Monitoring enteral nutrition efficacy in ICU patients: is there a place for the Brix value-derived fraction of enteral formula in gastric residual volume?

Achieving nutritional targets by means of enteral nutrition in critically ill (ICU) patients has been shown to be difficult and unpredictable. In this regard, the amount of enteral formula lost in gastric residual volume (GRV) remains unknown. In previous studies performed in a non-ICU population, bedside monitoring of the specific gravity (or relative density) of GRV with a refractometer (expressed as Brix value) has been shown to be an accurate tool to measure the concentration of enteral nutrition (% EF) in GRV [1,2]. The aim of this study is to evaluate the use of the Brix value in monitoring the concentration of enteral feeding in GRV of patients in the ICU.