Assessment of Digestive and Gastrointestinal Function

diagnostic test and procedures

Prepared by Suleman Shah

Clinical Instructor RAKCON

objectives

• Review the anatomy and physiology of digestive system• Describe the structure and function of the organs of the

gastrointestinal (GI) tract.• Describe the mechanical and chemical processes involved in

digesting and absorbing foods and eliminating waste products.• Use assessment parameters appropriate for determining the

status of GI function.• Describe the appropriate preparation, teaching, and follow-up

care for patients who are undergoing diagnostic testing of the GI tract.

Organs of the Digestive SystemReview A&P

Functions of the Digestive Tract

• Breakdown of food for digestion• Absorption of nutrients produced by

digestion into the bloodstream• Elimination of undigested foodstuffs

and other waste products

Gastric function

• Secrete Acidic fluid 2.4 L/day• pH as low as 1.(HCL)• Destruction of bacteria• Conversion of Pepsinogen to pepsin –

responsible for protein digestion.• Intrinsic factor for Vit. B 12 absorption.

Small intestine Function• Secretion comes from Pancrease,liver,and gall bladder

and glands in S.Intestine • Secretion of amylase, lipase and bile, Bicarbonate

(neutralizes the acid)• 1 L pancreatic Secreton,0.5 L Bile ,and 3L secretion

from glands of small intestine.

Action of Enzymes/Secretions That Digest carbohydrates

Enzyme/Secretion Enzyme Source Digestive Action

Ptyalin (salivary amylase) Salivary glands Starch→dextrin, maltose, glucose

Amylase Pancreas and intestinal mucosa

Starch→dextrin, maltose, glucoseDextrin→maltose, glucose

Maltase Intestinal mucosa Maltose→glucose

Sucrase Intestinal mucosa Sucrose→glucose, fructose

Lactase Intestinal mucosa Lactose→glucose, galactose

Action of Enzymes/Secretions That Digest Protein

Pepsin Gastric mucosa Protein polypeptides

Trypsin Pancreas Proteins and polypeptides→polypeptides, dipeptides, amino acids

Aminopeptidase Intestinal mucosa Polypeptides→dipeptides, amino acids

Dipeptidase Intestinal mucosa Dipeptides→amino acids

Hydrochloric acid Gastric mucosa Protein→polypeptides, amino acids

Action of Enzymes Secretions That Digest Fat (Triglyceride)

Pharyngeal lipase Pharynx mucosa Triglycerides→fatty acids, diglycerides, monoglycerides

Steapsin Gastric mucosa Triglycerides→fatty acids, diglycerides, monoglycerides

Pancreatic lipase Pancreas Triglycerides→fatty acids, diglycerides, monoglycerides

Bile Liver and gallbladder Fat emulsification

The Major Gastrointestinal Regulatory SubstancesNeuroregulators

Substance Stimulus for Production

Target Tissue Effect on Secretions Effect on Motility

Acetylcholine Sight, smell, chewing food, stomach distention

Gastric glands, other secretary glands, gastric and intestinal muscle

Increased gastric acid

decreased sphincter tone

Hormonal Regulators

Norepinephrine Stress, other various stimuli

Secretory glands, gastric and intestinal muscle

Generally inhibitory increased sphincter tone

Gastrin Stomach distention with food

Gastric glands Increased secretion of gastric juice, which is rich in HCL

Increased motility of stomach, decreased time required for gastric emptyingRelaxation of ileocecal sphincterExcitation of colonConstriction of gastroesophageal sphincter

Cholecystokinin Fat in duodenum

Gallbladder Release of bile into duodenum

Pancreas Increased production of enzyme-rich pancreatic secretions

Stomach Inhibits gastric secretion somewhat

Secretin pH of chyme in duodenum below 4–5

Stomach Inhibits gastric secretion somewhat

Pancreas Increased production of bicarbonate-rich pancreatic juice

Local Regulator

Histamine Unclear;substances in food

Gastric glands Increased gastric acid production

Colonic function

• Neutralize the end products formed by the colonic bacterial action. the mucus protects the colonic mucosa from the interluminal content and provides adherence for the fecal mass.

