In metabolic acidosis during cardiac arrest, which dose of sodium bicarbonate may be indicated?

• A. 0.5 mEq/kg
• B. 2 mEq/kg
• C. 1 mEq/kg
• D. 5 mEq/kg

Answer: (C)

During cardiac arrest, metabolic acidosis comes from lactic acid produced by poor perfusion. Sodium bicarbonate can buffer hydrogen ions, but it is used sparingly because it generates CO2. That CO2 must be eliminated by ventilation; if ventilation is not adequate, bicarbonate can worsen intracellular acidosis and blunt the response to CPR and vasopressors. Therefore, bicarbonate is considered only in specific situations where it’s likely to help (for example, known hyperkalemia or certain toxin overdoses) rather than as a routine measure.

If a dose is indicated, the best choice is a modest amount of 1 mEq/kg given intravenously (usually from the 8.4% solution, with careful monitoring). Higher doses, such as 2 or 5 mEq/kg, carry greater risks—electrolyte shifts, fluid overload, metabolic alkalosis, and increased CO2 load without proven benefit in routine cardiac arrest. In practice, use is cautious and coupled with reassessment of acid–base status and the patient’s ventilatory support.