The pulse oximeter was first introduced in 1970s and the first generation equipments were bulky and costly. The rapid changes in the technologies helped to reduce the size and cost of these equipments and as a result, the modern pulse oximeters are very compact in design, portable and cost effective. Today's oximeters integrate the state-of-the-art microprocessor and optical sensor technologies, to accurately measure the oxygen content in the bloods stream.
The basic principle behind the working of pulse oximeter, depends on the property of hemoglobin to absorb various wavelengths of lights according to varied oxygenation level. The oximeters have a light source and a light sensor, which is normally clamped to some translucent part of the body, such as finger tip or earlobe, in such a way that these sensor and source are in either sides of the body. The light source consists of two light emitting diodes that emit lights in red color and infra red. The light rays pass through the body and gets detected by the photo detector on the other end.
To measure the oxygen levels in the body, this instrument is normally clamped to the finger tip of the patient, and when clamped, the two light sources emit red and infrared light into the body. These lights pass through the patient's body and reach the photo detectors depending on some parameters. The amounts of these rays that pass through the body highly depend on the blood's oxygenation level. Oxygenated blood is red in color and it absorbs infrared radiation, whereas the de-oxyhemoglobin absorbs red color more. The systolic pressure, cause an inrush of highly oxygenated hemoglobin to the tissues, absorbing more infrared light, which in turn, reduces the quantity of IR rays that reach the photo sensor. At the same time, the red light is less affected, as the high oxygenated blood is less responsive to the red light.
The photo sensors in the oximeter sense these fluctuations and transmits the data to a microprocessor embedded in circuit boards. The micro processor is programmed to analyze all these parameters, and display the result in figures for better understanding by humans. By analyzing the data from photo sensors, the oximeter not only shows the SpO2 level, but also shows the pulse rate, Pulse Bar and Plethysmograph.
This wonderful device will enable the user to note oxygen saturation levels at both rest and during activity. This can help you to find out the de-saturation episodes and take treatments accordingly. Today it is possible to buy pulse oximeters online without having to trouble yourself shopping around.