监护用脉搏式血氧饱和度测试方法的研究

Study on Measuring Method of Pulse Oxygen Saturation in Clinical Monitor

根据红光和红外光透过动脉血管后的相对最大光强和光强最大变化量之比来计算血氧饱和度（ＳＯ２）的一般原理和推导出的实用算法，针对临床长期监护的特殊要求，设计了单片机反馈控制的自动基线调节电路，自动增益调节的可控积分电路及相应算法，有效地克服了因测量信号的漂移，特别是人体生理差异造成使系统工作恶化的影响，从而使本系统满足了临床生理监护的需要。

In this paper, a measuring system of pulse oxygen saturation is presented, which is based on the Lambertbeer Principle, using the relative intensities at two wavelengths in the red and infrared ranges. In order to meet the special demand of continuoue clinical physiological monitoring, two circuits and appropriate algorithms are designed, one circuit, a feedback circuit controlled by microcontroller, automatically regulates the base line of signal, another circuit is a controlled integral circuit which automatically regulates the amplitude of waveforms. As the result, the drift of base line in this system, especially the effects caused by the physiological differences of human bodies, which will deteriorate the system, have been reduced. The system is satisfactory to clinical monitoring.