If the enteral nutrition (EN) trial fails during HEG management, when is parenteral nutrition considered?

• A. No PN ever used
• B. Begin PN only after 72 hours of EN trial
• C. Begin PN if EN trial fails due to nausea/vomiting/diarrhea and residuals within 24-48 hours
• D. Start PN before any EN trial

Answer: (C)

When EN cannot meet the patient's nutritional needs because of intolerance, you escalate to parenteral nutrition promptly. If within about 24 to 48 hours the EN trial fails due to ongoing nausea, vomiting, diarrhea, or high residuals that prevent achieving energy/protein goals, PN should be started to ensure adequate nutrition and support both maternal and fetal health. EN is preferred first because it preserves gut function and carries fewer risks, but intolerance within a short window necessitates PN.

Why not wait longer or start PN before trying EN? Waiting beyond 48 hours risks malnutrition, and starting PN before attempting EN misses the benefits of enteral feeding and increases invasiveness and infection risk. The other options either ignore the need to escalate after EN intolerance or rely on PN too early.