Hyperventilation can cause which acid-base disturbance that explains perioral numbness?

Hyperventilation can cause which acid-base disturbance that explains perioral numbness?

• A. Metabolic acidosis
• B. Metabolic alkalosis
• C. Respiratory alkalosis
• D. Respiratory acidosis

Answer: (C)

Hyperventilation blows off CO2, lowering arterial CO2 and shifting the bicarbonate buffer system toward fewer hydrogen ions, which raises pH—this is respiratory alkalosis. The rise in pH increases calcium binding to albumin, reducing the level of ionized calcium in the blood. Low ionized calcium makes nerves more excitable, producing symptoms like perioral numbness and tingling. Other acid-base disturbances wouldn’t produce this same drop in ionized calcium linked to alkalemia, so respiratory alkalosis best explains the numbness around the mouth.