Figure 3.

Bohr effect. The oxyhemoglobin dissociation curve is shifted to the left in response to respiratory alkalosis (lower PaCO₂ and higher pH), with increased affinity of oxygen for the hemoglobin. Conversely, during respiratory acidosis (higher PaCO₂ and lower pH), the alveolar oxygen tension and systemic saturation improve, thus reducing alveolar carbon dioxide tension, as explained by the Bohr effect: the higher the acidity, the more carbon dioxide is eliminated.