Evaluation of calorie intake and nutritional status using indirect calorimetry for surgical patients in critical care unit

BACKGROUND & AIMS: Accurate estimation of energy requirements remains challenging in critically ill patients. This study compared predictive equations for resting energy expenditure (REE) with indirect calorimetry (IC) and explored metabolic characteristics and outcomes associated with IC-guided nutritional assessment. METHODS: This single-center, prospective observational cohort study was conducted in a Surgical Intensive Care Unit. Demographic data, laboratory parameters, and caloric and protein intake were extracted from electronic medical records. Adult patients requiring mechanical ventilation for >24 h and ICU stay ≥7 days were enrolled. In the IC group, REE was measured daily using IC, whereas energy requirements in the control group were estimated using weight-based equations. RESULTS: Eighty-six patients were included (43 in the IC group and 43 in the BW group), with a mean age of 65.2 ± 16.4 years. Measured REE tended to be higher than predicted values. Early caloric delivery was significantly greater in the IC group during the first five ICU days (p < 0.05). Larger discrepancies between measured and predicted REE were observed in patients aged >65 years, those with APACHE II scores >15, and those with m-NUTRIC scores >5. ICU mortality was lower in the IC group, although the difference was not statistically significant. CONCLUSIONS: IC-guided assessment was associated with greater early energy delivery in critically ill surgical ICU patients, although no significant difference in ICU mortality was observed. The clinical role of IC-guided nutritional assessment in this population warrants further investigation.