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## Pediatric Hypotonic Dehydration

*Aka: Pediatric Hypotonic Dehydration, Hypotonic Dehydration Management in Children*

- See Also
- Definitions
- Pediatric Hypotonic Dehydration
- Pediatric Dehydration AND Serum Sodium < 130
- Occurs when gastrointestinal losses are replaced with water (or other hypotonic solutions)

- Pediatric Hypotonic Dehydration
- Protocol: Example Case
- Weight: 35 kg Child
- Dehydration: 10%
- Serum Sodium: 120

- Protocol: Stabilization with Bolus Fluids (Phase I)
- See Pediatric Dehydration Management
- Give 20 ml/kg Normal Saline or Lactated Ringers over 10-15 minutes
- May repeat bolus until circulation stable
- May require up to 60 ml/kg within the first 1-2 hours

- Protocol: Calculate Replacement and Replace Phase 1 Fluids
- Approach as per Pediatric Dehydration Management
- Deficit: 3500 - 700 ml (Replaced Phase 1)
- Maintenance: 4*10+2*10+1*15= 75 ml/h
- Replacement of 2800 ml over 24 hours
- First 8 hours
- Total: 1400/8 ml/h + (maintenance 75 ml/h) for 8 hours
- Hourly: 250 ml/hour for 8 hours (2 Liters over 8h)
- NS delivers (154 meq/1000 ml)(250 ml/h) = 39 meq/h Sodium

- Next 16 hours
- Total: 1400/16 ml/h + (maintenance 75 cc/h) for 16 hours
- Hourly: 163 ml/hour for 16 hours (2.6L over 16h)
- NS delivers (154 meq/1000 ml)(163 ml/h) = 25 meq/h Sodium

- First 8 hours
- Replacement of 2800 ml over 48 hours
- First 16 hours
- Total: 1400/16 ml/h + (maintenance 75 ml/h) for 16 hours
- Hourly: 163 ml/hour for 16 hours (2.6 Liters over 16h)
- NS delivers (154 meq/1000 ml)(163 ml/h) = 25 meq/h Sodium

- Next 32 hours
- Total: 1400/32 ml/h + (maintenance 75 cc/h) for 32 hours
- Hourly: 118 ml/hour for 32 hours (3.78 L over 32h)
- NS delivers (154 meq/1000 ml)(118 ml/h) =18 meq/h Sodium

- First 16 hours

- Protocol: Calculate Sodium Deficit and Sodium Requirement
- Calculate Deficit
- Formula: 0.6 x (weight kg) x (135 - Serum Sodium)
- Where 0.6 is volume of distribution (per kg)
- Where 135 is the desired Serum Sodium

- Example: (0.6 x 35 kilograms) x (135-120) = 315 meq

- Formula: 0.6 x (weight kg) x (135 - Serum Sodium)
- Add Maintenance
- Formula: 3 meq/kg/day x (weight kg)
- Example: 3 meq/kg/24h x 35 kg = 105 meq Sodium/24 hours

- Subtract Replacement given Phase 1

- Calculate Deficit
- Protocol: Choose Appropriate solution to replace Sodium deficit
- Available solutions
- Normal Saline contains 154 meq/L Sodium (typical replacement)

- Example: Replacement over 24 hours
- Example: Replacement over 48 hours

- Available solutions
- Protocol: Example Summary - 35 kg Child with hypotonic dehydration
- Given the severe Hyponatremia on presentation, replacement over 48 hours appears safer
- When instead, replaced over 24 hours, initial 250 ml/h rate would supply double the Sodium requirement
- Delivering Fluid Replacement over 48 hours allows for slower, safer raising of Sodium

- Replacement over 48 hours

- Given the severe Hyponatremia on presentation, replacement over 48 hours appears safer
- Labs: Monitoring
- Monitor Serum Sodium every 2-4 hours
- Raise Serum Sodium <= 8-12 mEq/L/24 hours (or <0.5 mEq/hour, <2 mEq in 4 hours)

- Management: Special Circumstance - Hyponatremic Seizure
- Background
- Serum Sodium raised 5 meq/L with 6 ml/kg of 3% NaCl (513 meq/L)

- Protocol
- Give 3% NaCl at 3 to 5 ml/kg/hour until Seizure stops

- Background
- Resources
- Vega and Bhimji (2017) Pediatric Dehydration in Stat Pearls

- References
- Walton (2020) Crit Dec Emerg Med 34(6): 3-9
- Canavan (2009) Am Fam Physician 80(7):692-6 [PubMed]