Harry H. Holdorf PhD, MPA, RDMS (OB, Ab, BR), RT(ARRT-Ret.) AS(LRT) What every Sonographer should know about Contrast Media

 The purpose of contrast media  The routes of contrast media  Categories and types of Contrast agents  Intra-Venous contrast chemistry  Non-Ionic contrast agents  Ionic contrast agents  Viscosity  Dosing  Common Radiopaque agents  IV Contrast Agent Extravasation

 Allergy preparation: Special considerations  Adverse Reactions to iodinated contrast agents  Common responses to contrast agents  Mild adverse reactions  Moderate adverse reactions  Severe adverse reactions  Treating contrast agent reactions  Contraindications  Oral contrast  Contrast agents in Cardiology  Summary and conclusion

›To increase the difference in attenuation (radiation beam absorption) between adjacent structures ›X-Ray attenuation is directly related to the atomic number of the material in the path of the beam –Allows the biological nature of the material to be identifiable to the reading physician –Allows the reading physician to distinguish between vessels, lymph nodes, and other organs of the body from one another. Purpose of Contrast Media

›Enteral: Administered through the Gastro-Intestinal Tract –Includes the esophagus, stomach, small and large intestines ›Oral ›Gastric ›Rectal Common Contrast Media routes of delivery:

›Parenteral: Administered into the body in a manner other than the digestive tract –Intravenous ›Directly administered into a vein Common Contrast Media routes of delivery:

Barium Sulfite Water Soluble (iodinated) Positive Agents Air Carbon Dioxide Administered orally in granular form or rectally via insufflation Negative Agents Water VoLumen (Low density form of barium sulfate Neutral Agents ›Positive Contrast Agent –Contrast agent appears more radiopaque (white) than surrounding tissues –High atomic number ›Negative Contrast Agent –Contrast agent appears more radiolucent (dark) than surrounding tissues –Low atomic number ›Neutral –Appears similar to surrounding tissues Categories of Contrast Agents

The Types of Contrast Agents: Positive

The Types of Contrast Agents: Negative

The types of Contrast Agents: Neutral

Intra-Venous (IV) Contrast

›It is important to know the chemical properties of various contrast agents to chose for the best patient outcome with least risk of adverse side effects. ›Main Chemical Properties: –Osmolality ›Measurement of the total number of particles in the contrast solution per kilogram of water ›Direct measurement of the ionization of a solute in a solvent –Viscosity ›Amount of friction generated by the concentration and size of contrast molecules –Dosing ›Amount of contrast administered to a patient IV Contrast Agent Chemistry

›Low osmolality (particle) contrast media (LOCM) ›DOES NOT –Increase the osmolality of the blood serum –Change the osmotic pressure ›Sager for patients with compromised cardiac or renal status –Advantages ›Less hemodynamic effect ›More water soluble (hydrophilic) ›Less likely to be reactive with cells – Lower risk for allergic reactions Non-Ionic Contrast Agents

›High osmolality (particles) contrast media (HOCM) ›Increase water in blood which increases the total blood volume –Forces the heart to work harder in order to pump the increased volume –This phenomenon is referred to as INCREASED OSMOTIC PRESSSURE and results in ›Hypervolemia-increased blood volume ›Blood vessel dilation ›Shock in severely dilated patients –RENAL EFFECTS CAN BE SIGNIFICANT ›Expands kidney arteries which can cause: – Release of vasoconstrictors which can constrict the renal arteries ›Diminishes blood supply to the kidneys ›Decreases renal function ›These types of contrast agents are utilized infrequently because of their chemical properties and side effects. Ionic Contrast Agents

›Amount of friction generated by concentration and size of contrast molecules ›Higher the viscosity –THICKER the agent. More difficult to inject –Rapid injection can be more difficult with a more viscous agent ›Can trigger body’s pressure sensors, causing vasoconstriction and injection therefore can be painful –Important to heat the agent to body temperature before injection ›Reduces the viscosity –Heating can be achieved through ›Contrast warmer ›Manually. Using tepid water –Nonionic media is more viscous than ionic media at similar iodine concentrations Viscosity

›It is critical to avoid overdosing iodine ›Iodine Toxicity can occur at levels greater than grams –Symptoms of iodine overdose include: ›Tremors ›Irritability ›Tachycardia –If such symptoms occur ›STOP administration of medication immediately and initiate emergency action. Dosing

›Ominpaque (LOCM) ›Gastrografin (HOCM) ›Hypaque (HOCM) Common Radiopaque Agents

›IV contrast agent extravasation is the accidental extra-vascular injection of intravascular contrast media caused by: –Dislodgment of the cannula –Contrast leakage from the vessel puncture site –Rupture of the vessel wall ›Most common complication of intravenous injections –Occurs in less than 1% of patients ›Identifiable risk factors include: –Non communicative patient ›Pediatrics and geriatrics –Severely debilitated patients –Multiple punctures of the same vein –Injections performed on the dorsum of the hand and foot IV Contrast Agent Extravasation

Examples of Extravasation

›Signs and symptoms of IV contrast agent extravasation –Pain, tightness, or burning sensation at or near injection site –Swelling at or near the injection sight –Redness or discoloration at or near injection sight ›What to do in case of extravasation: –Immediately stop the injection or infusion –Remove the catheter from the injection site ›Treatment of IV contrast agent extravasation –Elevation of affected extremity above the hart –Alternating cold and hot packs ›15-60 minute applications three times daily (day 1-3) ›Follow institution’s protocol and consult a physician –Close observation for 2-4 hours –Inform referring physician and radiologist IV Contrast Agent Extravasation

