P397 - ENERGY REQUIREMENTS AND NUTRITIONAL STATUS OF CRITICALLY ILL PATIENTS - AN INDIVIDUALIZED APPROACH

P397

ENERGY REQUIREMENTS AND NUTRITIONAL STATUS OF CRITICALLY ILL PATIENTS - AN INDIVIDUALIZED APPROACH

B. Þ. Jónasson^1,*, Á. R. Ingadottir², K. Sigvaldason³

¹Faculty of Food Science and NutritionFaculty of Food Science and Nutrition, ²Faculty of Food Science and Nutrition, university of iceland, ³Intensive Care Unit in Fossvogur, Landspitali - University Hospital, Reykjavík, Iceland

Rationale: The role of nutrition in critical care is gaining attention, as it has been shown to have a considerable impact on clinical outcomes. This study aimed to describe the progression of measured resting energy expenditure (REE) compared with commonly used predictive equations. Secondly, to examine the nutritional status of critically ill patients.

Methods: This pilot prospective observational study included 16 mechanically ventilated ICU patients at Landspítali. Indirect calorimetry (IC) was conducted every 2–3 days until ICU discharge. Measured resting energy expenditure (REE) was compared to estimates from the Harris-Benedict equation (HBE-REE) and 25 kcal/kg/day (25-REE) using the Wilcoxon signed-rank test and mean absolute percentage error (MAPE), with results illustrated in multiple-line graphs. Body composition and phase angle (PhA) were assessed via bioelectrical impedance analysis (BIA). Nutritional risk and malnutrition were evaluated using a validated screening tool and the GLIM criteria.

Results: Among 16 patients, 54 IC measurements were performed. Median HBE-REE significantly underestimated REE by 267 kcal (86%, p<0.001), while 25-REE significantly overestimated it by 206 kcal (111%, p=0.02). MAPE was 26.1% for HBE-REE (range: 5.0–34.3%) and 28.0% for 25-REE (range: 6.1–47.7%). REE varied widely between individuals, with no clear trends based on gender or BMI. According to GLIM criteria, 50% were malnourished, including three classified as severely malnourished.

Conclusion: Energy expenditure (EE) varied rapidly and unpredictably, supporting repeated IC measurements to guide nutrition support in critically ill patients. Predictive equations failed to reflect individual REE changes, risking under- or overfeeding. Further research is needed to explore REE patterns in specific patient groups and the impact of IC-guided nutritional support on critically ill patient outcomes.

Disclosure of Interest: None declared