Quantitative evaluation of electrical parameters influenced by blood flow rate with multiple-frequency measurement based on modified Hanai mixture formula

Characteristics of electrical parameters (characteristic frequency fc, shape factor α, resistance at zero frequency R0 and resistance at infinite frequency R∞) in swine flowing blood have been clarified under various flow rates by multiple-frequency electrical impedance measurement to obtain the physical interpretations for the influence of blood flow rate. In order to quantitatively evaluate the experimental results, the conventional Hanai mixture formula for static colloids has been modified from the viewpoint of blood flow-dependent factors which are RBC (red blood cell) orientation, RBC deformation and EDL (electrical double layer) thickness around RBCs. The experimental results are compared with the theoretical evaluations by the modified Hanai mixture formula. This formula is applicable to evaluate the characteristics of electrical parameters of flowing blood since the small errors for fc, α, R0 and R∞ between the experimental and theoretical results which are only efc = 3.4%, eα = 19.3%, eR0 = 3.1% and eR1 = 1.7%. Blood flow-dependent factors (RBC orientation, RBC deformation, and EDL thickness) are clarified to be accountable for the variation of electrical parameters of flowing blood.]