Patient Care · ARRT Radiography
Contrast Media & Venipuncture for the ARRT Exam
Barium and iodinated agents, the perforation rule, ionic vs non-ionic osmolality, reaction grading, epinephrine in anaphylaxis, and venipuncture technique for the ARRT exam.
Overview
Contrast Media and Venipuncture is the chapter where the radiographer administers actual drugs. The ARRT outline covers the patient history, how the agent is given, what it is chemically, whether it suits the patient, and what you do when a reaction starts.
The chemistry comes down to atomic number, density and particle count. Iodine is atomic number 53 and barium is 56, high enough to absorb photons and appear white on the image. Barium sulfate is a suspension for the GI tract only, and the rule that matters most is that suspected perforation means no barium; a water-soluble iodinated agent takes its place. Iodinated agents split into two families: ionic media give three iodine atoms per two particles in solution, non-ionic media give three per one, so their osmolality sits closer to plasma and they cause fewer reactions.
Reactions are graded by how far they have gone, not by body system. Limited skin and stomach symptoms that settle are mild, widespread hives or wheezing with little or no drop in oxygen are moderate, and low blood pressure with a fast pulse, stridor, seizures or arrest are severe, whether the cause is anaphylaxis or a physiologic reaction. The first drug in anaphylaxis is epinephrine, before diphenhydramine or a corticosteroid such as hydrocortisone. Metformin gets flagged before any injection, because current ACR guidance stops it at or before the procedure when eGFR is under 30, when the patient has acute kidney injury, or before an arterial catheter study that could send emboli to the kidneys. It stays withheld for 48 hours and restarts only after renal function has been rechecked and found normal.
Torres lays venipuncture out in eleven steps: cleanse from the center outward three times, then insert the needle bevel up. The books differ on what comes after blood appears in the flashback chamber. Ehrlich and Coakes and Bontrager advance the catheter first and release the tourniquet after, while Torres (2010) releases the tourniquet first, then threads the needle 1/8 to 1/4 inch further. Follow your program's protocol or the source the question names. In Torres, two failed sticks means calling the IV team, and the peripheral intravenous route is the only parenteral route a radiographer may use for contrast.
What you’ll learn in this chapter
The 18 study slides and 15 quiz questions in this chapter break down as follows. 3 chapters are free in full with a free account. The others come with a paid plan, and paid plans open soon.
Patient Care
- Contrast Media & Venipuncture
The basics
- Positive and Negative Contrast
- Quiz
Positive agents
- Barium Sulfate
- Quiz
- Ionic, Non-ionic and Osmolality
Routes
- Which Route, Which Agent
- Quiz
Preparation
- The Questions You Must Ask
- Renal Function and Metformin
- Quiz
Reactions
- Three Different Things
- Mild, Moderate, Severe
- Quiz
- Anaphylaxis
- Quiz
Complications
- Extravasation
- Quiz
Venipuncture
- Site Selection
- Performing the Venipuncture
Equipment
- Needles, Syringes and Angles
Safe practice
- The Rights of Drug Administration
- Quiz
- Documenting What You Gave
- Quiz
Pharmacology
- Drugs You Will See Named
- Quiz
Recap
- What to Carry Out of This Chapter
- Quiz
- Quiz
- Quiz
- Quiz
- Quiz
Key terms in this chapter
These are 8 key terms from this chapter. Use them as a flashcard pre-quiz.
- Positive Contrast Agent
- A high atomic number agent, barium at 56 or iodine at 53, that absorbs x-ray photons and appears white, or radiopaque, on the image.
- Osmolality
- The number of dissolved particles per unit of solvent. Ionic agents give three iodine atoms per two particles; non-ionic give three per one, closer to plasma.
- Barium Sulfate
- A suspension for GI studies by mouth, rectum or duodenal tube. Contraindicated when perforation is suspected; a water-soluble iodinated agent replaces it.
- Extravasation
- Contrast escaping the vein into tissue, felt as pain with swelling and coldness at the site. Stop the infusion, notify the physician, remove the cannula and document.
- Anaphylaxis
- The severe systemic contrast reaction with laryngeal edema and hypotension. Epinephrine is given first, before antihistamines or steroids.
- Metformin
- An oral type 2 diabetes drug, brand name Glucophage, cleared by the kidneys. With eGFR under 30, acute kidney injury, or an arterial catheter study that could send emboli to the kidneys, it is stopped at or before the procedure, withheld 48 hours, and restarted only after renal function is rechecked and normal, because accumulation can cause lactic acidosis.
- Flashback
- Blood appearing in the needle's chamber, confirming vein entry. Ehrlich and Coakes and Bontrager then advance the catheter and release the tourniquet after; Torres releases the tourniquet first, then threads the needle further. Follow your program's protocol.
- Rights of Drug Administration
- Right patient, drug, dose, route and time, plus right documentation, the sixth right in the standard patient care text. Contrast is a medication, so all of them apply.
Sample practice question: Patient Interactions
One free sample question from the Patient Interactions subcategory, like those in its 391-question bank. Several chapters share each sample, so it may not match this chapter's topic. See the format, the rationale style, and the difficulty before you sign up.
A patient is scheduled for an upper GI series. Before starting the exam, which of the following is the radiographer's FIRST priority?
Show answer and rationale
A, Incorrect: ARRT's outline lists comparing the order to the clinical indication beside identification under verification, but asking the radiologist to confirm the order does not establish who the patient is.
B, Correct: Correct. The Joint Commission requires two patient identifiers (typically name and date of birth) before proceeding with care.
C, Incorrect: Barium administration starts the exam, so it waits until you know you have the right patient.
D, Incorrect: Positioning starts the exam, so it waits until you know you have the right patient.
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Frequently asked questions
What does the Contrast Media & Venipuncture for the ARRT Exam chapter cover?
Contrast Media and Venipuncture is the chapter where the radiographer administers actual drugs. The ARRT outline covers the patient history, how the agent is given, what it is chemically, whether it suits the patient, and what you do when a reaction starts.
How many study slides are in the Contrast Media & Venipuncture for the ARRT Exam chapter?
This chapter has 18 study slides and 15 quiz questions across 12 sections. The full chapter comes with a paid plan, and paid plans open soon. The free tier includes 3 complete chapters.
Is this chapter aligned with the current ARRT Content Specifications?
Every chapter on this site is mapped to the ARRT Radiography Content Specifications, but our line-by-line check against ARRT's outline isn't finished, so keep ARRT's outline beside it. Nothing here follows your exam date, so check which version applies to you. This chapter falls under the Patient Care domain of the official ARRT exam blueprint.