What is the treatment for severe metabolic acidosis with sodium bicarbonate (NaHCO3)?

From the Guidelines

Sodium bicarbonate (NaHCO3) is recommended for the treatment of severe metabolic acidosis, with an initial dose of 1-2 mEq/kg administered intravenously, targeting a pH > 7.2. The treatment of severe metabolic acidosis with sodium bicarbonate (NaHCO3) should be guided by the most recent and highest quality evidence available.

Key Considerations

• The initial dose of sodium bicarbonate is typically 1-2 mEq/kg, administered intravenously over 30-60 minutes, with subsequent dosing based on repeat blood gas measurements 1.
• For emergency situations, 50-100 mEq can be given as an IV bolus.
• The standard concentration of sodium bicarbonate is 8.4% (1 mEq/mL), though 4.2% may be used in children.
• Treatment should target a pH > 7.2 rather than complete normalization.
• Bicarbonate therapy carries risks including volume overload, hypernatremia, paradoxical CSF acidosis, and potential worsening of intracellular acidosis.
• It's most beneficial in cases of severe acidemia due to bicarbonate loss (renal tubular acidosis, diarrhea) or lactic acidosis with hemodynamic compromise.
• In diabetic ketoacidosis, respiratory acidosis, or mild-moderate acidemia, bicarbonate is generally not recommended as primary therapy, as several studies have shown that its use made no difference in the resolution of acidosis or time to discharge 1.

Monitoring and Concurrent Treatment

• Concurrent treatment of the underlying cause is essential.
• Patients should be monitored for electrolyte imbalances, particularly hypokalemia which can occur as acidosis resolves.
• The use of bicarbonate in patients with diabetic ketoacidosis is generally not recommended, and treatment should focus on restoration of circulatory volume and tissue perfusion, resolution of hyperglycemia, and correction of electrolyte imbalance and acidosis 1.

From the FDA Drug Label

Sodium Bicarbonate Injection, USP is indicated in the treatment of metabolic acidosis which may occur in severe renal disease, uncontrolled diabetes, circulatory insufficiency due to shock or severe dehydration, extracorporeal circulation of blood, cardiac arrest and severe primary lactic acidosis Vigorous bicarbonate therapy is required in any form of metabolic acidosis where a rapid increase in plasma total CO2 content is crucial - e. g., cardiac arrest, circulatory insufficiency due to shock or severe dehydration, and in severe primary lactic acidosis or severe diabetic acidosis.

The treatment for severe metabolic acidosis with sodium bicarbonate (NaHCO3) is vigorous bicarbonate therapy to minimize risks inherent to the acidosis itself, and it should be superimposed on measures designed to control the basic cause of the acidosis 2.

From the Research

Treatment of Severe Metabolic Acidosis with Sodium Bicarbonate (NaHCO3)

• The use of sodium bicarbonate to treat metabolic acidosis is intuitive, yet data suggest that not all patients benefit from this therapy 3.
• Severe metabolic acidosis is defined by a pH < 7.2 with HCO3- < 8 mE- q/L in plasma, and its best treatment is to correct the underlying cause 4.
• Intravenous NaHCO3 buffers severe acidemia, preventing the associated damage and gains time while the causal disease is corrected 4.
• The indication for sodium bicarbonate requires a risk-benefit assessment, considering its complications, such as hypernatremia, hypokalemia, ionic hypocalcemia, rebound alkalosis, and intracellular acidosis 4, 5.
• Bicarbonate therapy should be individualized, and in general, bicarbonate should be given at an arterial blood pH of < or =7.0 5.
• The amount of bicarbonate given should be what is calculated to bring the pH up to 7.2 5.
• The current literature suggests limited benefit from bicarbonate therapy for patients with severe metabolic acidosis (pH < 7.1 and bicarbonate < 6 mEq/L), but bicarbonate therapy does yield improvement in survival for patients with accompanying acute kidney injury 6.
• Patients with cardiac arrest secondary to sodium channel blockade or hyperkalemia, and those with concomitant acute kidney injury and lactic acidosis may benefit from sodium bicarbonate therapy 3.