10/27/2010. Disclaimer. Managing Adverse Events Part II: Contrast Enhanced CT. Outline. Objectives. Purpose of Contrast Media in CT

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1 Disclaimer Slide - 1 Managing Adverse Events Part II: Contrast Enhanced CT Carolyn Kaut Roth, RT (R)(MR)(CT)(M)(CV) FSMRT CEO, Imaging Education Associates candi@imaginged.com Presented by William H. Faulkner, BSRT (R)(MR)(CT)FSMRT CEO, Wm Faulkner & Associates Faulkner@t2star.com Produced by Imaging Education Associates Sponsored by an unrestricted educational grant from Bracco Diagnostics If you are viewing this presentation as an on-line (self study) module be sure to complete the post test to claim your credits. Copyright 2010 Imaging Education Associates, LLC. No part of this module may be reproduced or manufactured in any form or by any means, electronic or mechanical, including photocopying, recording or by any other information storage and retrieval system without permission in writing from the publisher (Imaging Education Associates, LLC). Accreditation Information: According to the standards set forth by the ARRT (SMRT and the ASRT): In order to be awarded with continuing education credit for this module, the attendee of this course must view the material, take and pass the post test with a score of 75% or above. Furthermore, the course attendee is allowed three (3) attempts to obtain this score of 75% or above. After 3 failing attempts, the user will be disabled from this educational offering (based on the accrediting agencies regulations). For this reason, we recommend that t the viewer re-review the material l( (after one try), even if the viewer does not obtain a passing score of 75%. This module may be available in several formats (on-line or CD). You may not redeem credit for this topic again in this or any subsequent biennium. Disclaimer: This continuing educational offering is provided as an overview of accrediting processes for the healthcare provider. The information within this module should not be considered as medical advice. If you are a non-medical viewer, please consult your physician regarding any medical issues relating to diseases, conditions, symptoms, diagnosis, treatment and/or side effects. The user of this module agrees to access and use this information at his/her own risk. Imaging Education Associates, LLC (and our speakers) disclaim any liability for the acts of any technologist, physician, individual, group, or entity acting independently or on behalf of any organization who receives any information on any medical procedure, activity, service, or other situation through this module. Imaging Education Associates assumes no responsibilities for errors or omissions that may include technical or other inaccuracies, or typographical errors and accept no legal responsibility for any accreditation failures, injury and/or damage to persons or property from any of the methods, products, instructions, or ideas contained herein. Slide - 2 Outline Objectives 1. CT Contrast Media This module will discuss what contrast agents are used in computed tomography (CT). 2. Properties of contrast media (CM) Next, various CM properties will be discussed. 3. Patient interactions with CM Furthermore, patient interaction with CM in CT will be explained. 4. Managing Adverse events Finally, reactions and adverse events associated with contrast administration in CT will be discussed. Navigation Information, for this video lecture Pause Volume Play Video Slider Restart Table of Contents Upon completion of this course, the learner should be able to: Discuss what contrast agents are used in CT. Describe the properties of contrast agents used in CT. Recognize patient interactions with CM. Explain how to manage adverse events in CT. Slide - 3 Slide - 4 Purpose of Contrast Media in CT IV Contrast Media in CT vs. MR Imaging To alter the inherent contrast property of selected tissues, thus giving them greater image contrast vs. adjacent tissues For CT this means altering the ability of blood & certain tissues to attenuate (or block) x-rays Structures that enhance with IV contrast media in CT will also enhance on MR images and visa-versa Enhanced CTA Enhanced MRI Unenhanced CT Enhanced CT CT Iodinated MR Gadolinium-based Axial T1 Weighted Image Pre-contrast Axial T1 Weighted Image Post-contrast (Gadolinium) Axial CT Pre-contrast Enhanced MR images included for comparison Slide # 6 Axial CT Post-contrast (Iodinated) Slide - 5 Slide - 6 1

