When to order sodium bicarbonate (NaHCO3) for treatment of acidosis with low bicarbonate levels or metabolic acidosis?

From the Guidelines

Sodium bicarbonate therapy should only be considered in patients with diabetic ketoacidosis (DKA) when the arterial pH is less than 6.9, as its use is generally not recommended in other cases, according to the most recent and highest quality study 1.

Key Considerations

• The use of bicarbonate in patients with DKA has been shown to make no difference in the resolution of acidosis or time to discharge, as stated in the study 1.
• The management goals for DKA include restoration of circulatory volume and tissue perfusion, resolution of ketoacidosis, and correction of electrolyte imbalance and acidosis, as outlined in the study 1.
• Continuous intravenous insulin is the standard of care for critically ill and mentally obtunded individuals with DKA or hyperosmolar hyperglycemia, as recommended in the study 1.

Treatment Approach

• Treatment should focus on addressing the underlying cause of the acidosis rather than bicarbonate administration, unless the patient has a severe metabolic acidosis with a pH less than 6.9, as suggested in the study 1.
• The standard initial dose of sodium bicarbonate is not specified in the most recent study, but it is essential to monitor electrolytes, pH, and clinical status continuously during treatment, with the goal of raising pH to safer levels, as implied in the study 1.

Potential Risks

• Bicarbonate therapy has potential risks, including paradoxical CNS acidosis, volume overload, hypernatremia, and hyperosmolality, which should be carefully considered before initiating treatment, as mentioned in the example answer.

Clinical Decision-Making

• The decision to use sodium bicarbonate therapy should be individualized based on a careful clinical and laboratory assessment, taking into account the patient's specific condition and the potential risks and benefits of treatment, as emphasized in the study 1.

From the FDA Drug Label

In cardiac arrest, a rapid intravenous dose of one to two 50 mL vials (44.6 to 100 mEq) may be given initially and continued at a rate of 50 mL (44. 6 to 50 mEq) every 5 to 10 minutes if necessary (as indicated by arterial pH and blood gas monitoring) to reverse the acidosis. The amount of bicarbonate to be given to older children and adults over a four-to-eight-hour period is approximately 2 to 5 mEq/kg of body weight - depending upon the severity of the acidosis as judged by the lowering of total CO2 content, blood pH and clinical condition of the patient The aim of all bicarbonate therapy is to produce a substantial correction of the low total CO2 content and blood pH, but the risks of overdosage and alkalosis should be avoided

Sodium bicarbonate administration should be considered when:

• Arterial pH is low, indicating acidosis
• Blood gas monitoring shows a need for correction of acidosis
• Total CO2 content is low
• Severe symptoms of metabolic acidosis are present

The decision to order sodium bicarbonate should be based on the severity of the acidosis, as judged by the lowering of total CO2 content, blood pH, and clinical condition of the patient 2. Repeated fractional doses and periodic monitoring by appropriate laboratory tests are recommended to minimize the possibility of overdosage 2.

From the Research

Ordering Sodium Bicarbonate

• Sodium bicarbonate is used to treat severe diabetic ketoacidosis, but its effectiveness in improving arterial pH is still debated 3, 4, 5.
• The American Diabetes Association recommends considering intravenous bicarbonate for patients with a pH less than 6.9 5.
• However, studies have shown that bicarbonate therapy may not be necessary for patients with mild to moderate acidosis, and its use may even have adverse effects 6, 4.
• A study found that intravenous bicarbonate therapy did not decrease time to resolution of acidosis or time to hospital discharge for patients with DKA with an initial pH less than 7.0 5.

pH and Bicarbonate Levels

• A diagnosis of diabetic ketoacidosis requires a plasma glucose concentration above 250 mg per dL, a pH level less than 7.30, and a bicarbonate level of 18 mEq per L or less 6.
• Serum bicarbonate levels of ≤16 mEq/L can predict intravenous to subcutaneous transition failures among patients with a normal anion gap at the time of transition 7.
• Bicarbonate levels can be used to monitor the effectiveness of treatment and predict the risk of transition failure 7.

Treatment Guidelines

• Intravenous insulin and fluid replacement are the mainstays of therapy for diabetic ketoacidosis, with careful monitoring of potassium levels 6.
• Bicarbonate therapy is rarely needed, and its use should be considered on a case-by-case basis 6, 4, 5.
• Treatment guidelines recommend transitioning to subcutaneous insulin when the anion gap closes, but transition failures due to recrudescent ketoacidosis are common 7.