving privileges. Discuss the implications of abnormal test results on the patient’s lifestyle. Provide teaching and information regarding the clinical implications of the test results, as appropriate. Emphasize, as appropriate, that good glycemic control delays the onset of and slows the progression of diabetic retinopathy, nephropathy, and neuropathy. Provide education regarding smoking cessation, as appropriate. Provide contact information regarding vision aids, if desired, for ABLEDATA (sponsored by the National Institute on Disability and Rehabilitation Research [NIDRR], available at www.abledata.com). Information can also be obtained from the American Macular Degeneration Foundation (www.macular.org), the Glaucoma Research Foundation (www.glaucoma.org), the American Diabetes Association (www.diabetes.org), or the American Heart Association (www.americanheart.org).
- Reinforce information given by the patient’s HCP regarding further testing, treatment, or referral to another HCP. Inform the patient that visual acuity and responses to light may change. Suggest that the patient wear dark glasses after the test until the pupils return to normal size. Inform the patient that yellow discoloration of the skin and urine from the radiographic dye is normally present for up to 2 days. Answer any questions or address any concerns voiced by the patient or family.
- Depending on the results of this procedure, additional testing may be performed to evaluate or monitor progression of the disease process and determine the need for a change in therapy. Evaluate test results in relation to the patient’s symptoms and other tests performed.
- Related tests include fructosamine, fundus photography, glucagon, glucose, glycated hemoglobin, gonioscopy, insulin, intraocular pressure, microalbumin, plethysmography, refraction, slit-lamp biomicroscopy, and visual field testing.
- Refer to the Ocular System table at the end of the book for related tests by body system.
fluorescent antibody. See immunofluorescence.