How do you calculate maintenance intravenous (IV) fluid using the Holliday Segar formula?

How to Calculate Maintenance IV Fluid Using Holliday-Segar

The Holliday-Segar formula calculates maintenance fluid as 100 ml/kg/day for the first 10 kg, plus 50 ml/kg/day for the next 10 kg (10-20 kg), plus 25 ml/kg/day for each kg above 20 kg, and remains the standard method for determining maintenance fluid requirements in children. 1, 2, 3, 4

Step-by-Step Calculation Method

Daily Volume Calculation

• For a child weighing 0-10 kg: Calculate 100 ml/kg/day for their total weight 3, 4
• For a child weighing 10-20 kg: Calculate 1000 ml (for first 10 kg) + 50 ml/kg/day for each kg above 10 kg 3, 4
• For a child weighing >20 kg: Calculate 1000 ml (for first 10 kg) + 500 ml (for second 10 kg) + 25 ml/kg/day for each kg above 20 kg 3, 4

Hourly Rate Conversion

• 4 ml/kg/hour for the first 10 kg 2
• 2 ml/kg/hour for the next 10 kg (10-20 kg) 2
• 1 ml/kg/hour for each kg above 20 kg 2

Critical Volume Adjustments Based on Clinical Context

You must adjust the calculated volume downward in most hospitalized children because the original formula was derived from healthy children, not acutely ill patients with elevated ADH, decreased caloric expenditure, and reduced urinary output. 3, 5

Specific Restriction Guidelines

• For children at risk of increased ADH secretion (most acutely ill children): Restrict to 65-80% of calculated Holliday-Segar volume 2, 3, 4
• For children with heart failure, renal failure, or hepatic failure: Restrict to 50-60% of calculated volume 2, 3, 4

Fluid Composition Selection

Use isotonic balanced crystalloid solutions (sodium 135-144 mEq/L) as first-line maintenance fluids, not hypotonic solutions. 3, 4

Preferred Solutions

• Balanced crystalloids (PlasmaLyte, Ringer's lactate, Isofundine) are superior to 0.9% saline because they reduce length of stay and minimize hyperchloremic metabolic acidosis 3
• Isotonic fluids must be used especially during the first 24 hours because hypotonic fluids significantly increase the risk of hospital-acquired hyponatremia and potentially fatal hyponatremic encephalopathy 1, 4, 5

Essential Additives

• Add glucose in sufficient amounts to prevent hypoglycemia but not excessive to avoid hyperglycemia, with monitoring at least daily 2, 4
• Add potassium 20-40 mEq/L (typically 2/3 KCl and 1/3 KPO4) once renal function is assured and serum potassium is known 4
• Keep chloride intake slightly lower than the sum of sodium and potassium intakes (Na + K - Cl = 1-2 mmol/kg/day) to avoid iatrogenic metabolic acidosis 1, 2

Total Fluid Accounting to Prevent "Fluid Creep"

Calculate total daily maintenance fluid by including ALL sources: IV fluids, blood products, all IV medications, arterial/venous line flushes, and enteral intake. 3, 4

• Failure to account for all fluid sources leads to fluid overload, which is an independent predictor of mortality, prolonged mechanical ventilation, and increased length of stay 4
• Fluid overload is defined as >10% increase in cumulative fluid balance from baseline 4

Monitoring Requirements

• Reassess fluid balance and clinical status at least daily 2, 4
• Monitor serum electrolytes regularly, especially sodium levels 2, 4
• Monitor blood glucose at least daily 2, 4
• The induced change in serum osmolality should not exceed 3 mOsm/kg/hour during fluid replacement 4

Common Pitfalls to Avoid

• Never use hypotonic solutions for maintenance therapy because they significantly increase hyponatremia risk 3, 4, 5
• Never administer full calculated Holliday-Segar volumes without considering clinical context because hospitalized children have different physiologic states than the healthy children used to derive the formula 3, 5, 6
• Never use 0.9% saline as the primary maintenance solution when balanced crystalloids are available, as they provide superior outcomes 3
• Never forget to account for all fluid sources including medications and line flushes, which can lead to unrecognized fluid overload 3, 4