Effects of normocaloric vs. hypocaloric enteral nutrition on whole-body protein turnover in critically ill patients

Enteral nutrition (EN) is a ubiquitous intervention in ICU patients but there is uncertainty regarding the optimal dose, timing and importance for patient-centered outcomes during critical illness. Our research group has previously found an improved protein balance during normocaloric versus hypocaloric parenteral nutrition in neurosurgical ICU patients. We now wanted to investigate if this could be demonstrated in a general ICU population with established enteral feeding, including patients on renal replacement therapy. Patients with EN >80% of energy target as determined by indirect calorimetry were randomized to or 50% or 100% of current EN rate. After 24 hours, whole body protein kinetics were determined by enteral and parenteral stable isotope tracer infusions. Treatment allocation was then switched, and tracer investigations repeated 24 hours later in a crossover design with patients serving as their own controls. The files give all data for calculating whole body protein kinetics and the amino acids and urea concentrations at the end of the two 24h intervention periods (day 1 and day 2). The file "Tracer infusions" gives the details of the preparation of the tracers infused during the two days, including the volumes taken up in the syringes, the dilutions and the final weight of the syringes. All this information is used to calculate the exact rates of infusion in micromol per kg bodyweight per hour. The file "Enrichments" includes the amount of the tracers (given as Molar Percent Excess) in the blood samples and in the dialysis samples as measured at the different time points during the 5 hours infusion of the tracers. The last 4 samples over the last 15 minutes of the two 24h periods are averaged and used for the calculations of the whole body protein turnover as specified in the publication. The file "Amino acids and Urea" gives the concentrations of all amino acids in plasma and in the dialysate (if appropriate) and of urea in plasma at the end of the two 24h intervention periods (last sample only).