Transcript GI assesment2

Health Alterations II
Management of Clients
with Problems of the
Gastrointestinal System
Lecture 1.2.
Asessment of the
Gastrointestinal, Biliary, and
Exocrine Pancreatic Systems
Major Gastrointestinal, Biliary, and
Exocrine Pancreas Blood and Urine Tests
Blood Test
Reference
Interval
Description and Purpose
Stomach gastrin
(fasting serum)
0-100 pg/ml
(0-1 mg/L)
Gastrin is a gastric hormone that is a powerful stimulus for
gastric acidsecretion. Elevated levels are found in those with
pernicious anemiaand Zollinger-Ellison syndrome.
Helicobacter pylori
None
Helicobacter pylori detected in serum is a highly sensitive but
less specificindicator of an active infection; H. pylori infection
Stomach
predisposes to pep-tic ulcer disease.
Biliary System
Total bilirubin
Conjugated (direct)
Alkaline phosphatase
0.3 to 1 mg/dl
0.1-0.4 mg/dl
35-150 U/L
Bilirubin is excreted in the bile. Obstruction in the biliary tract
contributes primarily to a rise in conjugated (direct) values.
Alkaline phosphatase is found in many tissues with high
concentrations in bone, liver, and biliary tract epithelium.
Obstructive biliary tract disease and carcinoma may cause
significant elevations.
Blood Test
Reference Interval
Description and Purpose
Amylase
25-125 U/L
Amylase is secreted normally by the acinar cells of the
pancreas. Damage to these cells or obstruction of the
pancreatic duct causes the enzyme to be absorbed into
the blood in significant quantities. It is a sensitive yet
nonspecific test for pancreatic disease.
Lipase
10-140 U/L
Lipase is a pancreatic enzyme normally secreted into
the duodenum. It appears in the blood when damage
occurs to the acinar cells. It is a specific test for
pancreatic disease.
Calcium
8.4-10.6 mg/dl
Calcium levels may be low in cases of severe
pancreatitis or steatorrhea, because calcium soaps are
formed from the sequestration of calcium by fat
necrosis.
Pancreas
Intestine
Total protein
(albumin/globulin)
Total protein: 6-8 g/dl
Albumin: 3.5-5.5 g/dl
Globulin:
Alpha1, 0.2-0.4 g/dl
Alpha2, 0.5-0.9 g/dl
Beta 0.6-1.1 g/dl
Gamma 0.7-1.7 g/dl
Although primarily a reflection of liver function, serum
protein level is also a measure of nutrition.
Malnourished patients have greatly decreased levels of
serum protein.
D-xylose
absorption test
Blood levels of 25-40
mg/dl
2 hr after ingestion
D-xylose is a monosaccharide that is easily absorbed by
the normal intestine but not metabolized by the body.
It does not require biliary or pancreatic function. Dxylose is administered orally and assists in the
diagnosis of malabsorption.
Lactose tolerance
test
Rise in blood glucose
level of >20 mg/dl
An oral dose of lactose is administered. In the absence
of intestinal lactase, the lactose is neither broken down
nor absorbed and plasma glucose levels do not rise.
The test assists in the diagnosis of lactose intolerance.
Carcinoembryonic
antigen(CEA)
CEA is a protein normally present in fetal gut tissue. It
is typically elevated in persons with colorectal tumors.
Although not useful as a screening tool, it is useful in
determining prognosis and response to therapy.
Urine
5-hydroxyindoleacetic acid
(5-HIAA)
Quantitative
Qualitative
<5 ng/ml
2-6 mg/24 h
Urine bilirubin
Negative
Bilirubin is not normally excreted in the urine.
Biliary stricture, inflammation, or stones may cause
its presence.
Urobilinogen
0.5-4 mg/24h
A sensitive test for hepatic or biliary disease.
Decreased levels are seen in those with biliary
obstruction and pancreatic cancer.
Urine amylase
<17U/h
A rise in level usually mimics the rise in serum
amylase. However, the level remains elevated for 710 days, which allows for retrospective diagnosis.
Negative
Carcinoid tumors are serotonin secreting and are
derived from neuroectoderm tissue. This
neurohormone is metabolized to 5-HIAA by the
liver and excreted in the urine.
