Implications of the dielectrical behaviour of human blood for continuous online measurement of haematocrit.
A study was designed to explore the possibility of detecting the haematocrit of blood by means of admittance measurements. The admittance and phase angle of blood kept in a measuring cell were determined at various frequencies between 60 kHz and 24 MHz. A reliable and accurate estimation of haematocrit was obtained in two ways. First, low-frequency admittance, high-frequency admittance and a factor x, which was the conductive percentage of cell content, were used. Secondly, the maximum phase angle was used. Both methods can be applied to obtain continuous on-line information about haematocrit for blood volume control during haemodialysis.
de Vries
P M
PM
Department of Internal Medicine, Free University Hospital, Amsterdam, The Netherlands.
Langendijk
J W
JW
Kouw
P M
PM
Visser
V
V
Schneider
H
H
D001810:Blood Volume / Q000502:physiology; D001811:Blood Volume Determination; D004553:Electric Conductivity; D006400:Hematocrit / Q000379:methods*; D006801:Humans; D006435:Renal Dialysis