Assessment Of Digestive And Gastrointestinal Function PDF

Assessment of Digestive and Gastrointestinal Function Chapter 38 1 LEARNING OUTCOMES On completion of this chapter, the learner will be able to: 1. D...

Assessment of Digestive and Gastrointestinal Function Chapter 38 1 LEARNING OUTCOMES On completion of this chapter, the learner will be able to: 1. Describe the structure and function of the organs of the gastrointestinal tract. 2. Explain the mechanical and chemical processes involved in digesting and absorbing nutrients and eliminating waste products. 3. Discriminate between normal and abnormal assessment findings of the gastrointestinal system. 4. Recognize and evaluate the major symptoms of gastrointestinal dysfunction by applying the patient’s health history and physical assessment findings. 5. Identify the diagnostic tests used to evaluate gastrointestinal tract function and related nursing implications. 2 Anatomic and Physiologic Overview 3 4 Anatomy of the Gastrointestinal System The GI tract is a pathway 7 to 7.9 meters Extends from the mouth to the esophagus, stomach, small and large intestines, and rectum, to the terminal structure, the anus. The esophagus is located in the mediastinum, anterior to the spine and posterior to the trachea and heart (hollow muscular tube, app 25 cm, passes through the diaphragm at the opening called diaphragmatic hiatus. 5 6  Anatomy of the Gastrointestinal System Stomach Situated in the left upper portion of the abdomen under the left lobe of the liver and the diaphragm, overlaying most of the pancreas. A hollow muscular organ with a capacity of approximately 1500 mL. Functions of stomach: - Stores foods during eating - Secretes digestive fluids - Propels the partially digested food into small intestine 7 Anatomy of the Gastrointestinal System Stomach: The gastroesophageal junction is the inlet to the stomach. The stomach has four anatomic regions: - Cardia (inlet) - Fundus - Body - Pylorus (outlet) 8 Anatomy of the Gastrointestinal System Small Intestine: The longest segment of the GI tract. (70 m). The surface area for secretion and absorption. It has three sections: The most proximal section is the duodenum, the middle section is the jejunum, and the distal section is the ileum. The ileum terminates at the ileocecal valve. Attached to the cecum is the vermiform appendix, an appendage that has little or no physiologic function. 9 10  11 Anatomy of the Gastrointestinal System Large intestine: Consists of an ascending segment, a transverse segment , and descending segment. The sigmoid colon, the rectum, and the anus complete the terminal portion of the large intestine. A network of striated muscle that forms both the internal and the external anal sphincters regulates the anal outlet. 12 Anatomy of the Gastrointestinal System Large intestine: The portal venous system is composed of five large veins: the superior mesenteric, inferior mesenteric, gastric, splenic, and cystic veins, which eventually form the vena portae that enters the liver. Blood flow to the GI tract is about 20% of the total cardiac output and increases significantly after eating. 13 14 Anatomy of the Gastrointestinal System Both the sympathetic and parasympathetic portions of the autonomic nervous system innervate the GI tract. 15 Function of the Digestive System Major functions of the GI tract include: Breakdown of food particles into the molecular form for digestion. Absorption into the bloodstream of small nutrient molecules produced by digestion. Elimination of undigested unabsorbed foodstuffs and other waste products. 16  PROCESS OF DIGESTION Chewing: Food is broken down into small particles that can be swallowed and mixed with digestive enzymes. Approximately 1.5 L of saliva is secreted daily from the parotid, the submaxillary, and the sublingual glands. Ptyalin, or salivary amylase, is an enzyme that begins the digestion of starches. 17 PROCESS OF DIGESTION Swallowing: Voluntary act that is regulated by the swallowing center in the medulla oblongata of the central nervous system (CNS). The lower esophageal sphincter closes tightly to prevent reflux of stomach contents into the esophagus. 