What is Oxygen Saturation?
Oxygen saturation refers to the amount of oxygen circulating in the blood. Oxygen is contained within and transported by the red blood cells. From the lungs, these cells will carry the oxygen molecules and supply the various tissues and organs of the body. These cells are called red blood cells simply because of the oxygen content in them.
When measuring the amount of oxygen in the blood, what is actually measured is the number of oxygen molecules that are being carried by a hemoglobin molecule. Normally, one hemoglobin molecule can only carry up to four oxygen molecules. If all hemoglobin molecules are carrying four oxygen molecules each, then the blood is said to be 100% saturated with oxygen. So in the case of 100 hemoglobin molecules carrying only 300 oxygen molecules, by calculating 300 over the maximum 400 oxygen molecules, we could say that the blood is 75% saturated.
Oxygen saturation may be measured through a procedure called Pulse Oximetry. This involves a simple setup with a clip on a person’s finger, earlobe or toe. The patient will not feel any discomfort or pain and the result is almost instant. The only problem is that this procedure is not applicable if the person’s skin is too cold. Patients wearing dark nail polish may also cause problems with this procedure as the light from the probe may not be able to accurately detect the redness of blood in the arteries.
Another test called ABG or arterial blood gas test may be administered for more accurate results. This procedure involves drawing of actual blood from the radial artery in the wrist area. Patients may feel a little bit of pain undergoing this procedure but it can be done quickly. Results from this test are also quick and may be available in just a few minutes.