What is the evidence for sodium bicarbonate in treating metabolic acidosis?

From the Guidelines

Sodium bicarbonate therapy should not be used to treat metabolic acidosis in patients with pH ≥ 7.15, as it does not improve hemodynamics or reduce vasopressor requirements, according to the most recent guidelines 1. The use of sodium bicarbonate in treating metabolic acidosis is a topic of debate, with evidence suggesting that it may not be beneficial in certain situations.

Key Points to Consider

• The Surviving Sepsis Campaign guidelines suggest against the use of sodium bicarbonate therapy in patients with hypoperfusion-induced lactic acidemia with pH ≥ 7.15 1.
• Two blinded, crossover RCTs failed to reveal any difference in hemodynamic variables or vasopressor requirements between equimolar saline and sodium bicarbonate in patients with lactic acidosis 1.
• Bicarbonate administration has been associated with sodium and fluid overload, an increase in lactate and Paco2, and a decrease in serum ionized calcium, but the directness of these variables to outcome is uncertain 1.
• The effect of sodium bicarbonate administration on hemodynamics and vasopressor requirements at lower pH, as well as the effect on clinical outcomes at any pH level, is unknown 1.

Clinical Considerations

• Sodium bicarbonate therapy may be useful in limiting tidal volume in ARDS in some situations of permissive hypercapnia, but this is not directly related to the treatment of metabolic acidosis 1.
• The American Heart Association guidelines do not recommend routine use of sodium bicarbonate for patients in cardiac arrest, except in special situations such as preexisting metabolic acidosis, hyperkalemia, or tricyclic antidepressant overdose 1.
• When bicarbonate is used, an initial dose of 1 mEq/kg is typical, and therapy should be guided by the bicarbonate concentration or calculated base deficit obtained from blood gas analysis or laboratory measurement 1.

Treatment Approach

• Treatment of metabolic acidosis should focus on addressing the underlying cause, rather than relying on sodium bicarbonate therapy.
• Continuous infusions may be preferred over bolus dosing to avoid rapid pH changes, with careful monitoring of serum electrolytes, pH, and clinical response.
• The use of sodium bicarbonate should be individualized and based on the specific clinical situation, taking into account the potential risks and benefits.

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 Treatment of metabolic acidosis should, if possible, be superimposed on measures designed to control the basic cause of the 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 evidence supports the use of sodium bicarbonate in treating metabolic acidosis. The drug label indicates that sodium bicarbonate is used to treat metabolic acidosis in various conditions, including:

• Severe renal disease
• Uncontrolled diabetes
• Circulatory insufficiency due to shock or severe dehydration
• Cardiac arrest
• Severe primary lactic acidosis The label also emphasizes the importance of addressing the underlying cause of the acidosis, while using bicarbonate therapy to minimize the risks associated with the acidosis itself 2.

From the Research

Evidence for Sodium Bicarbonate in Treating Metabolic Acidosis

• The use of sodium bicarbonate to treat metabolic acidosis is a topic of ongoing debate, with some studies suggesting limited benefit and potential harm 3, 4, 5, 6.
• A review of the literature found that sodium bicarbonate does not confer improved patient outcomes in diabetic ketoacidosis and may cause harm in pediatric patients 4.
• Another study found that the use of sodium bicarbonate in patients with lactic acidosis does not have any salutary effects and may have negative side effects 5.
• A systematic review of bicarbonate therapy for critically ill patients with metabolic acidosis found limited benefit from bicarbonate therapy for patients with severe metabolic acidosis, but improvement in survival for patients with accompanying acute kidney injury 7.
• The routine use of sodium bicarbonate is not indicated in high anion gap metabolic acidosis associated with lactic acidosis, diabetic ketoacidosis, and cardiopulmonary resuscitation, due to lack of evidence of benefits and potential side effects 6.

Specific Scenarios

• Patients with cardiac arrest secondary to sodium channel blockade or hyperkalemia may benefit from sodium bicarbonate therapy 4.
• Patients with concomitant acute kidney injury and lactic acidosis may benefit from sodium bicarbonate 4.
• Patients with nongap acidosis may benefit from sodium bicarbonate supplementation 4.
• Alkalinization of urine in rhabdomyolysis does not improve patient-centered outcomes 4.

Treatment Recommendations

• Treating the underlying disease is essential to reverse the process of metabolic acidosis 6.
• Emergency physicians should reserve the use of sodium bicarbonate to conditions with clear benefit to patients 4.
• The use of sodium bicarbonate should be considered on a case-by-case basis, taking into account the underlying cause of the metabolic acidosis and the potential risks and benefits of treatment 3, 4, 7, 5, 6.