18  PROCESS OF DIGESTION Gastric Function: This fluid, which can total 2.4 L/day, can have a pH as low as 1 and derives its acidity from hydrochloric acid (HCl) secreted by the glands of the stomach. The function of this gastric secretion is twofold (1) to break down food into more absorbable components and (2) to aid in the destruction of most ingested bacteria. Pepsin: an important enzyme for protein digestion, is the end product of the conversion of pepsinogen from the chief cells. Intrinsic factor: also secreted by the gastric mucosa, combines with dietary vitamin B12 so that the vitamin can be absorbed in the ileum. 19 PROCESS OF DIGESTION Because large food particles cannot pass through the pyloric sphincter, they are churned back into the body of the stomach. Food remains in the stomach for a variable length of time, from 30 minutes to several hours. Peristalsis in the stomach and contractions of the pyloric sphincter allow the partially digested food to enter the small intestine. This partially digested food mixed with gastric secretions is called chyme. 20  PROCESS OF DIGESTION Small Intestine Function: Duodenal secretions come from the accessory digestive organs—the pancreas, liver, and gallbladder—and the glands in the wall of the intestine itself. These secretions contain digestive enzymes: amylase, lipase, and bile. Pancreatic secretions have an Alkaline pH due to their high concentration of bicarbonate. Digestive enzymes secreted by the pancreas include (1) Trypsin: which aids in digesting protein (2) Amylase: which aids in digesting starch (3) Lipase: which aids in digesting fats. 21 PROCESS OF DIGESTION These secretions drain into the pancreatic duct, which empties into the common bile duct. Bile, secreted by the liver and stored in the gallbladder, aids in emulsifying ingested fats, making them easier to digest and absorb. 22  PROCESS OF DIGESTION Two types of contractions occur regularly in the small intestine: 1. Segmentation contractions: produce mixing waves that move the intestinal contents back and forth in a churning motion. 2. Intestinal peristalsis: propels the contents of the small intestine toward the colon. 23 PROCESS OF DIGESTION Ingestion of food: Carbohydrates are broken down into disaccharides, monosaccharides (glucose). Glucose is the major carbohydrate that tissue cells use as fuel. Proteins are a source of energy after they are broken down into amino acids and peptides. Fats become monoglyceides and fatty acid through emulsification. Chyme stays in the small intestine for 3 to 6 hours. 24  PROCESS OF DIGESTION Colonic Function: Within 4 hours after eating, residual waste material passes into the terminal ileum and slowly into the proximal portion of the right colon through the ileocecal valve. Bacteria, a major component of the contents of the large intestine, assist in completing the breakdown of waste material. Slow transport allows for efficient reabsorption of water and electrolytes, which is the major function of the colon. 25 PROCESS OF DIGESTION Waste Products of Digestion: Feces consist of undigested foodstuffs, inorganic materials, water, and bacteria. Fecal matter is about 75% fluid and 25% solid material. The brown color of the feces results from the breakdown of bile by the intestinal bacteria. Chemicals formed by intestinal bacteria are responsible in large part for the fecal odor. Gases formed contain methane, hydrogen sulfide, and ammonia, among others. Elimination of stool begins with distention of the rectum, which initiates reflex contractions of the rectal musculature and relaxes the normally closed internal anal sphincter. 26 Assessment of the Gastrointestinal System Health history Common Symptoms: 1. Pain: Pain can be a major symptom of GI disease; in particular, abdominal pain is a common presentation in the ambulatory setting. the character, duration, pattern, frequency, location, distribution of referred abdominal pain. 27 28 Assessment of the Gastrointestinal System 2. Dyspepsia: Upper abdominal discomfort associated with eating (commonly called indigestion)—is the most common symptom of patients with GI dysfunction. Dyspepsia affects 25% to 40% of the population over a lifetime. Gastroesophageal reflux disease (GERD), which manifests with dyspepsia (most frequently with heartburn) affects approximately 20% of adult Fatty foods cause the most discomfort because they remain in the stomach for digestion longer than proteins or carbohydrates. 