NG-411 · NUR 235

💧 Fluid balance & dehydration in children

A child holds a far larger share of their body weight as water and turns it over far faster, so they dehydrate in hours rather than days. Weight is the measurement that matters — not what the parents think they drank.

💧 Maintenance fluids

The calculation this course asks for by name.

Holliday-Segar, in three bands Work up through the bands. Do not apply one rate to the whole child. First 10 kg 100 mL/kg/day = 1000 mL Next 10 kg · up to 20 1000 mL + 50 mL/kg = 1500 mL Every kg beyond 20 1500 mL + 20 mL/kg + 20 each A 26 kg child: 1500 + (6 × 20) = 1620 mL/day
Divide the daily total by 24 for the hourly rate. 1620 ÷ 24 = 67.5 mL/hr.

🔢 Work one through

A child weighs 26 kg.

  • First 10 kg → 1000 mL
  • Next 10 kg → 10 × 50 = 500 mL
  • Remaining 6 kg → 6 × 20 = 120 mL
  • Total 1620 mL/day, which is 67.5 mL/hr

💧 Expected urine output

  • Infant — 1–3 mL/kg/hr
  • Child — 0.5 mL/kg/hr
  • Adolescent / adult — 40–80 mL/hr

Output below this is the earliest hard number you get that a child is dry.

👀 How dry is this child?

Weight is the truth. Everything else is a clue.

⭐ Percent lost = percent of body weight lost

A child who was 10 kg last week and is 9.5 kg now has lost 500 g, which is 5% — and in a child, 1 kg lost is 1 liter of fluid.

Mild · about 5%Thirsty Alert, moist-ish mouth, normal or slightly raised heart rate, urine still passing.
Moderate · about 10%Dry & tachycardic Dry mucous membranes, sunken fontanelle, reduced skin turgor, fewer wet diapers, irritable.
Severe · 15% or moreShock Lethargy, marked tachycardia, cool mottled skin, no tears, minimal urine. Blood pressure falls last.

🚨 The findings that matter most in an infant

  • Sunken fontanelle — and remember bulging means the opposite problem, raised ICP
  • Fewer wet diapers — ask how many today versus a normal day
  • No tears when crying
  • A change in behavior is a vital sign. Irritable, then lethargic, is the direction of travel.

🥤 Putting it back

✅ Oral rehydration first, when they can take it

  • An oral rehydration solution — not water, not juice, not soda
  • Small amounts, often: a teaspoon every few minutes beats a cup they will vomit
  • Keep going through the vomiting — slow and small, do not stop
  • Resume a normal diet as soon as they will take it; the old “rest the gut” advice is out

🚨 When it has to be IV

  • Severe dehydration, shock, or a child who cannot keep anything down
  • Only normal saline or lactated Ringer's
  • Bolus by weight, then reassess — heart rate, mental state, urine output
  • Strict intake and output, and daily weights on the same scale

💡 What tells you it is working

In order: heart rate settles, then the child brightens up, then urine output rises, then weight climbs. If the heart rate has not come down, nothing else you see is reassurance.

⚠️ Overload cuts the other way

🚨 A child can be given too much just as easily

  • Crackles, rising heart rate and rising blood pressure
  • Puffy eyelids, new peripheral edema, a sudden weight gain
  • Always on a pump, never by gravity, and never a free-flowing bag

Fluid is a drug in pediatrics. It is calculated, checked by two nurses, and pumped.

Peds