Pulse Oximeters

A pulse oximeter is used to monitor your oxygen levels. How does a pulse oximeter work?

The arteries are the pathway for transporting oxygenated blood from your heart to the rest of your body. Your veins transport the blood back to your heart. Hemoglobin an oxygen transport metalloprotein in the red blood cells. It transports oxygen from the lungs to the rest of the body, including the muscles, organs, and all the cells. Oxygen binds to four sites on the hemoglobin – when all four sites are full, the hemoglobin is fully saturated.

Fully saturated hemoglobin does not absorb light in the same way that unsaturated hemoglobin absorbs light. A hemoglobin fully saturated with oxygen absorbs every color but red – therefore red is reflected and that is the color that we see. This is why well-oxygenated blood looks red.

Pulse oximeters are non-invasive. You just need to place a pulse oximeter over your fingertip, or earlobe. Each pulse oximeter has a light source and a detector. As you recall from above, hemoglobin that is fully saturated with oxygen reflects light differently than hemoglobin that is not. Therefore, when the light source of the pulse oximeter is shined through your finger, the color of your blood is detected and the oxygen saturation level is discovered.

This is only a relatively condensed version of how pulse oximeters work. If you want a more specific explanation, you should ask your doctor or care provider.  It is important to note, though, that regardless of the reading that your pulse oximeter tells you, you should never change the flow of oxygen coming from your oxygen unit unless your caregiver and/or doctor approves.