Khan Musabbir, Pretty Christopher G, Amies Alexander C, Elliott Rodney B, Suhaimi Fatanah M, Shaw Geoffrey M, Chase J Geoffrey
Annu Int Conf IEEE Eng Med Biol Soc. 2015;2015:6405-8. doi: 10.1109/EMBC.2015.7319858.
Measurement of peripheral venous oxygen saturation (SvO2) is currently performed using invasive catheters or direct blood draw. The purpose of this study was to non-invasively determine SvO2 using a variation of pulse oximetry techniques. Artificial respiration-like modulations applied to the peripheral vascular system were used to infer regional SvO2 using photoplethysmography (PPG) sensors. To achieve this modulation, an artificial pulse generating system (APG) was developed to generate controlled, superficial perturbations on the finger using a pneumatic digit cuff. These low pressure and low frequency modulations affect blood volumes in veins to a much greater extent than arteries due to significant arterial-venous compliance differences. Ten healthy human volunteers were recruited for proof-ofconcept testing. The APG was set at a modulation frequency of 0.2 Hz (12 bpm) and 45-50 mmHg compression pressure. Initial analysis showed that induced blood volume changes in the venous compartment could be detected by PPG. Estimated arterial oxygen saturation (97% [IQR=96.1%-97.4%]) matches published values (95%-99%). Estimated venous oxygen saturation (93.2% [IQR=91.-93.9%]) agrees with reported ranges (92%-95%) measured in peripheral regions. The median difference between the two saturations was 3.6%, while the difference between paired measurements in each subject was statistically significant (p=0.002). These results demonstrate the feasibility of this method for real-time, low cost, non-invasive estimation of SvO2. Further validation of this method is warranted.
目前，外周静脉血氧饱和度（SvO2）的测量是通过侵入性导管或直接采血来进行的。本研究的目的是使用脉搏血氧测定技术的一种变体来无创测定SvO2。应用于外周血管系统的类似人工呼吸的调制被用于使用光电容积脉搏波描记法（PPG）传感器推断局部SvO2。为了实现这种调制，开发了一种人工脉冲生成系统（APG），以使用气动手指袖带在手指上产生可控的浅表扰动。由于显著的动静脉顺应性差异，这些低压和低频调制对静脉血容量的影响比对动脉血容量的影响大得多。招募了10名健康人类志愿者进行概念验证测试。APG设置为调制频率0.2 Hz（12次/分钟）和45 - 50 mmHg的压缩压力。初步分析表明，PPG可以检测到静脉腔中诱导的血容量变化。估计的动脉血氧饱和度（97% [四分位距=96.1%-97.4%]）与已发表的值（95%-99%）相符。估计的静脉血氧饱和度（93.2% [四分位距=91. - 93.9%]）与外周区域测量的报告范围（92%-95%）一致。两种饱和度之间的中位数差异为3.6%，而每个受试者配对测量之间的差异具有统计学意义（p = 0.002）。这些结果证明了该方法用于实时、低成本、无创估计SvO2的可行性。有必要对该方法进行进一步验证。
