Lozano A, Rosell J, Pallás-Areny R
Universitat Politècnica de Catalunya, Department d'Enginyeria Electrònica, Barcelona, Spain.
Physiol Meas. 1995 Nov;16(4):227-37. doi: 10.1088/0967-3334/16/4/003.
This paper discusses some important issues for the design of electrical impedance measurement systems intended for body fluid shift monitoring, in particular during dialysis treatments. We have studied two common signal generation systems: digital synthesis and carrier recovery. We have found that in prolonged measurement applications, digital synthesis yields the best performance. On the demodulation side, we balance the demodulator errors between the real and imaginary parts by rotating the demodulation axes. We use segmental multifrequency impedance measurements to estimate the values of intracellular and extracellular impedance by adjusting the parameters of a Cole-Cole model for each segment measured. We stress the need to perform segmental measurements in order to accurately measure the segments of interest, in particular the trunk during dialysis treatments. Our results show that there is a sharp disequilibrium between the intracellular and extracellular compartments in the very first dialysis period. This fact generates the need to continuously measure segmental impedance instead of comparing initial and final values.
本文讨论了用于监测体液转移（特别是在透析治疗期间）的电阻抗测量系统设计中的一些重要问题。我们研究了两种常见的信号生成系统：数字合成和载波恢复。我们发现，在长时间测量应用中，数字合成具有最佳性能。在解调方面，我们通过旋转解调轴来平衡解调器在实部和虚部之间的误差。我们使用分段多频阻抗测量，通过为每个测量段调整科尔 - 科尔模型的参数来估计细胞内和细胞外阻抗的值。我们强调需要进行分段测量，以便准确测量感兴趣的段，特别是在透析治疗期间的躯干部分。我们的结果表明，在第一个透析期，细胞内和细胞外间隙之间存在急剧的不平衡。这一事实使得需要连续测量分段阻抗，而不是比较初始值和最终值。