Assessment: History

• Include all information related to GI function– Abdominal pain, dyspepsia, gas, nausea and

vomiting, constipation, diarrhea, fecal continence, change in bowel patterns, characteristics of stool, jaundice, history of GI surgery or problems, appetite and eating patterns, teeth, and nutritional assessment, including weight patterns

• Psychosocial, spiritual, and cultural factors • Assess knowledge; need for patient education

Common Sites of Referred Abdominal Pain

Examination of the Abdomen

Quadrants of the Abdomen

Diagnostic Tests

• Diagnostic Evaluation• Stool specimens• Breath tests• Abdominal ultrasound• Imaging studies: CT, PET, MRI• Upper GI tract study• Lower GI tract study• GI motility studies• Endoscopic procedures• Other

Diagnostic Evaluation

• Initial diagnostic test begin with serum laboratory studies.

• CBC• Prothrombin time /partial thromboplastine time.• Triglycerides• LFT(liver function test)• Amylase• Lipase• CEA(carcinoembrynic antigen)• Cancer antigen(CA) 19-9• Alpha fetoprotein

General nursing interventions for patient who is under going a GI diagnostic evaluation

• Establish the nursing diagnosis• Provide needed information about the test and activities

required of the patient• Instruction regarding post procedure care and restriction• Providing teaching to patient and family regarding procedure• Helping the patient cope with discomfort and alleviating

anxiety.• Informing the physician and nurse practitioner regarding

medical condition or abnormal laboratory value that may affect the procedure.

• Assessing for hydration before ,after and during the procedure.

Stool specimens

• Examination of the stool specimen for consistency, color and occult blood.

• Additional studies includes, fecal urobilinogen, fecal fat, clostridium difficile,fecal leukocytes, calculation of stool osmolar gap,parasites,pathogen, food residues.

• Hem occult II(avoided in case of hemorrhoid bleeding)

• Avoid red meat,aspirin,nonsteroidal anti inflammatory drugs 72 hours before the test because it may cause false positive result.

Breath test

• Hydrogen breath test was developed to evaluate carbohydrate absorption.

• Urea breath test to detect H.pylori (the patient is advised to avoid antibiotic for a month before test,omeprazole for a week before and zantic 24 hours before)

Abdominal ultrasonography• It is noninvasive procedure in which high frequency sound waves are

passed into body structure and ultrasonic echoes are recorded on an oscilloscope as they strike tissue of different densities.

• Absence of ionizing radiation, no noticeable side effect, low cost, quick result

• Indication:• Detection of enlarge gallbladder, pancreas, the presence of gall

stone,larged ovary, an ectopic pregnancy,appendicitis,colonic diverticulitis.

• Endoscopic Ultrasonography.(EUS)• Nursing intervention:• Fast for 8 -12 hrs before procedure to decreases the amount of gases in

the bowel.• If gall bladder procedure is being performed then the fat free meal

evening before the test.• If barium study is being scheduled then it should scheduled after

Ultrasonograpgy.

DNA testing

• Research have refined methods for genitic risk factor assessment and preclinical diagnosis for certain GI disorder

• E.g gastric Ca,lactose deficiency,IBD,Ca colon,

But there legal and ethical issues in genetic testing.

Imaging studyUpper gastrointestinal tract study

• Radiopaque liguid(barium sulphate)is ingested in followed by fluoroscopic examination.

1. The anatomic and functional derangement of the upper GI organs or sphincter s are assessed. it helps in assessing GI motility, thickness of the gastric wall, mucosal pattern,patency of pyloric valve.obstruction,ileitis and diverticula can also be detected.

2. It aids in assessment ulcer,varies,tumors,regional enteritis and malabsorption syndromes.

3. During the procedure multiple X-rays films are taken

Upper gastrointestinal tract studydouble contrast study

• The double contrast studies methods of examining the upper GI tract involves administration of thick barium suspension to out line the stomach and esophagus wall ,after which tablets that release carbon dioxides in the presence of water are administered. this technique has the advantage of showing the esophagus and stomach in finer detail permitting signs of early detail, permitting signs of early superficial neoplasm to be noted.

enteroclysis• It also very detail study of all small intestine

that involves the continues infusion of barium thin suspension of barium of 500ml to 1000ml.after this methylcellulose is infused through the tube. the barium and methylcellulose fills the intestinal loop and observed continuously through fluroscopy.and viewed at frequent intervals they progress through the jejunum and ilium.this procedure takes up to 6 hours and can be uncomfortable for the patient.

