P407 - CHALLENGE IN ESTIMATING ENERGY EXPENDITURE IN CRITICALLY ILL PATIENTS: WHEN THE WEIGHT-BASED FORMULA FAILS

P407

CHALLENGE IN ESTIMATING ENERGY EXPENDITURE IN CRITICALLY ILL PATIENTS: WHEN THE WEIGHT-BASED FORMULA FAILS

V. M. Ludtke^1,*, H. Falcão², G. Gouveia³, N. G. Gallagher e Silva¹, C. D'Ávila⁴, T. D. L. Nery⁵

¹Nutrição, Hospital Americas, ²Hospital Central da Policia Militar, ³Terapia Intensiva, Instituto Nacional do Cancer, ⁴Terapia Intensiva, Universidade Federal do Rio de Janeiro - Hospital Universitário Clementino Fraga Filho, ⁵EMTN, Hospital Américas, Rio de Janeiro, Brazil

Rationale: Adequate caloric prescription in critically ill patients is associated with fewer complications, shorter duration of mechanical ventilation, and reduced mortality. Indirect calorimetry (IC) is the gold standard for determining energy expenditure, but its availability is limited in many hospitals. As an alternative, the weight-based formula is widely used in clinical practice, although its accuracy across different BMI categories remains under debate. This study evaluated the precision of this formula compared to IC on the third day of ICU stay, testing two hypotheses: (1) patients with BMI >30 have underestimated requirements; (2) overweight patients show greater variability in estimates.

Methods: Observational and retrospective study including 43 critically ill patients. Caloric requirements were estimated based on BMI category and compared to IC measurements. Paired t-tests and Pearson correlations were applied for the BMI groups ≤25, 25–30, and >30 kg/m².

Results: Obese patients had their caloric needs significantly underestimated. In the other groups, overestimations were not statistically significant but showed high individual variability.  BMI ≤25 (n=11): mean overestimation of +24.6%; p=0.13; r=0.33; BMI 25–30 (n=21): mean overestimation of +23.8%; p=0.20; r=0.40 and BMI >30 (n=11): mean underestimation of –39.3%; p<0.001; r=–0.04

Conclusion: The weight-based formula showed limited accuracy, especially in obese patients. In overweight individuals, the absence of specific guidelines may impair the precision of caloric prescription. IC remains essential to individualize nutritional therapy, particularly at BMI extremes.

Disclosure of Interest: None declared