Chapter 6: Nutritional Therapy

The content establishes physiological foundations by explaining how a functioning gastrointestinal tract maintains mucosal defenses through gut-associated lymphoid tissue, preventing pathogenic translocation into systemic circulation. Without adequate nutritional stimulation, intestinal villi deteriorate rapidly, compromising nutrient absorption capacity. The liver serves as the metabolic center, regulating lipid and vitamin processing, synthesizing coagulation factors, and performing gluconeogenesis when glycogen stores deplete. Nutritional assessment requires validated screening tools such as the Nutritional Risk Score and NUTRIC score within the first 24 hours of admission, incorporating medical history, physical examination findings, and swallowing capacity evaluation. Older adults above 65 years warrant particular attention due to compounding chronic conditions and medication interactions. Enteral nutrition represents the preferred delivery method for patients with intact gastrointestinal function and should commence within 24 to 48 hours of admission. Small-bore feeding tubes are favored over large-bore options, with postpyloric placement demonstrating advantages in reducing aspiration pneumonia and enhancing nutrient delivery for patients with gastric intolerance. Parenteral nutrition bypasses the digestive system entirely, delivering nutrients intravenously through central or peripheral access, and becomes indicated for patients with obstructions, intractable vomiting, or severe pancreatitis. Caloric requirements typically follow a 25 to 30 kilocalories per kilogram per day calculation, while protein demands escalate from 0.8 grams per kilogram for stable patients to 2.0 grams per kilogram or higher in critically stressed states. Immune-enhancing formulas containing arginine, glutamine, and omega-3 fatty acids benefit specific populations including burn patients and trauma victims. Critical nursing responsibilities encompass monitoring feeding tolerance, preventing refeeding syndrome through gradual nutritional reintroduction in severely malnourished patients, maintaining head-of-bed elevation at 30 to 45 degrees, and avoiding routine gastric residual volume measurement as an aspiration predictor. Laboratory assessment employs prealbumin as a sensitive acute nutritional marker and triglyceride monitoring, particularly in propofol recipients, while albumin's extended half-life limits its utility for acute changes.