1. A novel model for blood impedance for indirect viscosity measurement Zu-yao Chang, Gerard C.M. Meijer and Gheorghe A.M. Pop Faculty of Electrical Engineering, Mathematics and Computer Science,  Soz 2004.

2. Structure Introduction Contents of Blood Measurement techniques Measurement setup Experimental results Conventional Model Novel Model Conclusions  Soz 2004.

3. Introduction Heart and arterial diseases death cause no 1. Source: Centraal Bureau voor de Statistiek

4. Introduction Higher viscosity  higher risk of blood-clot forming Good correlation between blood viscosity and blood impedance.  Soz 2004.

5. Introduction  Soz 2004.

6. Contents of Blood Plasma (volume 55%) Blood Cells (volume 45%) –Leukocytes (white blood cells) –Thrombocytes (platelets) –Erythrocytes (red blood cells)  Soz 2004.

7. Two-electrode measurement technique Measurement technique Four-electrode measurement technique  Soz 2004. Z pol

8. Measurement setup (4-electrodes)  Z.Chang, 2003. LabVIEW Labview |Z|,  Gain G, Phase  Mathematical calculations HP4192A Gain Phase analyzer measurement circuit measurement cell Measurement cell Measurement circuit V osc Impedance of Blood

9. Experimental results Nyquist Plot Ht=45% T=24  C  Soz 2004. Polarization effects Blood Dielectric Properties of water

10. Conventional Model Resistor R p : plasma resistance with non- conducting blood cells. Capacitor C m : cell- membrane capacitance. Resistor R i : interior cell- resistance. RpRp RiRi CmCm Where is the dielectric capacitance of water ?  Soz 2004.

11. Conventional Model Blood, Ht=45%, T=24ºC Nyquist plot of four-electrodes measurement conv. model <1.2 MHz conventional model full freq. range  Soz 2004.

12. Conventional Model  Soz 2004. Nyquist plot of two-electrodes measurement Blood, Ht=45%, T=24ºC C li q Improved model total freq. fit

13. Novel Model Resistor R p : plasma resistance with non- conducting blood cells. Resistor R i : interior cell- resistance. RpRp RiRi  Soz 2004. Constant-Phase element C CPE_m : cell-membrane capacitance. C CPE_m C liq Capacitor C liq : dielectric capacitance.

14. Novel Model Blood, Ht=45%, T=24ºC Nyquist plot of four-electrodes measurement  Soz 2004. Conv. model, 3pnt Conventional model, all novel model

15. Novel Model Nyquist plot of two-electrodes measurement Blood, Ht=45%, T=24ºC  Soz 2004. Conventional model with C liq novel model

16. Conclusions It is possible to predict blood viscosity via blood impedance. The validity of the early model of blood impedance is limited. A novel model of blood impedance is found and its validity verified until 100MHz.  Soz 2004.

17. Questions ?  Soz 2004.