29 Assessment of the Gastrointestinal System 3. Intestinal Gas: The accumulation of gas in the GI tract may result in belching, or flatulence. Patients often complain of bloating, distention, or feeling “full of gas” with excessive flatulence as a symptom of food intolerance or gallbladder disease. 30  Assessment of the Gastrointestinal System 4. Nausea and Vomiting: Nausea is a vague, uncomfortable sensation of sickness or “queasiness” that may or may not be followed by vomiting. The causes of nausea and vomiting are many: 1. Anxiety 2. Side effects of medications 3. Torsion or trauma of the ovaries, testes, uterus, bladder or kidney 4. Inner ear disorders 5. Motion sickness (vestibular center) 31 Assessment of the Gastrointestinal System 5. Change in Bowel Habits and Stool Characteristics: Changes in bowel habits may signal colonic dysfunction or disease. Diarrhea, an abnormal increase in the frequency and liquidity of the stool Constipation—a decrease in the frequency of stool, or stools that are hard, dry, and of smaller volume than typical—may be associated with anal discomfort and rectal bleeding. Stool is normally light to dark brown; however, specific disease processes and ingestion of certain foods and medications may change the appearance of stool 32  Assessment of the Gastrointestinal System Blood in stool: If blood is shed in sufficient quantities into the upper GI tract, it produces a tarry-black color (melena). Blood entering the lower portion of the GI tract or passing rapidly through it will appear bright or dark red. Lower rectal or anal bleeding is suspected if there is streaking of blood on the surface of the stool or if blood is noted on toilet tissue. 33 Physical Assessment 1. Oral cavity: Inspection and palpation Lips Gums Tongue 34  35 Physical Assessment 2. Abdominal Inspection, Auscultation, Percussion, and Palpation: A. Inspection B. Auscultation always precedes percussion and palpation, because they may alter sounds (5-30 per min) C. Percussion is used to assess the size and density of the abdominal organs and to detect the presence of air-filled, fluid-filled, or solid masses. D. Light palpation is appropriate for identifying areas of tenderness or muscular resistance, and deep palpation is used to identify masses. 36  Physical Assessment 3. Rectal Inspection and Palpation: Positions for the rectal examination include knee-chest, left lateral with hips and knees flexed, or standing with hips flexed and upper body supported by the examination table. External examination Internal examination 37 Diagnostic Evaluation/ Laboratory 1. Serum laboratory studies: CBC, PT, PTT, Triglycerides, Liver Function Test, Amylase, and Lipase. 2. Stool tests: Colour, consistency, occult (not visible) blood. Guaiac-based fecal occult blood testing (gFOBT) it is used most frequently in early cancer detection programs. 3. Breath test: Urea breath tests detect the presence of Helicobacter pylori, the bacteria that can live in the mucosal lining of the stomach and cause peptic ulcer disease. 38  Diagnostic Evaluation/imaging Abdominal ultrasonography: Is a noninvasive diagnostic technique in which high frequency sound waves are passed into internal body structures. It is useful in the detection of an enlarged gallbladder or pancreas, the presence of gallstones, an enlarged ovary, an ectopic pregnancy, or appendicitis. Less cost, no radiation, immediate results. Not suitable to examine organs behind the bones. Endoscopic ultrasonography (EUS) is a specialized enteroscopic procedure that aids in the diagnosis of GI disorders by providing direct imaging of a target area. 39 40  Diagnostic Evaluation/imaging Nursing Intervention: -NPO for 8-12 before the procedure -If the study for the gallbladder, a fat-free meal at the evening before the procedure is instructed. -Patients who receive moderate sedation are observed for about 1 hour to assess for level of consciousness. 41 Diagnostic Evaluation/Imaging studies Tract Study: Upper Gastrointestinal - Introduction of a radiopaque liquid, to detect or exclude anatomic or functional disorders of the upper GI organs or sphincters. - It also aids in the diagnosis of ulcers, varices, tumors, regional enteritis, and malabsorption syndromes. - Multiple x-ray images are obtained during the procedure - The patient must first be assessed for allergy to iodine or contrast agent. - Clients should be npo from midnight - Oral medications are withheld on the morning of the study and resumed that evening. - A patient with insulin dependent diabetes the doses need to be adjusted. - Follow-up care is provided after the upper gi procedure to ensure that the 42 patient has eliminated most of the ingested barium.  