• This procedure aids in diagnosis of partial small bowel obstruction or diverticula.

Nursing intervention

• Nothing per oral midnight before procedure.• Liquid diet day before surgery.• Insulin adjustment in case of diabetes mellitus.• stop smoking before the procedure as it can stimulate

gastric motility.• Hold oral medication before the procedure, however

patient medication regimen should be evaluated on the individual basis.

• Follow of care to ensure that the patient has eliminated the most of ingested.

• Post procedure oral fluid intake may be increase.

Lower GI tract study• Visualization of lower GI tract is done after instillation

of barium.• This helps to detect the presence of polyps, tumors or

other lesion in the large intestine and demonstrate any anatomic abnormalities or malfunctioning of the bowel. each portion of the colon is observed.

• If fistula ,inflammatory disease or perforation of the colon is suspected ,then a water soluble iodinated contrast agent(gastrgrafin)can be used as it is rapidly eliminated from colon.

Nursing intervention

• Complete assessment regarding the GI assessment.• Preparation of patient includes emptying and cleaning

the lower bowel.• low residual diet is recommended 1 -2 days before the

procedure.• Clear liquid and laxative may be indicated day before

the procedure.• Keep patient NPO midnight before the procedure.• On the morning of the procedure Administration of

cleansing enema until returns are clear.• Post procedure increase fluid intake. evaluation of

bowel movement for evacuation of barium.

Computed tomogarghy(CT)

• CT provides cross-sectional images of the abdominal organs and structure. multiple images are taken from multiple angle, digitalized in a computer ,reconstructed and then viewed on a computer monitor.

• It helps in detecting and localizing many inflammatory condition in the colon, such as apendicitis,diverticulitis,regional enteritis and ulcerative colitis.

• It also helps in evaluating the abdomen for diseases of the liver,spleen,kidney,pancreas,and pelvic organs.

• This is pain less procedure but radiation doses are considerable.

Computed tomogarghy(CT)nursing intervention

• CT may be performed with or without IV or oral contrast. so assess the patient for allergy.

• Check for the serum creatinine level to assess kidney function.

• Patient allergic to the contrast may be premedicated Iv prednisone 24hrs,12hrs and 1 hour before the procedure.

• In addition administration of iv Bicarbonate I hour before and 6 hour after iv contrast and oral acetylcysteine(mucomyst)before or after the study.

• Both Na bicarbonate and acetylcysteine are free radical that sequester the contrast byproduct that are destructive to the renal cells.

Magnetic Resonance ImagingMRI is used in gastroenterology to supplement ultrasonography and CT. This noninvasive technique uses magnetic fields and radio waves to produce an image of the area being studied. The use of oral contrast agents to enhance the image has increased the application of this technique for the diagnosis of GI diseases. It is useful in evaluating abdominal soft tissues as well as blood vessels, abscesses, fistulas, neoplasm and other sources of bleeding.

Contraindication for MRIAny ferromagnetic objects (metals that contain iron) can be attracted to the magnet and cause injury. Items that can be problematic or dangerous include jewelry, pacemakers, dental implants, paperclips, pens, keys, IV poles, clips on patient gowns, and oxygen tanks. MRI is contraindicated for patients with permanent pacemakers, artificial heart valves and defibrillators, implanted insulin pumps, or implanted transcutaneous electrical nerve stimulation devices, because the magnetic field could cause malfunction. MRI is also contraindicated for patients with internal metal devices (eg, aneurysm clips).

Nursing Interventions for MRI

•Prestudy patient education includes NPO status 6 to 8 hours before the study • Removal of all jewelry and other metals. •The patient and family are informed that the study may take 60 to 90 minutes; during this time, the technician will instruct the patient to take deep breaths at specific intervals. •The close-fitting scanners used in many MRI facilities may induce feelings of claustrophobia, and the machine will make a knocking sound during the procedure.•Patients may choose to wear a headset and listen to music or to wear a blindfold during the procedure.•

Positron Emission Tomography (PET)

• PET scans produce images of the body by detecting the radiation emitted from radioactive substances. The radioactive substances are injected into the body IV and are usually tagged with a radioactive atom, such as carbon-11, fluorine-18, oxygen-15, or nitrogen-13. The atoms decay quickly, do not harm the body, have lower radiation levels than a typical x-ray or CT scan, and are eliminated in the urine or feces. The scanner essentially “captures” where the radioactive substances are in the body, transmits information to a scanner, and produces a scan with “hot spots” for evaluation by the radiologist or oncologist.

