Precise Quantitative Assessment of the Clinical Performances of Two High-Flux Polysulfone Hemodialyzers in Hemodialysis: Validation of a Blood-Based Simple Kinetic Model Versus Direct Dialysis Quantification

Sodium flux during hemodialysis and hemodiafiltration treatment of acute kidney injury: Effects of dialysate and infusate sodium concentration at 140 and 145 mmol/L

BACKGROUND

A higher sodium (Na) dialysate concentration is recommended during renal replacement therapy (RRT) of acute kidney injury (AKI) to improve intradialytic hemodynamic tolerance, but it may lead to Na loading to the patient. We aimed to evaluate Na flux according to Na dialysate and infusate concentrations at 140 and 145 mmol/L during hemodialysis (HD) and hemodiafiltration (HDF).

METHODS

Fourteen AKI patients that underwent consecutive HD or HDF sessions with Na dialysate/infusate at 140 and 145 mmol/L were included. Per-dialytic flux of Na was estimated using mean sodium logarithmic concentration including diffusive and convective influx. We compared the flux of sodium between HD140 and 145, and between HDF140 and 145.

RESULTS

Nine HD140, ten HDF140, nine HD145, and 11 HDF145 sessions were analyzed. A Na gradient from the dialysate/replacement fluid to the patient was observed with dialysate/infusate Na at 145 mmol/L in both HD and HDF (p = 0.01). The comparison of HD145 to HD140 showed that higher Na dialysate induced a diffusive Na gradient to the patient (163 mmol vs. -25 mmol, p = 0.004) and that of HDF145 to -140 (211 vs. 36 mmol, p = 0.03) as well. Intradialytic hemodynamic tolerance was similar across all RRT sessions.

CONCLUSIONS

During both HD and HDF, a substantial Na loading occurred with a Na dialysate and infusate at 145 mmol/L. This Na loading is smaller in HDF with Na dialysate and infusate concentration at 140 mmol/L and inversed with HD140. Clinical and intradialytic hemodynamic tolerance was fair regardless of Na dialysate and infusate.

Safety and Efficacy of Short Daily Hemodialysis with Physidia S3 System: Clinical Performance Assessment during the Training Period

Background: A growing body of scientific evidence indicates that clinical outcomes of hemodialysis patients can be improved with short daily dialysis treatment. Current in-center hemodialysis machines do not fulfill the requirements needed for self-care home hemodialysis (HHD) treatment. In line with the reviviscence of home therapy, several hemodialysis devices have been developed and deployed for treatment. Physidia S³ is one of these new dialysis delivery systems featuring an appealing design and functionalities intended for daily HHD treatment. Methods: In this French multicenter proof-of-concept study enrolling 13 training centers, we report our preliminary experience with a special focus on quantifying clinical performances in short daily HHD treatment performed during the training period of the patients. Results: Among the 80 patients included in this study, a total of 249 sessions could be analyzed. Dialysis dose, estimated from weekly standardized Kt/V, was maintained at 2.22 [1.95–2.61] with a normalized protein catabolic rate of 0.93 [0.73–1.18] g/kg/24 h. Furthermore, anemia and nutritional status were adequately controlled as indicated by 11.6 ± 1.4 g/dL of hemoglobin level and 39.4 ± 5.7 g/L of serum albumin as well as electrolyte disorders. Conclusions: The safety and efficacy of the S³ therapy concept relying on a short daily hemodialysis treatment using a bagged delivery system are in total agreement with daily HHD recommendations. Clinical performances are aligned to the metabolic needs of the vast majority of HHD patients. Currently ongoing studies at home will provide further evidence and value of this therapeutic approach.

A simple method for the calculation of dialysis Kt factor as a quantitative measure of removal efficiency of uremic retention solutes: Applicability to high-dialysate vs low-dialysate volume technologies