Diagnostic Evaluation/imaging Lower Gastrointestinal Tract Study: The barium enema can be used to detect the presence of polyps, tumors, or other lesions of the large intestine and demonstrate any anatomic abnormalities or malfunctioning of the bowel. The patient must first be assessed for allergy to iodine or contrast agent. The patient may feel some cramping or discomfort during this process. The contrast agent is eliminated readily after the procedure, so there is no need for post procedure laxatives. Barium enemas also are contraindicated in patients with signs of perforation or obstruction The patient includes emptying and cleansing the lower bowel. Npo after midnight 43 Increase fluid intake after procedure Diagnostic Evaluation/imaging Computed Tomography: - A CT scan provides cross-sectional images of abdominal organs and structures. - CT is a valuable tool for detecting and localizing many inflammatory conditions in the colon, such as appendicitis, diverticulitis, regional enteritis, and ulcerative colitis. - A CT scan may be performed with or without oral or intravenous (IV) contrast. - IV contrast agents include allergic reactions and acute kidney injury. - Any allergies to contrast agents, iodine, or shellfish, the patient’s current serum creatinine level. 44  Diagnostic Evaluation/imaging Magnetic Resonance Imaging: -Noninvasive technique uses magnetic fields and radio waves to produce images of the area being studied. -It is useful in evaluating abdominal soft tissues as well as blood vessels, abscesses, fistulas, neoplasms, and other sources of bleeding. -MRI is contraindicated in patients with any device containing metal because the magnetic field could cause malfunction. -NPO status 6 to 8 hours before. 45 Diagnostic Evaluation/imaging Positron Emission Tomography: -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 radioactive isotopes of oxygen, nitrogen, carbon, or fluorine -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. 46  47 Endoscopic Procedures Upper Gastrointestinal Fibroscopy / Esophagogastroduodenoscopy: -Fibroscopy of the upper GI tract allows direct visualization of the esophageal, gastric, and duodenal mucosa through a lighted endoscope. -EGD is valuable when esophageal, gastric, or duodenal disorders or inflammatory, neoplastic, or infectious processes are suspected. Endoscopic retrograde cholangiopancreatography (ERCP) - Therapeutic endoscopy can be used to remove common bile duct stones, dilate strictures, and treat gastric bleeding and esophageal varices. 48 49 50 51 52  Endoscopic Procedures Nursing Interventions: The patient should be NPO for 8 hours prior to the examination. the patient is given a local anesthetic gargle or spray. The patient is positioned in the left lateral position After gastroscopy, assessment includes level of consciousness, vital signs, oxygen saturation, pain level, and monitoring for signs of perforation (i.e., pain, bleeding, unusual difficulty swallowing, and rapidly elevated temperature). 53 Fiberoptic Colonoscopy Direct visualization of the bowel was the only means to evaluate the colon This procedure is used commonly as a diagnostic aid and screening. Tissue biopsies can be obtained as needed, and polyps can be removed and evaluated. The patient is lying on the left side with the legs drawn up toward the chest. Adequate colon cleansing provides optimal visualization and decreases the time needed for the procedure. Colonoscopy cannot be performed if there is a suspected or documented colon perforation, acute severe diverticulitis, or fulminant colitis. 54  Fiberoptic Colonoscopy Patients with prosthetic heart valves or a history of endocarditis require prophylactic antibiotics before the procedure. Informed consent is obtained Before the examination, an opioid analgesic agent or sedative During the procedure, the patient is monitored for changes in oxygen saturation, vital signs, color and temperature of the skin, level of consciousness, abdominal distention, vagal response, and pain intensity After the procedure, patients are maintained on bed rest until fully alert. If the procedure is performed on an outpatient basis, the nurse instructs the patient to report any bleeding 55