A finger pulse oximeter is a device designed to measure the oxygen level of the blood. Typically, the finger pulse oximeter clips onto the end of the finger, over the nail, and measures the hemoglobin saturation. The oximeter measures the difference in light absorption between the oxygenated hemoglobin molecule and the deoxygenated version. Comparing the difference allows the measurement to be taken with precision. The finger pulse oximeter takes advantage of the optical properties of the fingernail, and measures the light that passes through while comparing it with known statistics about light absorption by the body. The oximeter usually has two LED's, or light emitting diodes, that produce precise wavelengths. One is a red LED that emits at 660 nm, and another infared LED that produces radiation at 910 nm.
Finger pulse oximeters are important because they allow for a quick and easy way of measuring the oxygenation of the blood. Tracking a patient's blood oxygen level is important, because if the hemoglobin molecules in the blood are not transporting oxygen, the patient's organs will fail. The hemoglobin molecule has four points where oxygen can be attached. When all four are carrying oxygen molecules, the hemoglobin is fully saturated. The pulse oximeter measures the saturation of the blood in relation to normal levels, considered to be from 95 to 100% saturation.
If the hemoglobin loses oxygen saturation, skin will lose its pink colour, and will start to turn blue. In effect, the body begins to choke to death if the blood cannot carry oxygen, even if breathing is normal. Certain molecules like carbon monoxide can bond to the hemoglobin in place of oxygen, preventing the blood from carrying the oxygen.
Before finger pulse oximeters existed, many complicated blood tests had to be used to measure the oxygen level of the blood. Now that they are available, most as small and easy to carry devices, blood oxygen levels can be measured continuously, even by the patients themselves.
