Enteral and Parenteral Nutrition

Alternative routes of nutrient administration are available for patients who are unable to eat or digest sufficient food to prevent malnutrition. These routes include enteral (administered through the gastrointestinal tract) and parenteral (administered intravenously). This review details the clinical consequences of malnutrition, nutritional assessment, the benefits of nutrition support therapy,  determining the nutrient prescription, special considerations in nutrition support therapy, aspects of obtaining enteral or parenteral access, monitoring of patients receiving nutrition support therapy, and complications and ethical issues associated with enteral and parenteral nutrition. Figures include algorithms showing the identification of malnutrition, the nutrition support decision process, and the approach to gastric residual monitoring; nasogastric tube displacement leading to pneumothorax; proper placement of a long or “midline” catheter versus a peripherally inserted central catheter; and photographs of a 43-year-old man with Crohn disease complicated by enterocutaneous fistula formation, distal small bowel obstruction, and evisceration of the small bowel after developing a pelvic abscess. Tables list acute illness- or injury-related malnutrition; chronic disease−related malnutrition; social or environmental circumstances−related malnutrition; indications and contraindications to enteral and parenteral nutrition; selected examples of predictive equations; electrolyte provision in parenteral nutrition; parenteral vitamin and trace element requirements; complications associated with enteral and parenteral nutrition; and indications, contraindications, and complications of gastrostomy tube placement. This review contains 6 highly rendered figures, 11 tables, and 167 references.