Implications of the dielectrical behaviour of human blood for continuous online measurement of haematocrit

• Published in: Medical & biological engineering & computing Vol. 31; no. 5; pp. 445 - 448
• Main Authors: DE VRIES, P. M. J. M, LANGENDIJK, J. W. G, KOUW, P. M, VISSER, V, SCHNEIDER, H
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 01-09-1993
• Subjects: Biological and medical sciences; Blood Volume - physiology; Blood Volume Determination; Electric Conductivity; Hematocrit - methods; Hematology; Humans; Investigative techniques, diagnostic techniques (general aspects); Medical sciences; Pathology. Cytology. Biochemistry. Spectrometry. Miscellaneous investigative techniques; Renal Dialysis; Electrical conductivity; Hemodialysis; Exploration; Extracorporeal circuit; Experimental study; Electric admittance; Extracellular; In vitro; Blood; Blood plasma; Hematocrite; Intracellular; Measurement method; Biomedical engineering
• ISSN: 0140-0118; 1741-0444
• DOI: 10.1007/BF02441978

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.