Early Enteral Nutrition

By Lisa Moloney MS, RD, LDN

“If the gut works, use it”, a phrase all dietitians are familiar with by the end of their first medical nutrition therapy course.  This is evidence based practice confirmed by The American Society for Parenteral and Enteral Nutrion (ASPEN) and the Society for Critical Care Medicine (SCCM), 2009 standards stating that enteral nutrition (EN) should be used before parenteral nutrition (PN) to the greatest extent possible.

Greater emphasis is being placed not only on initiation of enteral nutrition but early initiation, as stated in a recent article, Early Enteral Nutrition in the Intensive Care Unit written by Elizabeth Pash Penniman, published in the December issue of Support Line.  The ASPEN and SCCM guidelines recommend starting EN within the first 24-48 hours following intensive care unit (ICU) admission and after fluid resuscitation.  Early enteral nutrition is especially important for ventilator dependant patients.  Penniman states that without adequate nutrition, respiratory breathing muscles may be catabolized and therefore lengthen time spent on the ventilator.  Nutrition support helps maintain normal pulmonary function to prepare the body for weaning from the ventilator.  Research suggests that initiation of EN within 3 days of ICU admission in mechanically ventilated patients reduces the duration of ventilator dependence.

Enteral nutrition is essential to maintain gut integrity.  Maintaining gut integrity may help prevent bacterial translocation through the epithelial mucosa to the portal and lymphatic circulations.  Bacterial translocation is associated with increased rates of infection and clinical complications which can lengthen time on mechanical ventilation.  Per Penniman, one study found that GI tract abnormalities can be found as early as 4 days without nutrition.  Early enteral nutrition preserves gut integrity thus decreasing bacterial translocation, and potentially decreasing rates of infection.

Shock is the body’s response to serious injury or trauma.  Within 24-48 hrs after shock, the hypermetabolic  flow phase begins.  Stored protein, lipid and carbohydrate are catabolized to maintain organ function.  Injured tissues increased need for energy ultimately results in breakdown of lean body mass.  Enteral nutrition is recommended early in the hypermetabolic flow phase, which peaks at 3 days post injury, to help preserve lean body mass.

Early enteral nutrition can decrease time on mechanical ventilators, preserve lean muscle mass and decrease ICU length of stay.  As dietitians, we have an opportunity to make a huge impact on clinical outcomes by initiating early enteral nutrition in appropriate ICU patients.