Respiratory acidosis

Respiratory acidosis is a result of inadequate elimination of CO₂ by the lungs (hypoventilation) and therefore acid gain. pCO₂ is increased and pH is decreased. With time, the kidneys compensate by increasing excretion of H+, and increasing reabsorption and generation of HCO₃^–. For every 10 mm Hg increase in pCO₂, the HCO₃^– concentration is expected to increase by 1.5 mmol/L in the acute phase and this may double in the chronic phase. As HCO₃^– reabsorption is increased, chloride excretion is increased in exchange.

For causes of respiratory acidosis, see Table 6.3

Respiratory alkalosis

Respiratory alkalosis is a result of increased elimination of CO₂ by the lungs due to hyperventilation and therefore acid loss. pCO₂ is decreased and pH is increased. With time, the kidneys compensate by increasing excretion of HCO₃^– in exchange for Cl^– to maintain electroneutrality. For every 10 mmHg decrease in pCO₂, the HCO₃^– concentration is expected to decrease by 2.5 mmol/L in the acute phase and this may double if chronic.

For causes of respiratory alkalosis, see Table 6.3