Scintigraphy• Scintigraphy (radionuclide testing) relies on the use of radioactive

isotopes (ie, technetium, iodine, and indium) to reveal displaced anatomic structures, changes in organ size, and the presence of neoplasm or other focal lesions, such as cysts or abscesses. Scintigraphic scanning is also used to measure the uptake of tagged red blood cells and leukocytes. Tagging of red blood cells and leukocytes by injection of a radionuclide is performed to define areas of inflammation, abscess, blood loss, or neoplasm. A sample of blood is removed, mixed with a radioactive substance, and re injected into the patient. Abnormal concentrations of blood cells are then detected at 24- and 48-hour intervals.

• Tagged red cell studies are useful in determining the source of internal bleeding when all other studies have returned a negative result

Gastrointestinal Motility Studies

• Radionuclide testing also is used to assess gastric emptying and colonic transit time.

• During gastric emptying studies, the liquid and solid components of a meal (typically scrambled eggs) are tagged with radionuclide markers. After ingestion of the meal, the patient is positioned under a scintiscanner, which measures the rate of passage of the radioactive substance from the stomach.

• This is useful in diagnosing disorders of gastric motility, diabetic gastro paresis, and dumping syndrome

• Colonic transit studies are used to evaluate colonic motility and obstructive defecation syndromes

• This is usually an outpatient study. The patient is given a capsule containing 20 radionuclide markers and follow a regular diet and normal daily activities. x-rays are taken every 24 hours until all markers are passed. takes 4 to 5 days, but in severe constipation it may take upto 10 days. Patients with chronic diarrhea may be evaluated at 8-hour intervals.

Upper Gastrointestinal Fibroscopy/Esophagogastroduodenoscopy

• Fibroscopy of the upper GI tract allows direct visualization of the esophageal, gastric, and duodenal mucosa through a lighted endoscope (gastroscope).

• EGD is especially valuable when esophageal, gastric, or duodenal abnormalities or inflammatory, neoplastic, or infectious processes are suspected.

• This procedure also can be used to evaluate esophageal and gastric motility and to collect secretions and tissue specimens for further analysis.

• Electronic video endoscopes also are available ,attached directly to a video processor, converting the electronic signals into pictures on a television screen. This allows larger and continuous viewing capabilities, as well as the simultaneous recording of the procedure.

Upper Gastrointestinal Fibroscopy/EsophagogastroduodenoscopyNursing intervention

• Pre-operative teaching.• NPO for 8 hours prior to the examination.• Before the introduction of the endoscope, the patient is given a local

anesthetic gargle or spray. • Midazolam (Versed), a sedative that provides moderate sedation and

relieves anxiety.• Atropine may be administered to reduce secretions. • The patient is positioned in the left lateral position to facilitate

clearance of pulmonary secretions and provide smooth entry of the scope

Nursing intervention continue• After gastroscopy, assessment includes level of consciousness, • vital signs, oxygen saturation,• pain level, and monitoring for signs of perforation (ie, pain, bleeding,• unusual difficulty swallowing, and rapidly elevated temperature). • After the patient's gag reflex has returned, lozenges, saline gargle, and

oral analgesics may be offered to relieve minor throat discomfort.• Patients who were sedated for the procedure must remain in bed until

fully alert. After moderate sedation, the patient must be transported home with a family member or friend if the procedure was performed on an outpatient basis.

• One study found that 69% of discharged patients could not recite post procedure instructions to a nurse the morning following the procedure (Gall & Bull, 2003).

Gastroscopy

Fiberoptic Colonoscopy

• These scopes have the same capabilities as those used for EGD but are larger in diameter and longer. Still and video recordings can be used to document the procedure and findings.

• This procedure is used commonly as a diagnostic aid and screening device.

