Why Sodium Bicarbonate is Diluted in 5% Dextrose (or Other Solutions)
Sodium bicarbonate is NOT typically diluted in 5% dextrose—this is actually contraindicated in most clinical scenarios. Instead, sodium bicarbonate is diluted with normal saline (0.9% NaCl) or sterile water to create isotonic solutions, as dextrose-containing solutions can cause compatibility issues and are not recommended by major guidelines 1.
Correct Dilution Practices for Sodium Bicarbonate
Standard Dilution Protocols
For pediatric patients under 2 years, the American Academy of Pediatrics mandates diluting 8.4% sodium bicarbonate 1:1 with normal saline or sterile water to achieve a 4.2% (0.5 mEq/mL) concentration before administration 1.
For newborn infants specifically, only the 0.5 mEq/mL (4.2%) concentration should be used, requiring dilution of the standard 8.4% stock solution 1.
For adults and children ≥2 years, the 8.4% solution may be used without dilution, though dilution is often performed for safety to reduce hyperosmolar complications 1.
Why Normal Saline (Not Dextrose) is Used
Isotonic bicarbonate solutions are prepared by diluting hypertonic 8.4% bicarbonate with normal saline to prevent hyperosmolarity, which can compromise cerebral perfusion pressure and worsen outcomes in critically ill patients 1.
The 8.4% sodium bicarbonate solution has an osmolality of approximately 2000 mOsm/L (extremely hypertonic), making dilution essential to avoid complications 1.
No commercially available isotonic bicarbonate solutions exist in the United States, requiring pharmacy compounding and creating risk for preparation errors 1.
Critical Safety Considerations
What NOT to Mix with Sodium Bicarbonate
Never mix sodium bicarbonate with calcium-containing solutions, as this causes precipitation 1.
Never mix with vasoactive amines (epinephrine, norepinephrine, dopamine, dobutamine), as bicarbonate inactivates catecholamines in alkaline solutions 1.
Flush IV lines with normal saline before and after bicarbonate administration to prevent drug interactions 1.
Why Dextrose is Problematic
Dextrose solutions do not provide the chloride needed for effective correction of metabolic acidosis, particularly in chloride-responsive alkalosis scenarios 2.
The combination may lead to unpredictable osmotic effects and does not address the underlying electrolyte derangements that accompany severe acidosis 1.
Specific Clinical Scenarios for Dilution
Severe Metabolic Acidosis (pH <7.1)
The American Diabetes Association recommends infusing 100 mmol sodium bicarbonate in 400 mL sterile water at 200 mL/h for adults with pH <6.9 in diabetic ketoacidosis 1.
For pH 6.9-7.0, use 50 mmol sodium bicarbonate in 200 mL sterile water at 200 mL/h 1.
Continuous Infusion Protocols
For sodium channel blocker toxicity, prepare a 150 mEq/L solution by appropriately diluting 8.4% bicarbonate, then infuse at 1-3 mL/kg/h 1.
The American Heart Association recommends this concentration for maintaining alkalosis after initial bolus therapy 1.
Common Pitfalls to Avoid
Do not use dextrose-containing solutions as the primary diluent for sodium bicarbonate—this is not supported by any major guideline and may cause compatibility issues 1.
Avoid hypertonic administration in volume-sensitive patients (heart failure, renal impairment) without proper dilution to 4.2% concentration 1.
Monitor for hypernatremia (target <150-155 mEq/L) and excessive alkalemia (pH not to exceed 7.50-7.55) during therapy 1.
Ensure adequate ventilation before administering bicarbonate, as it produces CO2 that must be eliminated to prevent paradoxical intracellular acidosis 1.