Indications, Contraindications, and Access for Nutrition Support
When to use nutrition support
Enteral nutrition (EN) is preferred whenever the gut works and the patient cannot meet needs orally. Indications include inadequate oral intake for 7-10 days, inability to swallow safely, major burns or trauma, and critical illness with contraindication to oral intake. Parenteral nutrition (PN) is indicated when EN is contraindicated or insufficient: short bowel, high-output fistula, severe malabsorption, prolonged ileus, or bowel obstruction not amenable to feeding tube. A common trap is choosing PN when EN is feasible - questions reward the "if the gut works, use it" principle.
Contraindications
EN contraindications: mechanical obstruction, severe ischemia, uncontrolled shock, active GI bleeding, high-output fistula distal to the tube. PN contraindications: functioning gut with adequate access, inability to obtain safe vascular access, and situations where short-term PN offers no benefit (e.g., brief uncomplicated ileus).
Access selection
Gastric feeding is preferred when aspiration risk is low and gastric emptying is intact. Post-pyloric (duodenal/jejunal) feeding suits gastroparesis, severe reflux, pancreatitis, and high aspiration risk. For short-term (<4 weeks), nasoenteric tubes are typical; for longer-term, consider PEG/PEJ. For PN, peripheral access is limited by osmolality (generally ≤900 mOsm/L) and duration; central access (PICC, tunneled catheter) is used for longer-term or concentrated formulas.
Worked rule of thumb
Ask: Can the gut be used safely? If yes, EN. If no or insufficient, PN. Then choose access based on duration and aspiration risk.