Unit6
Contrast Media
Barium Sulfate
Ionic Contrast Media
Nonionic Contrast Media
LOCM
HOCM
Osmolality
Viscosity
Mild, Moderate and Severe Contrast Reactions
Radiopharmaceuticals
Pharmacology
Medication Nomenclature
PDR
Pharmacokinetics
Pharmacodynamics
Six "rights" to avoid errors
Drug Administration Routes
Introduction to Radiologic Sciences and Patient Care 5th Edition ( Adler and Carlton)
Chapter 20 - Pages 261-288
Chapter 21 - Pages 289-306
Here is what you must complete within Unit 6!!!
1. Reading Assignment
2. Read through the Lesson
3. Complete the Unit 6 Test
1. Contrast media is used in Radiography in order to visualize anatomy normally not seen.
2. It requires the administration of media into the patient.
3. Technologists must pay close attention to indications and contraindications of contrast media.
4. The use of contrast media warrants serious attention to patient reactions.
5. Human tissues inherently have low subject contrast with each other.
6. Contrast Media is generally classified as negative or positive contrast agents.
7. Contrast media are used to increase the atomic number of tissues in order to visualize them through increased subject contrast.
8. Contrast materials are an indispensable part of medical imaging.
9. Classified as positive or negative.
The Perfect Contrast Material is:
A. Very–high-contrast visualization
B. Extremely low toxicity to patient
C. Persistence in patient anatomy until imaging is completed
D. Low cost
E. Minimal or no side effects
F. No residual effects within patient
Key Contrast Characteristics:
A. Ability of agent to mix with body fluids
B. Viscosity
C. Ionic strength
D. Persistence in the body
E. Iodine content
F. Osmolality
G. Potential for toxicity
Modern contrast media are water-soluble organic iodide compounds.
A. The ideal contrast medium has high viscosity, is of sufficient radiopacity, is biologically acceptable and biologically tolerable
B. Trade names for contrast media are created by the manufacturer and usually have suffixes or prefixes that correspond to the anatomical area in which they may be employed (Cardiografin)
C. Generic nomenclature is derived from the anion and cation of which they are composed (e.g., diatrizoate sodium)
1. although the preferred order (anion:cation) they may be transposed (sodium diatrizoate)
Popular Contrast Choices May Include:
A. Barium sulfate
B. Air/gas (CO2)
C. Oil-based iodine contrast agents
D. Water-soluble iodine contrast agents
Contrast Media Choices Are:
A. Barium
–Atomic no. 56
B. Iodine
–Atomic no. 53
C. Air or Gas
–Atomic no. 8
A. Negative contrast agents
B. Cause affected structures to be darker (increased density) than surrounding structures
C. Used in arthrography and in myelography for patients who are allergic to iodinated contrast
D. CO2 has best characteristics
–Nontoxic
–Not absorbed too rapidly
Barium Sulfate is used for barium studies of the GI tract.
Barium Sulfate = BaSO4
Ionic compounds disassociate into charged particles in the bloodstream.
Nonionics do not break down into charged particles.
Ionic Contrast Media (High Osmolar Contrast Media - HOCM)
Here are some characteristics of ionic contrast agents:
A. They are positive agents
B. Affected anatomy is whiter (decreased density) compared to surrounding structures
C. Aqueous agents
–Water soluble
–Mixes readily with blood and bodily fluids
D. R2 and R3 increase solubility and excretion by kidneys
E. Iodine-based contrast media can cause anaphylaxis
Structure
1. Triiodinated compounds derived from the benzoic acid ring structure
A. Benzene-a six carbon cyclic structure in which the double bonds rotate-C6H6
(1) Carbonyl group - Carbon double bonded to oxygen-CO
(2) Carboxylic acid - A carbonyl and a hydroxyl (OH) combined on the same carbon atom - COOH
(3) The addition of carboxylic acid (COOH) to benzene forms benzoic acid
(4) Salt - A compound containing a cation other than H+ and an anion other than -OH
2. The iodine or opacifying portion is located at parts 2, 4 and 6 of the ring
3. The anion (negatively charged ion) is located at the 3 and 5 positions
