Nutrition Support, Enteral and Parenteral Therapy
What this domain tests
This domain tests indications, routes, initiation, monitoring, and complications of enteral and parenteral nutrition, including refeeding syndrome.
Core rules
- Use the gut when it works. Enteral nutrition is preferred over parenteral nutrition because it maintains mucosal integrity and costs less.
- Short-term enteral access is usually a nasogastric tube; long-term access may be a gastrostomy. Confirm tube position before feeding.
- Head-of-bed elevation of 30–45 degrees reduces aspiration. Check gastric residual volume according to unit protocol rather than stopping feeding for every high residual.
- Parenteral nutrition is indicated when enteral nutrition is contraindicated or cannot meet needs. Central access is needed for hyperosmolar formulas.
- Refeeding risk: BMI under 16, unintentional loss over 15% in three to six months, little or no intake over 10 days, low potassium, magnesium, or phosphate. Start at 10–20 kcal/kg, give thiamine before feeding, and monitor electrolytes daily.
- Lipid infusion should not exceed about 2 g/kg/day in adults. Monitor triglycerides in hypertriglyceridemia.
Worked example
A 45-year-old postoperative patient has BMI 17, a 12% weight loss, and three weeks of poor intake. Refeeding risk is high. Obtain phosphate, potassium, and magnesium; give thiamine; start enteral feeding at 10–20 kcal/kg/day and advance over several days. Correct electrolytes before and during advancement. Do not start at goal rate.
Traps
Stopping enteral nutrition for a single high gastric residual without assessment; starting parenteral nutrition at goal rate; forgetting thiamine; missing hypophosphatemia; using parenteral nutrition when the gut is functional; ignoring catheter-related bloodstream infection prevention.