Measured resting energy expenditure and predicted resting energy expenditure based on ASPEN critical care guidelines for nutrition support: An agreement study.

Background: Predictive equations often inaccurately estimate energy needs in critically ill patients. This study evaluated the level of agreement between resting energy expenditure using 12 and 25 kcal/kg as recommended by the 2021 American Society for Parenteral and Enteral Nutrition critical care guidelines for nutrition support and energy expenditure measured by indirect calorimetry in patients in the intensive care unit.

Methods: An agreement study was conducted on mechanically ventilated adults who had a documented measured energy expenditure within 10 days of intensive care unit admission. Agreement was assessed using Bland-Altman plots and Wilcoxon signed rank tests. A subgroup analysis was performed for patients with a body mass index of ≥30 kg/m² using actual body weight, adjusted body weight, and ideal body weight. Correlations between measured energy expenditure and patient characteristics were also explored.

Results: Fifty-eight patients were included and were a median age of 64 years, 63.8% male, and a median body mass index of 28.0 kg/m. The 12 kcal/kg and 25 kcal/kg differed significantly from measured energy expenditure (P < 0.001). Bland-Altman plots showed mean biases of -644.6 kcal/day for 12 kcal/kg and 406.5 kcal/day for 25 kcal/kg. In the body mass index ≥30 kg/m² subgroup (n = 22), 12 kcal/kg underestimated measured energy expenditure across all weights, and 25 kcal/kg was more accurate when using ideal or adjusted body weights.

Conclusions: Predicted energy expenditure using 12 kcal/kg and 25 kcal/kg based on the 2021 American Society for Parenteral and Enteral Nutrition critical care guidelines for nutrition support had poor agreement with measured energy expenditure in mechanically ventilated patients.