2 Contrast Characteristics in CT & MR Elemental Components of Contrast Media Axial CT Pre-contrast Axial CT Post-contrast (Iodinated) Axial T1 Weighted Image Pre-contrast Axial T1 Weighted Image Post-contrast (Gadolinium) Radiographic contrast media are chosen for their ability to attenuate (block) x- rays Ba Barium I Iodine PERIODIC TABLE OF ELEMENTS MRI contrast media are chosen for their ability to exert a paramagnetic effect: Gd Gadolinium Mn Manganese Fe Iron White Structure On White Background White Structure On Gray Background White Structure On Dark Gray Background White Structure On Black Background Black Structure On Black Background Slide - 7 Slide - 8 Contrast (+) for Radiographic Procedures Contrast (-) for Radiographic Procedures Increase x-ray attenuation of: Tissues Lumens (vascular) Increased attenuation brighter appearance Positive (radiopaque) CM Barium Iodine Decrease the x-ray attenuation of: Lumens (bowel) Decreased attenuation darker appearance Negative (radiolucent) CM Air CO2 Coronal Recon CTA Abdomen Iodine CM, IV admin. Aorta & Iliac Arteries Axial CTA Abdomen Celiac Artery AP Radiograph Abdomen Oral Barium Stomach & Small bowel AP Radiograph Abdomen IV Iodine, CM Kidneys, Ureters, Bladder AP Radiograph Abdomen Rectal Barium Colon AP Radiograph Abdomen Decubitus Position (right side down) Rectal Barium & Air Colon (down side bright / up side dark) Axial CT Rectal Air, Colon dark Slide - 9 Slide - 10 Effect of Iodinated CM Iodinated CM: Increase x-ray attenuation Give brighter appearance To improve that effect: Increase concentration Increase injection volume Increase injection rate Optimize scan timing Injection Reflection Slide - 11 Slide

3 Contrast medium is used in CT to: a. Make all tumors appear bright. b. Make all tumors appear dark. c. Make the patient feel better. d. Alter the inherent property of blood and tissues to attenuate x-rays. Contrast medium is used in CT to: a. Make all tumors appear bright. b. Make all tumors appear dark. c. Make the patient feel better. d. Alter the inherent property of blood and tissues to attenuate x-rays. like to re-review this concept: Click back to slide 5 on the table of contents. Remember, you are NOW on slide 14. Click slide 14 to continue with this lecture. Slide - 13 Slide - 14 Positive (+) contrast media are used in CT to: a. Reduce the attenuation of the x-ray beam. b. Increase the attenuation of the x-ray beam. c. Reduce the peak kilovolt peak (kvp) used to produce the x-ray beam. d. Increase the kvp used to produce the x-ray beam. Positive (+) contrast media are used in CT to: a. Reduce the attenuation of the x-ray beam. b. Increase the attenuation of the x-ray beam. c. Reduce the peak kilovolt peak (kvp) used to produce the x-ray beam. d. Increase the kvp used to produce the x-ray beam. like to re-review this concept: Click back to slide 9 on the table of contents. Remember, you are NOW on slide 16. Click slide 16 to continue with this lecture. Slide - 15 Slide - 16 Properties of Iodinated Contrast Media -Merism Physicochemical Properties: -Merism Ionicity Viscosity Osmolality Iodine content (concentration) Contrast Enhanced Axial CT Abdomen A process of reacting monomer molecules together in a chemical reaction. In iodinated CM, refers to two basic types of molecular architecture: Monomeric based upon a single benzene ring Dimeric based upon two benzene rings joined together via side chains Dimeric CM molecules are thus about twice the size of monomeric CM molecules, and have twice the capacity to hold iodine atoms. Therefore: Dimeric CM have 6 iodine atoms per molecule, as opposed to 3 for monomeric CM This allows dimeric CM to have a lower concentration of particles in solution than monomeric CM, while providing the same iodine content However, it also causes dimeric CM to have greater viscosities than monomeric CM, so their solutions tend to be more viscous than monomeric CM solutions, even though they are much less concentrated with CM particles Slide - 17 Slide

4 Ionicity Viscosity The molecular property of containing a net electrical charge, either (+) or (-), when dissolved in solution. Most modern iodinated CM are nonionic i.e., their molecules contain no net electrical charges in solution, and are not accompanied by cations (positively-charged companion molecules, such as meglumine) Definition: The resistance of a fluid to flow Standard: The force needed to move water at 20º C one centimeter Unit: Centipoise (cp) For CM, viscosity depends on Molecular structure Concentration Temperature Slide - 19 Slide - 20 Osmolarity Osmola R ity Osmolality Osmola L ity Definitions: Solute = the substance (e.g., CM molecules) that is being dissolved into solution Solvent = the fluid (e.g., water) into which the solute is being dissolved 1 mole = 6.02 x particles of a substance Molarity = the concentration of particles in a solution, defined as the number of moles of solute per liter (L) of solvent 1 osmole = 6.02 x osmotically-active particles of solute Osmolarity = the concentration of osmotically active particles in a solution, defined as the number of osmoles per liter (L) of solvent, or Osm/L What does it mean to be osmotically-active? For a particle, it means that it dissolves in water, but can be trapped by a semi-permeable membrane that allows the water to pass through it. The significance of this is that the trapped osmotically-active particle will draw water through that membrane. Definition: Number of particles of osmotically-active solute dissolved in a solution, defined as the number of osmoles per kilogram of solvent, i.e. Osm/kg Human plasma has an osmolality of approximately 285 mosm/kg water (1000 mosm = 1 Osm) Osmolality is a measure of the osmoles of solute per unit of weight of solvent, usually kilograms (osmol/kg or Osm/kg). Molarity and osmolarity are not commonly used in osmometry (the measurement of the osmotic concentrations of solutions) because they are temperature dependent. Why? Because they are based on volume, and the volume of the solvent expands with higher temperatures (while its weight does not change at all)! Slide - 21 Slide - 22 Osmolality Values The Effects of Osmolality Are Not Simple Slide - 23 Medium Osmolality (mosm/kg water) Blood plasma 285 Ionic high-osmolar CM (HOCM) Nonionic low-osmolar CM (LOCM) Iso-osmolar CM 290 Slide - 24 A highly osmotic solution will attract water through a semipermeable membrane, so that a dilutional effect will occur (to equilibrate the osmotic pressures on both sides of the membranes). In the body this causes transient fluid shifts. High osmolar CM in blood will (at the capillary level, where the lining of blood vessels is permeable) cause fluid from the extravascular space to be drawn into the blood. However, at that level, CM particles will also move from the blood to the extravascular space, decreasing this effect. The CM particles in the extravascular space do not enter cells, and may thus draw fluid from cells into the extravascular space. But blood keeps flowing, and soon the CM particles are being swept away to the kidneys for excretion. 4

5 Osmolality of CM Effects of High-Osmolality CM (HOCM) Ionic CM have two or more osmotically active particles per base CM molecule So they are high osmolar, unless they can be made at low concentration Non-ionic CM have only one osmotically active particle per base CM molecule So they are low osmolar, and if made at low concentration, can be iso-osmolar What s the difference? Non-ionic CM have about 1/5 the adverse reactions of ionic CM Physiological effects most are transient, but Hypervolemia (fluid shift to intravascular space) Vasodilation (experienced as flushing ) Altered shape of RBCs (by drawing water out of them) Increased chance of causing seizures if cross a blood-brain b barrier (BBB) disrupted d by stroke, infection or tumor NOTE: The so-called BBB is the inner lining of blood vessels in the brain which, when intact, is very impermeable to most substances, including CM Increased excretory fluid and osmotic load on kidneys Stimulate histamine release in some patients leads to idiosyncratic allergoid reactions Slide - 25 Slide - 26 The Problems with HOCM High osmolality shifts fluids Greater hemodynamic changes Greater pain and burning upon injection Greater chance of renal dysfunction Ionicity interferes with Na/K/Ca channels Neuro-Cardiotoxicity (effects on EKG and contractility) Neurotoxicity (seizures, if brain exposed) Either osmolality, ionicity or both stimulate histamine release from mast cells Higher adverse event rate Injection Reflection Slide - 27 Slide - 28 Viscosity is: a. The resistance of fluid to flow b. The number of osmoles (Osm) of solute per liter (L) of solution(osmol/l or Osm/L) c. The number of particles in a solution per unit of weight d. The temperature of the contrast agent. Viscosity is: a. The resistance of fluid to flow b. The number of osmoles (Osm) of solute per liter (L) of solution(osmol/l or Osm/L) c. The number of particles in a solution per unit of weight d. The temperature of the contrast agent. like to re-review this concept: Click back to slide 20 on the table of contents. Remember, you are NOW on slide 30. Click slide 30 to continue with this lecture. Slide - 29 Slide

6 Osmolality is: a. The resistance of fluid to flow b. The number of osmoles (Osm) of solute per liter (L) of solution (Osmol/L or Osm/L) c. The number of particles in a solution per unit of weight d. The temperature of the contrast agent Osmolality is: a. The resistance of fluid to flow b. The number of osmoles (Osm) of solute per liter (L) of solution (Osmol/L or Osm/L) c. The number of particles in a solution per unit of weight d. The temperature of the contrast agent like to re-review this concept: Click back to slide 22 on the table of contents. Remember, you are NOW on slide 32. Click slide 32 to continue with this lecture. Slide - 31 Slide - 32 Patient Screening Prior IV contrast agent? If yes: Any reaction? What was the reaction? What was the contrast agent? Allergic to any medications or foods? Other allergies? Asthma? Medications? ALL Diabetic? Taking metformin? History of heart disease? History of kidney disease? Relevant lab results? (e.g., creatinine) Warnings / Precautions with Iodinated Contrast RED FLAG!! Pheochromocytoma Multiple myeloma Sickle cell anemia Hyperthyroidism Myasthenia gravis Slide - 33 Slide - 34 Diabetes Mellitus and Biguanides Hemodialysis Patients With diabetics taking biguanides (e.g., metformin): Check serum creatinine If normal: Discontinue metformin at time of iodinated contrast media (CM) administration for a minimum of 48 hours. If abnormal: Discontinue metformin and delay CM administration for 48 hours; continue with no metformin for another 48 hours post iodinated CM administration. Serum creatinine must be within normal limits, or at least at the patient s baseline level, prior to resuming metformin. Can be given contrast media as long as dialysis is performed soon afterwards Slide - 35 Slide

7 Cardiac Disease & Pulmonary Hypertension Seizure Increased possibility of hemodynamic changes or arrhythmias Very unlikely to occur when iodinated CM given IV / IA to patients with no brain lesions (i.e., with intact BBB) May occur with very high doses of iodinated Contrast Media More likely to occur with ionic CM Patients at risk for seizures and other CNS reactions are: Those with acute cerebral pathology (infection, stroke, tumor), or epilepsy Alcoholics & drug addicts Slide - 37 Slide - 38 Other At-risk Medical Conditions Pregnancy and Lactation Severe combined disturbance of hepatic and renal function (hepato-renal syndrome) Chronic renal disease Diabetes mellitus (largely because of the correspondence with renal disease) Other diseases including: Myesthenia gravis, Hyperthyroidism, Multinodular Goiter Pregnancy: Radiation is the problem Contrast media is a non-issue Lactation: CM are poorly excreted in breast milk, and poorly absorbed by infant GI tract Harm to nursing infant very unlikely Slide - 39 Slide - 40 Injection Reflection RED FLAGS for contrast administration in CT include all of the following EXCEPT: a. Pheochromocytoma. b. Multiple myeloma. c. Renal disease associated with Sickle cell disease. d. Cardiac disorders. Slide - 41 Slide