• tissue biopsies can be obtained as needed, and polyps can be removed and evaluated

• the procedure can be used to remove all visible polyps• Laser-compatible scopes provide laser therapy for bleeding

lesions or colonic neoplasms• Use of bipolar and unipolar coagulators, vasoconstrictors are all

possible during this procedure/

Nursing intervention for colonoscopy

• Cleansing the colon with laxative and saline enema.• polyethylene glycol electrolyte lavage solutions (Go-LYTELY, CoLyte, and

Nu-Lytely) are used as intestinal lavages for effective cleansing of the bowel.

• Clear liquid diet at noon day before procedure. Then the patient ingests the lavage solution orally at intervals over 3 to 4 hours.

• The use of lavage solutions is contraindicated in patients with intestinal obstruction or inflammatory bowel disease.

• Careful cardiac monitoring in heart patient• Special precaution in patient with implantable defibrillator and

pacemaker.• Monitoring of blood sugar in diabetic patient.

Colonoscopy

Sigmoidoscopy

Anoscopy, Proctoscopy, and Sigmoidoscopy

• Endoscope examination of the anus, rectum, and sigmoid and descending colon is used to evaluate chronic diarrhea, fecal incontinence, ischemic colitis, and lower GI hemorrhage and to observe for ulceration, fissures, abscesses, tumors, polyps, or other pathologic processes.

Nursing Interventions

• These examinations require only limited bowel preparation, including a warm tap water or Fleet's enema until returns are clear.

• Soap-suds and tap water enemas that were used in the past produced significantly greater returns, but patients were more uncomfortable.

• In addition, rectal biopsies showed surface epithelium loss after soap-suds and tap water enemas but not after Fleet's enema.

• Dietary restrictions usually are not necessary, and sedation usually is not required.

• During the procedure, the nurse monitors vital signs, skin color and temperature, pain tolerance, and vagal response.

• After the procedure, the nurse monitors the patient for rectal bleeding and signs of intestinal perforation (ie, fever, rectal drainage, abdominal distention, and pain). On completion of the examination, the patient can resume his or her regular activities and diet.

Manometry and Electrophysiologic Studies

• Manometry and electrophysiologic studies are methods for evaluating patients with GI motility disorders.

• The manometry test measures changes in intraluminal pressures and the coordination of muscle activity in the GI tract on a computer.

• Esophageal manometry is used to detect motility disorders of the esophagus and the upper and lower esophageal sphincter.

• these studies helpful in the diagnosis of achalasia, diffuse esophageal spasm, scleroderma, and other esophageal motor disorders.

• Procedure:• A pressure-sensitive catheter is inserted through the nose and is

connected to a transducer and a video recorder.• The patient then swallows small amounts of water while the resultant

pressure changes are recorded.• Evaluation of a patient for gastroesophageal reflux• disease (GERD) typically includes esophageal manometry.

• .

Nursing intervention :

• NPO(nothing per oral) 8 to 12 hours before the test.• Medications that could have a direct affect on motility (eg, calcium channel

blockers, anticholinergic agents, sedatives) are withheld for 24 to 48 hours.

• Gastro duodenal, small intestine, and colonic manometry procedures are used to evaluate delayed gastric emptying and gastric and intestinal motility disorders such as irritable bowel syndrome or atonic colon.

• This is often an ambulatory outpatient procedure lasting 24 to 72 hours. • Anorectal manometer measures the resting tone of the internal anal

sphincter and the contractibility of the external anal sphincter. It is helpful in evaluating patients with chronic constipation or fecal incontinence and is useful in biofeedback for the treatment of fecal incontinence.

Rectal sensory function studies

• Rectal sensory function studies are used to evaluate rectal sensory function and neuropathy.

• A catheter and balloon are passed into the rectum, with increasing balloon inflation until the patient feels distention.

• Then the tone and pressure of the rectum and anal sphincter are measured.

• The results are especially helpful in the evaluation of patients with chronic constipation, diarrhea, or incontinence.

• Electrogastrography, an electro physiologic study, also may be performed to assess gastric motility disturbances and can be useful in detecting motor or nerve dysfunction in the stomach.

• Electrodes are placed over the abdomen, and gastric electrical activity is recorded for up to 24 hours. Patients may exhibit rapid, slow, or irregular waveform activity

References

• Brunner and Suddarth's Textbook of Medical-Surgical Nursing, 11th Edition(page 1121-1140)