A Risk-Stratified, Volume-Based Plus Enteral Nutrition Protocol with Semi-Elemental Formula in Critically Ill Surgical Patients: A Before-and-After Implementation Study

Background and Objectives: Critically ill surgical patients frequently fail to achieve prescribed enteral nutrition targets because of feeding interruptions and variability in conventional physician-directed feeding practices. Although volume-based feeding (VBF) has been proposed to improve nutritional delivery, concerns remain regarding refeeding syndrome and gastrointestinal intolerance. The aim of this study was to evaluate whether a Volume-Based Plus (VBF+) protocol integrating volume-targeted feeding with mandatory refeeding risk stratification and a standardized semi-elemental enteral formula improves nutritional delivery without increasing gastrointestinal or metabolic complications. Materials and Methods: We conducted an ambispective before-and-after implementation study (retrospective control phase, prospective intervention phase) in the surgical intensive care unit of a tertiary care center between January 2023 and March 2026. Ninety-six patients requiring enteral nutrition for ≥3 days were enrolled (48 control and 48 intervention). Both groups underwent the same refeeding risk stratification to guide feeding strategy, while the intervention group additionally received the standardized VBF+ protocol with risk-stratified caloric advancement and volume-based compensation for feeding interruptions, and a standardized semi-elemental enteral formula. The primary outcomes were median daily caloric delivery (% of target) and mean daily protein delivery (g/kg/day). Multivariable regression analyses adjusted for Nutritional Assessment Form (NAF), APACHE II score, and Charlson Comorbidity Index (CCI) were performed. Results: The VBF+ protocol was independently associated with higher caloric delivery (β = 31.2 percentage points, 95% CI 17.6 to 44.8; p < 0.001) and higher protein delivery (β = 0.168 g/kg/day, 95% CI 0.040–0.297; p = 0.011). Longitudinal analysis showed a significantly faster increase in protein delivery in the intervention group (p < 0.001), while the group-by-time interaction for caloric delivery did not reach statistical significance (p = 0.073). Rates of gastrointestinal intolerance and metabolic complications were comparable between groups; as VBF+ bundled the compensatory algorithm with a semi-elemental formula, this gastrointestinal benefit is hypothesis-generating. Conclusions: In this before-and-after study, the VBF+ bundle protocol was associated with improved caloric and protein delivery and reduced gastrointestinal intolerance; because the algorithm and formula were not evaluated independently, the gastrointestinal benefit remains hypothesis-generating and requires confirmation in randomized trials.