Paradigm of early parenteral nutrition support in combination with insufficient enteral nutrition

Several observational studies have pointed out the negative effects of an energy deficit in long-staying ICU patients. Morbidity as well as mortality seem to be linked to such an energy deficit, which is often built up during the first week of stay. A combination of enteral and parenteral nutrition may be a strategy to avoid the development of an energy deficit.

A cumulated energy deficit is demonstrated to be connected to an increased infectious morbidity. The question is whether or not addition of parenteral nutrition to the enteral nutrition may prevent such morbidity. So far there is only one prospective randomized blinded clinical trial comparing enteral nutrition only to a combination of enteral and parenteral nutrition. This study was inconclusive for outcome, but demonstrated an effect upon length of hospital stay.

This field of intensive care medicine is clearly lacking prospective randomized trials. The diversity of opinions is broad, ranging from questioning the use of any nonvolutional nutrition to the use of a combination of enteral and parenteral nutrition to obtain full coverage of the energy needed early on during ICU stay. The arguments for the latter view are summarized in this review.