Intermittent versus continuous feeding in critically ill adults

Purpose of review Early enteral nutrition is recommended in critically ill adult patients. The optimal method of administering enteral nutrition remains unknown. Continuous enteral nutrition administration in critically ill patients remains the most common practice worldwide; however, its practice has recently been called into question in favor of intermittent enteral nutrition administration, where volume is infused multiple times per day. This review will outline the key differences between continuous and intermittent enteral nutrition, describe the metabolic responses to continuous and intermittent enteral nutrition administration and outline recent studies comparing continuous with intermittent enteral nutrition administration on outcomes in critically ill adults. Recent findings In separate studies, healthy humans and critically ill patients receiving intermittent nutrition (infused over 3h) had improved whole body protein balance from negative to positive. These studies did not have an isonitrogenous control group. A randomized controlled trial of intermittent bolus versus continuous enteral nutrition in healthy humans found that intermittent bolus feeding increased mesenteric arterial blood flow, increased insulin and peptide YY and reduced blood glucose concentration. A randomized controlled trial comparing intermittent bolus to continuous enteral nutrition in critically ill patients did not demonstrate clinically relevant differences in glycemic variability, insulin use or tube feeding volume or caloric intake between the two groups. Summary Studies in healthy humans suggest that intermittent nutrient administration, as opposed to continuous, improves whole body protein synthesis. Unfortunately, similarly designed studies are lacking for critically ill patients. Future studies evaluating the impact of intermittent versus continuous nutrition administration on critical care outcomes should take into account factors such as protein quantity, protein quality and delivery route (enteral and/or parenteral). Until further studies are conducted in critically ill patients, a recommendation for or against intermittent nutrition delivery cannot be made.