Cardiac Catheterization Techniques and Contrast Media Flashcards

Which contrast agent property is most responsible for contrast-induced nephropathy (CIN)?

Answer: High osmolality and viscosity causing renal tubular injury and vasoconstriction

High osmolality contrast agents cause renal tubular toxicity and medullary vasoconstriction, which are the primary mechanisms of contrast-induced nephropathy.

What is the standard pre-medication protocol for a patient with a prior contrast allergy undergoing elective catheterization?

Answer: Prednisone at 13, 7, and 1 hour before plus diphenhydramine 1 hour before

The standard contrast allergy premedication protocol uses oral corticosteroids at 13, 7, and 1 hour before the procedure plus diphenhydramine 1 hour prior.

The Cigarroa formula for maximum safe contrast dose is calculated as:

Answer: 5 cc × body weight (kg) ÷ serum creatinine

The Cigarroa formula (5 × body weight in kg ÷ serum creatinine) calculates the maximum safe contrast dose to reduce CIN risk based on individual renal function.

Iso-osmolar contrast agents such as iodixanol differ from low-osmolar agents primarily by:

Answer: Having osmolality equal to blood (~290 mOsm/kg), reducing osmotic stress on vessels and tubules

Iso-osmolar contrast agents have an osmolality matching blood (~290 mOsm/kg), which minimizes osmotic-induced endothelial and renal tubular cell damage.

A patient develops urticaria and bronchospasm during contrast injection — what is the first-line treatment?

Answer: Epinephrine 0.3–0.5 mg IM or IV

Epinephrine is the first-line treatment for anaphylaxis or severe contrast reactions with bronchospasm, acting on alpha and beta receptors to reverse life-threatening symptoms.

The primary mechanism by which IV hydration prevents contrast nephropathy is:

Answer: Increasing urine output to flush contrast through the kidneys, reducing tubular exposure time

IV hydration increases renal blood flow and urine output, which dilutes contrast and accelerates its excretion, reducing tubular exposure time and osmotic injury.