What are the recommended daily calorie and protein requirements for Pediatric Intensive Care Unit (PICU) patients?

Calorie and Protein Requirements for PICU Patients

For critically ill children in the PICU, provide a minimum of 57 kcal/kg/day and 1.5 g protein/kg/day during the acute phase, with energy intake not exceeding resting energy expenditure (REE) in the first 72-96 hours, then increasing to 1.4-1.5 times measured REE after the acute phase to achieve positive protein balance and prevent cumulative energy deficits. 1

Acute Phase (First 72-96 Hours)

Energy Requirements:

• Do not exceed resting energy expenditure during the acute phase to avoid overfeeding complications 1
• Target approximately 20 kcal/kg/day initially 2
• Use indirect calorimetry when available to measure REE accurately, as predictive equations frequently overestimate requirements 1
• If indirect calorimetry is unavailable, use the Schofield equation (for age and gender using accurate weight) without stress factors to estimate REE 1

Protein Requirements:

• Minimum 1.5 g/kg/day to avoid negative protein balance 1
• The 2020 ESPNIC guidelines explicitly state there is insufficient evidence to recommend protein intake higher than 1.5 g/kg/day during the acute phase for improved clinical outcomes, despite this preventing cumulative negative protein balance 1
• This represents a key divergence from some practices, as higher protein intake has not been shown to benefit mortality or morbidity during acute critical illness 1

Post-Acute/Recovery Phase (After Day 3-7)

Energy Requirements:

• Increase to 1.4-1.5 times measured REE after the acute phase 1
• Target delivery of at least two-thirds of prescribed daily energy requirement by the end of the first week in PICU 1
• Account for energy debt, physical activity, rehabilitation, and growth during recovery 1
• Cumulative energy deficits during the first week are associated with poor clinical and nutritional outcomes 1

Protein Requirements:

• Continue minimum 1.5 g/kg/day for enteral nutrition 1
• Higher protein intake may be needed during recovery to support anabolic reconstitution and prevent muscle wasting 2
• In mechanically ventilated children, higher protein delivery has been associated with lower 60-day mortality in observational studies 1

Special Population: Traumatic Brain Injury

• Critical consideration: Every 10 kcal/kg decrease in caloric intake is associated with a 30-40% increase in mortality rates in pediatric TBI patients 1
• Early initiation and achieving full caloric intake are positively correlated with shorter ICU length of stay 1
• Begin enteral nutrition within 72 hours with full replacement by 7 days 1
• Follow adult TBI guidelines adjusted for weight when pediatric-specific data are unavailable 1

Practical Implementation Algorithm

Step 1: Measure or Estimate Energy Needs

• First choice: Indirect calorimetry to measure REE 1
• Second choice: Schofield equation without stress factors 1
• Avoid: Harris-Benedict equations and RDAs, which are inaccurate in critical illness 1

Step 2: Initiate Early Enteral Nutrition

• Start within 24 hours of admission unless contraindicated 1
• Increase in stepwise fashion using a feeding protocol 1
• Enteral nutrition is preferred over parenteral nutrition 1

Step 3: Target Delivery

• Acute phase (Days 1-3): Energy ≤ REE, protein ≥ 1.5 g/kg/day 1
• Recovery phase (Days 4-7): Energy 1.4-1.5 × REE, protein ≥ 1.5 g/kg/day 1
• Achieve at least 67% of prescribed energy by end of week 1 1

Step 4: Monitor and Adjust

• Perform anthropometric measurements at admission and regularly during stay 1
• Express measurements as z-scores for standardized comparison 1
• Reassess energy expenditure after acute phase using indirect calorimetry 1

Common Pitfalls to Avoid

Overfeeding in Acute Phase:

• Providing energy above REE during the first 72-96 hours increases complications without improving outcomes 1, 2
• Predictive equations often overestimate requirements by 600+ kcal/day, leading to inadvertent overfeeding 3

Excessive Protein During Acute Illness:

• Despite preventing negative protein balance, protein >1.5 g/kg/day during acute phase has not demonstrated improved clinical outcomes (mortality, morbidity, quality of life) 1
• The exact threshold may overestimate requirements during acute critical illness 1

Underfeeding Due to Interruptions:

• Feeding interruptions are common (64% of patients) and result in significant energy and protein deficits 4
• Use feeding protocols to minimize avoidable interruptions 1
• Consider supplemental parenteral nutrition if <67% of enteral target achieved after 2 days 2

Inadequate Protein Delivery:

• Actual protein intake often reaches only 49% of estimated requirement due to prescription gaps and interruptions 4
• Commercial formulas may have inadequate protein-to-energy ratios; consider protein-enriched formulations 1

Relying on Weight Alone:

• Weight measurements may be misleading in fluid-overloaded critically ill children 5
• Use mid-upper arm circumference and triceps skinfold thickness for more accurate assessment 5