When should D5 (5% dextrose) 0.3 NaCl (sodium chloride) be given to a pediatric patient with moderate to severe dehydration due to diarrhea?

When to Use D5 0.3% NaCl in Pediatric Dehydration from Diarrhea

D5 0.3% NaCl (5% dextrose in 0.3% saline, containing approximately 51 mEq/L sodium) should be used for maintenance fluid therapy after initial rehydration is complete in children with moderate to severe dehydration from diarrhea, particularly in cases of hypernatremic dehydration where slower sodium correction is needed. 1

Initial Management: Rehydration Phase

Do not start with D5 0.3% NaCl for acute rehydration. The initial approach depends entirely on dehydration severity:

Severe Dehydration (≥10% fluid deficit)

• Administer immediate IV boluses of isotonic fluids (Ringer's lactate or 0.9% normal saline) at 20 mL/kg until pulse, perfusion, and mental status normalize 2, 3, 4
• Balanced crystalloid solutions like Ringer's lactate likely result in slightly shorter hospital stays and reduced risk of hypokalaemia compared to 0.9% saline 5
• Once circulation is restored, transition to oral rehydration solution (ORS) to complete the remaining deficit 2, 1

Moderate Dehydration (6-9% fluid deficit)

• First-line therapy is ORS at 100 mL/kg over 2-4 hours 2, 3, 4
• Use ORS containing 75-90 mEq/L sodium for active rehydration 6
• Only escalate to IV fluids if ORS fails, altered mental status develops, or intractable vomiting prevents oral intake 3

Mild Dehydration (3-5% fluid deficit)

• Administer ORS at 50 mL/kg over 2-4 hours 4, 6

When D5 0.3% NaCl Is Appropriate: Maintenance Phase

After successful rehydration, D5 0.3% NaCl becomes the appropriate maintenance solution in specific scenarios:

Hypernatremic Dehydration

• This is the primary indication for D5 0.3% NaCl (or D5 0.2% NaCl) 1
• Hypernatremic dehydration requires slow sodium correction over 2-3 days to prevent cerebral edema 1
• Use D5 0.2-0.3% NaCl with 20 mEq/L KCl for maintenance over 48-72 hours 1

Standard Maintenance After Rehydration

• For routine maintenance hydration in children who cannot tolerate oral intake after rehydration is complete, D5 0.2% NaCl with 20 mEq/L KCl is the standard recommendation 1
• D5 0.3% NaCl falls between maintenance (0.2% saline) and deficit replacement (0.45% saline) concentrations

Isonatremic Dehydration Requiring IV Maintenance

• If the child cannot tolerate ORS after initial rehydration, use D5 0.45% NaCl with 20 mEq/L KCl over 24 hours for isonatremic dehydration 1
• D5 0.3% NaCl would be suboptimal here—use 0.45% saline instead

Critical Algorithm for Fluid Selection

Step 1: Assess dehydration severity clinically (skin turgor, mucous membranes, mental status, capillary refill) 3, 4

Step 2: Determine sodium status (if available from labs or clinical presentation)

Step 3: Choose initial rehydration fluid:

• Severe dehydration → 0.9% saline or Ringer's lactate IV boluses 2, 3
• Moderate/mild dehydration → ORS (75-90 mEq/L sodium) 2, 6

Step 4: After rehydration, select maintenance fluid based on sodium status:

• Hypernatremic → D5 0.2-0.3% NaCl + 20 mEq/L KCl over 48-72 hours 1
• Isonatremic → D5 0.45% NaCl + 20 mEq/L KCl over 24 hours 1
• Hyponatremic → Alternate 0.9% saline and 0.45% saline (1:1 ratio) in D5 + 20 mEq/L KCl over 24 hours 1

Step 5: Replace ongoing losses with 10 mL/kg ORS per watery stool 2, 3, 4

Common Pitfalls to Avoid

• Never use D5 0.3% NaCl for initial resuscitation of severe dehydration—this is hypotonic and inadequate for restoring circulation 2, 1
• Do not use D5 0.3% NaCl for rapid correction of hypernatremia—the sodium concentration (51 mEq/L) may still correct too quickly; D5 0.2% NaCl (34 mEq/L) is safer 1
• Avoid using any dextrose-containing hypotonic solutions when ORS is tolerated—ORS is superior for ongoing loss replacement 2, 3
• When using fluids with >60 mEq/L sodium for maintenance, supplement with low-sodium fluids (breast milk, formula, or water) to prevent sodium overload 6

Practical Context

In real-world practice, D5 0.3% NaCl is rarely the optimal first choice for pediatric diarrheal dehydration. The evidence strongly supports:

1. ORS for mild-moderate dehydration (first-line) 2, 3
2. Isotonic fluids (0.9% saline or Ringer's lactate) for severe dehydration (initial resuscitation) 2, 5
3. D5 0.2% NaCl for hypernatremic maintenance or D5 0.45% NaCl for isonatremic maintenance after rehydration 1

The most appropriate use of D5 0.3% NaCl is as a compromise maintenance solution for hypernatremic dehydration when D5 0.2% NaCl is unavailable, or when transitioning from higher sodium concentrations in prolonged IV therapy. 1