When is D5 (Dextrose 5%) 0.3 NaCl (Sodium Chloride) used?

When D5 0.3% NaCl is Used

D5 0.3% NaCl (dextrose 5% in 0.3% sodium chloride) should generally be avoided in modern clinical practice, as it is a hypotonic solution that carries significant risk of iatrogenic hyponatremia and cerebral edema, particularly in hospitalized patients. 1, 2

Why This Solution is Problematic

Hyponatremia Risk

• D5 0.3% NaCl contains only approximately 51 mEq/L of sodium, making it significantly hypotonic compared to plasma 1
• Acutely ill patients frequently have non-osmotic stimuli for antidiuretic hormone (ADH) release, including pain, nausea, stress, postoperative states, medications, pneumonia, and CNS disorders, leading to syndrome of inappropriate antidiuresis (SIAD) 1
• When SIAD is present, hypotonic fluid administration is particularly dangerous as water retention occurs at the expense of plasma sodium 1
• Studies demonstrate significantly higher rates of hyponatremia with hypotonic solutions: at 12 and 24 hours, the incidence of mild and moderate hyponatremia was significantly more common with 0.45% saline (which has MORE sodium than 0.3% saline) compared to 0.9% saline (P < 0.001) 3

Cerebral Edema Risk

• In patients with acute brain injury, hypotonic solutions like 0.45% saline worsen cerebral edema within 2 hours after closed head trauma, with brain tissue specific gravity decreasing to 1.0366 compared to 1.0389 with isotonic saline 4
• D5 0.3% NaCl would be even more hypotonic than the 0.45% saline shown to cause harm 1, 4
• A multicenter study showed higher mortality with hypotonic Ringer's Lactate compared to isotonic 0.9% NaCl (HR 1.78,95% CI 1.04-3.04, p=0.035) in traumatic brain injury patients 2

Recommended Alternatives

When Dextrose AND Sodium Are Needed

• Use D5 0.9% saline (isotonic) - this is the appropriate maintenance fluid for most hospitalized patients requiring dextrose 1
• The American Academy of Pediatrics recommends isotonic solutions with appropriate dextrose and potassium chloride for maintenance therapy in pediatric patients 2
• Once serum glucose reaches 250 mg/dL in DKA management, fluid should be changed to 5% dextrose with 0.45-0.75% NaCl (not 0.3%) 5

When Only Free Water Replacement is Needed

• For hypernatremia correction requiring free water replacement, use D5W (no sodium) rather than D5 0.3% NaCl, as the latter provides some sodium and may slow correction inappropriately 2

For Adrenal Insufficiency (Historical Context)

• In pediatric adrenal insufficiency, guidelines recommend a fluid bolus of 20 mL/kg of D5NS (D5 0.9% saline) or D10NS during the first hour of treatment - NOT D5 0.3% NaCl 5

Critical Pitfalls to Avoid

• Do not assume that adding dextrose to hypotonic saline makes it "safer" - tonicity is determined by sodium/potassium content, not glucose 1
• Do not use hypotonic fluids in patients with CNS disorders, postoperative states, or respiratory infections - these are high-risk scenarios for SIAD 1
• Hyponatremic encephalopathy is a medical emergency that can be fatal or cause irreversible brain injury if inadequately treated 1

Specific Clinical Scenarios Where D5 0.3% NaCl Should NOT Be Used

• Acute brain injury or traumatic brain injury: Use isotonic crystalloid WITHOUT dextrose (0.9% NaCl preferred) 2
• Stroke patients: Glucose-containing solutions should be avoided entirely as glucose can have detrimental effects in acute brain injury 1
• Anaphylaxis resuscitation: Normal saline is specifically recommended - dextrose is rapidly extravasated from intravascular to interstitial space 1
• General hospitalized children: The American Academy of Pediatrics explicitly recommends isotonic fluids (0.9% saline) over hypotonic solutions for maintenance IV fluids, citing the risk of hospital-acquired hyponatremia and hyponatremic encephalopathy 1