All About the Pulse Oximeter and Oximetry

A pulse oximeter is a medical and clinical instrument used by professionals in monitoring the oxygen saturation found in the hemoglobin. The device also monitors the changes in the volume of the skin. Oximetry is the indirect way of measuring oxygen saturation. Blood sampling is the direct process. The pulse oximeter is physically composed of a probe which is attached to the finger or the ear lobe of the patient to produce input. The probe is attached to a computerized unit which displays the percentage of hemoglobin saturated with oxygen. An audible signal is an indication for heart beat and heart rate calculation. Some units also include the graphic display of the patient’s blood flow passing in the probe. Pulse oximeter was invented by Milliken in the 1940s. After 30 years, it was improved to what it is today by Aoyagi in Nihon Koden. It was made possible due to the ratio of red light to infrared light absorbance of pulsating components in the measuring. Biox commercialized it in the United States for the first time in 1981. However, it took years before it was totally adapted and was rampantly used. The device works in the principle that a source of light is emitted from the probe. If the LED is red, the wavelength is 660 nanometers, while the other one denotes 905 to 940 nanometers. The light will be absorbed by the hemoglobin in various amounts that shall differ whether it is saturated or desaturated with the oxygen content. The processor is now ready to compute the proportion of the oxygenated hemoglobin by calculating the absorption at the two wavelengths. The oximeter will depend on the pulsatile flow which will produce a graph showing the flow quality in the probe. Sluggish flow denotes that the oximeter is not functioning or working well enough to get exact readings. The computer attached in the machine is capable of distinguishing pulsatile flow from other static signals displayed on the arterial flow. A finger pulse oximeter can be utilized in diverse cases. It is in great value in cases of anesthesia process for the monitoring of oxygen levels and pulse rates. It is also widely used during a patient’s recuperation stage. The oxygen saturation should be above 95 percent to assure right oxygen content in the body. The readings are expected to be lower for individuals who have long standing respiratory disease or cyanotic congenital heart disease. Thus, this reflects the severity of the disease.