Dialysis dose and nutrition assessment by optical on-line dialysis adequacy monitor

In light of the variability of dialysis sessions, on-line monitoring could improve hemodialysis (HD) adequacy. A new optical Dialysis Adequacy Monitor (DIAMON) prototype enables to estimate dialysis dose and protein nitrogen appearance (PNA) at every dialysis session. The aim of this study was to compare the adequacy of dialysis treatment and the patient's nutritional status by pre-and post-dialysis blood samples, the DIAMON prototype and Total Dialysate Collection (TDC).

Ten patients were monitored during three consecutive hemodialysis sessions during one week. Blood samples were drawn before the start of dialysis and at the end of dialysis. The DIAMON prototype was connected to the fluid outlet of the dialysis machine with all spent dialysate passing through during the on-line experiments, and TDC was performed for all dialysis treatments. Equilibrated Kt/V (eKt/V) values were estimated from blood-urea (eKt/Vb) and from DIAMON (eKt/Va), and normalized PNA (nPNA) values from TDC and DIAMON, respectively. The variable volume single pool urea kinetic modeling (VVSP UKM) was also utilized for single-pool Kt/V (spKt/V) and nPNA estimation.

The mean +/- SD given by eKt/Vb was 1.08 +/- 0.22 (n = 30), and eKt/Va 1.05 +/- 0.21 (n = 28). The mean +/- SD of nPNA was 0.73 +/- 0.15 g/kg/day (n = 29) from TDC, and 0.73 +/- 0.14 g/kg/day (n = 28) using DIAMON prototype. The mean values of eKt/V from blood samples and nPNA from TDC were not statistically different from the corresponding values estimated by DIAMON (p < 0.05). Generally the delivered dialysis dose and dietary protein intake of the patients observed during the study using the DIAMON prototype was very similar to that obtained by TDC and VVSP UKM.

The optical dialysis adequacy sensor, DIAMON, provides continuous, on-line measurements of dialysis adequacy and permits longitudinal analysis of the delivered dialysis dose and patient's nutritional status, and can immediately identify, and alert to, any deviations in dialysis treatment.