Sodium Bicarbonate Dosing for Metabolic Acidosis
Initial Bolus Dose
For adults with severe metabolic acidosis (pH < 7.1), administer 1-2 mEq/kg IV (typically 50-100 mEq or 50-100 mL of 8.4% solution) given slowly over several minutes. 1, 2, 3
- For pediatric patients, the standard dose is 1-2 mEq/kg IV given slowly 1
- For newborn infants, use only 0.5 mEq/mL (4.2%) concentration, achieved by diluting 8.4% solution 1:1 with normal saline or sterile water 1
- In cardiac arrest, a rapid dose of one to two 50 mL vials (44.6 to 100 mEq) may be given initially and continued at 50 mL every 5-10 minutes as indicated by arterial pH monitoring 3
pH-Based Dosing Algorithm
The decision to administer bicarbonate should be guided by arterial pH, not just serum bicarbonate levels:
- pH < 6.9: Administer 100 mmol sodium bicarbonate in 400 mL sterile water infused at 200 mL/hour 1, 2
- pH 6.9-7.0: Administer 50 mmol sodium bicarbonate in 200 mL sterile water infused at 200 mL/hour 1, 2
- pH 7.0-7.1: Consider 1-2 mEq/kg IV bolus given slowly, with repeat dosing guided by arterial blood gas analysis 1, 4
- pH ≥ 7.15: Do not administer bicarbonate for hypoperfusion-induced lactic acidemia or sepsis-related acidosis 1, 2
Continuous Infusion Dosing
For ongoing alkalinization needs, prepare a 150 mEq/L solution and infuse at 1-3 mL/kg/hour. 1
- This is particularly indicated for sodium channel blocker toxicity or tricyclic antidepressant overdose after initial bolus 1
- For less urgent metabolic acidosis, 2-5 mEq/kg over 4-8 hours produces measurable improvement 3
Chronic Oral Supplementation
For maintenance dialysis patients or chronic kidney disease, oral sodium bicarbonate 2-4 g/day (25-50 mEq/day) effectively increases serum bicarbonate concentrations. 5
- Target serum bicarbonate ≥ 22 mmol/L in dialysis patients 5
- Higher dialysate bicarbonate concentrations (38 mmol/L) can also safely increase predialysis serum bicarbonate 5
Critical Monitoring Requirements
Monitor arterial blood gases and serum electrolytes every 2-4 hours during active bicarbonate therapy:
- Target pH of 7.2-7.3, not complete normalization 1, 3
- Avoid serum sodium > 150-155 mEq/L 1
- Avoid pH > 7.50-7.55 1
- Monitor and replace potassium, as bicarbonate shifts potassium intracellularly 1
- Monitor ionized calcium, especially with doses > 50-100 mEq 1
Special Clinical Scenarios
Sodium Channel Blocker/TCA Toxicity
Administer 50-150 mEq bolus using hypertonic solution (1000 mEq/L), followed by continuous infusion of 150 mEq/L at 1-3 mL/kg/hour. 1
Hyperkalemia
Use bicarbonate as adjunct therapy (1-2 mEq/kg IV) to shift potassium intracellularly while definitive treatments are initiated. 1
- Combine with glucose/insulin for synergistic effect 1
Diabetic Ketoacidosis
Bicarbonate is indicated only if pH < 6.9 in adult DKA patients. 1, 2
- For pH 6.9-7.0: 50 mmol in 200 mL sterile water at 200 mL/hour 1
- For pH < 6.9: 100 mmol in 400 mL sterile water at 200 mL/hour 1
- Do not use if pH ≥ 7.0 2
Critical Safety Considerations
Ensure effective ventilation is established before administering bicarbonate, as it produces CO2 that must be eliminated to prevent paradoxical intracellular acidosis. 1, 2
- Never mix bicarbonate with calcium-containing solutions or vasoactive amines 1, 2
- Flush IV line with normal saline before and after bicarbonate administration 1
- Bicarbonate can cause hypernatremia, hyperosmolarity, hypokalemia, decreased ionized calcium, and extracellular alkalosis 1, 2
When NOT to Use Bicarbonate
Do not administer bicarbonate for:
- Hypoperfusion-induced lactic acidemia with pH ≥ 7.15 1, 2
- Routine use in cardiac arrest (except specific toxicologic scenarios) 1
- Sepsis-related acidosis with pH > 7.15 1
- Diabetic ketoacidosis with pH ≥ 7.0 1, 2
The best treatment for metabolic acidosis remains correcting the underlying cause and restoring adequate circulation. 1 Bicarbonate therapy should be restrained and used only when clinical judgment suggests clear benefit, as indiscriminate use does not improve patient-centered outcomes and may cause harm. 4, 6