Optoelectronic online monitoring system for hemodialysis and its data analysis

An optoelectronic system is presented for online measuring the concentrations of uric acid and β2-microglobulin in dialysates during hemodialysis (HD). The optoelectronic system consists of two sets of ultra-violet (UV) light emitting diodes (LEDs), flow cell, and photodiodes (PD); one set is for absorbance measurement of uric acid at 278 nm, while the other set is for β2-microglobulin measurement at 315 nm. The flow cell is employed for dialysate passing through during HD and for the online absorbance measurement. Further, a cylindrical flow cell is applied to reduce the total internal reflection (TIR) and to abate the stray light radiation on the PD for better linearity and less deviation. The system is first calibrated with standardized solutions and integrated with a commercial HD machine to test and monitor dialysate from 10 HD sessions of six (6) patients in the clinical study. The concentrations of uric acid and β2-microglobulin in dialysate can be obtained using our optoelectronic systems; more they are used to predict the concentrations in the patients’ serum using supporting vector machine (SVM) regression. The results displayed very good correlations, R2 = 0.8482 for uric acid and 0.7208 for β2-microglobulin, showing the great potentials of our systems with online HD monitoring capability.