A. The three most commonly employed anions are diatrizoate, iothalomate and metrizoate
B. Anions are responsible for stabilizing and detoxifying the contrast media
4. The cation (positively charged ion), or salt, occupies the number 1 position
A. The salts most commonly used are sodium and methylglucamine (meglumine)
(1) Meglumine is less toxic but more viscous than sodium
B. Salts are responsible for the solubility of the medium
Examples:
1. Renocal-76
2. Reno-60
3. Cystografin-Dilute
4. Cystografin
5. Reno-30
6. Reno-Dip
7. Sinografin
8. Multihance
9. Feridex IV
10. Renografin-60
11. Optimark
12. Cholografin Meglumine
Concentration
1. The percentage of salts in the solution or the weight, in grams, of salts per 100 ml of solvent
A. Renografin-60 has 8% sodium and 52% meglumine
B. Reno M-60 is 60% meglumine
Amount of Iodine
1. Stated in g/ml or mg/ml or as a percentage
A. Conray 400 has a 40% iodine content or 40 g/ml
B. Renografin 60 has 288 mg/ml or approximately 28% iodine content
Here are some characteristics of nonionic contrast agents:
A. Do not dissociate into anions and cations
B. Water soluble
C. Six iodine atoms per molecule
D. Increased solubility in plasma
Advantages of Nonionic:
1. Lower osmolality
2. No ionic breakdown and less toxic at cellular level
3. More water soluble in blood plasma
4. Warmed to increase viscosity
5. Less likely to cause patient reaction
6. More tolerable by patients
7. High contrast effect resulting from number of iodine atoms per molecule
8. Reduced injection volumes
9. Nonionic, low-osmolality contrast agents have reduced patient reactions, but reactions are still a reality of imaging
Examples:
1. Iopamidol-370
2. Isovue-300
3. Isovue-370
4. Optiray 160
5. Optiray 240
6. Optiray 300
7. Optiray 320
8. Optiray 350
9. Oxilan
10. Visipaque
A. Made from fatty acids
B. Iodine added to ester groups
C. Insoluble in water
D. Long persistence in body
E. Infrequently used except for specific exams
F. Cannot be used with plastic syringes
Osmolality (Hypertonicity)
Osmolality - The measure of the total number of particles in solution per kilogram of water (Ions/ml in solution).
A. Great biologic significance
B. Most adverse reactions to contrast result from the osmolality of the agent
B. Ionic contrast agents are HOCM
C. Nonionic contrast agents are typically LOCM
D. Considered to be the responsible factor for vasodilation, pain and flushed feeling
E. The newer non-ionic compounds, Isovue and Omnipaque, exhibit lower osmolality and consequently fewer adverse reactions due to decrease of ions/ml
Viscosity – A measure of the resistance of fluid to flow.
1. Measured by the amount of force required to move a liquid under standard conditions
2. The standard used is the force needed to move water at 200 C (680 F) and measured in centipoise (cp)
3. Viscosity is inversely proportional to temperature
1. To minimize adverse reactions you should:
A. Ask patient history (Obtain accurate, thorough medical history)
B. Obtain informed consent
2. Focus on allergies
A. Check blood urea nitrogen (BUN), creatinine levels
- To check renal function (It is very important to check the renal function before injecting contrast agents, if renal function is low, the patient could go into renal failure)
B. Verify medications
- Especially those taken to treat diabetes, Type II
- Metformin (Glucophage) should be discontinued for 48 hours before and 48 hours after the use of iodine contrast media
1.History of kidney disease or kidney failure? Check inpatient charts for BUN and creatinine levels.
2.History of diabetes? If yes, check for a metformin medication.
3.History of heart disease or hypertension? Check current blood pressure.
4.Iodine contrast studies within the past 48 hours? If yes, check to determine when, which agent, concentration and dose. Provide this information to radiologist.
5.Any history of allergy?
6.Any history of asthma?
7.Previous allergic reaction to contrast medium? If yes, what agent and what reaction?
8.Current medications? Note particularly any beta-blockers, antihypertensive medications or metformin products.
1. Generally occur within the first minute of injection
2. Can be unpredictable (no predictors)
3. Mild reaction may worsen to severe at any time (range from mild to severe)
4. Reaction is different from a side effect
5. Begin injection with a small amount and wait to check for signs or symptoms
A. Protocol determines how long to wait before proceeding with administration
6. Monitor the patient continually
7. Patients at risk for reaction are premedicated
A. Antihistamine and/or corticosteroids can be used
8. Patient reactions and care are a constant responsibility of the radiologic sciences professional
1. Mild
2. Moderate
3. Severe
Reaction |
Treatment
|
Flushed |
Observe |
Sweating |
Observe |
Nausea |
Observe |
Vomiting |
Observe |
Cough |
Observe |
Warm Feeling |
Observe |
Headache |
Observe |
Dizziness |
Observe |
Shaking |
Observe |
Itching |
Observe |
Strange Taste (Metallic) |
Observe |
Pallor |
Observe |
Flushing Chills |
Observe |
Sweats |
Observe |
Uticaria |
Observe |
Nasal Stuffiness |
Observe |
Swelling of the Eyes and Face |
Observe |
Anxiety |
Observe |
Reaction |
Treatment
|
Urticaria |
25-50mg Diphenhydramine hydrochloride (Benadryl) |
Tachycardia |
|
Bradycardia |
|
Hypertension |
|
Pronounced Cutaneous Reaction |
|
Hypotension |
|
Pain at Injection Site |
Cold Packs; Additional Anesthetic |
Dyspnea |
|
Bronchospasm |
Bronchodilator (Drug by Inhalation) |
Erythema |
|
Wheezing |
|
Laryngeal Edema |
|
Reaction |
Treatment
|
Respiratory |
|
Laryngospasm |
0-30mg Succiynlcholine Chloride (Anectine); Possible Tracheotomy |
Respiratory Arrest |
Intubation with 100% Oxygen; Forced Ventilation |
Severe Asthmatic Attack |
0.5-1.0ml of 1 to 100 Epinephrine (subcutaneous); 250mg Aminophylline (slow IV); Potent Bronchodilator |
Laryngeal Edema |
Maintain Airway |
Convulsions |
|
Profound Hypotension |
|
Cardiac Arrhythmias |
|
Unresponsiveness |
Call a Code, Epinephrine (IV), Other Drugs Administered as Needed by Code Team |
Cardiac Arrest |
Call a Code, Epinephrine (IV), Other Drugs Administered as Needed by Code Team |
1. Not contrast agents
2. Radioactive material chemically attached to a pharmaceutical that is metabolized in the body
3. Biodistribution is very important
4. Typically emit gamma radiation
5. Detected by gamma camera in nuclear department
6. Effective for cellular physiology assessment
7. Contamination and spillage of critical importance
8. Radiopharmaceuticals are used to assess cellular physiology (Radiopharmaceuticals are used in Nuclear Medicine)
1. Administered under the supervision of a licensed physician with proper qualifications
2. Get patient assessment and history
3. Patient comfort and education
4. Recognize signs and symptoms of reaction and act appropriately
5. Patient care and surveillance
6. Postexam considerations for patient
Pharmacology - The science concerned with the origin, nature, effects and uses of drugs is called pharmacology.
1. A drug is any chemical substance that produces a biologic response in a living system.
2. A drug is a substance used as medicine to aid in the diagnosis, treatment or prevention of disease.
The radiologic technologist is expected to have a basic knowledge of pharmacology to prepare and administer drugs under the supervision of a licensed practitioner.
Nomenclature - A classified system of names.
A. Drugs and medication are interchangeable terms
B. Names of medications (Classifications)
1. Chemical - Identifies the actual chemical structure of the drug.
2. Generic – Indicates its chemical family. Generic medications are the same as, but less expensive than, proprietary medications.
3. Proprietary or Trade or Brand Names – Given to a drug by its manufacturer
C. Classification by Action
1. Drugs that have similar chemical actions are grouped into categories call drug families.
D. Legal Classifications
1. Are classified either prescription or nonprescription (over-the-counter)
E. Resources on medications
1. Physicians Desk Reference (PDR)
2. Clinical Pharmacology – recommended for RTs
Physicians Desk Reference (PDR)
