General pearls

General pearls

INTRAVENOUS CONTRAST AGENT ADMINISTRATION IN ADULTS

Renal impairment

• Renal impairment combined with diabetes mellitus carries significant risk

• Congestive heart failure, old age (> 70 years), and concurrent nephrotoxic drugs are also risk factors for contrast nephrotoxicity

• Insufficient evidence supporting the use of pharmacological means to reduce the incidence of contrast nephrotoxicity

• Serum creatinine is a poor indicator of renal function, and eGFR should be used where possible

All elective patients with renal disease or diabetes should have a recent eGFR (within 3 months)

All angiographic procedures require an eGFR (higher doses used)

• Renal impairment = eGFR < 60ml/min/1.73m

• eGFR 30-60ml/min/1.73m

Check scan indication

Ensure the patient is well hydrated before and after the procedure (PO or IV)

Use the smallest amount of contrast possible

Consider an iso-osmolar non-ionic dimeric contrast agent (e.g. Visipaque), although their exact preventative role is unclear

• eGFR < 30ml/min/1.73m

Use contrast only if essential and after discussion with referring clinicians

Previous allergies
• Review the need for contrast administration • No conclusive evidence that prophylactic steroids are of benefit • If contrast is required: Use a non-ionic low or iso-osmolar agent Maintain close medical supervision, leaving a cannula in place with 30 min of observation post investigation Ensure adequate resuscitation facilities are in place

• Metformin accumulation in renal impairment may result in lactic acidosis, although there is no convincing evidence that lactic acidosis is an issue after iodinated contrast medium in patients taking metformin

• eGFR > 60ml/min/1.73m

No need to stop metformin

• eGFR < 60ml/min/1.73m

Consult with referring clinician regarding stopping metformin for 48 h after contrast administration

Asthma
• No precautions necessary • If uncontrolled asthma, defer imaging

Pregnancy
• Administer iodinated contrast medium only in exceptional cases • Thyroid function should be measured in the fetus in the 1^st week after birth

Lactation
• No special precautions or cessation of breastfeeding required

• Iodinated contrast should not be given if the patient is hyperthyroid

• Iodinated contrast will preclude therapeutic radio-iodine therapy for 2 months – MRI is the preferred staging method

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Tags: Grainger & Allisons Diagnostic Radiology Essentials Expert Consu

Feb 27, 2016 | Posted by admin in GENERAL RADIOLOGY | Comments Off

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