Dextrose Concentration Calculation
Adding 2 ampules of D50 (25g/50mL each) to a 1L NS bag creates approximately D4.5 (4.5% dextrose solution).
Mathematical Calculation
- Total dextrose added: 2 ampules × 25g = 50g of dextrose 1
- Total volume: 1000mL (NS bag) + 100mL (two 50mL ampules) = 1100mL 1
- Final concentration: 50g ÷ 1100mL = 0.045g/mL = 4.5% dextrose solution 1
Clinical Context and Safety Considerations
This resulting D4.5 solution is hypotonic and carries important clinical implications:
- Hypotonic solutions like 5% dextrose (and by extension 4.5%) distribute into intracellular spaces after glucose metabolism and may exacerbate ischemic brain edema in stroke patients 2
- The American Heart Association recommends isotonic solutions such as 0.9% saline over hypotonic dextrose solutions for patients with acute ischemic stroke 2
- D5 with 0.45% NaCl is hypotonic and can cause hyponatremia in acutely ill patients with SIAD-like states 3
Appropriate Use of This Solution
This D4.5 solution is NOT appropriate for acute hypoglycemia treatment:
- For acute severe hypoglycemia, administer 5-gram aliquots of D50 repeated every 1-2 minutes until symptoms resolve or blood glucose exceeds 70 mg/dL 3, 4
- The FDA recommends 10-25 grams of dextrose (20-50mL of 50% dextrose) for insulin-induced hypoglycemia 5
- Traditional 25-gram D50 boluses frequently cause overcorrection with post-treatment glucose levels of 169 mg/dL versus 112 mg/dL with titrated D10 1
This D4.5 solution may be appropriate for:
- Maintenance fluid therapy to prevent hypoglycemia during insulin infusions (though D5 is more standard) 3
- Gradual glucose supplementation in patients requiring both volume resuscitation and glucose support 3
Critical Safety Warning
Concentrated dextrose solutions >10% requiring sustained infusion need central venous access to minimize thrombosis risk 3. However, this D4.5 solution is below this threshold and can be administered peripherally.