Stool Examination
Stool specimens are collected for culture, determination of fat content,
and examination for the presence of ova, parasites, and fresh or occult
blood. Special collection procedures may be necessary to enhance the
identification of bacteria (Salmonella, Shigella, and Staphylococcus
aureus), ova, and parasites. A fresh, warm stool specimen is optimal
for laboratory analysis.
Detection of occult blood in the stool is useful in identifying bleeding in
the GI tract. Occult blood may be identified by one of three tests:
guaiac (Hemoccult), benzidine, or orthotoluidine (Occultest). Meat,
poultry, or fish eaten within 3 days before testing can cause a falsepositive test as well as aspirin or antiinflammatory drugs taken within 7
days; vitamin C in quantities of greater than 500 mg/day may cause a
false-negative test if consumed 3 days before testing with benzidine or
orthotoluidine.
Determination of fecal fat may be done as part of a workup for
malabsorption. Elevations in fecal fat will be present with biliary or
pancreatic obstructions and many intestinal malabsorption disorders.
Stool Examination
Interpretation of Feces Color
Color
Interpretation
White
Barium
Gray, tan (clay)
Lack of bile, biliary obstruction
Red
Lower GI bleeding
Black
Tarry Rapid peristalsis with blood present
Dry Upper GI bleeding
Green
Rapid peristalsis with bile present
Radiologic Tests
Visualization of the GI tract may be performed by barium
swallow, upper GI series, or barium enema. Barium is a
radiopaque substance that, when ingested or given by enema,
outlines the passageways of the GI tract for viewing by
fluoroscopy or x-ray films.
Nursing responsibilities commonly involve cleansing of the GI
tract with enemas and laxatives. It is important for the nurse to
monitor the patient's fluid and electrolyte status because
extensive bowel cleansing may cause significant fluid losses,
particularly in elderly persons. The nurse should provide
psychologic support to the patient because the procedures can
be intrusive and uncomfortable. The nurse must also address
the educational needs of the patient, explaining the procedure,
the rationale for use, and procedural steps, which will assist in
reducing anxiety.
Upper Gastrointestinal Series
An upper GI series involves visualization of the esophagus, stomach, duodenum, and
upper jejunum through the use of a contrast medium. It is a fluoroscopic x-ray test that
permits the examination of the structure, position, peristaltic activity, and motility of the
organs. It can assist in the detection of tumors, ulceration, inflammation, abnormal
anatomy, or malposition. The upper GI series used to be the foundation of a diagnostic
workup for many GI disorders, but the ready availability of endoscopy has now relegated
the test to a seldom used status.
An upper GI series involves swallowing the contrast medium (usually barium), which is
prepared in a flavored milk shake form. The barium is unpleasant tasting and may cause
vomiting. It is administered cold. The barium outlines the structures as it flows by gravity
through the esophagus and stomach into the intestinal loops. Films are taken at intervals
during the test, and the entire test takes about 45 minutes. The procedure is termed a
barium swallow if only the function of the esophagus is to be evaluated and takes about
15 minutes. If the small bowel is the primary focus of the test, it may be termed a small
bowel series.
No special preparation is necessary before a GI series; however, the patient maintains
nothing-by-mouth (NPO) status for at least 6 hours before the test. After an upper GI
series, the patient is prescribed a laxative to hasten elimination of the barium; barium
that remains in the colon may become hard and difficult to expel, leading to fecal
impaction. The stool should return to its normal color (barium is white) after the barium is
expelled.
Barium Enema
A barium enema clearly outlines most of the large intestine through the use of a
contrast medium. It is used to detect colon polyps, tumors, and chronic
inflammatory bowel disease. If both an upper GI series and a barium enema are
to be performed, the barium enema is done first, before barium from the upper
GI series reaches the colon.
The procedure involves the instillation of barium through a rectal tube with an
inflatable balloon to hold the barium in the colon. The patient is then placed in
various positions while the radiologist observes on a monitor as the barium flows
through the colon. The procedure takes about 30 minutes, and the instillation
and retention of the barium can cause the patient considerable embarrassment
and discomfort.
