Chapter 38: Assessment of Digestive & GI Function

9 meter pathway that manages the essential functions of ingestion, digestion, absorption, and elimination. The digestive process begins with chewing, utilizing salivary amylase for starch breakdown, and continues in the stomach where glands secrete highly acidic hydrochloric acid (HCl) to destroy bacteria and break food down into chyme. The stomach also produces intrinsic factor, vital for vitamin B12 absorption. Subsequent digestion and the majority of absorption occur in the small intestine, supported by accessory organ secretions including pancreatic trypsin and lipase, and liver-secreted bile, which is crucial for fat emulsification. Motility and secretory rates are tightly controlled by the autonomic nervous system and local hormones such as gastrin, secretin, and cholecystokinin. The large intestine handles final waste material breakdown, electrolyte, and water reabsorption, assisted significantly by the gut microbiota, which supports immune function and vitamin synthesis. Nursing assessment involves a targeted health history to identify chief complaints, including dyspepsia (indigestion), pain, nausea, vomiting, and alterations in bowel habits like diarrhea or constipation. Physical examination proceeds through inspection, auscultation for bowel sounds, percussion, and palpation of the abdomen, followed by evaluation of the rectum and anus. Diagnostic evaluation incorporates serum laboratory studies (e.g., liver enzymes, amylase), stool tests for occult blood (FIT, gFOBT), and breath tests for Helicobacter pylori. Imaging modalities span ultrasonography, CT, MRI, and scintigraphy to assess structure and motility. Endoscopic visualization is achieved through procedures like Esophagogastroduodenoscopy (EGD) for the upper GI tract and colonoscopy for the large intestine, often requiring rigorous bowel preparation. Specialized tests such as Endoscopic Retrograde Cholangiopancreatography (ERCP) and esophageal manometry further assist in evaluating bile ducts, the pancreas, and GI motility disorders.