Conductivity measures coupled with treatment with ion-exchange resin for the assessment of sodium concentration in physiological fluids: analyses on artificial solutions

2013 Joint IMEKO (International Measurement Confederation) TC1-TC7-TC13 Symposium: Measurement Across Physical and Behavioural Sciences

Tura, A.^1 ; Sbrignadello, S.^1 ; Mambelli, E.^2 ; Ravazzani, P.^1 ; Santoro, A.^2 ; Pacini, G.^1

Institute of Biomedical Engineering, National Research Council, Padova, Italy^1

Nephrology Dialysis and Hypertension Unit, Policlinico S. Orsola-Malpighi, Bologna, Italy^2

关键词: After-treatment;    Laboratory equipments;    Manual intervention;    NaCl concentration;    On conductivities;    Physiological fluids;    Simple approach;    Sodium chloride (NaCl);   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/459/1/012062/pdf
DOI  :  10.1088/1742-6596/459/1/012062

来源: IOP

【 摘 要 】

In humans, sodium is essential for the regulation of blood volume and pressure. During hemodialysis, sodium measurement is important to preserve the patient from hypo- or hyper-natremia Usually, sodium measurement is performed through laboratory equipment which is typically expensive, and requires manual intervention. We propose a new method, based on conductivity measurement after treatment of dialysate solution through ion-exchange resin. To test this method, we performed in vitro experiments. We prepared 40 ml sodium chloride (NaCl) samples at 280, 140, 70, 35, 17.5, 8.75, 4.375 mEq/l, and some «mixed samples», i.e., with added potassium chloride (KCl) at different concentrations (4.375-17.5 mEq/l), to simulate the confounding factors in a conductivity-based sodium measurement. We measured the conductivity of all samples. Afterwards, each sample was treated for 1 min with 1 g of Dowex G-26 resin, and conductivity measured again. On average, the difference in the conductivity between mixed samples and corresponding pure NaCl samples (at the same NaCl concentration) was 20.9%. With treatment with the resin, it was 9.9%, only. We conclude that ion-exchange resin treatment coupled with conductivity measures may be a possible simple approach for continuous and automatic sodium measurement during hemodialysis.