Preparation for a barium enema involves thorough cleansing of the bowel by
laxatives, enemas, or both. Thorough preparation is essential because retained
fecal material obscures the normal bowel anatomy. The patient may be asked to
restrict dairy products, follow a liquid diet for 24 hours before the test, and
remain NPO for at least 8 hours before the test. Laxatives are frequently
administered after the test to facilitate the removal of the barium. The stools
may be white tinged for several days. Inpatients are closely monitored for
complications after the test, such as perforation of the bowel. Outpatients are
instructed to report the development of abdominal pain and to monitor carefully
for constipation.
Ultrasonography
Ultrasonography involves the use of high-frequency sound waves that
are transmitted into the abdomen and create echoes that vary with
tissue density. The echoes bounce back to a transducer and are
electronically converted into pictorial images of the organs. This reveals
organ size, shape, and position and is extremely useful in diagnosing
cysts, tumors, and stones. Ultrasonography has gradually become the
procedure of choice for diagnosing gallbladder disease because it does
not expose the patient to radiation. The procedure is both painless and
safe.
Patient preparation is straightforward. The patient remains NPO for 8 to
12 hours before the test, because gas in the bowel may interfere with
the results. If the gallbladder is the focus of the test, the patient is
instructed to eat a low-fat meal the evening before the test so that bile
will accumulate in the gallbladder, thereby enhancing visualization. The
patient resumes a normal diet and activity after the test.
Computed Tomography
Computed tomography (CT) can also be used to assess patients with
gallbladder, biliary ductal system, or pancreatic problems. It is helpful in
identifying problems similar to those described for ultrasonography. Multiple xrays are passed through the abdomen. A computer reconstructs the data into
two-dimensional images on a television screen. Still photographs can also be
taken of the images. Contrast medium can be used with the CT scan to better
visualize the biliary tract or to accentuate differences in tissue density of the
pancreas. The test is comparable to ultrasonography in effectiveness. It is used
less often because of its significantly higher cost and moderate radiation
exposure for the patient. It is extremely useful with obese individuals, however,
because increased tissue density limits the effectiveness of ultrasound
transmission.
The patient should remain NPO for 8 to 12 hours before the test. If contrast
medium is to be used, the patient should be assessed for allergies to iodine,
seafood, or contrast medium. Barium studies, if necessary, should be done at
least 4 days before CT scan or after the scan, because the barium can interfere
with test results. There are no special after-care considerations. The patient may
resume pretest diet and activity.
Radionuclide Imaging
GI scintigraphy may be used to localize the site of GI
bleeding. Endoscopy provides excellent visualization
of gastric or esophageal bleeding, but other areas of
the GI tract are much more difficult to visualize and
pinpoint. An intravenous injection of 99mTc sulfur
colloid is administered. Pooling of the radionuclide
will occur at the bleeding site. No pretest preparation
is required, and no discomfort is experienced.
Patients in unstable condition may not be candidates
for this test if they are unable to travel safely to the
nuclear medicine department for the 30 minutes
required for the test.
Cholecystography
Oral cholecystography involves the radiographic examination of the gallbladder
after the administration of a contrast medium. A normal liver will remove
radiopaque drugs, such as iodoalphionic acid (Priodax), iopanoic acid
(Telepaque), and iodipamide methylglucamine (Cholografin Meglumine), from
the bloodstream and store and concentrate them in the gallbladder. The dyefilled gallbladder shows on x-ray examination as a dense shadow. If no shadow
is seen, this indicates a nonfunctioning gallbladder. Stones, which are not
radiopaque, show as dark patches on the film. Ultrasonography has largely
replaced this once commonly used test in the diagnosis of gallbladder disease.
Cholecystography is primarily used today when the ultrasound picture is
inconclusive.
Patient preparation involves instruction to eat a fat-free meal the evening before
the test. The radiopaque substance (usually iopanoic acid) is administered orally
2 to 3 hours after the evening meal. The dose is based on body weight, and the
tablets are administered one at a time at 5- to 10-minute intervals with several
swallows of water after each pill. The patient then maintains NPO status until
the test. The patient is carefully assessed for allergies to contrast dyes, seafood,
or iodine.
Cholangiography
Cholangiography involves x-ray examination of the bile ducts to confirm the
presence of stones, strictures, or tumors. The radiopaque substance may be
administered intravenously or injected directly into the common bile duct with a
needle or catheter during surgery or endoscopy. After surgery on the common
bile duct, a radiopaque drug such as iodipamide methylglucamine is instilled
through a drainage tube such as the T tube to determine the patency of the
duct before the tube is removed (T tube cholangiography). The dye also may be
injected through the skin and abdominal wall directly into a bile duct within the
main substance of the liver (percutaneous transhepatic cholangiography). The
technique is useful in visualizing the location and extent of a pathologic process,
such as obstructive jaundice, and permits decompression of the liver.
Complications from the test are rare, but include bile leakage leading to bile
peritonitis or bleeding caused by accidental rupture of a blood vessel.
The patient remains NPO for about 8 hours before the test. The injection of the
contrast medium may cause temporary pain or a feeling of pressure or
epigastric fullness. The patient is carefully monitored for bleeding or adverse
reactions to the dye. Vital signs are monitored, and the patient typically rests in
bed for about 6 hours after the test, lying on the right side as much as possible.
The needle insertion site is carefully monitored for signs of bleeding or infection.
Special Tests
Esophageal Function Tests
Several diagnostic tests may be used to evaluate the functioning of the
esophagus and aid in the diagnosis of esophageal reflux or motility problems.
These tests can be performed by having the patient swallow two or three tiny
tubes that are attached to an external transducer. Once the tubes are located
in the stomach, they are slowly pulled back into the distal esophagus at
varying levels. Lower esophageal sphincter pressure, swallowing activity, pH,
and effectiveness of clearance can all be measured in about 30 to 45 minutes.
However, 24-hour pH monitoring may be performed because it is considered
the "gold standard" for the accurate diagnosis of esophageal reflux.
In preparation for these tests, it is important to provide the following
instructions to the patient: (1) remain NPO for 8 hours before the
procedure(s), (2) avoid alcohol and smoking the day before, and (3) do not
take medications such as antacids, H2-receptor antagonists, proton pump
inhibitors and anticholinergics before the test(s). Sedation is not required but
may be used if the patient experiences persistent choking or gagging during
the procedure. After removal of the tubes, a mild sore throat is common.
Manometry
This test is used to measure the pressure in the lower esophageal sphincter and
record the duration and sequence of peristaltic movements within the
esophagus. Readings are taken at various levels in the esophagus with the
patient at rest and during swallowing. Baseline sphincter pressure is normally
about 20 mm Hg. The test is used primarily to diagnose esophageal reflux, but
the graphic record of muscular activity during swallowing may also help
document the presence of achalasia or esophageal spasm.
pH Monitoring
This test evaluates the competency of the lower esophageal sphincter (LES) by
obtaining a single measurement of the esophageal pH. An electrode is placed
above the LES and attached to a manometry catheter. Normally, the esophagus
maintains a pH of more than 6.0. Serial measurements may be obtained by
maintaining the electrode in place for 24 hours. The probe must be inserted
transnasally and connected to a recording box similar to a Holter monitor that is
worn about the waist. The patient can then be monitored at home while eating
a normal diet; 24-hour pH monitoring is the most sensitive and specific
diagnostic test for the presence of abnormal acid reflux.
Esophageal Clearance Test
In conjunction with the previous two tests, esophageal clearance tests evaluate
the function of both the upper and lower esophageal sphincters along with the
body of the esophagus in response to swallowing. Normally, esophageal function
allows for the complete clearance of acid material from the esophagus in less
than 10 swallows. Readings are recorded from the catheter tip to determine the
rate and efficiency of acid clearance.
Acid Perfusion Test (Bernstein Test)
Confusion surrounding the origin of heartburn symptoms is often resolved with
the Bernstein test, which attempts to reproduce the pain. Small quantities of HCl
are instilled into the distal esophagus by nasogastric tube. The test is positive if
the acid produces pain. Saline is instilled to rinse out the acid, and an antacid
may be administered to relieve the discomfort.
Tests of Gastric Function
Gastric Analysis (Basal Gastric Secretion and
Gastric Acid Stimulation Tests)
Examination of the fasting contents of the stomach may be helpful in
establishing a diagnosis of gastric disease. The purpose is to quantify gastric
acidity in the fasting and stimulated states. Abnormal secretion may be
related to ulcers, malignancy, pernicious anemia, or Zollinger-Ellison
syndrome. A nasogastric tube is inserted, and gastric contents are aspirated.
Gastric contents may then be aspirated every 15 minutes for 90 minutes.
The patient is instructed to restrict food, fluid, and smoking for 8 to 12 hours
before the test. The flow of gastric acid is then stimulated by betazole
hydrochloride, histamine phosphate, or pentagastrin given subcutaneously.
The person may experience side effects from the medication, including
flushing, a feeling of warmth, slight headache, or itching. Epinephrine is given
to counteract the effects of histamine if sensitivity occurs.
Tubeless Gastric Analysis (Diagnex Blue Test)
Tubeless gastric analysis may be used for detection of gastric achlorhydria. The test will indicate the
presence or absence of free hydrochloric acid but cannot be used to determine the amount of free
hydrochloric acid that is present. A gastric stimulant such as caffeine is given and then a cation
exchange resin containing azure A is given orally an hour later. If free hydrochloric acid is present in the
stomach, introduction of the resin will cause a substance to be released in the stomach that will be
absorbed from the small intestine and excreted by the kidneys as blue dye within 2 hours. Absence of
detectable amounts of blue dye in the urine indicates that free hydrochloric acid probably was not
secreted.
Schilling Test
The Schilling test evaluates vitamin B12 absorption. In the normal GI tract, vitamin B12 combines with
the intrinsic factor that is produced by the parietal cells in the gastric mucosa and is absorbed in the
distal portion of the ileum. Pernicious anemia develops if intrinsic factor is lacking or malabsorption
exists. This is a concern in patients who have had the terminal ileum removed for diseases such as
Crohn's disease.
The patient is kept NPO for 8 to 12 hours before the test and then administered an oral preparation of
radioactive vitamin B12, followed by an intramuscular injection of nonradioactive vitamin B12 to saturate
the tissue-binding sites. Urinary B12 levels are measured after urine is collected for 24 to 48 hours. With
normal absorption of vitamin B12, the ileum absorbs more vitamin B12 than the body needs and excretes
the excess into the urine. With impaired absorption of vitamin B12, little or no vitamin B12 is excreted
into the urine. Intrinsic factor preparations may also be administered to differentiate intestinal problems
from pernicious anemia.
Urea Breath Test
Testing for H. pylori has been both technically difficult and expensive. The urea breath
test (UBT) is based on the principle that the H. pylori organism is able to produce large
amounts of urease, a surface enzyme that catalyzes the urea in gastric secretions into
bicarbonate and ammonia. Patients are administered an oral solution of carbon isotopelabeled urea in water. If H. pylori is present in the stomach the urea is metabolized. The
labeled bicarbonate is excreted in the form of labeled carbon dioxide, which can be
collected and measured. The patient exhales into a balloon or other receptacle, and the
carbon dioxide is measured with a scintillation counter. The sample can be collected 20
minutes after the solution is ingested. The test has minimal risks associated with
radioactivity and is estimated to be 97% sensitive for H. pylori and 100% specific.
Biopsy
Upper Gastrointestinal Biopsy
A biopsy of the oral cavity or tongue may be done on any lesion or ulcerated
area that requires a differential diagnosis. This procedure is usually performed
with a local anesthetic. After the biopsy, the biopsy site is assessed for bleeding.
Biopsy of the stomach is typically performed during fiberoptic endoscopy.
Intestinal Biopsy
Biopsy of the small or large bowel may also be performed during the course of
endoscopic examination to allow tissue analysis of lesions, polyps, or masses. A
knife blade or snare is typically used to obtain the tissue sample. The procedure
is not usually painful, although a feeling of pressure may be experienced.
Bleeding from the site of the biopsy is uncommon. If bleeding does occur, the
patient is instructed to report this to the physician and to curtail physical activity
until examined by a physician.
Endoscopy
Today most endoscopic procedures are performed on
an ambulatory basis, even with the elderly. Oral
fiberscope insertion is uncomfortable and may
precipitate gagging or choking despite the use of
topical anesthetic sprays or gargles. Premedication
with an IV sedative such as midazolam (Versed) or
diazepam (Valium) or an analgesic such as
meperidine (Demerol) is used. Thus the patient is
conscious but sedated; amnesia is often experienced
when high doses of these drugs are used.
