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Sifuna MW, Kawashima D, Matsuura K, Obara H, Nakajima Y, Takei M. Simultaneous electrical online estimation of changes in blood hematocrit and temperature in cardiopulmonary bypass. J Artif Organs 2022; 25:305-313. [PMID: 35254539 DOI: 10.1007/s10047-022-01320-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 02/16/2022] [Indexed: 11/26/2022]
Abstract
Two equations have been developed from multi-frequency measurements of blood impedance Zb for a simultaneous electrical online estimation of changes in blood hematocrit ΔH [%] and temperatures ΔT [K] in cardiopulmonary bypass (CPB). Zb of fixed blood volumes at varying H and T were measured by an impedance analyzer and changes in blood conductivity σb and relative permittivity εb computed. Correlation analysis were based on changes in σb with H or T at f = 1 MHz while H and T equations were developed by correlating changes in εb with H and T at dual frequencies of f = 1 MHz and f = 10 MHz which best capture blood plasma Zp and red blood cell cytoplasm Zcyt impedances respectively. Results show high correlations between σb and H (R2 = 0.987) or σb and T (R2 = 0.9959) indicating dependence of the electrical parameters of blood on its H and T. Based on computed εb, changes in blood hematocrit ΔH and temperature ΔT at a given time t are estimated as ΔH(t) = 1.7298Δεb (f = 1 MHz) - 1.0669Δεb (f = 10 MHz) and ΔT(t) = -2.186Δεb (f = 1 MHz) + 2.13Δεb (f = 10 MHz). When applied to a CPB during a canine mitral valve plasty, ΔH and ΔT had correlations of R2 = 0.9992 and R2 = 0.966 against H and T respectively as measured by conventional devices.
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Affiliation(s)
- Martin Wekesa Sifuna
- Department of Mechanical Engineering, Graduate School of Science and Engineering, Chiba University, 1-33, Inage-ku, Chiba-shi, Chiba, 263-8522, Japan
| | - Daisuke Kawashima
- Department of Mechanical Engineering, Graduate School of Science and Engineering, Chiba University, 1-33, Inage-ku, Chiba-shi, Chiba, 263-8522, Japan.
| | - Katsuhiro Matsuura
- VCA Japan Shiraishi Animal Hospital, 4 Chome-33-2, Saitama, Sayamadai, Sayama, 350-1304, Japan
- Department of Veterinary Medicine, Tokyo University of Agriculture and Technology, 3Chome-8-1, Harumicho, Fuchu, Tokyo, 183-8538, Japan
| | - Hiromichi Obara
- Department of Mechanical System Engineering, Tokyo Metropolitan University, 6-6 Asahigaoka, Hino-shi, Tokyo, 191-0065, Japan
| | - Yusuke Nakajima
- Department of Mechanical Engineering, Graduate School of Science and Engineering, Chiba University, 1-33, Inage-ku, Chiba-shi, Chiba, 263-8522, Japan
| | - Masahiro Takei
- Department of Mechanical Engineering, Graduate School of Science and Engineering, Chiba University, 1-33, Inage-ku, Chiba-shi, Chiba, 263-8522, Japan.
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