What is the role of sodium bicarbonate (NaHCO3) in the treatment of lactic acidosis?

From the Guidelines

Sodium bicarbonate is not recommended for the treatment of lactic acidosis in patients with pH ≥ 7.15, as it has not been shown to improve hemodynamics or reduce vasopressor requirements 1.

Treatment Approach

The primary focus of treatment should be on addressing the underlying cause of lactic acidosis, such as:

• Improving tissue perfusion
• Treating infection
• Discontinuing offending medications

Use of Sodium Bicarbonate

Sodium bicarbonate may be considered in severe cases with pH < 7.1 or when acidosis is compromising hemodynamic stability. If used, it should be administered as an IV infusion of 1-2 mEq/kg over 30-60 minutes, with careful monitoring 1.

Rationale for Limited Use

The limited use of sodium bicarbonate is due to its potential to:

• Worsen intracellular acidosis by generating CO2 that readily crosses cell membranes
• Cause volume overload, hypernatremia, and paradoxical CSF acidosis
• Mask the resolution of the underlying condition causing the lactic acidosis

Monitoring and Ventilation

If sodium bicarbonate is used, it should be accompanied by:

• Adequate ventilation to eliminate the CO2 produced
• Frequent reassessment of acid-base status, electrolytes, and clinical response 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.

Sodium bicarbonate treatment is indicated for severe primary lactic acidosis. The treatment should be used to minimize risks inherent to the acidosis itself, and vigorous bicarbonate therapy is required in cases where a rapid increase in plasma total CO2 content is crucial 2.

• Key points:
  • Sodium bicarbonate is indicated for severe primary lactic acidosis
  • Vigorous bicarbonate therapy is required in severe cases
  • Treatment should be used to minimize risks inherent to the acidosis itself

From the Research

Lactic Acidosis Treatment with Sodium Bicarbonate

• The use of sodium bicarbonate to treat lactic acidosis is a controversial topic, with some studies suggesting it may not be effective in improving patient outcomes 3, 4, 5.
• Sodium bicarbonate may have negative side effects, such as decreasing vasomotor tone, decreasing myocardial contractility, and inducing intracellular acidosis 5, 6.
• The Surviving Sepsis guidelines recommend against the use of bicarbonate in patients with pH at least 7.15, while deferring judgment in more severe acidemia 4.
• Some studies suggest that bicarbonate use may be beneficial in patients with severe acidemia (pH < 7.2) and acute kidney injury, but the evidence is limited 5.
• Alternative treatments, such as dichloroacetate, THAM, or Carbicarb, or dialysis, may be considered as they may provide base with fewer untoward effects 7, 6.

Mechanisms and Rationale

• Lactic acidosis can result from various etiologies, including hypoperfusion, medications, organ dysfunction, and sepsis 5.
• Acidemia can have deleterious effects on organ systems, but it can also have positive effects, such as increasing localized blood flow and oxygen delivery 5.
• The use of sodium bicarbonate to correct severe acidemia may be tempting, but its effectiveness is unclear, and it may have negative side effects 3, 4, 5.

Clinical Considerations

• If sodium bicarbonate is used, it should be given as a slow IV infusion in the setting of adequate ventilation and calcium replacement to mitigate its untoward effects 4, 5.
• The target pH for treatment with sodium bicarbonate is unclear, but some studies suggest a lower target pH of 7.00 or less 4.
• Effective therapy of lactic acidosis due to shock is to reverse the cause, rather than relying solely on sodium bicarbonate treatment 4.