What percentage of body weight loss triggers initiation of parenteral nutrition when EN fails in HEG management?

• A. Greater than 10%
• B. Any weight loss triggers PN
• C. Greater than 2%
• D. Greater than 5%

Answer: (D)

In this scenario, the trigger to start parenteral nutrition when enteral nutrition cannot meet the patient's needs is tied to a measurable weight loss that signals a clinically meaningful energy deficit. A threshold of greater than 5% body weight loss is used because it reflects a balance point where the catabolic state becomes significant enough to risk adverse maternal and fetal outcomes if nutrition is still delivered solely by the failing enteral route. Initiating PN at this point helps ensure adequate nutrient delivery when EN cannot maintain target energy and protein intake.

Choosing a higher threshold like greater than 10% would delay PN until more severe decline, increasing risk, while requiring PN for any weight loss would be overly aggressive and expose patients to PN-related risks too early. A threshold of greater than 2% is also too low, likely prompting PN too frequently. Therefore, the 5% weight loss cutoff best fits the goal of timely, appropriate escalation in nutrition support.