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46 terms

Contrast Media & Injections - 46

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esophagogram may evaluate
1. Achalasia
2. Varices
3. Dysphagia
4. Hiatal hernia
esophagogram positions usually include
posteroanterior, right anterior oblique, and right lateral.
varices
Dilated twisted veins; varices, of the esophagus are frequently associated with obstructive liver disease or cirrhosis of the liver. These esophageal veins enlarge and can rupture, causing serious hemorrhage
Achalasia
dilation of the esophagus as a result of the cardiac sphincter's failure to relax and allow food to pass into the stomach.
Dysphagia
refers to difficulty swallowing and is the most common esophageal complaint.
Hiatal hernia
another common esophageal problem; it is characterized by protrusion of a portion of the stomach through the cardiac sphincter. It is a common condition, and many individuals with the condition are asymptomatic
parenteral route
route of drug administration is one that bypasses the digestive system
Administration of contrast agents for radiographic purposes is usually performed by which of the following parenteral routes?
Intravenous
subcutaneous
under the skin
intramuscular
through the skin and into the muscle
intradermal
between the layers of the skin
intravenous
into the vein
What is the needle angle usually recommended for intramuscular drug injection?
90°
For subcutaneous injections the needle should form a
45° angle
Intravenous injections generally require that the needle form about a
15° angle with the arm
In which of the following conditions is a double-contrast barium enema (BE) essential for demonstration of the condition?
1. Polyps
2. Colitis
Double-contrast studies of the large bowel are particularly useful for demonstration of
the bowel wall, and anything projecting into it; A single-contrast study would most likely obliterate these mucosal conditions, but coating of the bowel mucosa with barium and subsequent filling the bowel with air (double contrast) provides optimal delineation.
Polyps
projections of the bowel wall mucous membrane into the bowel lumen.
Colitis
inflammation of the large bowel, often associated with ulcerations of the mucosal wall
Single-contrast studies
will demonstrate projections from/outpouchings of the intestinal wall (e.g., diverticulosis)
The advantages of using nonionic, water-soluble contrast media include
1. low toxicity.
2. fewer adverse reactions.
side effect
an effect that is unintended but possibly expected and fundamentally not harmful
adverse reaction
a harmful unintended effect
Possible side effects of iodinated contrast agents include
a warm, flushed feeling, a metallic taste in the mouth, nausea, headache, and pain at the injection site.
Adverse reactions include
itching, anxiety, rash or hives, vomiting, sneezing, dyspnea, and hypotension
Mild reactions
usually temporary and transient; Treatment is usually not necessary for mild reactions; include warmth, itching, flushing, nausea, pallor, hives, anxiety, chills
Moderate adverse effects include
hypertension, dyspnea, hypotension, bronchospasm. Patients must be closely observed for possible worsening of reaction; treatment might be required depending on progression of the reaction
Severe reactions include
arrhythmia, cardiopulmonary arrest, laryngeal edema. Clearly, severe reactions require immediate recognition and treatment.
The legal doctrine res ipsa locquitur means
The thing speaks for itself
Respondeat superior
"let the master answer" or "the one ruling is responsible." If a radiographer were negligent, there may be an attempt to prove that the radiologist was responsible, because the radiologist oversees the radiographer.
Res judicata
a thing or matter settled by justice
Stare decisis
refers to a matter settled by precedent.
dyspnea
difficult or labored respiration
ampule
a small container that usually holds a single dose of medication
vial
a larger container that holds several doses of the medication
bolus
an amount of fluid to be injected
The diameter of a needle is termed its
gauge. The higher the gauge number, the smaller the diameter and the thinner the needle.
hub
the portion of the needle that attaches to a syringe
bevel
the slanted tip of the needle. For IV injections, the bevel should always face up
Oral administration of barium sulfate is used to demonstrate
upper digestive system—the esophagus, fundus, body, and pylorus of the stomach—and barium progression through the small bowel. The small bowel includes the duodenum, jejunum, and ileum
Which of the following sites are commonly used for an intravenous injection?
Either the antecubital vein or the basilic vein, both found in the elbow region, may be used for an IV injection
In classifying intravenous (IV) contrast agents, the total number of dissolved particles in solution per kilogram of water defines
osmolality
toxicity
defines how noxious or harmful a contrast agent is. Contrast agents with low osmolality have been found to cause less tissue toxicity than the ionic IV contrast agents
viscosity
defines the thickness or concentration of the contrast agent. The viscosity of a contrast agent can affect the injection rate. A thicker, or more viscous, contrast agent will be more difficult to inject (more pressure is needed to push the contrast agent through the syringe and needle or the angiocatheter)
miscibility
of a contrast agent refers to its ability to mix with body fluids, such as blood. Miscibility is an important consideration in preventing thrombus formation
To further understand osmolality
whenever IV contrast media are introduced, there is a notable shift in fluid and ions. This shift is caused by an inflow of water from interstitial regions into the vascular compartment, which increases the blood volume and cardiac output. Consequently, there will be an increase in systemic arterial pressure and peripheral vascular resistance with peripheral vasodilation. Additionally, the pulmonary pressure and heart rate increase. When the effects of osmolality on the patient are understood, it becomes clear that an elderly patient or one with cardiac disease or impaired circulation would greatly benefit from the use of an agent with lower osmolality