“The oxyhemoglobin dissociation curve is a vital tool for comprehending how blood transports and releases oxygen. Oxygen is carried throughout the body primarily by a protein molecule, hemoglobin, which is present inside red blood cells. Oxygen can also be carried throughout the body by dissolving in blood plasma, but this dissolved portion only constitutes a small portion of the total amount of oxygen transported in the bloodstream. Only 2% of oxygen in the bloodstream is dissolved directly in the plasma component of blood compared to 98% of oxygen in the protein-bound state to hemoglobin.
It is important to note the difference between oxygen saturation (SaO2)which is the percentage of hemoglobin bound to oxygen and partial pressure of oxygen in the blood (PaO2) which is the amount of oxygen dissolved in the blood. The oxyhemoglobin dissociation curve helps describe the relationship between these two important concepts.”
More on the Physiology, Oxygen Transport And Carbon Dioxide Dissociation Curve (2020) via StatPearls.