Adequacy in hemodialysis: new concepts derived from online urea monitoring

Ensuring hemodialysis adequacy by dialysis dose monitoring with UV spectroscopy analysis of spent dialyzate

Introduction:

Patients’ session-to-session variation has been shown to influence outcomes, making critical the monitoring of dialysis dose in each session. The aim of this study was to detect the intra-patient variability of blood single pool Kt/V as measured from pre-post dialysis blood urea and from the online tool Adimea^®, which measures the ultraviolet absorbance of spent dialyzate.

Methods:

This open, one-armed, prospective non-interventional study, evaluates patients on bicarbonate hemodialysis or/and on hemodiafiltration. Dialysis was performed with B. Braun Dialog+ machines equipped with Adimea^®. In the course of the prospective observation, online monitoring with Adimea^® in each session was established without the target warning function being activated. A sample size of 97 patients was estimated.

Results:

A total of 120 patients were enrolled in six centers in China (mean age 51.5 ± 12.2 years, 86.7% males, 24.2% diabetics). All had an AV-fistula. The proportion of patients with blood Kt/V < 1.20 at baseline was 48.3%. During follow-up with Adimea^®, the subgroup with Kt/V > 1.20 at baseline remains at the same adequacy level for more than 90% of the patients. Those with a Kt/V < 1.20 at baseline, showed a significant increase of Kt/V to 60% of the patients reaching the adequacy level >1.20. The coefficient of variation for spKt/V as evaluated by Adimea^® was 9.6 ± 3.4%, not significantly different from the 9.6 ± 8.6% as blood Kt/V taken at the same time.

Conclusion:

Online monitoring of dialysis dose by Adimea^® improves and maintains dialysis adequacy. Implementing online monitoring by Adimea into daily practice moves the quality of dialysis patient care a significant step forward.

Molecular kinetics modeling in hemodialysis: on-line molecular monitoring and spectral analysis

The knowledge of the underlying molecular kinetics is a key point for the development of a dialysis treatment as well as for patient monitoring. In this work, we propose a kinetic inference method that is general enough to be used on different molecular types measured in the spent dialysate. It estimates the number and significance of the compartments involved in the overall process of dialysis by means of a spectral deconvolution technique, characterizing therefore the kinetic behavior of the patient. The method was applied to 52 patients to reveal the underlying kinetics from dialysate time-concentration profiles of urea, which has a well-known molecular kinetic. Three types of behaviors were found: one-compartmental (exponential decay Tau = 180 +/- 61.64 minutes), bicompartmental (Tau1 = 24.96 +/- 19.33 minutes, Tau2 = 222.32 +/- 76.59 minutes), and tricompartmental (Tau1 = 23.03 +/- 14.21 minutes; Tau2 = 85.75 +/- 27.48 minutes; and Tau3 = 337 +/- 85.52 minutes). In patients with bicompartmental kinetics, the Tau2 was related to the level of dialysis dose. The study concluded that spectral deconvolution technique can be considered a powerful tool for molecular kinetics inference that could be integrated in on-line molecular analysis devices. Furthermore, the method could be used in the analysis of poorly understood molecules as well as in new hemodialysis target biomarkers.

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