Why is early enteral nutrition recommended in moderate-severe TBI, and when should it begin if feasible?

• A. To reduce edema; begin after 1 week.
• B. To support metabolic needs and repair; begin within 4-6 days.
• C. To prevent hyperglycemia; begin after 72 hours.
• D. To support metabolic needs and repair; begin within 24-48 hours of injury or ICU admission if possible.

Answer: (D)

Early enteral nutrition in moderate-severe TBI is about meeting the body's increased metabolic and repair needs as soon as it’s feasible. After a brain injury, the body enters a hypermetabolic, catabolic state and requires substrates—calories and protein—for healing, immune function, and to preserve gut integrity. Providing nutrition through the gut supports these processes, reduces infection risk, and can improve outcomes. Because the gut is often functional early on, starting nutrition within 24-48 hours of injury or ICU admission (if feasible) maximizes these benefits. Delays, like waiting a week or even several days, miss an important window for metabolic support. While managing blood glucose is important, the primary reason to start early nutrition is to support metabolic needs and repair, not solely to prevent hyperglycemia.