Development Of Blood Oxygen Saturation Measure Instrument Based On ARM Technology

Biological tissue cells obtain oxygen which is carried by blood to process metabolism. Hemoglobin (Hb), an intracellular protein, is the primary vehicle for transporting oxygen in the blood. It carries the oxygen and exchanges this for carbon dioxide oxygen released by the processes of metabolism from the cells. Hemoglobin forms an unstable, reversible bond with oxygen. It is oxy-hemoglobin in its oxygen-loaded form and is deoxy-hemoglobin in the oxygen-unloaded form. Oxygen saturation refers to the ratio of oxy-hemoglobin to all hemoglobin, it is a important measure of evaluating how well the lungs are providing oxygen to the blood. Near-infrared spectroscopy (NIRS) is a technique of great attention these years for the investigation of biological tissues oxygen saturation because of the different absorption of water, oxy-hemoglobin and deoxy-hemoglobin in the near-infrared region. The measurement relies upon the changes in photon absorption of hemoglobin in the tissue as changes occur in the hemoglobin concentration and oxygen content.With the development of micro-processor, ARM core embedded system will be the main platform for homely used pulse oxygen saturation measurement. In the paper an embedded system based on ARM920T core which focuses on Family Health Care is developed. SAMSUNG' s S3C2410X 16/32-bit ARM microprocessor is used as it' s core, and Windows CE 5. 0 as it' s OS. This paper gives a solid background towards a ready-to-use instrument that can continuously, in real-time, measure pulse waveform and blood oxygenation. This paper expounds the theoretical model of oxygen saturation' s measurement and fully discusses the dual-wavelength method, analyzes the hardware functional circuit in details, develops the drivers and the applied software based on WinCE 5.0 operating system. The blood-oxygen saturation measure instrument is accomplished finally, attains the basic function of pulse blood-oxygen saturation measure. It can plot the pulse wave and calculate the blood-oxygen saturation at real time. The arithmetic of pulse wave is discussed and analyzed in the thesis at the same time. Some arithmetic has been already porting into the system. Applying high-powered ARM microprocessor as system core, not only the pulse signal can be measured and analyzed at real time, but also abundant interfaces for equipment can be integrated into the whole system. It is a trend that the blood oxygen saturation measure system has further more precision, systematic integration and miniaturization.As medical treatment develops, Family Health Care instruments have a wide market, pulse blood-oxygen saturation measure instrument will be one of the wide-used applications in families because of it' s fast, real-time, convenient and continuous measurement.