1. Commonly called PDR
2. Annual publication that contains current product information
3. Pages are color coded and list drugs by both their generic and their brand names
4. PDR gives the accepted uses, side effects, contraindications, and doses for available drugs
5. If PDR unavailable, speak with pharmacist
•Pharmacokinetics
•Pharmacodynamics
Pharmacokinetics - Defined as the study of the way the body processes a drug
A. Includes how drugs are absorbed, reach their site of action, are metabolized and are eliminated from the body.
B. Affects the response of persons to drugs
1. Varies according to age, physical condition, sex, weight time of day, emotional state, other drugs in the body, genetic variations, disease state of the body or immune status
A. Absorption
B. Distribution
C. Metabolism
D. Excretion
A. Absorption
1. How it gets into the circulatory system
2. Bioavailability is the amount of drug that reaches systemic circulation
3. Drugs must be absorbed in order to begin activity
B. Distribution
1. Absorption of drug into the body and its travel to the intended site of activity via circulatory system
2. Affected by several factors
C. Drug Metabolism (Biotransformation)
1. The metabolism of the drug by altering its chemical structure
2. Most drugs metabolized by liver in the hepatic microsomal enzyme system
3. Biotransformation occurs through four major pathways
4. Metabolism affected by many factors
D. Excretion
1. Removal of drug from the body
2. Principally performed by the kidneys
3. Also occurs by way of:
A. Biliary tract
B. Lungs
C. Sweat
D. Saliva
E. Breast milk
Pharmacodynamics - Defined as the study of the effects of drugs on the normal physiological functions of the body
A. Agonist - A drug that produces such a specific action and promotes the desired result
B. Antagonist - A drug that attaches itself to the receptor, preventing the agonist from acting
1. Used to counteract the effects of other drugs, such as sedatives and analgesics
2. Examples – Flumazenil (Romazicon) and aloxone (Narcan)
A. Medication administration becomes a radiographer's responsibility during contrast imaging procedures
1. Injected iodinated media
2. Ingested contrast media
B. Antianxiety and anesthetic medications are administered to patients so they can tolerate imaging procedures
C. Check allergic history of patients
D. Prepare medication for administration
E. Verify patient ID
F. Assist the physician
G. Monitor the patient after administration
H. If state regulations and hospital policies permit:
1. Might also administer and chart the medication or contrast medium
Six "rights" to avoid errors:
1. The right dose (Right Amount)
2. Of the right medication (Right Drug)
3. To the right patient (Right Patient)
4. At the right time (Right Time)
5. By the right route (Right Route)
6. With the right documentation
You Must:
1. Record Name of Drug
2. Record Route of Administration
3. Record Time of Administration
4. Record Patient's Reaction to the Drug
A. Normal dosage is provided in package insert
1. Available in the PDR and online at http://www.clinicalpharmacology.com
B. Physicians are not required to prescribe the usual dose
1. If there are dosage questions, verify the accuracy of the order before proceeding
A. Enteral Routes - Common and familiar administrations. Digestive process can reduce therapeutic effect.
1. Oral
2. Rectal - Alternative for those unable to swallow or with an unretentive stomach. Dosage may be unreliable because of early expulsion.
3. Vaginal
4. Nasogatric Tube (NG Tube) - Also an alternative to oral administration. More reliable and more easily controlled.
B. Medication Inhalation
1. Provide therapy direclty to lungs / respiratory system
2. Used in nuclear medicine for administration of radioactive gases for lung ventilation studies
C. Topical Route
1. May be used to provide local therapy, such as creams for rashes
2. Transdermal patches provide therapy by adhering medications to the skin, which is eventually absorbed into the boldstream
D. Sublingual and Buccal Routes
Sublingual = under the tongue
Buccal = inside the cheek
A. Topical route variation
1. Absorption through mucosal tissues into the bloodstream
2. This bypasses GI tract
E. Parenteral Routes (Injections)
1. Used to deliver drugs that cause irritation of the GI tract or cannot be absorbed by the GI tract. These are needed rapidly to site of action.
F. Parenteral Routes
1. Intramuscular (IM)
2. Intravenous (IV) - Provides most immediate effect
3. Subcutaneous (SB)
4. Intrathecal
5. Intradermal
a. Ampule
b. Vial
c. Prefilled syringe
d. Infusion Drip
1. Drugs that are injected have a rapid onset of action because they are absorbed directly into the bloodstream
2. All forms of parenteral administration require the use of a needle, syringe, and container
3. Requires aseptic technique
4. Four routes of injection
Injection Procedure:
1. Greet the patient.
2. Check patient ID and explain the procedure.
3. Select the appropriate injection site.
4. Don clean gloves.
5. Cleanse the selected area with the alcohol wipe.
6. Hold the skin taut with your nondominant hand.
7. Insert the needle at the correct angle, and pull back slightly on the plunger.
8. If no blood is present, inject the medication.
9. Withdraw the needle quickly, and wipe the injection site.
10. See to the patient's comfort.
11. Remove your gloves and perform hand hygiene.
12. Chart the medication.
13. Discard the container and any remaining medication.
1. Drug is placed directly into a vein.
2. Needle length and gauge depend on the viscosity of the drug, the site selected, and the specific method of injection.
3. While injecting, observe site for extravasation or infiltration.
4. If extravasation occurs, the first step is to remove the needle, apply pressure to the injection site, and apply cold packs to relieve the discomfort.
