What is the role of sodium bicarbonate in treating metabolic acidosis?

From the Guidelines

Sodium bicarbonate is a crucial treatment for metabolic acidosis, and its administration should aim to maintain serum bicarbonate levels at or above 22 mmol/L to mitigate the adverse effects of acidemia on protein metabolism and overall health. When treating metabolic acidosis, sodium bicarbonate can be administered orally, typically at a dose of 2 to 4 g/d or 25 to 50 mEq/d, to effectively increase serum bicarbonate concentrations 1. The correction of acidemia due to metabolic acidosis has been associated with increased serum albumin, decreased protein degradation rates, and increased plasma concentrations of branched chain amino acids and total essential amino acids 1.

Key Considerations for Sodium Bicarbonate Administration

• The goal of sodium bicarbonate therapy in metabolic acidosis is to normalize the serum bicarbonate concentration, which can be achieved through oral supplementation or higher dialysate bicarbonate concentrations in patients undergoing dialysis 1.
• Oral sodium bicarbonate is effective for chronic, less severe acidosis, while intravenous administration may be necessary for severe metabolic acidosis, with careful monitoring to avoid complications such as fluid overload and electrolyte imbalances.
• The dosing of sodium bicarbonate should be tailored to the individual patient's needs, taking into account the severity of the acidosis, the patient's weight, and the desired increase in serum bicarbonate concentration.

Recent Guidelines and Evidence

Recent guidelines, such as those from the Surviving Sepsis Campaign, suggest against the use of sodium bicarbonate therapy to improve hemodynamics or reduce vasopressor requirements in patients with hypoperfusion-induced lactic acidemia with pH ≥ 7.15, due to the lack of evidence supporting its effectiveness in this context 1. However, this recommendation does not apply to the treatment of metabolic acidosis in general, where sodium bicarbonate remains a valuable therapeutic agent.

Monitoring and Adjustments

Treatment with sodium bicarbonate should be accompanied by regular monitoring of serum bicarbonate levels, as well as other electrolytes, to ensure that the desired therapeutic range is achieved without causing undue side effects. Adjustments to the dose or administration route may be necessary based on the patient's response to therapy and the presence of any complications. The primary focus should always be on maintaining optimal serum bicarbonate levels to improve morbidity, mortality, and quality of life outcomes in patients with metabolic acidosis.

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 - e.g., insulin in uncomplicated diabetes, blood volume restoration in shock. But since an appreciable time interval may elapse before all of the ancillary effects are brought about, bicarbonate therapy is indicated to minimize risks inherent to the acidosis itself. Intravenous sodium bicarbonate therapy increases plasma bicarbonate, buffers excess hydrogen ion concentration, raises blood pH and reverses the clinical manifestations of acidosis.

The role of sodium bicarbonate in treating metabolic acidosis is to:

• Increase plasma bicarbonate
• Buffer excess hydrogen ion concentration
• Raise blood pH
• Reverse the clinical manifestations of acidosis It is indicated to minimize risks inherent to the acidosis itself, and should be used in conjunction with measures to control the underlying cause of the acidosis 2, 2.

From the Research

Role of Sodium Bicarbonate in Treating Metabolic Acidosis

• Sodium bicarbonate is used to treat metabolic acidosis, but its effectiveness is still debated 3, 4, 5, 6, 7
• The use of sodium bicarbonate is intuitive, but data suggest that not all patients benefit from this therapy, and it may even cause harm in certain scenarios 3
• Sodium bicarbonate can be beneficial in specific situations, such as:
  • Patients with concomitant acute kidney injury and lactic acidosis 3
  • Patients with cardiac arrest secondary to sodium channel blockade or hyperkalemia 3
  • Patients with nongap acidosis 3
• However, sodium bicarbonate may not be effective in other situations, such as:
  • Lactic acidosis, where its use is not recommended due to lack of evidence supporting its benefits 4
  • Diabetic ketoacidosis, where its use does not confer improved patient outcomes and may cause harm in pediatric patients 3, 5
  • Rhabdomyolysis, where alkalinization of urine does not improve patient-centered outcomes 3
• The administration of sodium bicarbonate should be reserved for conditions with clear benefits to patients, and its use should be guided by evidence-based recommendations 3, 6, 7
• The dosing of sodium bicarbonate is also important, and it should be correlated with body weight and the severity of metabolic acidosis 6
• Potential harm from excessive sodium bicarbonate administration includes paradoxical respiratory acidosis, intracellular acidosis, hypokalemia, hypocalcemia, alkalosis, impaired oxygen delivery, cerebrospinal fluid acidosis, and neurologic dysfunction 7