8 RED FLAGS for contrast administration in CT include all of the following EXCEPT: a. Pheochromocytoma. b. Multiple myeloma. c. Renal disease associated with Sickle cell disease. d. Cardiac disorders. like to re-review this concept: Click back to slide 34 on the table of contents. Remember, you are NOW on slide 43. Click slide 43 to continue with this lecture. With respect to using contrast media on pregnant patients: a. Contrast is contraindicated. b. Radiation is NOT advised; contrast media are a non-issue. c. Pregnant patients are allergic to contrast. d. Lactating mothers are hypersensitive to contrast media. Slide - 43 Slide - 44 Adverse Reactions to Contrast Media With respect to using contrast media on pregnant patients: a. Contrast is contraindicated. b. Radiation is NOT advised; contrast media are a non-issue. c. Pregnant patients are allergic to contrast. d. Lactating mothers are hypersensitive to contrast media. like to re-review this concept: Click back to slide 40 on the table of contents. Remember, you are NOW on slide 45. Click slide 45 to continue with this lecture. Chemotoxic Taste Warmth Nausea Allergoid Mild Moderate Severe How can we interpret what went wrong if we did not know the patient status at the beginning of the exam? First, know your patient. Then, know about your contrast agent. Slide - 45 Slide - 46 Adverse Events and Adverse Reactions Adverse Event a harmful or otherwise undesired effect occurring after the administration of a drug or the use of a medical device; causal relationship is not implied Adverse Reaction a harmful or otherwise undesired effect that is thought to be caused by the administration of a drug or the use of a medical device Idiosyncratic Reaction is defined as an individualizing quality or characteristic of a person or group We expect nausea we get projectile vomiting! NO CONTRAST MEDIA ARE RISK-FREE They are used on a risk vs. benefit basis. Prior to their use, patients must be properly educated regarding potential adverse events. Trends in Adverse Events After IV Administration of Iodinated CM Published in 2001 Reported on 90,473 administrations of iodinated CM, from which there were 391 adverse events Involved 3 sequential periods of different CM use patterns, with different adverse event rates Ionic use only: 6-8% Selective use: 0.6% ionic, 0.7% non-ionic Non-ionic use only: 0.2% Cochran ST, et al. AJR 2001 Jun;176(6): Slide - 47 Slide

9 Slide - 49 More Trends in Adverse Events After IV Administration of Iodinated CM More than 90% of adverse reactions were allergoid' (allergic-like). Seven severe reactions (0.05%) and no deaths occurred in the ionic group. During the selective use period, one death occurred in the nonionic group. No severe reactions or deaths occurred during the first 5 years of universal nonionic use. After that, 10 severe reactions (0.02%) and one death occurred. Cochran ST, et al. AJR 2001 Jun;176(6): Slide - 50 Adverse Reactions to Iodinated CM The most common chemotoxic reactions are a warm or hot "flushed" sensation during the injection, and a "metallic" taste in the mouth, which usually last less than a minute or so. These can vary depending on the type of CM used, the rate at which it is administered, and individual patient sensitivity. No treatments are necessary. A common mild allergoid reaction is urticaria (hives), consisting of wheals (bumps) and flares (flushed patches) on the skin, associated with pruritus (itching). This can last from several minutes to several hours after the injection. This type of reaction by itself requires no treatment, but for patient comfort is often treated with antihistamines and corticosteroids. Serious reactions, although much less likely, can be caused by the allergoid physiology of vasodilation and bronchoconstriction, leading to breathing difficulty, hypotension, and other respiratory and cardiovascular symptoms. These reactions can be life-threatening or fatal if not recognized and properly treated immediately. Classification of Severity of Adverse Events Mild Adverse Events Mild DOES NOT require treatment Mild skin/mucosal effects or brief sensations E.g., itchy eyes; a few hives; brief nausea Moderate OFTEN requires treatment Not considered life-threatening May (or may not) progress to a more severe reaction if not treated; watch closely E.g., widespread edema, wheezing Severe DOES require timely, effective treatment Are life-threatening May lead to permanent injury or death What to watch for in CT Warmth / flushing Headache Lightheadedness Hives/urticaria Itching Mild Hypotension Transient nausea / vomiting Sweats Shakes Altered taste (metallic) Nasal stuffiness Allergic conjunctivitis Anxiety Localized patches of swelling (angioedema) NOTE: A true drug-induced rash is a different phenomenon, with a delayed time course, somewhat similar to the poison ivy reaction. Slide - 51 Slide - 52 Moderate Adverse Events Severe Adverse Events What to watch for in CT More severe degree of previously mentioned signs and symptoms or Systemic signs & symptoms including: Multiple areas of angioedema Tachycardia Hypotension (moderate) Bronchospasm (mild) Laryngeal edema (mild) Dyspnea / wheezing Close observation Treatment often indicated What to watch for in CT Life-threatening Moderate to severe laryngeal edema Moderate to severe bronchospasm Unresponsiveness Ventricular arrhythmias Shock (severe hypotension with organ failure) Respiratory arrest Cardiac arrest Require prompt recognition and timely, appropriate, and effective treatment Almost always require hospitalization Slide - 53 Slide

10 Adverse Reactions Specific Allergoid (Allergic-Like) Reactions Slide - 55 What to watch for in CT Acute kidney dysfunction Contrast nephropathy (in CKD) Micro-infarctions (in sickle cell disease) Protein deposition (in multiple myeloma) Seizures (mainly with HOCM) Venous thrombosis (mainly with HOCM) Adrenergic crisis (with pheochromocytoma) Aggravation of myasthenia gravis Iodine effects Salivary gland swelling ( iodine mumps ) Thyroid stimulation (in hyperthyroidism) or suppression Arrhythmias/conduction disturbances Pulmonary edema Slide - 56 What to watch for in CT Idiosyncratic (unpredictable) reactions to contrast media have the same manifestations as type I hypersensitivity reactions, but they are not true hypersensitivity reactions, because antibodies are not involved. Therefore, prior sensitization does not occur, so: They are not predictable in occurrence or recurrence. They are not predictable in severity. For these reasons, idiosyncratic reactions to CM are called allergoid reactions, and when life-threatening are called anaphylactoid reactions. Allergoid Reactions Allergoid Reactions Slide - 57 Histamine Release Histamine is released by specialized circulating white blood cells (WBCs) called mast cells and basophils. Its purpose is to help create the inflammatory response, which helps the body to fight local infection and to heal local trauma The inflammatory response is: Vasodilation to bring more blood to the region Increased blood vessel permeability to bring more fluid, nutrients and WBCs to the tissue Bronchoconstriction to shut down air flow to the injured or sick area of the lungs Slide - 58 Histamine Release The inflammatory response makes perfect sense in the setting of local injury or infection. BUT, the release of histamine unfortunately also occurs in unwanted/unnecessary immunological responses, which we call allergic reactions. But with contrast media, there is no true immunological response. So why is histamine released by mast cells and basophils in some patients who receive CM? Theory: in sensitive individuals, the CM bolus directly induces the mast cells and basophils to release histamine. But by what means do CM exert this effect? Is it their ionicity? Osmolality? Viscosity? And, if it is one or more of these physicochemical properties, at what point can they initiate such an effect? NO ONE KNOWS. Allergic vs. Allergoid Reactions Vasovagal Reaction Allergic Ex: Bee sting Immune system either is or is not already primed to react to the antigen Reaction: Antibodies bind antigen and stimulate release of histamine, etc. Predictably gets stronger (and more dangerous) with each exposure Allergoid Ex: CT Contrast administration Bolus of foreign molecules either does or does not directly stimulate release of histamine, etc. Reaction: No antibodies are involved Occurrence and severity are unpredictable Must be distinguished from allergoid reactions Is the result of stimulation of the vagus nerve In evolutionary terms, it is the diving reflex, which slows oxygen consumption in diving mammals (e.g., whales, dolphins, seals). The hallmark is bradycardia, which results in hypotension and sometimes fainting or GI symptoms Usually caused by pain/discomfort and anxiety Often associated with fear of needles and the sharp pain of the needle stick, but can be related to claustrophobia, or fear of the CM Treatment Symptomatic treatment for hypotension (elevate legs, give IV fluids) If severe, can give atropine to reverse the bradycardia Close observation until recovery Slide - 59 Slide

11 Vasovagal Reaction Preparations to Handle Adverse Events in CT By inducing heightened systemic parasympathetic activity, ICM can precipitate bradycardia (e.g., decreased discharge rate of sinoatrial node, delayed atrioventricular nodal conduction) and peripheral vasodilatation. The end result is systemic hypotension with bradycardia. This may be accompanied by other autonomic manifestations, including nausea, vomiting, diaphoresis, sphincter dysfunction, and mental status changes. Untreated, these effects can lead to cardiovascular collapse and death in high-risk patients. Some vasovagal reactions may be a result of coexisting circumstances such as emotion, apprehension, pain and abdominal compression, rather than contrast media administration. Nasir H Siddiqi, MBBS, MD, emedicine.com Premedication for allergoid reactions Corticosteroids Antihistamines IV catheter in place Emergency equipment in place, with people who are trained to use it! Slide - 61 Slide - 62 Injection Reflection Mild reactions include all of the following EXCEPT: a. Respiratory arrest b. No treatment is required c. Transient nausea / vomiting d. Flushing / skin reaction Slide - 63 Slide - 64 Mild reactions include all of the following EXCEPT: a. Respiratory arrest b. No treatment is required c. Transient nausea / vomiting d. Flushing / skin reaction Severe reactions include: a. Respiratory arrest b. No treatment is required c. Transient nausea / vomiting d. Flushing / skin reaction like to re-review this concept: Click back to slide 52 on the table of contents. Remember, you are NOW on slide 65. Click slide 65 to continue with this lecture. Slide - 65 Slide

12 Contrast Induced Nephropathy (CIN) Severe reactions include: a. Respiratory arrest b. No treatment is required c. Transient nausea / vomiting d. Flushing / skin reaction like to re-review this concept: Click back to slide 54 on the table of contents. Remember, you are NOW on slide 67. Click slide 67 to continue with this lecture. Applied Radiology, January 2005 Refers to impaired renal function that occurs within 3-5 days following IV iodinated contrast administration in the absence of an alternative etiology. Important cause of hospital-acquired renal failure. Important problem as population ages, have more co-morbid conditions and undergoes more procedures that utilize IV iodinated contrast media. Slide - 67 Slide - 68 What s the Concern? Identifying CIN Patients with underlying chronic kidney disease (CKD), who are at risk for CIN, are common. Even a small decrease in renal function may have a profound effect on certain individuals. Substantial morbidity and even mortality can result from CIN. (CJASN 2009; 4: ) Sepsis, bleeding, coma and respiratory failure are frequently observed in patients in renal failure. The goal is to prevent acute kidney dysfunction! Fortunately, the risk of CIN is low (@ 0%-2%) in persons with normal renal function. Definition: Increase in serum creatinine (SCr) level by 25% or 0.5 mg/dl over baseline levels Usually peaks within 3-5 days post contrast Mild proteinuria and/or oliguria may occur, but there may also be no symptoms Overall incidence of CIN: 0.6%-2.3% The problem: Renal function is rarely measured after contrast administration to outpatients. Slide - 69 Slide - 70 Who s at Risk? Nephrotoxic Drugs Patients with pre-existing renal impairment Serum creatinine (SCr) > 1.5 mg/dl Large doses of contrast and multiple administrations of contrast within 72 hours Patients who are dehydrated Patients with chronic heart failure (CHF) Patients taking nephrotoxic drugs Patients with hypertension, hyperuricemia, proteinuria (i.e., signs of kidney disease) Use of high osmolar contrast media (HOCM) Medications for various uses May cause: Impaired renal function Prolonged nephropathy EXAMPLES ACE-inhibitors Aminoglycosides Amphotericin Antineoplastics Methotrexate Acyclovir Cyclosporin Tacrolimus NSAIDs Lithium Vancomycin Slide - 71 Slide

