What is the role of sodium bicarbonate (NaHCO3) in the treatment of cardiac arrest?

From the Guidelines

Sodium bicarbonate is not recommended for routine use in cardiac arrest situations, except in specific cases such as severe metabolic acidosis, hyperkalemia, or tricyclic antidepressant overdose. The use of sodium bicarbonate in cardiac arrest is generally discouraged due to its potential to worsen outcomes by causing paradoxical intracellular acidosis, shifting the oxygen-hemoglobin dissociation curve, producing excess carbon dioxide, causing hypernatremia, and potentially decreasing coronary perfusion pressure 1.

Key Considerations

• The focus in cardiac arrest management should remain on high-quality CPR, defibrillation when appropriate, airway management, and addressing reversible causes rather than routine buffer therapy.
• When sodium bicarbonate is indicated, the typical adult dose is 1 mEq/kg IV initially, followed by 0.5 mEq/kg every 10 minutes as needed based on arterial blood gas results 1.
• Administration requires a large-bore IV or IO access, and the solution should not be mixed with calcium-containing medications as precipitation may occur.
• Other non–CO2-generating buffers such as bicarb, THAM, or tribonate have shown potential for minimizing some adverse effects of sodium bicarbonate, but clinical experience is limited and outcome studies are lacking 1.

Special Situations

• Sodium bicarbonate may be beneficial in special resuscitation situations, such as preexisting metabolic acidosis, hyperkalemia, or tricyclic antidepressant overdose 1.
• In these cases, an initial dose of 1 mEq/kg is typical, and bicarbonate therapy should be guided by the bicarbonate concentration or calculated base deficit obtained from blood gas analysis or laboratory measurement 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. In cardiac arrest, however, the risks from acidosis exceed those of hypernatremia.

Sodium bicarbonate treatment for cardiac arrest involves administering a rapid intravenous dose of 44.6 to 100 mEq, which may be repeated every 5 to 10 minutes as needed, based on arterial pH and blood gas monitoring 2.

• The treatment aims to reverse acidosis in cardiac arrest patients.
• The risks associated with acidosis in cardiac arrest outweigh the potential risks of hypernatremia.

From the Research

Cardiac Arrest Treatment with Sodium Bicarbonate

• The use of sodium bicarbonate in cardiac arrest treatment is a topic of ongoing debate, with some studies suggesting its potential benefits and others recommending against its routine use 3, 4, 5.
• A systematic literature review published in 2024 found that sodium bicarbonate was associated with lower rates of return of spontaneous circulation (ROSC) and outcomes, and its use is not recommended for conventional use in patients with cardiac arrest, except in specific conditions such as hyperkalemic cardiac arrest, severe cardiotoxicity, or overdose due to tricyclic antidepressants 3.
• Another study published in 1996 suggested that sodium bicarbonate may be helpful in outcome from cardiac arrest, and its administration may mitigate the adverse physiological effects of acidemia, improve response to exogenously administered vasopressor agents, or increase venous return due to an osmolar effect 4.
• The management of cardiovascular complications of tricyclic antidepressant poisoning with sodium bicarbonate has been studied, and the results suggest that it may be effective in reducing cardiotoxicity and improving outcomes 6.
• Current guidelines and literature reviews recommend against the routine use of sodium bicarbonate in cardiac arrest, except in specific circumstances such as hypokalemia or tricyclic antidepressant overdose 5.
• A survey of physicians found that despite recommendations against routine use, sodium bicarbonate is still administered in approximately 50% of adult and pediatric in-hospital cardiac arrest cases, with the most common indications being hyperkalemia, metabolic acidosis, tricyclic antidepressant overdose, and prolonged arrest duration 7.

Specific Conditions for Sodium Bicarbonate Use

• Hyperkalemic cardiac arrest: sodium bicarbonate may be effective in reducing cardiotoxicity and improving outcomes 3, 6.
• Severe cardiotoxicity: sodium bicarbonate may be effective in reducing cardiotoxicity and improving outcomes 3, 6.
• Tricyclic antidepressant overdose: sodium bicarbonate may be effective in reducing cardiotoxicity and improving outcomes 3, 6, 5.
• Prolonged arrest duration: sodium bicarbonate may be used as a "last ditch effort" in prolonged arrests, although its effectiveness is not well established 7.

Physiological Effects of Sodium Bicarbonate

• Mitigation of adverse physiological effects of acidemia: sodium bicarbonate may improve response to exogenously administered vasopressor agents, or increase venous return due to an osmolar effect 4.
• Increase in coronary perfusion pressure: sodium bicarbonate may increase coronary perfusion pressure, which may improve outcomes in cardiac arrest 4.
• Adverse effects: sodium bicarbonate may also have adverse effects, such as worsening acidemia or alkalemia, and decreasing coronary perfusion pressure 4.