Policy for administering water soluble oral contrast to patients with a history of prior IV contrast reaction:
- The oral contrast used for CT for in-patients and ER patients is dilute water soluble iodinated contrast (omnipaque). Approximately 1-2% of this is absorbed through the gut in normal patients. Therefore, there is a theoretic risk of a contrast reaction in a patient with a previous IV contrast allergy who gets oral omnipaque.
- Patients with a history of previous moderate or severe reaction to IV contrast should not get oral omnipaque unless premedicated. If the patient is not premedicated, barium may be used or the scan can be done without oral contrast.
- Moderate reactions are defined as: tachycardia, bradycardia, hypertension, generalized or diffuse erythema, dyspnea, bronchospasm, wheezing, laryngeal edema, mild hypotension.
- Severe reactions are defined as: severe or rapidly progressing laryngeal edema, unresponsiveness, cardiopulmonary arrest, convulsions, profound hypotension, clinically manifest arrhythmias.
Policy for administering IV or oral water soluble contrast to patients with a history of anaphylactic reaction (life threatening allergic reaction):
- Patients with a history of allergy (including contrast, food, seasonal) are at increased risk for a contrast reaction. The relationship between the allergy and the reaction is difficult to define, since many individuals have at least a minor allergy (seasonal rhinitis) and do not experience reactions.
- If a patient who has not been premedicated needs to emergently receive IV or oral contrast (omnipaque) and has had a previous anaphylactic reaction (to any allergen other than contrast material), the contrast material may be administered as long as the referring physician and radiologist discuss the case and feel that the benefits outweigh the risks of the procedure, that this is discussed with the patient, and the referring physician documents this in the patients chart. Barium may be administered as oral contrast without premedication. If the patient has had an anaphylactic reaction to contrast material, they should not receive IV or water soluble oral contrast.