Is bicarbonate (sodium bicarbonate) given during cardiac arrest?

Bicarbonate Administration During Cardiac Arrest

Routine use of sodium bicarbonate is not recommended for patients in cardiac arrest (Class III, LOE B). 1

Rationale Against Routine Use

The American Heart Association guidelines clearly state that there is insufficient evidence supporting bicarbonate therapy during cardiac arrest. Multiple studies have shown:

• No evidence that bicarbonate improves defibrillation success or survival rates in ventricular fibrillation cardiac arrest 1
• Studies have either shown no benefit or found associations with poor outcomes 1
• A multicenter retrospective pediatric study found that sodium bicarbonate administered during cardiac arrest was associated with decreased survival 1

Potential Adverse Effects of Bicarbonate

Administration of bicarbonate during cardiac arrest can cause several harmful effects:

• Compromises coronary perfusion pressure by reducing systemic vascular resistance
• Creates extracellular alkalosis that shifts the oxyhemoglobin saturation curve and inhibits oxygen release
• Produces hypernatremia and hyperosmolarity
• Generates excess CO₂, which diffuses into myocardial and cerebral cells, potentially worsening intracellular acidosis
• Exacerbates central venous acidosis
• May inactivate simultaneously administered catecholamines 1

Special Circumstances Where Bicarbonate May Be Beneficial

Despite the general recommendation against routine use, bicarbonate may be beneficial in specific resuscitation situations:

1. Preexisting metabolic acidosis
2. Hyperkalemia
3. Tricyclic antidepressant overdose 1, 2, 3

Dosing When Indicated

When bicarbonate is used in special situations:

• Initial dose: 1 mEq/kg IV 1
• For cardiac arrest due to sodium channel blocker toxicity: 1-2 mEq/kg IV bolus 2
• In emergencies: 44.6-100 mEq (1-2 50mL vials) rapidly IV, may continue at 44.6-50 mEq every 5-10 minutes if necessary 4

Monitoring and Guidance

If bicarbonate is administered:

• Therapy should be guided by bicarbonate concentration or calculated base deficit from blood gas analysis 1
• Do not attempt complete correction of calculated base deficit to minimize risk of iatrogenically induced alkalosis 1
• Monitor arterial blood gases, plasma osmolarity, arterial blood lactate, hemodynamics and cardiac rhythm 4

Current Practice vs. Guidelines

Despite clear guidelines against routine use, recent research shows that bicarbonate is still administered in approximately 50% of adult and pediatric in-hospital cardiac arrests 5. Common reasons cited by physicians include:

• Metabolic acidosis (76%)
• Prolonged arrest duration (64%)
• "Last ditch effort" in prolonged arrests (75%) 5

This practice persists despite lack of supporting evidence in the AHA guidelines.

Alternative Buffers

Other non-CO₂-generating buffers (THAM, tribonate) have shown potential for minimizing adverse effects of sodium bicarbonate, but clinical experience is limited and outcome studies are lacking 1.

Conclusion

The evidence strongly supports avoiding routine administration of sodium bicarbonate during cardiac arrest. Focus should remain on high-quality CPR, appropriate ventilation with oxygen, and addressing the underlying cause of the arrest rather than attempting to correct acidosis with bicarbonate administration.