Energy Expenditure Estimation in Pediatric Patients: Clinical Setting-Specific Approach

Direct Answer

Use the Schofield equation for calculating resting energy expenditure (REE) in general pediatric ward patients and outpatients, while critically ill children in the PICU should ideally have measured energy expenditure via indirect calorimetry when feasible, with Schofield as a backup when measurement is unavailable. 1

Pediatric ICU (Critically Ill Children)

Gold Standard Approach

Indirect calorimetry is the preferred method for measuring energy expenditure in critically ill children, particularly those who are mechanically ventilated, have suspected metabolic alterations, or severe malnutrition. 1
Measured REE in mechanically ventilated pediatric ICU patients shows they are hypermetabolic, with actual energy expenditure averaging 1.48 times predicted basal energy expenditure. 2
Standard predictive equations (including Schofield, WHO, and others) frequently result in significant errors in the PICU setting, leading to unintended underfeeding (34.3% of measurements) or overfeeding (53.3% of measurements). 3

When Indirect Calorimetry is Not Available

Use the Schofield equation as the backup method for calculating REE in the acute and stable phases of critical illness. 1
In the acute phase, provide 60-85 kcal/kg/day depending on age (lower end for older children, higher for infants), which represents approximately REE without additional activity factors. 1
In the stable phase, multiply REE by approximately 1.3 to enable growth and catch-up growth. 1
Critical pitfall: Applying adult injury factors (1.35-1.62) overestimates pediatric needs; the injury factor for pediatric multiple trauma should be 1.25, not 1.35. 2

Specific PICU Energy Requirements by Phase

Acute phase: 60-85 kcal/kg/day for ages 0-1 year; 55-75 kcal/kg/day for ages 1-7 years; 40-65 kcal/kg/day for ages 7-12 years; 25-55 kcal/kg/day for ages 12-18 years. 1
Stable phase: Similar ranges as acute phase, representing REE with minimal activity (PAL ~1.0-1.2). 1
Recovery phase: 40-50 kcal/kg/day for ages 0-1 year; 40-45 kcal/kg/day for ages 1-7 years; 30-40 kcal/kg/day for ages 7-12 years; 20-30 kcal/kg/day for ages 12-18 years. 1

Important PICU Considerations

Measured energy expenditure remains stable over the first 7 days of PICU admission and does not change significantly over time, making a single indirect calorimetry measurement reasonably representative. 4
Overfeeding in the PICU is associated with significantly longer PICU length of stay (median 45.5 days vs 16.5 days for underfed patients), suggesting conservative energy provision may be beneficial. 3
Withholding parenteral nutrition for 1 week in critically ill children while providing micronutrients can be considered as an acceptable strategy. 1

General Pediatric Ward

Primary Method

Use the Schofield equation to calculate REE, then add appropriate factors for physical activity and growth needs. 1
The Schofield equation using weight and height is least likely to underestimate REE compared to measured values and is therefore the preferred calculation method. 1

Schofield Equations by Age and Sex

Ages 0-3 years: Boys: 59.5 × (weight in kg) + 30 kcal/day; Girls: 58.3 × (weight in kg) + 31 kcal/day. 1, 5
Ages 3-10 years: Boys: 22.7 × (weight in kg) + 504 kcal/day; Girls: 20.3 × (weight in kg) + 486 kcal/day. 1, 6
Ages 10-18 years: Boys: 17.7 × (weight in kg) + 658 kcal/day; Girls: 13.4 × (weight in kg) + 692 kcal/day. 1, 6

Adding Activity and Growth Factors

Multiply calculated REE by physical activity level (PAL): hospitalized/bed rest = 1.2-1.3; light activity = 1.5; moderate activity = 1.7; vigorous activity = 2.0. 1, 6
Add energy for growth: 20 kcal/day for ages 6-12 months and prepubertal children; 30 kcal/day during peak pubertal growth velocity. 1, 6
For catch-up growth in malnourished children, calculate energy requirements based on ideal weight for height age (not chronological age) plus additional allowance for accelerated growth. 5, 7

When to Escalate to Indirect Calorimetry

Consider measuring REE via indirect calorimetry in ward patients with moderate to severe failure to thrive, suspected metabolic problems, or when initial weight management approaches have been unsuccessful. 1, 6

Pediatric Outpatient Department

Standard Approach

Use the Schofield equation as the primary method for calculating REE in outpatient settings. 1
This is the most practical approach for routine outpatient nutritional assessment and counseling. 6, 5

Total Energy Expenditure Calculation

Calculate TEE = REE × PAL + growth energy needs. 1, 6
For healthy outpatients, use PAL of 1.5 (light activity) to 1.7 (moderate activity) depending on the child's typical activity level. 1, 6

Special Outpatient Populations

Pediatric Obesity Management

Calculate REE using Schofield equation with actual body weight (not ideal body weight), as body weight is the main predictor of energy expenditure. 6, 8
Create a 500-750 kcal/day deficit from calculated maintenance needs (TEE), ensuring intake never falls below 900 kcal/day minimum under medical supervision. 6
Critical consideration: Use actual weight in the Schofield equation for obese children, as the equations were developed using actual weight. 6

Chronic Malnutrition/Catch-Up Growth

Use Schofield equation to calculate baseline REE, then adjust for catch-up growth needs. 5, 7
Start with 45-55 kcal/kg/day in the acute refeeding phase to prevent refeeding syndrome, then advance to 60-85 kcal/kg/day in the stable/recovery phase depending on age. 5
Provide protein at 1.5-2.0 g/kg/day (140-190% of standard requirements) for catch-up growth in children ages 1-3 years. 7

Why NOT to Use WHO or PDRI Equations as Primary Methods

WHO/FAO/UNU Equations

The 2018 ESPGHAN/ESPEN guidelines explicitly moved away from the 1985 FAO/WHO/UNU recommendations to the 2004 recommendations, which resulted in substantially lower energy recommendations. 1
The Schofield equation is specifically recommended over WHO equations because it was least likely to underestimate REE compared to measured values. 1
WHO equations are mentioned as historical context but are not the preferred method in current pediatric practice. 1

PDRI (Pediatric Dietary Reference Intake)

PDRI values represent population-level recommendations for healthy children and are useful for public health guidance, not individualized clinical estimation. 7
For clinical purposes requiring individualized energy expenditure estimation, the Schofield equation provides a more accurate patient-specific calculation. 1
PDRI may be referenced for establishing baseline protein requirements (e.g., 1.05 g/kg/day for ages 1-3 years), but energy needs should be calculated using Schofield. 7

Common Pitfalls to Avoid

Never apply adult injury factors to pediatric patients: The injury factor for pediatric multiple trauma is 1.25, not the adult value of 1.35-1.62. 2
Avoid using predictive equations alone in critically ill children: Standard equations fail to predict energy expenditure within clinically accepted ranges in PICU patients, leading to 60% underfeeding and 28% overfeeding. 3, 8
Do not use ideal body weight in Schofield equations for obese children: Always use actual body weight, as this is how the equations were validated. 6, 8
Recognize that standard equations are unreliable but may be necessary: While all predictive equations (including Schofield) have limitations, Schofield performs better than alternatives when indirect calorimetry is unavailable. 8, 9
Avoid overfeeding in the PICU: Conservative energy provision (even slight underfeeding) is associated with shorter mechanical ventilation days and PICU length of stay compared to overfeeding. 3

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