The Holliday-Segar Formula for Daily Fluid Requirements
The Holliday-Segar formula calculates maintenance fluid requirements in children by determining water needs based on weight alone: 100 ml/kg/day (4 ml/kg/h) for the first 10 kg of body weight, plus 50 ml/kg/day (2 ml/kg/h) for weight between 10-20 kg, plus 25 ml/kg/day (1 ml/kg/h) for each kg above 20 kg. 1, 2
Detailed Breakdown of the Formula
- For children weighing up to 10 kg: 100 ml/kg/day (or 4 ml/kg/hour) 1, 2
- For children weighing 10-20 kg: 1000 ml + 50 ml/kg/day for each kg above 10 kg (or 40 ml/hour + 2 ml/kg/hour for each kg above 10 kg) 1, 2
- For children weighing >20 kg: 1500 ml + 25 ml/kg/day for each kg above 20 kg (or 60 ml/hour + 1 ml/kg/hour for each kg above 20 kg) 1, 2
Clinical Application Example
For a child weighing 30 kg, the calculation would be:
- 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
Historical Context and Modern Relevance
- Developed in 1957, the Holliday-Segar formula was based on the relationship between weight, energy expenditure, and physiologic losses in healthy children 3, 4
- The formula assumes that water requirements parallel energy needs with approximately 1 kcal per 1 ml water 1
- Despite being over 60 years old, this formula is still regarded as appropriate in clinical settings according to current guidelines 1
Important Clinical Considerations
- While the formula provides baseline calculations, fluid requirements may need adjustment based on clinical circumstances 1
- Factors that may increase fluid needs include fever, hyperventilation, hypermetabolism, and gastrointestinal losses 1, 2
- Factors that may decrease fluid needs include renal failure and congestive heart failure 1, 2
- Modern guidelines recommend using isotonic rather than hypotonic fluids for maintenance hydration in sick children, especially during the first 24 hours, to reduce the risk of hospital-acquired hyponatremia 1, 3, 5
Monitoring and Adjustment
- Regular assessment of fluid balance, serum electrolytes, and clinical signs of dehydration or fluid overload is necessary 2
- Failure to adjust maintenance rates in special clinical scenarios can lead to adverse outcomes 2
- In critically ill children, fluid overload (>5% or >10% cumulative fluid balance) is common and associated with increased morbidity and mortality 6
The Holliday-Segar formula remains a fundamental tool for calculating maintenance fluid requirements in pediatric patients, though clinicians should be prepared to adjust fluid therapy based on individual patient needs and clinical circumstances.