What is the Holiday Segar formula for calculating maintenance intravenous (IV) fluids in children?

Holiday-Segar Formula for Calculating Maintenance IV Fluids in Children

The Holiday-Segar formula calculates maintenance IV fluid requirements in children as: 100 mL/kg/day for the first 10 kg, plus 50 mL/kg/day for the next 10 kg, plus 25 mL/kg/day for each additional kg above 20 kg. 1

Detailed Calculation Method

The formula can be broken down as follows:

Weight	Daily Fluid Requirement	Hourly Fluid Requirement
First 10 kg	100 mL/kg/day	4 mL/kg/hour
Second 10 kg (10-20 kg)	50 mL/kg/day	2 mL/kg/hour
Each kg above 20 kg	25 mL/kg/day	1 mL/kg/hour

Practical Application:

• For a 10 kg child: 10 × 100 = 1000 mL/day (or 42 mL/hour)
• For a 15 kg child: (10 × 100) + (5 × 50) = 1250 mL/day (or 52 mL/hour)
• For a 25 kg child: (10 × 100) + (10 × 50) + (5 × 25) = 1625 mL/day (or 68 mL/hour)

Important Considerations for Fluid Management

Fluid Composition

• Current guidelines recommend isotonic solutions (Na 140 mmol/L) rather than traditional hypotonic solutions for maintenance IV fluids in hospitalized children 1
• Isotonic balanced solutions are preferred to reduce the risk of hospital-acquired hyponatremia and hyponatremic encephalopathy 1
• Daily electrolyte requirements should include:
  • Sodium: 1-3 mmol/kg/day
  • Potassium: 1-3 mmol/kg/day
  • Chloride: 2-4 mmol/kg/day 1, 2

Fluid Volume Adjustments

In certain clinical scenarios, the calculated maintenance fluid volume should be adjusted:

• Fluid Restriction (65-80% of calculated volume) for children at risk of increased ADH secretion 1, 2
• More Severe Restriction (50-60% of calculated volume) for children with edematous states (heart failure, renal failure, hepatic failure) 1, 2
• Increased Fluid Requirements may be needed for:
  • Fever (additional 12% per °C above normal)
  • Hyperventilation
  • Increased gastrointestinal losses 2

Monitoring

Regular monitoring is essential when administering maintenance fluids:

• Daily assessment of fluid balance and clinical status
• Regular monitoring of electrolytes, especially sodium levels
• Monitoring of serum glucose to prevent hypo/hyperglycemia 1, 2

Pitfalls to Avoid

1. Using hypotonic fluids in hospitalized children, which increases the risk of hyponatremia 1, 2
2. Failure to account for "fluid creep" - the total daily fluid intake should include IV medications, blood products, arterial and venous line flush solutions 1
3. Not adjusting fluid rates in children with conditions affecting fluid balance (renal failure, heart failure, critical illness) 1, 2
4. Overlooking the need for glucose in maintenance fluids, which should be provided in sufficient amounts to prevent hypoglycemia 1

The Holiday-Segar formula remains the standard method for calculating baseline maintenance fluid requirements, but the composition and volume should be adjusted based on the child's clinical condition, with a preference for isotonic balanced solutions in most hospitalized children.