GI Tract contrast, patient care, biliary system

What is a contrast media?

A special agent used to enhance soft tissue structures.

-Negative

-Positive

Negative contrast media

Negative contrast= Radiolucent

low absorption of radiation

ex. Air or gas (fizzes and room air= air in straw)

Positive contrast media

Positive contrast= radiopaque
higher absorption of radiation

-Barium

-Gastrografin= Water-Soluble Iodine ingestable compound

-Iodinated Media (Ionic and nonionic)

-Ethiodized Oils- NO LONGER USED = Does not mix with the blood

History of contrast media

1896 - lead subacetate & bismuth subnitrate - high atomic # but toxic to body
1910 - bariun sulfate nontoxic (inert and insoluble)
1918 - air in ventricles
1927 - water-soluble iodinated contrast (sodium iodide)
1930 - non-toxic water soluble carrier molecule
1950 - three iodine atom (triiodinated molecules)

Barium Sulfate

• Chemical formula= BaSO4- (compound)

• atomic number = 56

• Inert powder- main ingredient is salt

• Chalky

• No Flavor- Flavor must be added

• Chemically pure-non toxic

• Insoluble

Barium mixture

• Barium and water form a colloidal suspension = the insoluble barium sulfate particles disperse in water rather than dissolving, forming a chalky liquid

• Barium does not dissolve in water

  • Thin barium = one part barium and one part water

  • Thick barium=3-4 parts barium to one part water

• Suspending agents added to avoid barium settling

• Flocculation= barium clumping or coming out of
  suspension

• Stabilizing agents added to avoid flocculation

  • Powder that requires water be added

  • Concentrated liquid suspensions

  • Paste and a variety of thicknesses

  • Tablets

Contraindications to barium sulfate

1. Pre-surgical patients
2. Perforations = ruptures
3. Large intestine obstruction
4. Some post surgical (bariatric studies)

• No one is allergic to barium but could be allergic to the agents in barium

If you cant use barium then have to use gastrograhin

Gastrograhin/Gastroview

Indications + Contraindications

• Ingestible Water-Soluble Iodinated = can be allergic

• Contrast Media Indications

  • Patients who can’t tolerate barium

  • Pre or post-surgical procedures

  • Perforations

• Contraindications

  • Hypersensitivity to iodine

  • Younger patients

  • Dehydrated patients

Disadvantages→Cost, Contrast= not as high atomic number as barium, Allergic Reactions to Iodine

Single contrast

Thin barium

higher kv 100-125 = using a bunch of thin so need to penetrate the high atomic number

Double contrast

positive and negative = thick barium and air
lower kv 90-100 = little bit of barium

Upper GI contrast

Double contrast study

Barium – Radiopague (Thick Barium)
Air- Radiolucent

• Air is achieved by:
  ○ Calcium and magnesium citrate (fizzies)
  ○ Room air/carbon dioxide gas (air in straw the patient swallows through)

Air contrast

• Negative contrast/radiolucent

• Atomic #8

• Administration into body

• Effervescent crystals (fizzies)

• Room air pumped in
  

• Double Contrast studies of GI Tract

  • UGI =Thick barium and effervescent crystals

  • BE = Thick barium and room air pumped in

Fluoroscopy = R/F Equipment

Fluoroscopy tube under the table, if tube was above= more radiation

Overheads = using xray tube (not fluoro equipment) and lining up to bucky to take images

• Image appearance on fluoro monitor = negative image

  • Radiodense =black = barium

  • Radiolucent= white = air

Sequencing of multiple exams

-Iodinated contrast studies first (IVU and CT)

-Make sure barium won’t superimpose any structures that need to be visualized

-Barium enema first when paired with other GI studies

-esophagus, upper GI, small bowel done in one day

Patient prep - Modified Swallow

None

Patient prep - Esophagram

None

Patient prep - UGI

NPO after midnight

Patient prep - small bowel

NPO after midnight

Cathartics optional

Patient prep - Barium Enema

Diet
Cathartics (saline laxatives)
Suppository
Cleansing enema

Cathartics (laxative)

Contraindications

Used for barium enema prep

A substance that produces frequent, soft or liquid bowel movements
- Two types: irritant (rarely used) and saline

• Contraindications to Cathartics
  1. Gross bleeding
  2. Severe diarrhea
  3. Obstruction
  4. Inflammatory lesions

Discharge Instructions For Barium Studies

-drink plenty of fluids specifically water
-stool may be white or lighter color
-Take mild laxative if bowel movements do not get back to normal

Enema Tip Insertion

-Sims position
-Remember patient’s modesty
-Wear gloves
-Communicate

-Tip Well Lubricated
-Deep Breaths
-Insert first towards umbilicus
-3-4 cm maximum
-Stop if too much resistance
-Hemmorhoids
-Blow up retention cuff (fluoro can be utilized for safety)

Barium enema procedure - Safety

-Height of enema bag should be no higher than 24 inches above the table.
-Verify the water temperature of the contrast media = water 85-90 degrees F