What are the guidelines for calculating pediatric maintenance fluid?

Pediatric Maintenance Fluid Calculation Guidelines

The Holliday and Segar formula remains the standard method for calculating pediatric maintenance fluid requirements, providing 100 ml/kg/day for the first 10 kg, 50 ml/kg/day for 10-20 kg, and 25 ml/kg/day for each kg above 20 kg. 1, 2

Basic Calculation Method

• The Holliday and Segar formula calculates maintenance fluid requirements based on weight alone and is still considered appropriate in the clinical setting 1
• For hourly rates, this translates to:
  • 4 ml/kg/hour for the first 10 kg
  • 2 ml/kg/hour for the next 10 kg (10-20 kg)
  • 1 ml/kg/hour for each kg above 20 kg 2

Example Calculation

• For a 30 kg child:
  • First 10 kg: 10 kg × 100 ml/kg/day = 1000 ml/day (or 40 ml/hour)
  • Next 10 kg: 10 kg × 50 ml/kg/day = 500 ml/day (or 20 ml/hour)
  • Remaining 10 kg: 10 kg × 25 ml/kg/day = 250 ml/day (or 10 ml/hour)
  • Total: 1750 ml/day (or 70 ml/hour) 2

Fluid Composition Recommendations

• Isotonic fluids should be used as intravenous maintenance fluid therapy in acutely and critically ill children, especially during the first 24 hours 1, 3
• Glucose provision should be included in sufficient amounts to prevent hypoglycemia but not excessive to avoid hyperglycemia, with monitoring at least daily 1
• Appropriate potassium supplementation should be added based on the child's clinical status and regular potassium monitoring 1
• Chloride intake should be slightly lower than the sum of sodium and potassium intakes to avoid iatrogenic metabolic acidosis 1

Special Clinical Considerations

• For children at risk of increased antidiuretic hormone (ADH) secretion, restrict maintenance fluid volume to 65-80% of the calculated Holliday and Segar formula to avoid fluid overload and hyponatremia 1
• For children with heart failure, renal failure, or hepatic failure, restrict maintenance fluid volume to 50-60% of the calculated volume 1, 4
• The total daily amount of maintenance fluid therapy should include IV fluids, blood products, all IV medications, line flush solutions, and enteral intake 1
• Avoid fluid overload and cumulative positive fluid balance to prevent prolonged mechanical ventilation and increased length of stay 1

Monitoring Recommendations

• Reassess acutely and critically ill children at least daily regarding fluid balance and clinical status 1
• Regularly monitor electrolytes, especially sodium levels 1
• Individual patient needs may deviate markedly from the recommended ranges depending on clinical circumstances such as fluid retention, dehydration, or excessive water losses 1

Common Pitfalls to Avoid

• Using hypotonic fluids as maintenance therapy, which increases the risk of iatrogenic hyponatremia 3, 5
• Failing to adjust maintenance rates in special clinical scenarios (fever, hyperventilation, gastrointestinal losses) 2
• Not considering the total fluid intake from all sources, leading to "fluid creep" 1
• Continuing maintenance rates without reassessment as clinical conditions change 2

By following these guidelines and adjusting for individual patient needs, clinicians can provide appropriate maintenance fluid therapy for pediatric patients while minimizing the risk of complications.