Contrast Media- Iodinated Agents Flashcards
What studies are iodinated contrast media used for?
GI tract Urography Biliary tract ie, ERCP Circulatory Spinal studies Hysterosalpinography
How is iodinated contrast administered?
Ingestion-gastrografin and gastroview
Intravascular
Catheter/tube
Intrathecal
What is the atomic weight of iodine?
127
How many carbon atoms are on a benzene ring?
6
At what points is iodine added to the benzene ring?
2-4-6
By adding iodine to a benzene ring what happens to the molecular density?
It increases the molecular density
What does trio-iodo refer to?
Refers to the number of iodine atoms on the benzene ring = 3
What is iodine substituted for on the benzene ring?
Hydrogen
What are the requirements for patients on metformin when receiving contrast media?
Pt must stop metformin 24 hours prior to contrast and stop metformin for 24 hours after contrast studies
What is density?
The weight of a substance per volume per unit
What is the primary influencer on the weight of the iodinated benzene molecule?
The number to iodine molecules
Explain the significance of the concentration of the contrast agent.
The concentration is determined by the quantity of the solute or the particles in the mixture… Not the liquid
What does a changing concentration indicate?
Either osmosis or diffusion of the solution
What is osmosis?
The movement of a liquid or solvent from a region of low concentration to high concentration
What is diffusion?
The movement of a liquid or solvent from a region of high concentration to low concentration
What is osmolarity?
The number of particles in a solution
What happens to an ionic agent when placed in solution?
- It undergoes ionization and dissociates into cation and anion particles
- it increases the number of particles in the blood stream
What is dissociate?
The splitting of compounds into smaller particles
What happens with osmolarity with non ionic agents?
- they are non ionizing so they don’t dissociate into particles in solution
Why are non ionic agents preferred for people who have a history of adverse reactions to contrast?
Because they have lower particles and less impact on fluid shifts
How does the osmolality of iodinated CM compared to plasma?
CM has a higher osmolality than plasma
What is the difference between a monomer and a dimer?
The number of benzene rings in the molecular structure
- dimer has two molecules
- monomers have one molecule
What is the difference between ionic and non ionic?
Ionic monomers and dimers contain salt
What are the advantages of a dimer?
- They have more iodine which means a higher density
- They have a higher ratio which means a lower osmolality
What is a mild adverse reaction to CM?
Metallic tastes, warm feeling
What is a moderate reaction to CM?
Nausea and swelling
What are severe reactions to CM?
Heart failure and laryngeal swelling
What are cardiovascular and pulmonary effects of CM?
-Dyspnea, chest tightness, and coughing
- hyper/hypotension
-bradycardia
Shrinkage of RBCs
What is a true allergic reaction?
-requires an initial exposure-sensitize
What is a pseudo allergy?
Mild local reactions such as hives