IV Fluid Rate Calculation for a 29 kg Child
For a 29 kg child, administer 1600 mL per day (approximately 67 mL/hour) using the Holliday-Segar formula, but restrict this to 65-80% (1040-1280 mL/day or 43-53 mL/hour) if the child is acutely or critically ill to prevent hyponatremia and fluid overload. 1
Standard Maintenance Calculation
Using the Holliday-Segar formula for a 29 kg child: 2, 1
- First 10 kg: 100 mL/kg/day = 1000 mL/day
- Second 10 kg (10-20 kg): 50 mL/kg/day = 500 mL/day
- Remaining 9 kg (20-29 kg): 20 mL/kg/day = 180 mL/day
- Total: 1680 mL/day (approximately 70 mL/hour)
This calculation assumes 1 mL of water per 1 kcal of energy expenditure, which parallels metabolic needs in healthy children. 2
Fluid Restriction for Acutely/Critically Ill Children
If this child is hospitalized with acute illness, restrict maintenance fluids to 65-80% of the calculated Holliday-Segar volume to prevent hyponatremia from elevated antidiuretic hormone (ADH) secretion. 2, 1
- 65% restriction: 1092 mL/day (45 mL/hour)
- 80% restriction: 1344 mL/day (56 mL/hour)
The 2022 ESPNIC guidelines strongly recommend this restriction based on meta-analysis evidence showing reduced hyponatremia risk without adverse outcomes. 2 Acutely ill children have decreased urinary output, reduced caloric expenditure, and elevated ADH levels that make full Holliday-Segar rates inappropriate. 3, 4
Fluid Composition
Use isotonic balanced crystalloid solutions (such as lactated Ringer's or Plasma-Lyte) with 5% dextrose. 2, 1
- Isotonic fluids (sodium 140 mmol/L) significantly reduce hyponatremia risk compared to hypotonic solutions. 2, 4
- Add 5% dextrose to prevent hypoglycemia, monitoring blood glucose at least daily. 2, 1
- Once renal function is confirmed, add potassium 20-40 mEq/L (using 2/3 KCl and 1/3 KPO4). 1
Never use hypotonic solutions (<0.45% NaCl) for routine maintenance in hospitalized children, as they dramatically increase the risk of potentially fatal hyponatremic encephalopathy. 2, 4
Special Clinical Scenarios Requiring Further Restriction
For children with heart failure, renal failure, or hepatic failure, restrict maintenance fluids to 50-60% of Holliday-Segar volume: 2, 1
- 50% restriction: 840 mL/day (35 mL/hour)
- 60% restriction: 1008 mL/day (42 mL/hour)
These edematous states require aggressive fluid restriction to prevent worsening organ dysfunction. 2
Total Fluid Accounting to Prevent "Fluid Creep"
Calculate total daily fluid intake by including ALL sources: 2, 1, 5
- IV maintenance fluids
- All IV medications (both continuous infusions and bolus drugs)
- Arterial and venous line flush solutions
- Blood products
- Enteral intake
Research shows that "fluid creep" (fluids given as drug vehicles) accounts for 34-56% of total fluid intake in critically ill children and is the most common cause of inadvertent fluid overload. 5 For a 29 kg child receiving multiple IV medications, this could easily add 300-500 mL/day beyond calculated maintenance.
Mandatory Monitoring Requirements
Reassess the patient at least daily for: 2, 1
- Fluid balance calculation (intake minus output)
- Clinical examination for edema, perfusion, vital signs
- Serum sodium and other electrolytes
- Body weight (if feasible)
Check electrolytes more frequently (every 6-12 hours) if: 1
- Sodium is abnormal at baseline
- The child is critically ill or mechanically ventilated
- Rapid fluid shifts are occurring
Critical Pitfalls to Avoid
Do not apply full Holliday-Segar rates to hospitalized children without considering their clinical state. 2, 1, 3 The original 1957 formula was derived from healthy children with normal ADH levels and normal urinary output—conditions rarely present in hospitalized patients.
Do not forget to account for all fluid sources when calculating daily totals. 2, 5 Ignoring medication diluents, line flushes, and enteral intake leads to unrecognized positive fluid balance.
Do not continue the same fluid rate for days without reassessment. 2, 1 Clinical status changes rapidly in children, requiring frequent adjustments to fluid prescriptions based on evolving needs.