Oxygen–hemoglobin dissociation curve

The oxygen–hemoglobin dissociation curve is a graph that describes the relationship between the partial pressure of oxygen (pO2) and the oxygen saturation (SO2) of hemoglobin. This curve is an important tool in understanding how blood carries and releases oxygen.

Physiological Basis

The curve is typically sigmoidal (S-shaped) due to the cooperative binding of oxygen to hemoglobin. As one molecule of oxygen binds to hemoglobin, it increases the affinity for the next oxygen molecule. This is known as cooperative binding.

Factors Affecting the Curve

Several factors can shift the oxygen–hemoglobin dissociation curve:

• pH: A decrease in pH (acidosis) shifts the curve to the right, while an increase in pH (alkalosis) shifts it to the left. This is known as the Bohr effect.
• Carbon dioxide (CO2): An increase in CO2 levels shifts the curve to the right, while a decrease shifts it to the left.
• Temperature: An increase in temperature shifts the curve to the right, while a decrease shifts it to the left.
• 2,3-Bisphosphoglycerate (2,3-BPG): An increase in 2,3-BPG shifts the curve to the right.

Clinical Significance

Understanding the oxygen–hemoglobin dissociation curve is crucial in various clinical settings:

• In respiratory therapy, to assess the effectiveness of oxygen delivery.
• In anesthesia, to monitor oxygenation during surgery.
• In critical care, to manage patients with respiratory failure.

Related Concepts

• Hemoglobin
• Oxygen transport
• Hypoxia
• Anemia

See Also

• Bohr effect
• Haldane effect
• Carboxyhemoglobin
• Methemoglobin