Chapter 18. Radiographic Contrast Media
Cardiovascular physiologic effects of radiographic contrast media include which of the following?
A. Arteriolar vasodilation
B. Electrocardiogram (ECG) QRS prolongation
C. Ventricular hypercontractility
Hemodynamic effects of intraventricular contrast administration include a mild and transient decrease in ventricular function and increase in ventricular filling pressures. Another hemodynamic effect of intra-arterial contrast administration is transient arteriolar vasodilation, resulting in decreased vascular resistance, increased blood flow, and potentially decreased systemic pressure. Electrophysiologic effects of intracoronary contrast administration include transient changes on the surface electrocardiogram such as QRS prolongation, axis shift, ST-segment depression, P-R prolongation, and QT prolongation. Bradyarrhythmias, such as sinus bradycardia and asystole, may also occur. All these electrophysiologic effects are more common with the high-osmolar agents than the low- or iso-osmolar agents.
Dose- and/or infusion rate–dependent adverse reactions that occur immediately after radiographic contrast media administration include all the following except:
Immediate reactions that are due to radiographic contrast media’s physiologic and chemotoxic effects are generally dependent on dose and infusion rate. Symptoms include warmth, flushing, nausea, emesis, burning, and/or pain. These reactions are usually transient and self-limited. However, immediate hypersensitivity reactions are generally independent of dose and infusion rate. Seventy percent of these reactions occur within 5 minutes of contrast media administration, and 96% occur within 20 minutes. Clinical manifestations can include pruritus, urticaria, angioedema, abdominal pain, diarrhea, bronchospasm, wheezing, laryngeal edema, stridor, and hypotension.
Risk factors for immediate hypersensitivity reactions (IHRs) include which of the following?
B. Contact dermatitis to povidone-iodine
Risk factors for IHRs include a prior IHR as well as asthma and atopy. Shellfish or seafood allergies are not independent risk factors for IHRs, nor is prior contact dermatitis to povidone-iodine skin disinfectant.
Delayed hypersensitivity reactions can manifest as all the following except: