Schofield Equation vs WHO for Energy Requirements in Pediatric Critical Care
The Schofield equation is recommended over WHO equations for calculating energy requirements in critically ill pediatric patients, as it is least likely to underestimate resting energy expenditure (REE) compared to measured values. 1, 2
Primary Guideline Evidence Supporting Schofield
The 2018 ESPGHAN/ESPEN/ESPR/CSPEN guidelines explicitly state that "The Schofield-equation using weight and height to calculate REE was least likely to underestimate REE compared to measured REE and is therefore preferred" over WHO recommendations. 1 This represents a deliberate shift from the 2005 guidelines, which had relied on 1985 FAO/WHO/UNU recommendations, to the current preference for Schofield equations. 1
Multiple international pediatric critical care societies now formally recommend the Schofield equation as the preferred estimation method when indirect calorimetry is unavailable. 1, 2
Supporting Research Evidence
A 2018 systematic review analyzing 22 studies with 2,326 indirect calorimetry measurements in 1,102 critically ill children found that the Schofield equations predicted REE within ±15% of measured energy expenditure in approximately 50% of observations—the best performance among tested equations. 3 The Harris-Benedict equation, by contrast, overestimated REE in two-thirds of patients. 3
A 2012 prospective study of 369 measurements in ventilated critically ill children concluded that "the Schofield equation seemed to have the lowest SD" and "performed better than other predictive methods in predicting energy expenditure." 4
Critical Caveats and Limitations
All predictive equations, including Schofield, remain significantly inaccurate at the individual patient level, with large standard deviations of bias (±200-300 kcal/day). 3, 5, 4 A 2016 study of 236 hospitalized children found that while WHO, Schofield, and Oxford formulae gave accurate estimates at the population level (small mean bias), none were accurate enough for individual clinical use due to large variability. 5
Indirect calorimetry remains the gold standard when feasible, particularly for mechanically ventilated children, those with suspected metabolic alterations, or severe malnutrition. 1, 2 The 2020 ESPNIC guidelines explicitly recommend measuring REE using validated indirect calorimetry to guide nutritional support after the acute phase. 1
Practical Application in Critical Care
For the acute phase of critical illness, provide 60-85 kcal/kg/day depending on age (approximately REE without additional activity factors). 1, 2 In the stable phase, multiply calculated REE by approximately 1.3 to enable growth and catch-up growth. 1, 2
Use the Schofield equation with actual body weight and height, as weight is the main predictor of energy expenditure. 1, 6 The age- and sex-specific equations are: for ages 0-3 years: 59.5 × (weight in kg) + 30 kcal/day for boys and 58.3 × (weight in kg) + 31 kcal/day for girls; for ages 3-10 years: 22.7 × (weight in kg) + 504 for boys and 20.3 × (weight in kg) + 486 for girls; for ages 10-18 years: 17.7 × (weight in kg) + 658 for boys and 13.4 × (weight in kg) + 692 for girls. 1, 2, 6
Common Pitfalls to Avoid
Do not add stress factors to the Schofield equation in critically ill children, as this leads to overfeeding. 1 Multiple studies demonstrate that most predictive equations with added stress factors cause unintended overfeeding. 1
Do not use Harris-Benedict equations or RDAs (Dietary Reference Intakes) in critically ill children, as these are inappropriate for this population. 1
A 2003 study demonstrated that critically ill children are not hypermetabolic as traditionally assumed, with measured REE significantly lower than Schofield predictions (37.2 vs 42.7 kcal/kg/day). 7 This supports conservative energy provision during acute illness.