Indications for Dextrose Normal Saline (DNS)
Dextrose normal saline (DNS) is primarily indicated for the treatment of hypoglycemia, dehydration with potential hypoglycemia risk, and as a source of carbohydrate calories in patients with restricted oral intake. 1
Primary Indications
Treatment of hypoglycemia: DNS is indicated for treating insulin hypoglycemia or hypoglycemic states to restore blood glucose levels, particularly in patients who cannot tolerate oral intake 1, 2
Rehydration with prevention of hypoglycemia: For patients with dehydration who are at risk of developing hypoglycemia, such as those with prolonged fasting or malnutrition 3, 4
Nutritional support: As a source of carbohydrate calories in patients whose oral intake is restricted or inadequate to maintain nutritional requirements 1, 3
Severe volume depletion with hypoglycemia risk: For patients with severe dehydration who also need glucose supplementation 3
Specific Clinical Scenarios
Diabetic Ketoacidosis (DKA) Management
Once serum glucose reaches 250 mg/dl during DKA treatment, fluid should be changed to 5% dextrose and 0.45–0.75% NaCl with appropriate potassium supplementation 3
This prevents hypoglycemia while continuing insulin therapy to resolve ketoacidosis 3
Geriatric Dehydration Management
For older adults with measured serum osmolality >300 mOsm/kg who appear unwell, subcutaneous or intravenous fluids should be offered 3
Appropriate volumes of subcutaneous dextrose infusions (in the form of half-normal saline-glucose 5%, 40 g/L dextrose and 30 mmol/L NaCl, or 5% dextrose solution and 4 g/L NaCl, or two-thirds 5% glucose and one-third normal saline) can be used effectively 3
Infectious Diarrhea with Severe Dehydration
In severe dehydration with inability to drink, patients may require 5% dextrose 0.25 normal saline solution with 20 mEq/L potassium chloride intravenously 3
This is particularly important when patients cannot tolerate oral rehydration therapy 3
Dosing and Administration Considerations
Concentration selection: Lower concentrations (5-10%) are preferred for maintenance and rehydration, while higher concentrations (25-50%) are used for acute hypoglycemia 5, 2
Rate of administration: Slow infusion of hypertonic dextrose solutions is essential to ensure proper utilization of dextrose and avoid production of hyperglycemia 1, 6
Monitoring: Blood glucose should be monitored regularly during administration, particularly in diabetic patients who may experience significant hyperglycemia 2, 6
Special Populations
Pediatric Patients
In pediatric patients with dehydration, once renal function is assured and serum glucose reaches 250 mg/dl, fluid should be changed to 5% dextrose and 0.45–0.75% NaCl with appropriate potassium supplementation 3
For infants unable to drink, administering either 5% dextrose 0.25 normal saline solution with 20 mEq/L potassium chloride intravenously is recommended 3
Critically Ill Patients
In critically ill patients with hypoglycemia, 10-20g of hypertonic (50%) dextrose is recommended, titrated based on the initial hypoglycemic value 3
For maintenance in ICU patients, dextrose-containing solutions help prevent hypoglycemia, especially in patients receiving insulin therapy 3
Cautions and Contraindications
Risk of hyperglycemia: Administration of dextrose solutions, particularly at higher concentrations, can cause significant hyperglycemia, especially in non-diabetic patients 6, 2
Fluid overload: Rapid administration of large volumes can lead to fluid overload, particularly in patients with renal or cardiac compromise 3
Electrolyte imbalances: Dextrose solutions without adequate electrolyte supplementation may lead to electrolyte abnormalities 3, 4
Evidence Quality and Considerations
The evidence supporting the use of DNS for hypoglycemia is strong, with multiple guidelines recommending its use 1, 3
For rehydration purposes, the evidence is more mixed, with some studies showing no significant clinical benefit of adding dextrose to rehydration solutions in certain populations 7
The optimal concentration of dextrose for various clinical scenarios remains somewhat controversial, with recent studies suggesting that lower concentrations may be equally effective with fewer side effects in some situations 5, 2