基于超声波的相对血容量检测仪的研制

Development of Ultrasound-based Monitor of Relative Blood Volume

准确评估干体重是提高血液透析患者透析质量的重要环节。本文提出了一种基于超声波的相对血容量（RBV）检测技术和实现方法。利用血液浓度的变化与声速的相关关系，通过测定声速，然后计算出RBV，进而评估透析患者的干体重。系统以MSP430微处理器为控制核心，采用TDC—GP2高精度测时芯片检测超声波传播时间。检测仪样机测得RBV介于71.3％～108．1％之间，检测结果与Fresenius4008SBVM相比基本一致，具有实时、便捷、可重复、非侵人性等优点。

Assessing dry weight accurately is crucial in providing effective and safe haemodialysis. Biases towards dry weight assessment may bring a series of dialysis complications. This study introduces an online detection technique of relative blood volume（RBV） based on ultrasound, which analyzes the correlation between changes in blood density and sound speed. By measuring the attenuation in sound velocity, this method was employed to calculate RBV, and then to evaluate the dry weight of patients on dialysis. TDC GP2 time measurement chip and MSP430 Single chip Microcontroller （SCM） were used in the system to measure the ultrasonic travel time. In the clinical trials, RBV val ues range between 71. 3% and 108. 1%, showing consistent result with Fresenius 4008S blood volume monitor （BVM）. This detection method possesses several advantages, such as real time, convenient, reproducible, non-inva sire, and etc.