Bicarbonate Administration in Metabolic Acidosis
Bicarbonate therapy is recommended when pH falls below 7.0, but is not necessary if pH is 7.0 or higher. 1
pH-Based Recommendations for Bicarbonate Administration
- For patients with pH < 7.0: Administer sodium bicarbonate to prevent complications associated with severe acidemia 1
- For patients with pH 6.9-7.0: Administer 50 mmol sodium bicarbonate diluted in 200 ml sterile water and infuse at a rate of 200 ml/h 1
- For patients with pH ≥ 7.0: No bicarbonate therapy is required as reestablishing insulin activity (in DKA) or treating the underlying cause will resolve the acidosis 1
Special Considerations by Condition
Diabetic Ketoacidosis (DKA)
- In adult DKA patients with pH < 7.0, bicarbonate administration may help prevent complications while the underlying cause is being addressed 1
- In pediatric DKA patients, if pH remains < 7.0 after initial hour of hydration, administer 1-2 mEq/kg sodium bicarbonate over 1 hour 1
- Bicarbonate can be added to NaCl with required potassium, ensuring solution does not exceed 155 mEq/L sodium 1
Sepsis-Induced Lactic Acidosis
- Bicarbonate therapy is not recommended for hypoperfusion-induced lactic acidemia with pH ≥ 7.15 1
- For pH < 7.15 in sepsis, evidence is limited, but severe acidemia may warrant bicarbonate therapy based on clinical judgment 1
Monitoring During Bicarbonate Administration
- Monitor serum potassium levels closely as insulin and bicarbonate therapy lower serum potassium 1
- Maintain potassium supplementation in intravenous fluids and monitor carefully 1
- Perform serial blood gas measurements to assess response to therapy 2
- Monitor for complications of bicarbonate therapy including hypernatremia, hypokalemia, ionic hypocalcemia, and rebound alkalosis 3
Evidence Quality and Considerations
- Prospective randomized studies have failed to show beneficial or deleterious effects of bicarbonate therapy in patients with pH between 6.9 and 7.1 1
- No prospective randomized studies exist for bicarbonate use in patients with pH < 6.9 1
- Recent research suggests possible benefit of bicarbonate therapy in patients with both severe metabolic acidosis and acute kidney injury 4
Cautions and Contraindications
- Bicarbonate administration can cause sodium and fluid overload, increased lactate and PCO2, and decreased serum ionized calcium 1
- In mechanically ventilated patients receiving bicarbonate, ventilator settings may need adjustment to facilitate CO2 elimination 3
- Isotonic solutions should be preferred over hypertonic bicarbonate to minimize complications 3
The decision to administer bicarbonate should be based primarily on pH level, with pH < 7.0 being the clearest indication for therapy, while recognizing that the underlying cause of acidosis must always be addressed simultaneously.