What are the contraindications of Dextrose‑Normal Saline (DNS)?

Contraindications of Dextrose-Normal Saline (DNS)

DNS solutions are absolutely contraindicated in traumatic brain injury, neurosurgical patients, and acute stroke because the hypotonic effect after glucose metabolism exacerbates cerebral edema and worsens neurological outcomes.

Absolute Contraindications

Neurological Conditions

• Traumatic brain injury and severe head trauma – DNS worsens brain edema within 2 hours of administration, with animal studies demonstrating decreased brain tissue specific gravity (1.0368 vs. 1.0395 in controls) and increased mortality rates up to 50% compared to isotonic saline 1, 2, 3
• Neurosurgical patients – hypotonic dextrose-containing solutions must be avoided to prevent cerebral edema, as maintaining normal plasma osmolarity is critical in this population 4, 5
• Acute stroke – DNS can exacerbate brain swelling through its hypotonic effect once dextrose is metabolized 5

Hemodynamic Instability

• Hypovolemic shock and severe volume depletion – DNS fails to provide adequate electrolyte replacement for rapid hemodynamic stabilization and is inappropriate during the initial resuscitation phase 4, 6
• Hypotensive states – initial resuscitation must employ isotonic crystalloids (0.9% saline or balanced solutions) at 5-10 mL/kg within the first 5 minutes, not DNS 6

Metabolic Conditions

• Severe hyperglycemia – DNS administration causes significant hyperglycemia even in non-diabetic patients, with plasma glucose exceeding 10 mmol/L in 72% of patients receiving 500 mL of D5NS 7
• Known asthma (for ATP test protocols using dextrose solutions) – contraindicated due to bronchospastic reactions 8
• Significant coronary disease (for ATP test protocols) – contraindicated due to risk of coronary steal 8

Relative Contraindications

High-Risk Populations

• Patients with syndrome of inappropriate antidiuresis (SIAD) – DNS can contribute to hyponatremia and cerebral edema in this vulnerable population 4
• Geriatric patients – require careful monitoring for fluid overload and pulmonary edema when receiving DNS 6
• Pediatric patients under 20 years with osmolality disturbances – particularly close observation needed for cerebral edema during correction, with total isotonic bolus not exceeding 50 mL/kg within first 4 hours before switching to DNS 6
• Renal or cardiac compromise – frequent reassessment required to prevent pulmonary edema and congestive states 6

Specific Clinical Scenarios

• Volume resuscitation – DNS is not suitable because dextrose rapidly leaves the intravascular compartment, providing minimal effective plasma expansion 5
• Diabetic ketoacidosis (initial phase) – DNS should only be used after initial isotonic resuscitation when serum glucose falls to ≤250 mg/dL, not during the initial resuscitation phase 8, 6

Critical Pitfalls to Avoid

Administration Errors

• Never initiate resuscitation with DNS – always begin with isotonic saline at 15-20 mL/kg/h in adults or 10-20 mL/kg/h in children before transitioning 6
• Avoid bolus administration in hypernatremic dehydration – DNS should not be given as a bolus due to risk of rapid decrease in serum sodium and cerebral edema 8

Monitoring Failures

• Ignoring osmolality changes – correction rate must not exceed 3 mOsm/kg/h to prevent cerebral edema 6
• Inadequate glucose monitoring – serum glucose requires hourly assessment during acute resuscitation, then every 2-4 hours once stable 6
• Failure to assess for osmotic diuresis – hyperglycemia from DNS can lead to osmotic diuresis, worsening dehydration 4

Appropriate Clinical Uses (When Not Contraindicated)

Specific Indications

• Diabetic ketoacidosis maintenance – switch to DNS when serum glucose reaches 250 mg/dL, with 20-30 mEq/L potassium supplementation 8, 6
• Pediatric maintenance after isotonic resuscitation – use D5 0.45% NS at approximately 1.5× the 24-hour maintenance rate when serum sodium is normal or elevated 6
• Acute burn resuscitation – DNS as maintenance fluid combined with Ringer's lactate for resuscitation maintains sodium levels (137-138 mEq/L) and prevents hyponatremia seen with RL alone 9
• Medication carrier requiring dextrose – DNS may be used but clinicians must account for high chloride load (154 mEq/L) and impact on patients with diabetes 5

Monitoring Requirements When DNS Is Used

• Serum osmolality – check frequently to ensure change does not exceed 3 mOsm/kg/h 6
• Cardiac, renal, and mental status – assess regularly for fluid overload or electrolyte disturbances 6
• Serum sodium – monitor to maintain correction rate ≤8 mEq/day for hyponatremia 6
• Blood glucose – hourly during acute phase, then every 2-4 hours once stable 6