Vivalyte Dosage for a 9-Year-Old with Moderate Dehydration
For a 9-year-old child with moderate dehydration, administer 100 mL/kg of Vivalyte (or any reduced osmolarity oral rehydration solution) over 2-4 hours, which translates to approximately 2,500-3,000 mL total volume for an average-weight child in this age group. 1, 2
Initial Rehydration Phase
- Administer 100 mL/kg of oral rehydration solution over 2-4 hours for moderate dehydration (6-9% fluid deficit), as this is the standard guideline-recommended volume 3, 1
- Start with small, frequent volumes using a cup or spoon, gradually increasing as tolerated 2
- For a typical 9-year-old weighing 25-30 kg, this translates to 2,500-3,000 mL total during the initial rehydration period 1
The 2017 IDSA guidelines establish reduced osmolarity ORS (containing 50-90 mEq/L sodium) as first-line therapy for moderate dehydration with strong evidence 3. This recommendation applies universally to children and adults regardless of the underlying cause of dehydration.
Ongoing Loss Replacement
- After initial rehydration, replace ongoing losses with 120-240 mL of ORS for each diarrheal stool or vomiting episode in children over 10 kg 2
- An alternative calculation is 10 mL/kg for each watery stool and 2 mL/kg for each vomiting episode 2
- Continue replacement therapy until diarrhea and vomiting resolve 3
Monitoring and Reassessment
- Reassess hydration status after 2-4 hours by evaluating skin turgor, mucous membrane moisture, mental status, capillary refill, and urine output 1, 2
- If dehydration persists or worsens after the initial rehydration period, restart the rehydration protocol or escalate to intravenous therapy 1, 2
- Target urine output should be >1 mL/kg/hour to indicate adequate rehydration 2
Nutritional Management
- Resume age-appropriate normal diet during or immediately after rehydration is complete 3, 1
- Do not delay feeding or "rest the bowel"—early refeeding improves outcomes 1
- Continue any breastfeeding throughout the illness without interruption 3
Critical Pitfalls to Avoid
- Never use sports drinks, juice, or soda for rehydration—these have inappropriate electrolyte content and excessive osmolality that can worsen diarrhea 1, 2
- Do not give antimotility drugs (like loperamide) to children under 18 years with acute diarrhea, as this carries significant risks 3
- Avoid antimicrobials unless specific pathogens (cholera, Shigella, amoebic dysentery) are identified 4
When to Escalate to IV Therapy
- Switch to intravenous rehydration if the child develops severe dehydration, shock, altered mental status, inability to tolerate oral intake despite adequate trial, or paralytic ileus 3, 1
- For IV therapy, administer 20 mL/kg boluses of isotonic crystalloid (lactated Ringer's or 0.9% normal saline) until pulse, perfusion, and mental status normalize 3, 1
- Once stabilized with IV fluids, transition back to ORS for remaining deficit replacement 1
The evidence strongly supports ORS as equally effective to IV therapy for moderate dehydration, with the added benefits of faster initiation time, lower hospitalization rates, and less invasive administration 5, 6. A 2005 randomized controlled trial demonstrated that ORT achieved successful rehydration in 50% of moderately dehydrated children at 4 hours (identical to IV therapy), while requiring 21 minutes less time to initiate treatment 5.