Dialysis urea removal metrics may not translate into proportional removal efficiency of non-urea solutes. We show that the Kt factor (plasma volume totally cleared of any solutes) differentiates removal efficiency of non-urea solutes in different technologies, and can easily be calculated by instant blood-dialysate collections. We performed mass balances of urea, creatinine, phosphorus and beta₂-microglobulin by whole dialysate collection in 4 low-flux and 3 high-flux hemodialysis, 2 high-volume post-hemodiafiltration and 7 short-daily dialysis with the NxStage-One system. Instant dialysate/blood determinations were also performed at different times, and Kt was calculated as the product of the D/P ratio by volume of delivered dialysate plus UF. There were significant differences in single session and weekly Kt (whole dialysate and instant calculations) between methodologies, most notably for creatinine, phosphorus and beta₂-microglobulin. Urea Kt messured in balance studies was almost equal to that derived from the usual plasma kinetic model-based Daugirdas’ equation (eKt/V) and independent V calculation, indicating full correspondence. Non-urea solute Kt as a fraction of urea Kt (i.e. fractional removal relative to urea) showed significant differences between technologies, indicating non-proportional removal of non-urea solutes and urea. Instant Kt was higher than that in full balances, accounting for concentration disequilibrium between arterial and systemic blood, but measured and calculated quantitative solute removal were equal, as were qualitative Kt comparisons between technologies. Thus, we show that urea metrics may not reliably express removal efficiency of non-urea solutes, as indicated by Kt. Kt can easily be measured without whole dialysate collection, allowing to expand the metrics of dialytic efficiency to almost any non-urea solute removed by dialysis.

Randomised trial on clinical performances and biocompatibility of four high-flux hemodialyzers in two mode treatments: hemodialysis vs post dilution hemodiafiltration

This prospective multicenter randomized comparative cross-over trial aimed at evaluating the influence of hemodialysis vs post-dilution hemodiafiltration with high-flux dialyzers in solute clearance and biocompatibility profile. 32 patients were sequentially dialyzed with Leoceed-21HX, Polypure-22S+, Rexsys-27H and VIE-21A. Primary outcome was β2-microglobulin removal. Secondary outcomes were (i) extraction of other uremic solutes (ii) parameters of inflammation and nutrition and (iii) comparative quantification of perdialytic albumin losses (using total ‘TDC’ vs partial ‘PDC’ collection of dialysate). Significant increases in removal rates of β2-microglobulin (84.7 ± 0.8 vs 71.6 ± 0.8 mg/L), myoglobin (65.9 ± 1.3 vs 38.6 ± 1.3 µg/L), free immunoglobulin light chains Kappa (74.9 ± 0.8 vs 55.6 ± 0.8 mg/L), β-trace protein (54.8 ± 1.3 vs 26.8 ± 1.4 mg/L) and orosomucoid (11.0 ± 1.1 vs 6.0 ± 1.1 g/L) but not myostatin (14.8 ± 1.5 vs 13.0 ± 1.5 ng/mL) were observed in HDF compared to HD when pooling all dialyzers. Rexsys and VIE-A use in both HD and HDF subgroups was associated to a better removal of middle/large-size molecules compared to Leoceed and Polypure, except β2-microglobulin for Rexsys. Inflammatory parameters were unchanged between dialyzers without any interaction with dialysis modality. Mean dialysate albumin loss was comparable between TDC and PDC (1.855 vs 1.826 g/session for TDC and PDC respectively). In addition, a significant difference in albumin loss was observed between dialyzers with the highest value (4.5 g/session) observed using Rexsys. Use of all dialyzers was associated with good removals of the large spectrum of uremic toxins tested and good biocompatibility profiles, with an additional gain in removal performances with HDF. Larger surface area, thinner wall and resultant very high ultrafiltration coefficient of Rexsys should be taken into account in its clear performance advantages.

Artificial Organs 2018: A Year in Review

In this Editor's Review, articles published in 2018 are organized by category and summarized. We provide a brief reflection of the research and progress in artificial organs intended to advance and better human life while providing insight for continued application of these technologies and methods. Artificial Organs continues in the original mission of its founders "to foster communications in the field of artificial organs on an international level." Artificial Organs continues to publish developments and clinical applications of artificial organ technologies in this broad and expanding field of organ Replacement, Recovery, and Regeneration from all over the world. Peer-reviewed special issues this year included contributions from the 13th International Conference on Pediatric Mechanical Circulatory Support Systems and Pediatric Cardiopulmonary Perfusion edited by Dr. Akif Undar, and the 25th Congress of the International Society for Mechanical Circulatory Support edited by Dr. Marvin Slepian. Additionally, many editorials highlighted the worldwide survival differences in hemodialysis and perspectives on mechanical circulatory support and stem cell therapies for cardiac support. We take this time also to express our gratitude to our authors for offering their work to this journal. We offer our very special thanks to our reviewers who give so generously of time and expertise to review, critique, and especially provide meaningful suggestions to the author's work whether eventually accepted or rejected. Without these excellent and dedicated reviewers the quality expected from such a journal could not be possible. We also express our special thanks to our Publisher, John Wiley & Sons for their expert attention and support in the production and marketing of Artificial Organs. We look forward to reporting further advances in the coming years.