Page 26 - Radiology Book

contrast media reactions continued
Non-allergic like
• Sign cant vasovagal
Severe Contrast Reactions
Usually allergic-like and may be life-threatening. Close monitoring during contrast administration is imperative to recognize those who may develop severe reactions. Prompt awareness of the following is necessary to improve response time:
• respiratory distress
• alerted mental status
• diffuse erythema
• severe hypotension
• sudden cardiac arrest
Most severe reactions require treatment with epinephrine and close monitoring.
CONTRAST ALLERGY STEROID PREPARATION PROTOCOLS
Several premedication regimens have been proposed to reduce the frequency and/or severity of reactions to contrast media. Any patient with a history of iodine contrast allergy is required to be premedicated. A history of a prior allergy-like reaction to contrast media is associated with an up to ve fold increased likelihood of the patient experiencing a subsequent reaction (1).
• Premedication starts 12 hours prior - and again at two hours prior to a CT scan with IV contrast.
• Oral steroids are preferable to IV steroids with prednisone and methylprednisolone are equally effective.
• H-1 antihistamine (oral or IV) may reduce the frequency of urticarial, angioedema, and respiratory distress.
Routine Pretreatment Regimen #1
Prednisone 50 mg (by mouth) q6 hours x 3 doses starting 13 hours prior to scan as:
13 hours + 7 hours + 1 hour prior to scan
Dosing regimen:
Dose 1 – Prednisone 50 mg 13 hours prior to scan
Dose 2 – Prednisone 50 mg 7 hours prior to scan
Dose 3 ( nal dose) – Prednisone 50 mg one hour with Diphenhydramine (Benedryl) 50mg IV/IM/PO prior to scan or IV push ve minutes before contrast given.
If patient unable to take oral medications, then 200 mg Hydrocortisone IV or methylprednisolone (Solumedrol) 40 mg IV can be substituted for oral prednisone.
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