Your patient is on a pulse oximeter and the reading is 100% saturation. What does this value represent?

The reading of 100% saturation on a pulse oximeter indicates that 100% of the hemoglobin in the patient's red blood cells is bound to oxygen. This means that all available binding sites on the hemoglobin molecules are occupied by oxygen, which is a positive sign of adequate oxygenation in the patient's blood.

While it might be assumed that 100% saturation correlates with the patient receiving oxygen therapy or a specific partial pressure of oxygen in the blood, saturation levels indicate the functionality of the hemoglobin in transporting oxygen rather than the specific conditions under which that saturation occurs. Thus, the saturation value is primarily reflective of the hemoglobin's oxygen-carrying capacity, not necessarily the external oxygen supply or respiratory mechanics involved.