Maintenance Fluid Regimen for a 30kg Child
For a 30kg child, administer 1,700 mL/day (71 mL/hour) of isotonic balanced crystalloid solution (such as lactated Ringer's or PlasmaLyte) with 5% dextrose and appropriate potassium supplementation, using the Holliday-Segar formula calculation. 1, 2, 3
Volume Calculation
Using the Holliday-Segar formula for a 30kg child 1, 2, 3:
- First 10 kg: 100 mL/kg/day = 1,000 mL/day (or 4 mL/kg/hour = 40 mL/hour) 1, 2
- Second 10 kg (10-20 kg): 50 mL/kg/day = 500 mL/day (or 2 mL/kg/hour = 20 mL/hour) 1, 2
- Remaining 10 kg (20-30 kg): 25 mL/kg/day = 250 mL/day (or 1 mL/kg/hour = 10 mL/hour) 1, 2
- Total: 1,750 mL/day or approximately 73 mL/hour 1, 2
Fluid Composition
Use isotonic fluids (sodium 130-154 mEq/L) exclusively to prevent hospital-acquired hyponatremia, which has caused over 50 cases of neurologic morbidity including 26 deaths in children receiving hypotonic fluids. 2, 3 The American Academy of Pediatrics strongly recommends isotonic solutions over hypotonic fluids for all hospitalized children 28 days to 18 years of age. 2, 3
Prefer balanced crystalloid solutions (lactated Ringer's or PlasmaLyte) over 0.9% normal saline, as balanced solutions reduce length of stay in both acutely and critically ill children. 1, 2, 3 This represents the most current evidence-based recommendation from the 2022 ESPNIC guidelines. 1
Add 5% dextrose (or 2.5-5% depending on glucose monitoring) to prevent hypoglycemia, with blood glucose checked at least daily. 1, 2, 3
Add potassium supplementation (typically 20-40 mEq/L) once renal function is confirmed and serum potassium levels are known, based on clinical status and regular monitoring. 1, 2, 3
Volume Adjustments for High-Risk Situations
If the child has conditions associated with increased ADH secretion (pneumonia, CNS infections, postoperative state, dehydration), restrict maintenance fluid volume to 65-80% of the calculated Holliday-Segar volume (approximately 1,140-1,400 mL/day or 47-58 mL/hour) to prevent hyponatremia and fluid overload. 1, 2, 3, 4
If the child has heart failure, renal failure, or hepatic failure, restrict to 50-60% of calculated volume (approximately 875-1,050 mL/day or 36-44 mL/hour). 3, 4
Total Fluid Accounting
Include all fluid sources when calculating total daily maintenance: IV fluids, blood products, all IV medications (infusions and bolus), arterial/venous line flushes, and enteral intake. 1, 2, 3, 4 This prevents "fluid creep" and unintentional fluid overload, which independently predicts prolonged mechanical ventilation and increased length of stay. 3, 4
Monitoring Requirements
- Reassess daily: fluid balance, clinical status, weight, and intake/output 1, 2, 4
- Monitor electrolytes (especially sodium) at least daily 1, 2, 3, 4
- Check blood glucose at least daily 1, 2, 3
- Avoid cumulative positive fluid balance to prevent prolonged mechanical ventilation 1, 4
Critical Pitfalls to Avoid
Never use hypotonic fluids (sodium <130 mEq/L) as this practice has directly caused fatal hyponatremic encephalopathy in children. 2, 3 This represents the single most important safety consideration in pediatric maintenance fluid therapy. 2
Do not ignore hidden fluid sources from medications, flushes, and blood products, as these contribute significantly to total daily intake and can lead to unrecognized fluid overload. 1, 2, 3
Avoid continuing full maintenance rates in children with established fluid overload (>10% increase in cumulative fluid balance from baseline) or oliguria, as fluid overload is an independent predictor of mortality and morbidity. 3, 4