What is the recommended maintenance fluid volume, rate, and composition for an 11‑year‑old child (~40 kg) who will be NPO?

Maintenance Fluid for an 11-Year-Old Child

For an 11-year-old child (~40 kg) who will be NPO, administer isotonic balanced crystalloid (lactated Ringer's or PlasmaLyte) with 2.5–5% dextrose at approximately 60 mL/hour (1,500 mL/day), adjusted to 65–80% of this rate if the child has conditions associated with increased ADH secretion. 1, 2

Calculation Method

Use the Holliday-Segar formula as the standard approach: 1, 2

• First 10 kg: 100 mL/kg/day (= 1,000 mL)
• Second 10 kg: 50 mL/kg/day (= 500 mL)
• Remaining 20 kg: 20 mL/kg/day (= 400 mL)
• Total = 1,900 mL/day or approximately 79 mL/hour 1

Alternatively, the hourly calculation yields: 4 mL/kg/h for first 10 kg + 2 mL/kg/h for next 10 kg + 1 mL/kg/h for remaining 20 kg = 80 mL/hour 1

Fluid Composition

Isotonic balanced crystalloids (lactated Ringer's or PlasmaLyte) are the preferred first-line maintenance fluids because they modestly shorten hospital length of stay and avoid hyperchloremic metabolic acidosis compared to 0.9% NaCl. 1, 2, 3

Add 2.5–5% dextrose to prevent hypoglycemia, with daily glucose monitoring required. 1, 2

Potassium supplementation should be individualized based on clinical status and regular monitoring to prevent hypokalemia. 1, 2

The sodium concentration should be 130–154 mEq/L to prevent hospital-acquired hyponatremia. 1 Hypotonic fluids (sodium <130 mEq/L) must be avoided due to the risk of fatal hyponatremic encephalopathy. 1, 4

Volume Adjustments for Clinical Conditions

The full calculated rate should be reduced in specific high-risk situations: 1, 2, 3

Reduce to 65–80% of calculated volume (≈51–63 mL/hour):

• Pneumonia, CNS infection, or postoperative state (conditions with increased ADH secretion) 1, 2
• Mechanical ventilation 1
• Temperature-controlled environments 1
• Dehydration on admission 1

Reduce to 50–60% of calculated volume (≈40–48 mL/hour):

• Renal failure 1, 2
• Heart failure 1, 2, 3
• Hepatic failure 1, 2, 3

Increase above calculated volume:

• Fever, hyperventilation, or hypermetabolism 1
• Ongoing gastrointestinal losses 1

Total Fluid Accounting

The calculated maintenance rate must include ALL fluid sources: 1, 2, 3

• Primary IV maintenance fluids
• Blood products
• All IV medications (continuous infusions and boluses)
• Arterial and venous line flush solutions
• Enteral intake

This is a critical safety consideration—hidden fluid sources from medications and line flushes frequently cause inadvertent fluid overload, which can prolong mechanical ventilation and increase length of stay. 1, 3

Replacement fluids for acute losses or resuscitation boluses are NOT included in the maintenance calculation. 1

Monitoring Requirements

Reassess at least daily: 1, 2, 3

• Overall fluid balance and clinical status
• Serum sodium concentration (to detect hyponatremia)
• Blood glucose levels (at least daily)
• Potassium levels
• Signs of fluid overload (increased work of breathing, rales, gallop rhythm, hepatomegaly) or dehydration

Adjust the maintenance rate promptly if the patient develops oliguria, fluid overload, or any change in clinical condition. 1

Common Pitfalls to Avoid

Do not use hypotonic fluids for routine maintenance—multiple studies demonstrate increased risk of iatrogenic hyponatremia without benefit. 1, 4, 5

Do not continue full maintenance rates without reassessment in children who develop fluid overload or whose clinical condition changes. 1

Do not overlook hidden fluid sources—medications, flushes, and blood products must be counted toward total daily fluid intake. 1, 3

Avoid lactate-buffered solutions in severe liver dysfunction to prevent lactic acidosis. 2