How should metabolic acidosis be addressed during arrest?

• A. Treat underlying cause (e.g., improve oxygenation and perfusion); bicarbonate is reserved for specific circumstances.
• B. Administer bicarbonate aggressively to correct acidosis
• C. Increase ventilation without addressing perfusion
• D. Do not treat acidosis

Answer: (A)

During arrest, metabolic acidosis mainly reflects poor tissue perfusion from reduced cardiac output. The priority is to restore circulation and oxygen delivery so tissues can be re-oxygenated and acid slowly cleared. That means continuing high‑quality chest compressions, appropriate ventilation, defibrillation when indicated, and addressing reversible causes that are driving the arrest.

Giving bicarbonate routinely during CPR doesn’t reliably improve pH or outcomes and can actually cause harm. When bicarbonate is buffered, it forms CO2, which readily crosses cell membranes and can worsen intracellular acidosis while extracellular pH rises. This mismatch can impair myocardial and cerebral function and may reduce coronary perfusion pressure during compressions. It also adds sodium and can contribute to edema and electrolyte disturbances. Because the underlying issue is lack of perfusion, improving oxygenation and perfusion addresses the root problem more effectively.

Bicarbonate is kept for specific situations where there is a clear reason to correct acidosis, such as known pre‑existing metabolic acidosis or certain toxin ingestions (for example, conditions where acidosis directly drives the problem or hyperkalemia), rather than used as a routine step in arrest.