Combination enteral and parenteral nutrition in critically ill patients: harmful or beneficial? A systematic review of the evidence

Objective. A combination of enteral (EN) and parenteral nutrition (PN) is often used as a strategy to optimize nutritional intake in critically ill patients; however, the effects of this intervention on clinically important outcomes have not been widely studied. This paper systematically reviewed studies that compare EN + PN to enteral nutrition (EN) alone in critically ill patients. Methods. We searched bibliographic databases, personal files, and relevant reference lists to identify randomized controlled trials that compared combination EN + PN to EN alone. Results. Only five studies met the inclusion criteria. In all these studies PN was started at the same time as EN in the experimental group. When the results of these trials were aggregated, EN + PN had no significant effect on mortality. There was no difference between the two groups in rates of infectious complications, length of hospital stay, or ventilator days. Conclusions. In critically ill patients who are not malnourished and have an intact gastrointestinal tract, starting PN at the same time as EN provides no benefit in clinical outcomes over EN alone. More research is needed to determine the effects of combination EN + PN on clinical outcomes in critically ill patients who are poorly intolerant to EN.