IV Lactated Ringer's Dosage for 16.4kg Child with Moderate Dehydration
For a 16.4kg child with moderate dehydration, oral rehydration solution (ORS) at 50-100 mL/kg over 3-4 hours (820-1640 mL total) is the first-line therapy, and IV Lactated Ringer's should only be used if ORS fails or the child cannot tolerate oral intake. 1, 2
When IV Fluids Are Actually Indicated
IV fluids are reserved for specific situations in moderate dehydration: 1, 3
- Failure of ORS therapy after adequate trial
- Inability to tolerate oral intake despite attempts
- Altered mental status precluding safe oral administration
- Presence of ileus 1
Before resorting to IV therapy, consider nasogastric ORS administration at 15 mL/kg/hour for children who cannot drink adequately but are not in shock. 1, 2, 3
IV Lactated Ringer's Protocol (If Truly Needed)
Initial Bolus Therapy
- Administer 20 mL/kg bolus (328 mL for 16.4kg child) of isotonic crystalloid (Lactated Ringer's or 0.9% Normal Saline) 3
- Reassess after each bolus for improvement in perfusion, mental status, and vital signs 3
- Repeat 20 mL/kg boluses as needed until clinical signs of dehydration resolve 1
Transition Strategy
Once the child is alert, has normal perfusion, and can tolerate oral intake, transition immediately to ORS to complete rehydration. 1, 3 The remaining fluid deficit should be replaced orally rather than continuing IV therapy. 1
Maintenance IV Fluids (If Admission Required)
If the child requires hospitalization and continued IV support: 3
- Use isotonic fluids (0.9% saline with 5% dextrose) for maintenance
- Calculate rate using Holliday-Segar formula but restrict to 65-80% of calculated volume to prevent hyponatremia
- Add potassium 20 mEq/L after confirming adequate urine output
- For 16.4kg child: Maintenance rate = approximately 54 mL/hour (using 100 mL/kg/day for first 10kg + 50 mL/kg/day for next 6.4kg = 1320 mL/day)
Ongoing Loss Replacement
Replace each diarrheal stool or vomiting episode with 120-240 mL ORS (up to ~1 L/day maximum) for this >10kg child. 1, 2, 3
Lactated Ringer's vs Normal Saline
Both are acceptable isotonic crystalloids for pediatric dehydration: 4, 5
- Lactated Ringer's may provide modest benefit in correcting metabolic acidosis compared to normal saline 6
- No significant difference in sodium correction or overall outcomes between the two fluids 4, 5
- Either can be used based on availability 1
Critical Monitoring
- Monitor serum sodium at least daily while on IV fluids to prevent iatrogenic hyponatremia 3
- Monitor blood glucose daily 3
- Reassess hydration status after 3-4 hours to determine if rehydration is adequate 2
- Resume age-appropriate diet immediately after rehydration—do not "rest the bowel" 2, 3
Common Pitfalls to Avoid
- Do not use hypotonic fluids (0.18% or 0.45% saline) as they increase risk of hyponatremia 3
- Do not bypass ORS trial unless contraindicated—IV therapy should not be first-line for moderate dehydration 1, 2
- Do not use sports drinks, juices, or sodas for rehydration due to inappropriate electrolyte content 2, 3
- Do not give excessive IV fluids—fluid overload prolongs recovery 3