When your oxygen saturation is too low, this is an indication that something inside your body is going wrong. When the oxygen level in your blood is low, that means that the cells, including your heart and brain cells, can't get the oxygen they need. This can indicate a problem with your cardiorespiratory system. A pulse oximeter is a small machine that can make a big difference in your doctor's understanding of your condition.
Pulse Oximetry
A pulse oximeter is a small machine that usually clamps to one of your fingers. It uses a small infrared light that passes through your fingertip, which the machine uses to measure the level of oxygen saturation in your blood. This is the amount of oxygen that the hemoglobin inside your blood is carrying.
Anatomy and Physiology
The red blood cells are the mechanism by which your blood carries oxygen and carbon dioxide. Each red blood cells contains a hemoglobin molecule which attaches itself to gas. The body moves blood around the body and to the lungs where it expels carbon dioxide, a produce of cellular metabolism, and picks up oxygen. The oxygen content of your blood is very important because every cell inside your body relies on oxygen to live.
Normal Readings
A pulse oximeter delivers a reading in percentages. 100 percent is the best reading you can get, meaning that your hemoglobin is fully saturated. A normal and healthy adult should have a pulse oximeter reading as close to 99 percent as possible. The normal reading is somewhere between 95 and 99 percent. Trouble may start when your pulse oxygen saturated begins to head toward 92 percent or lower.
Limitations
Like everything else in life, pulse oximetry is not perfect. There are certain limitations to this machine. For example, there must be a strong pulse in the finger for it to work. Decreased blood flow or even a cold hand can cause the machine to give an inaccurate reading. A pulse oximeter cannot tell the difference between oxygen and carbon monoxide, which also binds to hemoglobin. For this reason, a pulse oximeter should not be used by someone who has inhaled smoke, as a false positive reading will be given.
