Oxygen saturation.

Hemoglobin molecules are a protein in the blood that carries oxygen from the lungs to the rest of the body’s tissues. Each hemoglobin has the capacity of carrying four oxygen molecules. Not all hemoglobin molecules will carry four oxygen molecules when they depart the lungs in the blood stream and that is what a pulse oximeter will help determine. Let’s assume that 970 oxygen molecules have attached to 1000 hemoglobin molecules. With a little math, we see the following; (970 / 1000) x100 =97%. In this case, the pulse oximeter would display 97% SPO2.