›Given to patients with a known contrast reaction history –Reduces the risk of a severe adverse reaction ›Optimal Pre-Treatment Regimen –Three 50mg doses of oral prednisone ›Taken 13, 7, and 1 hours prior to procedure –Diphenhydramine 50mg dose ›Taken 1 hour prior to procedure ›Pre-Treatment regimen for Emergency Procedures: –Methyprednisone (40mgIV) every 4 hours until procedure –Diphenhydramine (50 mg IV) I hour prior to procedure ALLERGY Preparation: Special Considerations

›MOST reactions occur within 5 minutes of injections but may occur as late as 24 hours post injection. ›ALWAYS have a crash cart and emergency drug box available ›Diagnostic Medical Sonographers must be CPR certified ›Anaphylactic reactions are believed to be caused by the release of histamine in the body –Released from certain cells in the lungs, stomach and lining of blood vessels Adverse Reactions to Iodinated Contrast Media

SIGNS and SYMPTOMSRESPONSES Warmth or flush feelingNo treatment necessary Metallic tasteSymptoms resolve rapidly NauseaIf vomiting occurs: Vomiting Turn patient on their side to prevent Coughing aspiration Common Responses to Contrast Agents

Signs/SymptomsResponses Mild urticarial (Hives)Notify radiologist and physician CoughingObserve patient in the department Dizziness Nasal stuffiness Shaking Itching/pruritus Mild Adverse Reactions to Contrast Agents

Signs/SymptomsResponses ErythemaNotify radiologist or physician Moderate or severe urticariaPrepare to help administer antihistamine or epinephrine if ordered BronchospasmPrepare IV fluids and Oxygen if ordered Wheezing Moderate Adverse Reactions to Contrast Agents

Signs/SymptomsResponses Respiratory or cardiac arrestMaintain airway SeizuresCall rapid response or code HypotensiveTreat for shock, respiratory or cardiac arrest as symptoms require Laryngeal or bronchial edema Severe Adverse Reactions to Contrast Agents

›Always notify the radiologist and nurse of any reaction ›Your Emergency Drug Box should contain the following: –Epinephrine –Hydrocortisone –Atropine –Benadryl –Sodium Chloride (saline) –Lactated ringers –Oxygen Treating Contrast Agent Reactions

›Reversible renal failure ›Previous anaphylaxis reactions ›Pregnant patients –Contrast DOES cross the placental barrier ›Multiple myeloma (cancer of the blood) –Leads to acute renal failure ›Pheochromocytoma (adrenal tumor) –Releases large amounts of adrenaline ›ALWAYS consult with a radiologist or physician before making the decision to administer IV contrast Contraindications to IV Contrast Agents

Oral contrast: Barium Sulfate

Barium 2% mixture Suspended in water Contraindicated if patient is suspected of: –colon/gastro-intestinal obstruction or perforation –Tracheoesophageal fistula –Obstructing lesions of the small intestine –Pyloric stenosis –Inflammation or neoplastic lesions of the rectum –Recent rectal biopsy or colonoscopy Oral contrast Agents: BARIUM SULFATE

›Gastrografin, Gastrovue, Ominpaque –Water soluble, ionic, high osmolality contrast media –Prescription drug intended to be therapeutically and biologically inert when ingested/injected into the body for use in organ or tissue enhancement. –Particularly suited for times when a more viscous agent such as barium sulfate (NOT water soluble) is not feasible or potentially dangerous. Oral Contrast Agents-Water Soluble

›Patient care factors ›Take into account patient history, diagnosis, and contraindications ›Which contrast agent(s) are to be utilized for which procedures and protocols and for which diagnosis ›Consent ›Venipuncture ›Documentation and labeling of contrast media ›Storage of contrast media ›Joint Commission guidelines for contrast media Other Factors to be Considered

Microbubble contrast agents have been developed and are introduced as a safe and effective echo-enhancer in present-day clinical practice. Contrast echocardiography has evolved rapidly in the last decade, with major developments in both contrast media and ultrasound equipment. Understanding of the physical principles underlying the interaction of ultrasound and microbubbles has enhanced our ability to optimize the technique. Contrast Agents in Echocardiography

›Used predominantly for the detection of intra-cardiac shunts, the wide usage of Contrast-Enhanced Ultrasound more importantly resulted in routine use of contrast for left heart opacification. › CEU is also used for the assessment of left ventricular function during stress echocardiography and when imaging is suboptimal.

›Contrast agents help the radiologist’/cardiologist distinguish between different structures and organs of the body ›Sonographers must be educated and mindful when either using or observing the administration of contrast agents ›If utilized and administered properly, contrast agents present a relatively low risk for patients › Important and crucial to inform/educate patients about what they are being administered, risks involved, and purpose Summary and Conclusions

›ACR manual on contrast media ›Contrast agent tutorial: Department of Radiology/University of Wisconsin ›Radiologyinfo.org-patient safety Further information…

›How is contrast utilized in ultrasound, especially Echocardiography? Project: Presentation Contrast Enhanced Ultrasound