13 Reducing Incidence of CIN Food for Thought Hydrate with IV normal saline or bicarbonate Consider prophylactic medications (though none are truly proven to be effective) Use LOCM Use smallest possible amount of contrast medium Avoid intervals of less than 48 hours between IV contrast administrations If possible, avoid administration of nephrotoxic drugs 24 hours prior to contrast administration. Consider other imaging alternatives - although MR with contrast may not be the best choice! A patient who has renal insufficiency before administration of contrast media (CM) is 5-10 times more likely to develop contrast-induced nephropathy (CIN). Patients who have experienced an allergoid reaction from CM may not experience a repeat reaction on re-exposure. Patients with a history of asthma (even if under control) have double the risk of developing an allergoid reaction. No substantive data support the myth that patients with a seafood allergy (which is actually a food intolerance to the animal proteins) are at higher risk of allergoid reaction to CM. NO ONE IS, OR CAN BE, ALLERGIC TO IODINE! Iodine is an elemental atom, and as iodide (I-) it is an electrolyte; it cannot stimulate an allergic response Iodine is essential to life, as a necessary component of thyroid hormone Slide - 73 Slide - 74 More Food for Thought Iodinated CM Minor adverse events occur 5% of patients. Most severe reactions occur within first 5 minutes. 95% of all reactions occur within first 20 minutes. Life-threatening reactions occur 0.1% of patients. Reactions tend to occur most often in patients years of age. Patients with urticaria and food allergies of unknown cause are more likely to have a reaction of some type. NOTE: None of the above refers to CIN. Ionic High Osmolar Greater number of AEs No difference among high osmolar agents Non-Ionic Low Osmolar 1/5 number of AEs No difference among low osmolar agents Slide - 75 Slide - 76 Summary: Iodinated CM Adverse Events Slide - 77 Idiosyncratic (allergoid) or chemotoxic Ionics 5x > Non-ionics Disease- or organ-based reactions Most occur with equal (and low) probability with any iodinated CM Contrast-induced nephropathy Main risk factors: Renal dysfunction Large CM dose HOCM > LOCM / IOCM Among LOCM / IOCM, new ACC/AHA guidelines state that iohexol (Omnipaque ) and possibly ioxaglate (Hexabrix ) provide greater CIN risk, but all other LOCM / IOCM provide similar lower risk. Slide - 78 Injection Reflection 13

14 Contrast induced nephropathy (CIN) refers to: a. Renal failure b. Impaired renal function that occurs prior to the administration of IV iodinated contrast c. Impaired renal function that occurs within 3-5 days of the administration i ti of IV iodinated d contrast, t without alternative etiology d. High BUN and creatinine Contrast induced nephropathy (CIN) refers to: a. Renal failure b. Impaired renal function that occurs prior to the administration of IV iodinated contrast c. Impaired renal function that occurs within 3-5 days of the administration i ti of IV iodinated d contrast, without alternative etiology d. High BUN and creatinine like to re-review this concept: Click back to slide 68 on the table of contents. Remember, you are NOW on slide 80. Click slide 80 to continue with this lecture. Slide - 79 Slide - 80 Reducing the incidence of CIN includes all of the following EXCEPT: a. Hydration with normal saline or bicarbonate b. Discontinuing nephrotoxic drugs c. Daily injection of iodinated d CM d. Use of low-osmolar contrast media (LOCM) Reducing the incidence of CIN includes all of the following EXCEPT: a. Hydration with normal saline or bicarbonate b. Discontinuing nephrotoxic drugs c. Daily injection of iodinated d CM d. Use of low-osmolar contrast media (LOCM) like to re-review this concept: Click back to slide 73 on the table of contents. Remember, you are NOW on slide 82. Click slide 82 to continue with this lecture. Slide - 81 Slide - 82 Outline Objectives 1. CT Contrast Media This module will discuss what contrast agents are used in computed tomography (CT) 2. Properties of contrast media (CM) Next, various CM properties p will be discussed. 3. Patient interactions with CM Furthermore, patient interaction with CM in CT will be explained. 4. Managing Adverse events Finally, reactions and adverse events associated with contrast administration in CT will be discussed. Upon completion of this course, the learner should be able to: Discuss what contrast agents are used in CT. Describe the properties of contrast agents used in CT. Recognize patient interactions with CM. Explain how to manage adverse events in CT. Slide - 83 Slide

15 Thank you for your attention! Managing Adverse Events Part II: Contrast Enhanced CT Carolyn Kaut Roth, RT (R)(MR)(CT)(M)(CV) FSMRT CEO, Imaging Education Associates Presented by William H. Faulkner, BSRT (R)(MR)(CT)FSMRT CEO, Wm Faulkner & Associates Produced by Imaging Education Associates Sponsored by an unrestricted educational grant from Bracco Diagnostics Slide - 85 If you are viewing this presentation as an on-line (self study) module be sure to complete the post test to claim your credits. 15