What is the recommended intravenous fluid (IVF) and dosage for a 21-month-old child?

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Last updated: October 26, 2025View editorial policy

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Intravenous Fluid Therapy for a 21-Month-Old Child

For a 21-month-old child, isotonic balanced fluid such as Plain Lactated Ringer's solution with added glucose should be administered at a maintenance rate of 80-120 mL/kg/day (restricted to 65-80% of calculated volume) to prevent hyponatremia and fluid overload. 1, 2

Fluid Composition

  • Use isotonic balanced fluids as the standard maintenance fluid to prevent hospital-acquired hyponatremia and hyponatremic encephalopathy 2, 1
  • Plain Lactated Ringer's solution is recommended as the first-line isotonic fluid for maintenance therapy 1
  • Add glucose to prevent hypoglycemia - typically D5 (5% dextrose) is appropriate 2, 1
  • Add potassium (1-3 mmol/kg/day) based on the child's clinical status and regular potassium monitoring 2, 1

Volume Calculation

For a 21-month-old child (falls in the 1-2 year age group):

  • Recommended maintenance fluid volume: 80-120 mL/kg/day 2
  • This volume should be restricted to 65-80% of the calculated amount to avoid fluid overload and prevent hyponatremia in acutely ill children 2, 1
  • For children at risk of increased ADH secretion (pain, nausea, stress, postoperative state), fluid restriction is particularly important 2

Holliday-Segar Formula (Alternative Calculation Method)

  • First 10 kg: 100 mL/kg/day (4 mL/kg/hour) 2, 1
  • Second 10 kg: 50 mL/kg/day (2 mL/kg/hour) 2, 1
  • Each kg above 20 kg: 25 mL/kg/day (1 mL/kg/hour) 2

Administration Guidelines

  • Include all sources of fluid in the total daily maintenance calculation: IV fluids, blood products, IV medications, line flush solutions, and any enteral intake 2, 1
  • Monitor the child daily for fluid balance, clinical status, and electrolytes (especially sodium levels) 2, 1
  • For children with heart failure, renal failure, or hepatic failure, restrict maintenance fluid volume further to 50-60% of the calculated volume 2

Common Pitfalls and Caveats

  • Avoid hypotonic fluids (e.g., 0.2% NaCl, 0.45% NaCl) as they increase the risk of hospital-acquired hyponatremia and potentially fatal hyponatremic encephalopathy 2, 3
  • Recognize that many hospitalized children have conditions that increase ADH secretion, impairing free water excretion and placing them at risk for hyponatremia when given hypotonic fluids 2
  • Monitor blood glucose at least daily to prevent both hypoglycemia and hyperglycemia 2, 1
  • Be aware that fluid overload and cumulative positive fluid balance can lead to prolonged mechanical ventilation and increased length of stay 2
  • Traditional maintenance fluid practices using hypotonic saline solutions are outdated and potentially dangerous 2, 3

Special Considerations

  • If the child is minimally dehydrated and able to tolerate oral intake, transition to oral hydration as this is preferred over IV maintenance fluids 1
  • For children with ongoing losses (vomiting, diarrhea, etc.), additional replacement fluids may be needed beyond maintenance requirements 4, 5
  • Consider the child's underlying condition when selecting fluid composition and volume 2, 1

References

Guideline

Maintenance Fluid Regimen for Children

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Preventing neurological complications from dysnatremias in children.

Pediatric nephrology (Berlin, Germany), 2005

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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