What is an oximeter
What is an oximeter for? What is an oximeter? An oximeter is an instrument that measures blood oxygen. Hypoxic patients should use an oximeter for a long time to detect blood oxygen content, which can effectively prevent the occurrence of danger. The original oximeter was developed by Millikan in the 1940s. It monitors the ratio of oxygen-carrying hemoglobin to oxygen-free hemoglobin in arteries. A typical oximeter has two LEDs. The two LEDs face the part of the patient to be tested – usually the fingertip or earlobe.
The main measurement indexes of the oximeter were pulse rate, blood oxygen saturation, and perfusion index (PI). Blood oxygen saturation is one of the important basic data in clinical medicine. Oxygen saturation refers to the percentage of bound O2 volume in the total blood volume of the total bound O2 volume.
Oximeter principle
Oximeter works by Detect the ratio of the absorbance change rate (R/IR value) of the peripheral tissues of the congested human body such as fingers or earlobes to different wavelengths of red light and infrared light to calculate the arterial oxygen saturation (SaO2) of the tissue, according to the Beer-Lambert law , the functional relationship between the ratio R/IR and arterial oxygen saturation (SaO2) should be linear, but because biological tissue is a complex optical system with strong scattering, weak absorption and anisotropy [2-4], it is not completely It conforms to the classic Beer-Lambert law, which makes it difficult to establish a mathematical model that expresses the relationship between the measured value of the relative change of red and infrared light absorbance (R/IR value) and arterial oxygen saturation (SaO2). The corresponding relationship between R/IR and SaO2, that is, the calibration curve, can only be determined experimentally. Most pulse oximeter manufacturers use experimental methods to obtain empirical calibration curves to complete the pre-calibration of the products before leaving the factory.
