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Erschienen in:
01.12.2015 | Original Article
Relative permittivity measurement during the thrombus formation process using the dielectric relaxation method for various hematocrit values
Erschienen in: Journal of Artificial Organs | Ausgabe 4/2015
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The relative permittivity ε′ and the dielectric loss ε″ for various hematocrit values H for static bovine blood condition have been measured using the dielectric relaxation method to detect thrombosis in real time. The suitable measurement frequency f
m ranged within 60 kHz to 1 MHz, and the relaxation frequency of red blood cells (RBCs) f
rc was observed to be 2 MHz. In the f
m, the temporal change of normalized ε′ exhibited a minimum (called as bottom point). The bottom point was observed to be exponentially shortened as H increased. This characteristic of the ε′* minimum is discussed from three viewpoints: during fibrin formation, direct thrombus formation, and rouleaux formation processes. ε′* during the fibrin formation process decreased over time, irrespective of f. However, ε′* in f
m during the direct thrombus formation process and during the aggregation formation process increased immediately and rapidly over time. Therefore, the ε′* bottom point in f
m might be the indication of micrometer-scale thrombus formation by RBC aggregation due to fibrin formation.