How Is Normal Oxygen Saturation Determined?

Oxygen saturation refers to the volume ratio of oxygenated hemoglobin to effective hemoglobin, and in a broad sense, the percentage of oxygen content in a blood sample to the maximum oxygen content in the blood of the sample. The oxygen saturation in arteries is generally greater than that in veins.

Oxygen saturation

Broadly defined oxygen saturation, often referred to as

Pao2, SaO2, CaO2 are reduced due to hypoxia due to insufficient oxygen supply or lung ventilation and ventilation failure.

Because of the patient's anemia, hemoglobin decreases, and the oxygen carried in the blood decreases, CaO2 decreases, and PaO2 and SaO2 are normal.

(3) Due to heart failure, shock, etc., blood circulation is stagnant, and insufficient blood flow through the tissue leads to tissue hypoxia. At this time, PaO2, SaO2, CaO2 can be normal, but PvO2, SvO2, and CvO2 are significantly reduced.

In severe acidosis and alcoholism, tissue utilization of oxygen decreases, PaO2, SaO2, and CaO2 are normal, but PvO2, SvO2, and CvO2 increase.

In the case of carbon monoxide poisoning and methemoglobinemia, the ability of hemoglobin and oxygen to decrease is reduced, PaO2 is normal, and SaO2 and CaO2 are decreased.