Moderate or severe dehydration 

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–Infants with moderate or severe dehydration require isotonic fluids (typically normal saline [0.9% NaCl]), given as an initial fluid bolus and/or higher rates of administration (1.5 to 2 times maintenance) until the calculated fluid deficit is repleted, followed by maintenance intravenous fluids.

To calculate the fluid and electrolyte requirements for an infant with moderate dehydration, you need to determine the following:

1. Degree of Dehydration

• Mild dehydration: 3-5% of body weight lost.
• Moderate dehydration: 6-10% of body weight lost.
• Severe dehydration: >10% of body weight lost.

For moderate dehydration, the fluid deficit is approximately 60-100 mL/kg of the infant's body weight.

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2. Maintenance Fluid Requirements

Calculate the maintenance fluids based on the Holliday-Segar method:

• 100 mL/kg for the first 10 kg of body weight.
• 50 mL/kg for the next 10 kg of body weight.
• 20 mL/kg for each additional kg above 20 kg.

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3. Replacement of Deficit

• Estimate the fluid deficit using body weight and degree of dehydration.

\text{Fluid Deficit (mL)} = \text{Body Weight (kg)} \times \text{Percent Dehydration (e.g., 0.08 for 8%)} \times 1000

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4. Ongoing Losses

Replace ongoing losses (e.g., from vomiting or diarrhea) by estimating the volume of losses and adding them to the total requirement.

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5. Electrolytes

• Sodium: Usually replaced as normal saline (0.9% NaCl) or Ringer’s lactate, with a sodium content of ~130-154 mEq/L.
• Potassium: Add 20 mEq/L potassium chloride to the IV fluids once the infant has adequate urine output.
• Dextrose: Include 5% dextrose in maintenance fluids to prevent hypoglycemia.

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Plan for Moderate Dehydration

1. Rehydration Phase (First 4-6 hours):

   • Administer the calculated fluid deficit over 4-6 hours using isotonic fluids (e.g., normal saline or Ringer’s lactate).
   • Example: For an 8-kg infant with 8% dehydration: Fluid Deficit=8 kg×0.08×1000=640 mL.\text{Fluid Deficit} = 8 \, \text{kg} \times 0.08 \times 1000 = 640 \, \text{mL}.

2. Maintenance Phase (24 hours):

   • Administer maintenance fluids adjusted for ongoing losses.
   • Example: For an 8-kg infant: Maintenance Fluids=100 mL/kg×8 kg=800 mL/day.\text{Maintenance Fluids} = 100 \, \text{mL/kg} \times 8 \, \text{kg} = 800 \, \text{mL/day}.

3. Ongoing Losses:

   • Replace estimated ongoing losses, typically with isotonic fluids.

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Example Calculation

For an 8-kg infant with 8% dehydration:

• Deficit: 640 mL.
• Maintenance: 800 mL/day.
• Total in 24 hours: 640 mL + 800 mL = 1440 mL.
• Administer rehydration fluids over 6 hours, then provide maintenance fluids with ongoing loss replacement.

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Close monitoring of hydration status, electrolytes, and urine output is critical. Adjust the plan based on clinical response and laboratory values.

Renal function should be assessed before adding potassium to the intravenous fluids.

 

 

 

 

 

 

 

 

 

 

 

For formula-fed babies:

- If vomiting once, give half the regular amount of formula every 1-2 hours[1].
- If vomiting multiple times, offer oral rehydration solution (ORS) like Pedialyte for 8 hours[1].
- Give small amounts frequently - 1-2 teaspoons every 5 minutes[1].

For breastfed babies:

- If vomiting once, nurse for half the usual time every 1-2 hours[1].
- If vomiting multiple times, nurse for 5 minutes every 30-60 minutes[1].
- If continued vomiting, switch to pumped breastmilk in small amounts[1].

## Feeding

- Stop all solid foods for 8 hours[1].
- Gradually reintroduce formula/breastmilk after 4-8 hours without vomiting[1].
- Slowly increase feeding amounts as tolerated[1].

## Other Measures

- Keep the baby lying on their stomach or side to prevent aspiration[2].
- Do not give over-the-counter medications unless prescribed by a doctor[1][2].
- Let the baby sleep, as this can help settle the stomach[1].

## When to Seek Medical Care

Call the doctor if the baby:
- Shows signs of dehydration
- Cannot keep down any fluids
- Has forceful projectile vomiting after every feed
- Has blood or bile in the vomit
- Seems unwell or has concerning symptoms[1][3]

The vomiting should improve within 12-24 hours in most cases. Focus on hydration and gradually returning to normal feeding as tolerated. Seek medical attention if symptoms persist or worsen.

Citations:
[1] https://www.seattlechildrens.org/conditions/a-z/vomiting-0-12-months/
[2] https://www.healthychildren.org/English/health-issues/conditions/abdominal/Pages/treating-vomiting.aspx
[3] https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/children-and-vomiting
[4] https://kidshealth.org/en/parents/vomiting-sheet.html
[5] https://www.nhsinform.scot/illnesses-and-conditions/stomach-liver-and-gastrointestinal-tract/vomiting-in-children-and-babies/
[6] https://www.merckmanuals.com/professional/pediatrics/symptoms-in-infants-and-children/nausea-and-vomiting-in-infants-and-children
[7] https://healthy.kaiserpermanente.org/health-wellness/health-encyclopedia/he.vomiting-in-children-3-months-to-1-year-care-instructions.zx4670