| The correlation between oxygen saturation and PaO2 is determined by the dissociation curve of oxyhemoglobin. |
| As oxyhemoglobin circulates to deoxygenated tissue, oxygen is incrementally unloaded and the affinity of hemoglobin for oxygen is reduced. |
| The iron of hemoglobin is normally in the reduced or ferrous state, in both oxyhemoglobin and deoxyhemoglobin. |
| In addition, the enzyme systems for reducing methemoglobin to oxyhemoglobin are incompletely developed in infants under six months of age. |
| This process occurs when oxygen atoms bond to an iron atom at the center of a complex protein molecule known as oxyhemoglobin. |
| Energy is also required to convert methemoglobin to oxyhemoglobin and to prevent the oxidation of other constituents of the red cell. |
