Contrast

contrast is a ____

medication

contrast media is

a diagnostic agent that can be injected using several different routes into the vascular system, joints, ducts and organs to enhance subject contrast in anatomic areas where low subject contrast exists

what is ASRT scope of practice

scopes of practice delineate the parameters of practice and identify the boundaries for practice

what is ASRT advisory opinion

interpretation of the practice standards. they are intended for clarification and guidance for specific issues

contrast media through the scope of practice can only be administered by people if it is

prescribed by a licensed practitioner

what are the different routes of administration of contrast material

• enteral (2)

• parenteral (4)

what is enteral

• ingested (oral)

• rectal (retrograde)

what is parenteral

• intravenous

• intrathecal

• intra-articular

• intra-arterial

ingested (oral) is

contrast that can be swallowed or given via G tube

advantages of ingested contrast agents

safest, most economical, and most convenient way of giving medication

disadvantages of ingested contrast agents

• may have bad taste, odor, or may be large quantities

• may irritate gastric mucosa- nausea and vomiting

• seriously ill or uncooperative person might aspirate

• digestive enzymes may destroy them

rectal contrast agents are…

reasonably convenient and safe when oral route cannot be used

advantages of rectal contrast agents

• meds can be given when stomach is traumatized

• good method if drug has bad taste or odor

• good method if digestive enzymes can destroy drug

• avoids irritation of UGI tract

disadvantages of rectal contrast agents

unpredictable retention of drug, absorption is erratic

parenteral administration route is

• administered by injection or by a route other than the GI tract

• anything done by injection

• usually syringe and needle or catheter and container

• drugs must be sterile, absorbable, and nonirritating

• most hazardous route- acts rapidly and is irretrievable

in radiology, you will see the parenteral route done most commonly…

intravenous administration is

• directly into bloodstream

• through a vein'; allows patient to respond rapidly to medications

• used for delivering emergency meds when rapid response is necessary

what is the most hazardous/ most rapid method of administration

intravenous

venipuncture can be done with-

• hypodermic needle

• butterfly set

• IV catheter

intrathecal is administration of medication into

spinal subarachnoid space; myelogram

intra-articular is administration of medication into

joint space; can inject steroids into space or contrast; arthrogram

intra-arterial is administration of medication into

an artery; arteriogram or angiography

what is extravasation

leakage of the contrast (vesicant) into the surrounding tissues

what to do when extravasation occurs

• remove the needle, apply pressure, and a COLD compress to relieve discomfort

• elevate the affected area

what are the 6 rights of drug administration

1. right medication

2. right dose

3. right patient

4. right time

5. right route

6. right documentation

Right medication:

• check for correct spelling and dosage of the medication

• read the label 3 times (check name carefully)

  • when removed from storage

  • when removed from container

  • when container is replaced

• CONFIRM CONTENTS AND EXPIRATION DATE

whenever a contrast product or medication is transferred to another container and not immediately administered, set down for any reason or period, the new container must be labeled immediately, including the minimum:

• contrast of medication name

• strength

• amount/quantity

• expiration date

• expiration time

right dose:

• radiology- protocols for dosing that are appropriate for each examination

• concentration awareness

  • ask for pharmacists of colleague to double check calculation

  • check drug references for correct dose

• known concentration of medication

right patient:

• verify the patient’s identification each time a medication is given

• check

  • patient’s ID bracelet

  • name

  • DOB

• patient allergies

right time:

• physician/practitioner responsible for ordering drug and determining time of administration

• RT does NOT determine the time

  • follow facility protocols

• once dug/medication administered- do not leave the patient unattended

right route:

• physician specifies route

• radiology follow protocols

most common routes of administration:

oral, rectal, IV

things to consider when choosing a route of administration

• absorption

• conscious state

• ability to swallow

right documentation:

• follow employer policy

• any time a drug is administered to a patient, relevant info must be recorded in patient’s chart

• including:

  • name and dose of drug

  • route of administration

  • date and time

  • if pt refused

  • adverse effects or errors

why are the 6 rights of drug administration so important to know?

• contrast is considered a medication

• medication errors are high in radiology

• looks alike/sounds alike drugs

• communication- handoffs

• proper storage and disposal

where does contrast go (IV)?

• circulates through the heart

• passes into the arteries

• through capillaries

• then into veins

• back to the heart

  • the kidneys and liver eliminate the contrast from the blood

factors that affect the radiographic densities

• absorption characteristic of the tissues

• technical factors used

• characteristics of the image receptor

• automatic image processing

• contrast media agents used

tissues with ___ atomic numbers absorb more x-ray photons than tissues with ___ atomic numbers

• high

• low

the body absorbs x-ray photons depending on the various ____

tissues

basic principles of contrast studies:

diagnostic agents are administered into body orifices or injected into vascular system, joints, or ducts to enhance subject contrast in areas where it is low

advantages of contrast studies

• better anatomic definition

• can assess function

contrast media changes the density of the organs therefore changing:

• subject contrast

• radiographic contrast

what are the two classifications of contrast media

negative and positive

negative contrast is

radiolucent

positive contrast is

radiopaque

what is radiolucent media

• negative contrast agent

• decrease attenuation of the x-ray beam

• low atomic #s

• appear darker of radiographs (density=black)

• commonly used _air (chest)_

types of radiolucent compounds

• gaseous (things that produce air)

  • gas filled microbubbles (US)

  • gas producing tablets

  • soda water (EZ gas)

  • CO2 crystals

can air be used alone as an agent?

yes air alone provides negative contrast for upper airway, BUT it is not used alone due to cells absorbing O2 quickly

complication of using negative contrast agents

• minimal complication typically

• air can cause an emboli

  • lodge in blood vessels, pain and loss of O2 to the area

what is radiopaque media

• positive contrast agent

• increase attenuation of the x-ray beam

• high atomic #s

• appear light on x-rays (white)

• commonly used _barium_

types of radiopaque media

• metallic salts

  • barium sulfate

  • gadolinium (MRI)

• organic iodides

  • ionic or nonionic contrast agents

contrast in influenced by

• radiation quality (kVp)

• image contrast

• radiographic object (patient)

barium- ____ kVp (higher atomic #)

90-120

iodines-_____ kVp (lower atomic #)

below 90

barium with appear ___ on an image

white

air will appear ____ on an image

black

impact of atomic number, higher # = ___ absorption

greater

atomic number of fat=

6.46

atomic number of water=

7.51

atomic number of muscle=

7.64

atomic number of bone=

12.31

what are the ideals for contrast agents

• high atomic #

• nontoxic

• cheap and plentiful

• excreted

SLIDE 44