What are the indications and dosing guidelines for sodium bicarbonate in clinical practice?

From the Guidelines

Sodium bicarbonate is primarily indicated for the treatment of severe metabolic acidosis, cardiac arrest with prolonged resuscitation, certain drug overdoses, and hyperkalemia, with dosing guided by the most recent evidence from 2023 1.

Indications and Dosing Guidelines

The indications for sodium bicarbonate include:

• Severe metabolic acidosis (pH <7.1)
• Cardiac arrest with prolonged resuscitation
• Certain drug overdoses, such as tricyclic antidepressant overdose
• Hyperkalemia The standard dosing for sodium bicarbonate varies depending on the indication:
• For metabolic acidosis, the initial dose is 1-2 mEq/kg IV, followed by infusion based on arterial blood gas results
• During cardiac arrest, the initial dose is 1 mEq/kg IV, with 0.5 mEq/kg every 10 minutes during prolonged resuscitation
• For hyperkalemia, 50 mEq IV over 5 minutes can temporarily shift potassium into cells
• In cases of tricyclic antidepressant overdose, sodium bicarbonate at 1-2 mEq/kg IV bolus is used to achieve serum alkalinization (target pH 7.45-7.55) 1

Administration and Monitoring

Administration of sodium bicarbonate should be accompanied by monitoring of:

• Arterial blood gases
• Serum electrolytes
• Clinical response Caution is necessary as inappropriate use can cause metabolic alkalosis, hypernatremia, hyperosmolality, and paradoxical intracellular acidosis 1.

Special Considerations

In cases of tricyclic antidepressant overdose, experts recommend avoiding extremes of hypernatremia (serum sodium not to exceed 150–155 mEq/L) and alkalemia (serum pH not to exceed 7.50–7.55) to avoid iatrogenic harm 1. Sodium bicarbonate works by increasing blood pH through the provision of bicarbonate ions, which buffer excess hydrogen ions in the bloodstream. Key points to consider when using sodium bicarbonate include:

• The need for careful monitoring of arterial blood gases, serum electrolytes, and clinical response
• The risk of metabolic alkalosis, hypernatremia, hyperosmolality, and paradoxical intracellular acidosis with inappropriate use
• The importance of avoiding extremes of hypernatremia and alkalemia in cases of tricyclic antidepressant overdose
• The use of sodium bicarbonate as part of a comprehensive treatment plan for severe metabolic acidosis, cardiac arrest with prolonged resuscitation, certain drug overdoses, and hyperkalemia.

From the FDA Drug Label

INDICATIONS & USAGE SECTION 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 DOSAGE & ADMINSTRATION Sodium Bicarbonate Injection, USP is administered by the intravenous route. In cardiac arrest, a rapid intravenous dose of one to two 50 mL syringes (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 indications for sodium bicarbonate in clinical practice include:

• Metabolic acidosis due to severe renal disease, uncontrolled diabetes, or circulatory insufficiency
• Cardiac arrest
• Severe primary lactic acidosis
• Certain drug intoxications
• Severe diarrhea

The dosing guidelines are:

• In cardiac arrest: 1-2 50 mL syringes (44.6-100 mEq) initially, followed by 50 mL (44.6-50 mEq) every 5-10 minutes as needed
• In less urgent forms of metabolic acidosis: 2-5 mEq/kg body weight over 4-8 hours
• Therapy should be monitored by measuring blood gases, plasma osmolarity, arterial blood lactate, hemodynamics, and cardiac rhythm 2
• The treatment of metabolic acidosis should be superimposed on measures designed to control the basic cause of the acidosis 2

From the Research

Indications for Sodium Bicarbonate

• Sodium bicarbonate is indicated for the treatment of metabolic acidosis, particularly in patients with severe acidaemia 3, 4.
• It is also used to treat patients with cardiac arrest secondary to sodium channel blockade or hyperkalemia 5.
• Patients with concomitant acute kidney injury and lactic acidosis may benefit from sodium bicarbonate therapy 5.
• Sodium bicarbonate can be used to treat nongap acidosis, and patients with this condition may benefit from supplementation 5.

Dosing Guidelines

• The dose of sodium bicarbonate should be individualized and based on the patient's clinical situation 4.
• In general, bicarbonate should be given at an arterial blood pH of ≤7.0, and the amount given should be what is calculated to bring the pH up to 7.2 4.
• A 4.2% intravenous sodium bicarbonate infusion can be used to maintain the arterial pH above 7.30 3.
• The volume of each infusion should be within the range of 125-250 mL in 30 min, with a maximum of 1000 mL within 24 h after inclusion 3.

Clinical Scenarios

• Sodium bicarbonate can be administered as a hypertonic push, as a resuscitation fluid, or as an infusion 5.
• In patients with diabetic ketoacidosis, the use of sodium bicarbonate does not confer improved patient outcomes and may cause harm in pediatric patients 5.
• Alkalinization of urine in rhabdomyolysis does not improve patient-centered outcomes 5.
• Patients with lactic acidosis and cardiac arrest may not benefit from routine use of sodium bicarbonate, except in certain circumstances 5.

Side Effects and Precautions

• Metabolic alkalosis, hypernatraemia, and hypocalcaemia are potential side effects of sodium bicarbonate therapy 3.
• Hypercapnia, hypokalemia, ionized hypocalcemia, and QTc interval prolongation are also associated with sodium bicarbonate therapy 6.
• The potential impact of regular sodium bicarbonate therapy on worsening vascular calcifications in patients with chronic kidney disease has been insufficiently investigated 6.