Sources of error in bioimpedance spectroscopy
Sources of error in bioimpedance spectroscopy
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DOI：
10.1088/0967-3334/19/2/011
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发表时间：
1998-05-01
影响因子：
3.2
通讯作者：
Elia, M
中科院分区：
文献类型：
--
作者：
Bolton, MP;Ward, LC;Elia, M
使用两种不同型号的生物阻抗谱仪(UniQuest-SEAC SFB3和Xitron 4000B)对志愿者和重症监护病人进行了一系列测量。尽管在模型电阻-电容电路上进行台式测试时，每台机器在5到500 kHz的频率范围内都是准确的，但在活体使用时，它们记录的阻抗参数出现了显著的差异，特别是在重症监护患者身上。在模拟体内情况的每台机器上进行了一系列实验室测试，以确定造成这些差异的可能原因。虽然环境中的杂散电容被认为是高频性能变化的主要原因，但电极阻抗和导线定位之间的相互作用也是一个因素。Xitron建模软件中使用的随频率或时间延迟的观测相移(T-d)似乎是由杂散电容引起的时间常数的结果，因此不太可能具有任何生物学意义。生物阻抗波谱仪产生的活体数值的显著差异可能归因于仪器设计、数据处理，特别是临床环境。
Two different makes of bioimpedance spectrometer (UniQuest-SEAC SFB3 and Xitron 4000B) were used for a series of measurements on volunteers and patients in intensive care. Although each machine was accurate over the frequency range 5 to 500 kHz when bench tested on model resistor-capacitor circuits, significant differences in their recorded impedance parameters appeared when used in vivo, especially on intensive care patients. A series of laboratory tests was performed on each machine simulating the situation in vivo to identify possible reasons for these differences. Whilst stray capacitance in the environment was identified as the major contributor to variability in high-frequency performance, interaction between electrode impedance and lead positioning was also a factor. The observed phase shift with frequency or time delay (T-d) used in the Xitron modelling software appears to be the result of a time constant caused by stray capacitance and so is unlikely to have any biological meaning. Significant differences in the in vivo numerical values produced by bioimpedance spectrometers may be attributed to instrument design, data processing and, in particular, the clinical environment.