Role of Sodium Bicarbonate in Cardiac Arrest
Routine use of sodium bicarbonate is not recommended for patients in cardiac arrest (Class III, LOE B). 1
Evidence Against Routine Use
- Multiple studies have shown no benefit or found a relationship with poor outcomes when sodium bicarbonate is used routinely during cardiac arrest 1
- There is no evidence that bicarbonate improves the likelihood of defibrillation or survival rates in animals with ventricular fibrillation cardiac arrest 1
- A recent systematic review (2024) concluded that sodium bicarbonate was associated with lower rates of return of spontaneous circulation (ROSC) and worse outcomes in most cardiac arrest scenarios 2
Potential Adverse Effects
Bicarbonate administration during cardiac arrest has been linked to several adverse effects:
- May compromise coronary perfusion pressure by reducing systemic vascular resistance 1
- Creates extracellular alkalosis that shifts the oxyhemoglobin saturation curve and inhibits oxygen release 1
- Produces hypernatremia and hyperosmolarity 1
- Generates excess CO2, which diffuses into myocardial and cerebral cells, potentially contributing to intracellular acidosis 1
- Can exacerbate central venous acidosis 1
- May inactivate simultaneously administered catecholamines 1
Special Situations Where Bicarbonate May Be Beneficial
Despite the recommendation against routine use, sodium bicarbonate may be beneficial in specific cardiac arrest scenarios:
- Preexisting metabolic acidosis (arterial pH < 7.1 and base excess < -10) 1
- Hyperkalemia 1, 3
- Tricyclic antidepressant overdose 1, 4
- Sodium channel blocker toxicity 3, 5
Dosing When Indicated
When sodium bicarbonate is used in these special situations:
- Initial dose of 1 mEq/kg is typical 1, 3
- For cardiac arrest specifically, FDA labeling indicates a rapid intravenous dose of one to two 50 mL vials (44.6 to 100 mEq) initially, continued at a rate of 50 mL every 5-10 minutes if necessary 4
- Therapy should be guided by bicarbonate concentration or calculated base deficit from blood gas analysis when possible 1
- To minimize iatrogenically induced alkalosis, complete correction of the calculated base deficit should not be attempted 1
Current Clinical Practice
- Despite guidelines recommending against routine use, a recent survey (2024) found that sodium bicarbonate is administered in approximately 50% of adult and pediatric in-hospital cardiac arrests 6
- Physicians commonly cite metabolic acidosis (76%) and prolonged arrest duration (64%) as indications for intra-arrest sodium bicarbonate, despite these not being supported by guidelines 6
Alternative Buffer Considerations
- Non-CO2-generating buffers such as THAM or tribonate may potentially minimize some adverse effects of sodium bicarbonate 1
- However, clinical experience with these alternatives is limited, and outcome studies are lacking 1
Conclusion
The mainstays of acid-base balance restoration during cardiac arrest remain:
- Appropriate ventilation with oxygen
- Support of tissue perfusion with high-quality chest compressions
- Rapid achievement of return of spontaneous circulation 1