Esophagogastroduodenoscopy
Upper GI endoscopy may be limited to the esophagus (esophagoscopy), stomach
(gastroscopy), or duodenum (duodenoscopy); or it may involve examination of the
entire region (esophagogastroduodenoscopy [EGD]). It is particularly useful for
identifying the source of upper GI bleeding and for differentiating gastric
malignancies from benign ulcers, and gastric ulcers from duodenal ulcers. Other
uses include visualization of esophageal strictures, varices, tumors, achalasia, and
hiatal hernias; and surgical removal of gastric polyps.
Preparation for an EGD involves instructing the patient to remain NPO for 8 hours
before the test. Because air is typically introduced as the endoscope is advanced to
improve visibility, the patient should be told that a feeling of pressure or fullness will
likely be experienced. The entire test lasts about 15 to 30 minutes unless additional
treatments are planned.
After the procedure the patient is monitored carefully for signs of dyspnea, pain,
bleeding, or acute dysphagia. Vital signs are taken every 30 minutes for 3 to 4
hours, and no oral food or fluids are administered until the nurse determines that
the gag reflex is fully intact. Throat lozenges or saline gargles may be used to
relieve sore throat after the test. Complications are rare but include aspiration,
perforation, and bleeding.
Endoscopic Retrograde
Cholangiopancreatography
Endoscopic retrograde cholangiopancreatography (ERCP) also involves the oral
insertion of an endoscope, but this device has a side-viewing tip and a cannula that
can be maneuvered into the ampulla of Vater. Dye may be injected to outline the
pancreatic and biliary ducts. The procedure may be combined with papillotomy to
enlarge the sphincter and release gallstones. Glucagon may be administered to
minimize spasm in the duodenum and sphincter.
Care after the procedure is similar to that previously described for an EGD. The
patient is monitored carefully for signs of abdominal pain, nausea, and vomiting,
which might indicate the development of pancreatitis.
Colonoscopy
Fiberoptic colonoscopy allows the examination of the entire colon in most patients. It is
used to evaluate benign and malignant growths, remove polyps, take biopsy
specimens, and localize sites of bleeding. A colonoscopy is the current "gold standard"
for diagnosing colorectal cancers. Screening colonoscopies for colorectal cancer are
recommended after age 50.
Thorough bowel preparation is essential before the test, which is especially difficult for
elderly persons. A 1-day preparation with an oral osmotic solution is now standard
because it reduces overall fluid and electrolyte loss. A gallon (3,78 l) of polyethylene
glycol (Colyte) solution is administered rapidly (8 ounces (237 ml) every 15 minutes)
and induces a profuse watery diarrhea within 30 to 60 minutes, which lasts about 4
hours. In some cases, the patient may receive a 2- to 3-day preparation consisting of a
clear liquid diet, strong laxatives, and an enema the day of the test. All patients are
NPO for about 8 hours before the test.
Patients are sedated before the colonoscopy. The fiberoptic colonoscope, which is 105
to 185 cm (42 to 72 inches) long, is advanced through the colon and the colon is
visualized simultaneously. Air is introduced as the colonoscope is inserted to increase
visualization of the mucosa. The air commonly causes abdominal cramping. The
procedure lasts from 20 to 60 minutes.
Afterward the nurse assumes responsibility for carefully monitoring the patient and
ensuring full recovery from sedation. Any changes in vital signs or development of
severe abdominal pain, rectal bleeding, or fever should be immediately reported to the
physician. In addition, arrangements for transportation home are important because
the patient should not drive.
Colonoscopy
Sigmoidoscopy may be performed rather than colonoscopy. The cost of a
sigmoidoscopy is considerably less than a colonoscopy but only allows for visualization
of the anus, rectum, and distal sigmoid colon. Approximately 75% of all polyps and
tumors of the large intestine can be visualized with a flexible sigmoidoscope. Pretest
preparation instructions vary widely. The patient may be instructed to prepare with a 2day clear liquid diet and pretest fasting. Fleet enemas may be ordered, or a cleansing
enema may be preferred. The knee-chest position and a strong urge to defecate that is
produced by the larger-diameter sigmoidoscope make this an uncomfortable and
unpopular procedure for patients. Sedation is not usually used. Aftercare involves
monitoring for distention, increased tenderness, and bleeding. The patient may initially
pass large amounts of flatus from the instillation of air during the procedure. Slight
rectal bleeding may occur if biopsies have been taken.