What is the recommended dose of bicarbonate (sodium bicarbonate) in cardiac arrest?

Sodium Bicarbonate Dosing in Cardiac Arrest

The recommended dose of sodium bicarbonate in cardiac arrest is 1 mEq/kg (equivalent to 1 mL/kg of 8.4% solution or 2 mL/kg of 4.2% solution) given as a slow intravenous bolus, which may be repeated every 5-10 minutes if necessary based on arterial blood gas monitoring. 1, 2

Primary Dosing Recommendations

Adult Dosing

• Initial bolus: 1-2 mEq/kg IV administered slowly during ongoing resuscitation 1, 2
• The FDA label specifies this translates to one to two 50 mL vials (44.6 to 100 mEq) given rapidly initially 2
• May continue at 50 mL (44.6 to 50 mEq) every 5-10 minutes as indicated by arterial pH and blood gas monitoring 2

Pediatric Dosing

• Children: 1-2 mEq/kg IV given slowly 3, 1, 4
• Newborn infants: Use only 0.5 mEq/mL (4.2%) concentration by diluting 8.4% solution 1:1 with normal saline 1, 4
• For children under 2 years, the 8.4% solution must be diluted 1:1 with normal saline before administration 1

Critical Timing and Indications

The American College of Cardiology explicitly recommends AGAINST routine use of sodium bicarbonate in cardiac arrest 1. However, specific indications exist:

When to Consider Bicarbonate in Cardiac Arrest:

• After the first dose of epinephrine has been ineffective in asystolic arrest 3
• Documented severe metabolic acidosis (pH < 7.1) with effective ventilation already established 3, 1
• Hyperkalemia as a precipitating cause 1
• Tricyclic antidepressant or sodium channel blocker overdose causing cardiac arrest 1
• Prolonged arrest duration (typically after 10-20 minutes of CPR) with severe acidosis 3, 5

Critical Prerequisite:

Effective ventilation MUST be established before bicarbonate administration, as ventilation is required to eliminate the excess CO2 produced by bicarbonate 1. This is a common pitfall—giving bicarbonate without adequate ventilation causes paradoxical intracellular acidosis 1.

Administration Technique

Preparation and Concentration:

• Adults and children ≥2 years may receive undiluted 8.4% solution 1
• Pediatric patients <2 years require 4.2% concentration (dilute 8.4% solution 1:1 with normal saline) 1, 4
• Newborns require 0.5 mEq/mL concentration 1, 4

Critical Safety Points:

• Flush the IV cannula with normal saline before and after bicarbonate to prevent inactivation of simultaneously administered catecholamines 3, 1
• Never mix bicarbonate with calcium-containing solutions or vasoactive amines 1, 4
• Administer as a slow IV push, not rapid bolus, to minimize complications 3, 2

Monitoring and Repeat Dosing

• Repeat dosing should be guided by arterial blood gas analysis, not empirically 2
• In the European Resuscitation Council pediatric guidelines, a single bolus of 1 mmol/kg is given before the second dose of epinephrine if the first epinephrine dose was ineffective 3
• The FDA label indicates continuation every 5-10 minutes may be necessary in cardiac arrest, but this should be guided by pH monitoring 2

Important Caveats and Pitfalls

Potential Adverse Effects During Arrest:

• Hypernatremia and hyperosmolarity from hypertonic solutions 1, 2
• Paradoxical intracellular acidosis if ventilation is inadequate to clear CO2 1
• Extracellular alkalosis shifting the oxyhemoglobin curve and inhibiting oxygen release 1
• Inactivation of catecholamines if not properly flushed 1
• Decreased ionized calcium affecting cardiac contractility 1

Common Pitfall:

The most frequent error is routine administration without specific indication. A 2024 survey found that 24-49% of physicians would give bicarbonate in asystolic arrest scenarios despite guidelines recommending against routine use 6. The evidence shows bicarbonate improves acid-base status but does not improve return of spontaneous circulation or neurologic outcomes 5.

Evidence Nuance:

While one retrospective study suggested bicarbonate administration was associated with increased ROSC (odds ratio 2.49) 7, a prospective randomized trial in patients with severe metabolic acidosis during prolonged CPR found no improvement in sustained ROSC (4% vs 16%, p=0.349) or neurologic survival 5. The preponderance of guideline evidence favors restricted use 1.

Practical Algorithm for Decision-Making

1. Is cardiac arrest present? → Initiate standard ACLS/PALS protocols first
2. Has first dose of epinephrine been given and failed? → If no, continue standard protocol
3. Is ventilation adequate? → If no, establish effective ventilation before considering bicarbonate
4. Is there a specific indication? (severe acidosis pH <7.1, hyperkalemia, TCA overdose) → If yes, proceed to dosing
5. Give 1 mEq/kg IV slowly (use appropriate concentration for age)
6. Flush line with normal saline
7. Repeat only if guided by arterial blood gas showing persistent severe acidosis 3, 1, 2