1. Wear gloves
2. Dispose of all syringes and needles directly into a puncture-proof container without recapping
3. Use safety-designed needles and needleless devices whenever possible
4. Always follow established rules of aseptic technique
5. Read the label three times: before drawing up the medication, after drawing it up, and with the physician before administration
6. Label the syringe with the medication name and strength (concentration) if the medication will not be administered immediately
7. Check patient ID before administration
8. Check for allergies
9. Monitor patient carefully for side effects
1. Radiographers who chart medications must use the exact procedure established by the institution
2. Routine entry made in proper section of chart:
A. Date
B. Time of day
C. Drug name
D. Dosage
E. Route of administration
3. Each entry must be signed
4. Contrast media are charted as medication
A. Contrast agent's name
B. Volume administered
C. Date and time of administration
A. Leakage or injection of IV fluids outside of the vessel
B. Also called infiltration
C. Infiltration refers to diffusion of the fluid into the surrounding tissues
D. Extravasation is the presence of fluid outside
the vessel
E. Painful and often dangerous condition
F. Treatment is to remove the needle or catheter, apply pressure and apply cold packs to the site
1. Allergic Reaction - When your body reacts to an allergen, it causes an allergic reaction. Allergens that cause a reaction can come in contact with the skin, be inhaled, or be eaten. Allergens can also be used to diagnose allergies and even be injected as form of treatment.
2. Idiosyncratic Reaction - Unpredictable adverse drug reactions that do not occur in most patients, but when they do occur, they can be life-threatening.
3. Iatrogenic Reaction - Reaction caused by Doctor's errors and prescription drug related causes.
1. Medications Used to Treat Allergic Reactions
2. Antimicrobials
3. Anticonvulsants
4. Antiarrhythmics
5. Analgesics
6. Sedatives and Tranquilizers
7. Antagonists
8. Local Anesthetics
9. Paralytic Agents
10. Hypoglycemic Agents
Medications Used to Treat Allergic Reactions
Medications used to treat allergic reactions are termed antihistamines.
1. Diphenhydramine hydrochloride (Benadryl) is more commonly used in imaging.
2. Epinephrine (adrenaline) is administered for severe reactions.
Antibiotics
An agent that either kills or inhibits the growth of a microorganism.
2. Examples - Erythromycin, Penicillin, Bacitracin
Antimicrobials
1. Category includes antiseptics, such as Betadine
2. Antibiotics are also in this category
Anticonvulsants
1. Used to control or prevent seizures
2. Example – diazepam (Valium)
Antiarrhythmics
1. Used to treat chronic cardiac arrhythmias
Analgesics
1. Relieve pain without causing a loss of consciousness
2. Range from controlled narcotics to over-the-counter (OTC) medications, such as ibuprofen and aspirin
Sedatives and Tranquilizers
1. Exert a quieting effect, often inducing sleep
2. Tranquilizers reduce anxiety better than sedatives
3. Examples – lorazepam (Ativan) and diazepam (Valium)
Antagonists
1. Used to counteract the effects of other drugs, such as sedatives and analgesics
2. Examples – flumazenil (Romazicon) and naloxone (Narcan)
Local Anesthetics
1. Used to eliminate sensation in a specific area before a painful procedure
2. Example – lidocaine (Xylocaine)
Paralytic Agents
1. A skeletal muscle relaxant
A. May be administered for insertion of an endotracheal airway or to combative patients to facilitate diagnosis and treatment
Hypoglycemic Agents
1. Control the level of glucose in the blood, primarily as a treatment for diabetes mellitus
2. Type I is usually treated with insulin
3. Type II may be treated with metformin (Glucophage), a sulfonylurea (Amaryl or Glucotrol), tolbutamide (Orinase), chlorpropamide (Diabinase), or rosiglitazone (Avandia)
General Precautions
1. Any of these drugs may cause an allergic reaction
2. Know the location of the emergency (crash) cart, resuscitation, and oxygen, as well as the code routine of your facility
1. Patient name, room number, address, and ID number
2. Drug name
3. Dosage
4. Dosage form
5. Route of administration
6. Date order is written
7. Signature of prescriber