From the Guidelines
Patients preparing for procedures involving iodine contrast should follow guidelines to minimize risks, including adequate hydration, recent kidney function tests for those with risk factors, and premedication with corticosteroids for those with allergic history. To minimize the risks associated with iodine contrast procedures, several key guidelines should be followed.
- Adequate hydration is essential before and after the procedure, with oral fluids recommended for outpatients and IV fluids for inpatients or those unable to drink.
- Patients with risk factors for contrast-induced nephropathy (CIN) should have recent kidney function tests (within 3 months for stable outpatients, 7 days for inpatients or unstable patients) 1.
- Those with eGFR <30 ml/min/1.73m² require special consideration and possible alternative imaging.
- For patients with allergic history, premedication with corticosteroids is recommended: oral prednisone 50mg at 13,7, and 1 hour before the procedure, plus diphenhydramine 50mg 1 hour before.
- In emergency situations, IV methylprednisolone 40mg can be given every 4 hours until contrast administration, with diphenhydramine 50mg added 1 hour before.
- Metformin should be discontinued 48 hours before the procedure in patients with renal impairment and resumed only after confirming normal kidney function.
- The use of iso-osmolar or low-osmolar iodinated contrast media is recommended over high-osmolar iodinated contrast media in patients at increased risk of CIN 1. These precautions help prevent adverse reactions like CIN and allergic responses by reducing kidney stress and suppressing immune overreaction to the contrast material. According to the most recent and highest quality study, the KDIGO guideline recommends using either iso-osmolar or low-osmolar iodinated contrast media, rather than high-osmolar iodinated contrast media, in patients at increased risk of CI-AKI 1. Additionally, the guideline suggests using oral NAC, together with i.v. isotonic crystalloids, in patients at increased risk of CI-AKI 1. It is also recommended to use i.v. volume expansion with either isotonic sodium chloride or sodium bicarbonate solutions, rather than no i.v. volume expansion, in patients at increased risk for CI-AKI 1. Overall, these guidelines aim to minimize the risks associated with iodine contrast procedures and ensure the best possible outcomes for patients.
From the Research
Guidelines for Preparing Patients for Iodine Contrast Procedures
To minimize the risk of contrast-induced nephropathy, several guidelines can be followed when preparing patients for procedures involving iodine contrast:
- Identify patients at high risk for contrast-induced nephropathy, including those with preexisting renal failure, diabetes mellitus, advanced age, and congestive heart failure 2.
- Use the lowest possible dose of nonionic isosmolar dimeric or nonionic low-osmolar monomeric contrast medium 3.
- Provide volume expansion before, during, and after contrast media administration 3, 4.
- Consider prophylactic administration of oral n-acetylcysteine or sodium bicarbonate infusion in emergency situations 5, 3.
- Avoid using high-dose intraarterial gadolinium chelates, as they may not decrease the incidence of contrast-induced nephropathy and may increase the risk of dialysis and death 5.
Patient-Related Risk Factors
Patient-related risk factors for contrast-induced nephropathy include:
- Preexisting renal failure 2, 4
- Diabetes mellitus 2, 5, 4
- Advanced age 2
- Congestive heart failure 2
- Metabolic syndrome, prediabetes, and hyperuricemia 2
Non-Patient-Related Risk Factors
Non-patient-related risk factors for contrast-induced nephropathy include: