Online Urea Concentration Estimation from Spent Dialysate Using Optical Sensor

摘要

The aim of this study was to estimate urea concentration on-line in the spent dialysate by a novel miniaturized optical sensor during hemodialysis and hemodiafiltration with different settings, and to compare the results with urea concentrations measured in laboratory. Ten end-stage kidney disease patients were enrolled for this study and the dialysate samples were collected, and signals were recorded with optical sensor during 5 midweek dialysis sessions with 5 different modalities for each patient. Using samples and optical signals from calibration set, the linear model was calculated to estimate urea concentration. For linear model the determination coefficient R2, the systematic error as BIAS and the standard error (SE) were 0.876, 0.00 ± 1.60 mM/L (calibration set) and 0.841, 0.01 ± 1.68 mM/L (validation set), respectively. In summary, the novel miniaturized optical sensor enables on-line estimation of urea concentrations during dialysis sessions and accuracy outperforms the measurement accuracy of UV-absorbance based urea concentration method from a previous study.