Sodium Bicarbonate Dosing for Metabolic Acidosis
For metabolic acidosis, sodium bicarbonate should be administered at an initial dose of 1-2 mEq/kg IV bolus for severe cases (pH < 7.0), followed by 2-5 mEq/kg over 4-8 hours depending on severity, with careful monitoring of blood gases and electrolytes. 1, 2
Dosing Guidelines Based on Severity
Severe Metabolic Acidosis (pH < 7.0)
- Initial dose: 1-2 mEq/kg IV bolus 1
- In cardiac arrest: 44.6-100 mEq (1-2 50mL vials) rapidly, then 44.6-50 mEq every 5-10 minutes as needed 2
- Maintenance: 2-5 mEq/kg over 4-8 hours 1, 2
Less Urgent Metabolic Acidosis
- 2-5 mEq/kg body weight over 4-8 hours 2
- Target initial correction: Aim for serum bicarbonate of approximately 20 mEq/L within first 24 hours 2
- Important: Do not attempt full correction in first 24 hours to avoid rebound alkalosis 2
Administration Principles
Stepwise Approach
- Start with initial dose based on severity
- Monitor response with arterial blood gases
- Adjust subsequent dosing based on clinical response
- Avoid overcorrection (target pH ~7.2-7.3 initially rather than complete normalization) 1, 2
Rate Considerations
- Severe cases: More rapid administration
- Less urgent cases: Slower administration over 4-8 hours
- Caution with very rapid infusion of large quantities due to hypertonicity 2
Essential Monitoring During Treatment
- Arterial blood gases
- Serum electrolytes (especially potassium, sodium, calcium)
- ECG
- Blood pressure
- Mental status 1
Important Precautions and Potential Complications
Potential Adverse Effects
- Hypernatremia
- Hyperosmolarity
- Extracellular alkalosis with paradoxical intracellular acidosis
- Excess CO₂ production
- Hypocalcemia
- Hypokalemia
- Inactivation of simultaneously administered catecholamines 1
Special Considerations
- In mechanically ventilated patients: Increase minute ventilation to compensate for additional CO₂ production 1
- In renal failure: Consider lower doses and slower administration 1
- Bicarbonate therapy is not recommended for mild metabolic acidosis with pH ≥ 7.15 1
Calculation Approach
The dose can be estimated using the following approach:
- Calculate deficit: (Desired HCO3⁻ - Current HCO3⁻) × 0.5 × Body weight (kg)
- The factor 0.5 accounts for the distribution volume of bicarbonate
Clinical Pearls
- Bicarbonate therapy should always be planned in a stepwise fashion since response is not precisely predictable 2
- Achievement of total CO₂ content of about 20 mEq/L at the end of the first day usually results in normal blood pH 2
- Sodium bicarbonate decreases serum potassium levels, making it beneficial in patients with concurrent hyperkalemia 1, 3
- Inspect parenteral solutions visually for particulate matter and discoloration prior to administration 2