👤 By the CinnaRN Clinical Content Team🕐 Updated 2026-08-23🏷️ Physiological Adaptation🔖 Free to read, print, and share
Also known as: IV fluid calculation kids · maintenance fluids pediatric · 4-2-1 rule · child rehydration
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Use this quick-reference guide to spot, treat, and prevent Pediatric Fluid Maintenance on the NCLEX. Keep it handy during review and on exam day!
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📒 The 1-minute cheat sheet
📌 Rule
First 10 kg → 4 mL/kg/hr
Next 10 kg → 2 mL/kg/hr
Each kg > 20 → 1 mL/kg/hr
📌 Dehydration
Sunken fontanel, no tears
↓ UO, dry mucosa, ↑ HR
Cap refill > 2 sec, lethargy
✅ Do
Best UO sign: ≥ 1 mL/kg/hr
Weigh diapers, daily weight
Oral rehydration first-line
🚩 Report
No wet diaper 6-8 hr
📚 Pediatric Fluid Maintenance — full study notes
The cheat sheet above is your quick recall card. These notes go deeper — what it is, what to do first, what must be reported, and what to teach.
Children have higher fluid needs and lose fluid faster than adults, so maintenance fluid requirements are weight-based. Maintenance fluids replace normal daily losses (urine, stool, insensible losses). Key principle: the 4-2-1 (or 100-50-20) rule calculates hourly and daily needs, and infants decompensate quickly with even small deficits.
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Key points
Understand these first
The 4-2-1 hourly rule: 4 mL/kg for the first 10 kg, plus 2 mL/kg for the next 10 kg, plus 1 mL/kg for each kg over 20.
The Holliday-Segar daily method: 100 mL/kg for the first 10 kg, 50 mL/kg for the next 10 kg, 20 mL/kg per kg above 20.
Infants and young children have a higher body water percentage and surface-area ratio, so they dehydrate rapidly.
Adequate urine output is at least 1-2 mL/kg/hr in infants and small children and confirms hydration.
Early dehydration signs include dry mucous membranes, decreased tears, sunken fontanel, and tachycardia.
Maintenance solutions commonly use dextrose with isotonic or near-isotonic saline plus potassium once voiding is confirmed.
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Nursing priorities
What to do, in order
Calculate maintenance fluids accurately by current weight and verify the rate with a second nurse for high-alert situations.
Use a programmable infusion pump and document the rate; never free-flow IV fluids in a child.
Monitor strict intake and output, daily weights, and urine specific gravity.
Assess hydration status frequently: fontanel, mucous membranes, capillary refill, skin turgor, and vital signs.
Add potassium to fluids only after the child has voided and renal function is confirmed.
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Red flags — report now
Escalate immediately
Urine output under 1 mL/kg/hr, sunken fontanel, or no tears signal worsening dehydration and need prompt action.
Fluid overload (crackles, periorbital edema, bounding pulse, sudden weight gain) requires slowing fluids and notifying the provider.
Never add potassium to IV fluids before the child voids; hyperkalemia risk.
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Labs & values
Numbers to know
Serum sodium: 135-145 mEq/L
Serum potassium: 3.5-5.0 mEq/L
Urine specific gravity: 1.005-1.030 (elevated with dehydration)
BUN/creatinine (elevated with dehydration)
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Patient teaching
What patients must know
For mild illness at home, offer small frequent sips of an oral rehydration solution rather than plain water or juice.
Watch for and report fewer wet diapers, no tears, dry mouth, or unusual sleepiness.
Continue breastfeeding or formula during diarrheal illness unless told otherwise.
❓ Pediatric Fluid Maintenance: NCLEX FAQs
What are the priority nursing interventions for Pediatric Fluid Maintenance?
Calculate maintenance fluids accurately by current weight and verify the rate with a second nurse for high-alert situations. Use a programmable infusion pump and document the rate; never free-flow IV fluids in a child. Monitor strict intake and output, daily weights, and urine specific gravity. Assess hydration status frequently: fontanel, mucous membranes, capillary refill, skin turgor, and vital signs.
What are the warning signs of Pediatric Fluid Maintenance a nurse must report?
Urine output under 1 mL/kg/hr, sunken fontanel, or no tears signal worsening dehydration and need prompt action. Fluid overload (crackles, periorbital edema, bounding pulse, sudden weight gain) requires slowing fluids and notifying the provider. Never add potassium to IV fluids before the child voids; hyperkalemia risk.
What do I need to know about Pediatric Fluid Maintenance for the NCLEX?
The 4-2-1 hourly rule: 4 mL/kg for the first 10 kg, plus 2 mL/kg for the next 10 kg, plus 1 mL/kg for each kg over 20. The Holliday-Segar daily method: 100 mL/kg for the first 10 kg, 50 mL/kg for the next 10 kg, 20 mL/kg per kg above 20. Infants and young children have a higher body water percentage and surface-area ratio, so they dehydrate rapidly. Adequate urine output is at least 1-2 mL/kg/hr in infants and small children and confirms hydration.
What patient teaching is important for Pediatric Fluid Maintenance?
For mild illness at home, offer small frequent sips of an oral rehydration solution rather than plain water or juice. Watch for and report fewer wet diapers, no tears, dry mouth, or unusual sleepiness. Continue breastfeeding or formula during diarrheal illness unless told otherwise.
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Quick Tip
The 4-2-1 hourly rule: 4 mL/kg for the first 10 kg, plus 2 mL/kg for the next 10 kg, plus 1 mL/kg for each kg over 20.