which patients should receive a feeding tube requires consideration of several factors including the patient’s clinical status, diagnosis, prognosis, risk-benefit ratio, discharge plans, quality of life, ethical considerations, and the patient/family wishes. Specific indications for EN are listed in Table 83.2.
TABLE 83.1 POTENTIAL BENEFITS OF USING THE ENTERAL ROUTE FOR NUTRITION SUPPORT
TABLE 83.2 INDICATIONS AND CONTRAINDICATIONS FOR ENTERAL NUTRITION SUPPORT
most nutrients occurs in the duodenum and proximal jejunum, whereas the distal 100 cm of ileum is responsible for absorption of vitamin B12 and bile salts. Patients with jejunal resections generally tolerate EN unless more than 75% has been resected. The transit time is usually normal and they retain the ability to absorb vitamin B12 and bile salts. Resections of the ileum are associated with greater malabsorption. Malabsorption of bile salts can cause fat malabsorption, steatorrhea, and loss of fat-soluble vitamins (42). Since the terminal ileum is the site of vitamin B12 absorption, the patient will require supplemental parenteral or nasal vitamin B12 for life if the terminal ileum is resected. Patients may also experience rapid intestinal transit and small bowel bacterial overgrowth leading to intolerance of enteral formula. Loss of the ileocecal valve may result in decreased transit time through the proximal gut and loss of fluid and nutrients. Without the ileocecal valve, colonic bacteria can reflux and colonize the small bowel (bacterial overgrowth), which inhibits digestive enzyme activity and worsens chronic diarrhea and GI nutrient loss. For the patient with SBS, bacteria in the colon metabolize undigested carbohydrate and soluble fiber into short-chain fatty acids which provide a source of energy, aid in fluid and electrolyte absorption, and stimulate intestinal adaptation.