Enteral and Parenteral Nutrition Support
Core concepts
Candidates must know indications for enteral nutrition (functioning gastrointestinal tract but inadequate oral intake), contraindications (bowel obstruction, ischemia, severe shock), and the preference for enteral over parenteral feeding when the gut works. Understand access routes: nasogastric, nasojejunal, gastrostomy, and jejunostomy, plus formula selection by protein, calorie density, fiber, and specialty composition. Know initiation and advancement principles, including trophic feeding and refeeding syndrome risk with electrolyte monitoring (phosphate, potassium, magnesium). For parenteral nutrition, understand central versus peripheral access, dextrose and lipid limits, and complications such as catheter-related infection, hyperglycemia, and hepatic effects.
Traps
Questions often test the gut-use principle and whether enteral feeding is contraindicated. Another trap is failing to identify refeeding syndrome risk in a severely malnourished patient. Watch for items that confuse peripheral with central parenteral nutrition osmolality limits, or that recommend advancing feeds too rapidly. Also beware of questions that assume parenteral nutrition is superior for all malnourished patients.
Worked example
A patient with severe malnutrition before feeding should have electrolytes checked and corrected, with thiamine supplementation and slow caloric advancement. Rule of thumb: if the gut works, use it; start low and advance slowly, and monitor phosphate, potassium, and magnesium closely in high-risk patients.