Energy expenditure in critically ill children

Area of Science:

• Pediatric critical care medicine
• Clinical nutrition
• Metabolic research

Background:

• Accurate assessment of energy expenditure is crucial for critically ill children.
• Existing formulas for predicting energy needs may not be reliable in this population.
• Protein-energy malnutrition is a concern in critically ill pediatric patients.

Purpose of the Study:

• To measure energy expenditure in critically ill children using indirect calorimetry.
• To compare measured energy expenditure (MEE) with predicted values from standard formulas.
• To correlate MEE with nutritional status and clinical severity.

Main Methods:

• Prospective clinical study in a pediatric intensive care unit.
• Indirect calorimetry to measure oxygen consumption and carbon dioxide production.
• Calculation of measured energy expenditure (MEE) using the modified Weir formula.
• Assessment of nutritional status (e.g., chronic and acute protein-energy malnutrition) and illness severity (e.g., Pediatric Risk of Mortality Score).

Main Results:

• MEE was significantly lower than predicted energy expenditure and recommended daily allowances in most patients.
• MEE was lower in patients with multiple organ system failure.
• Protein intake, nutritional markers (midarm muscle/fat area), vasoactive agent use, and sedation correlated with MEE.
• Depletion of protein stores was associated with higher incidence of multiple organ system failure, and fat stores depletion with increased mortality.

Conclusions:

• Standard formulas and stress-related corrections overestimate energy expenditure in critically ill children.
• Measured energy expenditure (MEE) is often close to or lower than resting energy expenditure (PBMR).
• Lower MEE is associated with increased morbidity, highlighting the need for individualized nutritional support based on MEE to avoid over- or underfeeding.