Preparation and Examination of the

Gastrointestinal TractChapter 9

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Classification of Contrast Media

• Barium Sulfate

• Water-soluble iodinated

• Oily iodine

• gases

Scheduling and Sequencing

• Proper scheduling of GI exams requires COMMUNICATION (between doctors and nurses, nurses and the department, etc.)

• Considerations must be made as to all the procedures that are going to be performed on the patient so that the correct sequence can be followed

Guide to Sequencing Order for Diagnostic Studies

• All exams not requiring contrast media and any lab studies for iodine uptake

• Exams of the urinary tract (IVP)

• Radiographic exams of the biliary system (gallbladder)

• Lower GI series (BE)

• Upper GI series

Ensuring Compliance with Preps

• Nurses are responsible for inpatient preps

• Radiographer is usually responsible for explaining preps to outpatients or those scheduling outpatient procedures

• Scout films are taken to evaluate patient prep

Preparation for Examination

• Most common reason for prep is for cleansing purposes

• Cleansing of the bowel usually requires several steps: diet, cathartics, suppositories or enemas. May utilize several or all of these methods.

Diet

• Patients may be placed on a low-residue diet for several days prior to the exam

• Liquid intake is encouraged or forced

• For 24 hours before exam, patient may be restricted to clear liquids (water, broths, gelatin, tea)

• Fasting may be employed (NPO 8-12 hours)

Cathartics

• Laxative preparations that aid in cleansing the bowel

• Fluid intake increases the effectiveness of cathartics

• Bisacodyl or Dulcolax tablets or magnesium citrate (carbonated beverage) are common cathartics

• Heavy doses of cathartics may cause painful bowel spasms; patients may have persistant diarrhea.

• Patients should always be told what to expect from their bowel preparation

Suppositories

• Rectal suppository is a semi-solid nugget of medication that is inserted into the rectum to stimulate peristaltic action in the colon to cause evacuation of the distal portion of lower bowel

• Suppository should remain for at least 30 minutes before evacuation

Cleansing Enema• Procedure to dislodge and flush out any fecal contents• This is usually carried out at the patient’s home or by their nurse (if

they are an inpatient)• Occasionally, this duty may be assigned to the radiographer• Items needed: enema bag with tubing, disposable rectal catheter, iv

pole• Mix a soapsuds enema of 1000 ml of tap water and 30 ml of castile

soap (don’t use any other kind as it may be an irritant to the bowel)• Run the liquid through the tubing to eliminate air, lubricate the tip,

explain the procedure, place patient in Sim’s position, hand enema bag approx. 18 in above the table (too high can cause to rapid a flow), insert tip

Inserting the Tip

• The insertion of the tip will remain the same for any type of enema; however, there will be several differences from a cleansing enema to a BE

Barium Sulfate

• Inert, organic salt, packaged in many forms, may be given oral or rectal, forms a colloidal suspension.

• No flavor (unless flavored for drinking), but hard to swallow because of it’s chalky consistency; easier to drink really cold and with a straw (keeps it from coating the mouth)

• Although a warm solution of barium for lower GI studies would seem more comforting, cold barium is less likely to cause bowel spasms

• The proper viscosity or thickness is important in GI exams- much variation from doc to doc

More about Barium

• Being an inert compound, it does not react chemically with the body to any appreciable extent- allergies are almost never a problem and few side effects occur

• Barium is hygroscopic (has a tendency to absorb water); this nature can cause a barium impaction- to decrease the risk, patients should be instructed to drink lots and lots of fluids and a laxative may be recommended.

• Always check with patients about latex allergies; a few cases of allergy to the enema tip have been reported

Iodinated Media

• Used when barium is contraindicated or if abdominal surgery is likely in the immediate future

• Also used when there is a high risk of impaction and occasionally for neonatal studies

• More expensive than barium, produce less contrast, can cause dehydration and are hazardous if aspirated

• Radiologist will guide you as far as what media to use

Air

• Negative contrast

• Can be produced from crystals or room air

Glucagon

• drug used to treat hypoglycemia

• Causes relaxation of smooth muscles in the GI tract

• Slows peristalsis

• Prevents cramping

• Can be administered IM or IV

Routine BE

• Scout film to ensure cleansing has occurred• Prepare a bag of 1200-1500 ml (compared to

about 1000 ml in a cleansing enema)• Enema bag is suspended at a height of 24-30

inches (compared to 18 in for cleansing enema) This is due to the viscosity of the barium; requires greater hydrostatic pressure to maintain a proper flow rate

• Larger rectal catheter is used than in a cleansing enema; has a cuff to inflate a balloon to help hold in place

BE Considerations• Patients with unusual conditions may require special care when undergoing

a BE• Enlarged Colon like congenital megacolon or Hirschsprung’s Disease: distal

colon where no peristalsis occurs- results in chronic constipation and extremely large colon

• When colon is enlarged, more water absorption can occur, increasing the chances of developing a barium impaction; If this condition is known ahead of time, water soluble contrast may be used; if not, follow up care is necessary to insure the patient avoid an impaction

• Colon enlargement can also cause hypervolemia or fluid overload; the colon absorbs so much water that it changes the concentration of fluid in the blood. This can lead to CHF and in extreme cases lead to total physical collapse.

• If it is of concern, water absorption can be minimized by mixing barium with normal saline

• Potential colon perforation: if this is suspected, do not use barium. Use a water soluble contrast. If barium is extravasated into the peritoneal cavity, it can cause a condition known as barium peritonitis.

• ostomies

UGI

• NPO 8 hours prior• No smoking or gum chewing (increases gastric

secretion)• Valsalva maneuver for hiatal hernia or reflux• Pylorospasm: stomach does not empty into the

duodenum because of constriction of the sphincter muscle between the stomach and duodenum; patient will be asked to lie in the RAO position which allows gravity to assist in the normal flow of gastric contents

Double Contrast UGI

• Shows mucosal surface

• Utilizes the crystals

Hypotonic Duodenography

• Used for the detection of lesions in the duodenum distal to the duodenal bulb and also for the diagnosis of pancreatic disease

• This study is declining and being replaced by US, double contrast GI, CT and ERCP