Most recently developed polyester polymer alloy dialyzer: A new medium cut-off membrane?

BACKGROUND: New versions of the polyester polymer alloy (PEPA) membrane have appeared over the years, with increases in both the pore size and the amount of polyvinylpyrrolidone (PVP) to optimize hydrophilicity performance. This study aimed to assess the efficacy of the most recently developed PEPA dialyzer, the FDY series, in hemodialysis (HD) modality in terms of uremic toxin removal and albumin loss and to compare it with that of several high-flux dialyzers currently used in HD and post-dilution hemodiafiltration (HDF) treatments. METHODS: A prospective study was carried out in 21 patients. All patients underwent six dialysis sessions with the same routine dialysis parameters; only the dialyzer and/or the dialysis modality varied: FX80 in HD, FDY 180 in HD, Clearum HS17 in HDF, Elisio 19H in HDF, Vitapes 180 in HDF, and FX80 in post-dilution HDF. The reduction ratios (RR) of urea, creatinine, ß2-microglobulin, myoglobin, κFLC, prolactin, α1-microglobulin, α1-acid glycoprotein, λFLC, and albumin were compared intraindividually. Dialysate albumin loss was also measured. RESULTS: Both membranes FDY and FX80 are high-flux dialyzers and are applied here in high-flux HD. The average RR of ß2-microglobulin was slightly lower in the two HD treatments than in the HDF treatments. Comparison of dialysis treatments revealed that the PEPA FDY dialyzer in the HD modality was more effective than the FX80 dialyzer in high-flux HD and was as effective as post-dilution HDF, especially in terms of myoglobin, κFLC, prolactin, α1-microglobulin, and λFLC RRs. The FDY treatments obtained similar albumin RR in blood and slightly higher dialysate albumin loss, although the values were clinically acceptable. CONCLUSIONS: The most recently developed PEPA dialyzers in the HD modality were as effective as all treatments in the HDF modality and were clearly superior to high-flux helixone HD treatment. These results confirm that this dialyzer should be categorized within the medium cut-off (MCO) membrane classification.

Efficacy and Safety of the Medium Cut-Off Elisio HX Dialyzer.

INTRODUCTION: The medium cut-off Elisio HX dialyzer by Nipro became commercially available in Europe in 2021, but there are still no reports of in vivo data. This study aimed to evaluate the safety and efficacy of it compared with previously evaluated hemodialysis (HD), expanded HD (HDx), and postdilution hemodiafiltration (HDF) treatments. METHODS: A prospective study was carried out on 18 patients who underwent 5 dialysis sessions: FX80 Cordiax in HD, Elisio H19 in HD, Elisio HX19 in HDx, Theranova 400 in HDx, and FX80 Cordiax in HDF. The reduction ratios of urea, creatinine, ß2-microglobulin, myoglobin, kappa FLC, prolactin, α1-microglobulin, α1-acid glycoprotein, lambda FLC, and albumin were compared. Dialysate albumin loss was measured. RESULTS: The comparison between the different dialysis modalities revealed no difference for small molecules, but HDx and HDF were significantly more efficient than HD for medium and large molecule removal. The efficacy of Elisio HX19 dialyzer in HDx was similar to the Theranova 400, superior to both dialyzers in HD, and slightly lower than HDF. Albumin losses in dialysate with HD dialyzers were less than 1 g, but between 1.5 and 2.5 g in HDx and HDF. The global removal score (GRS) values with HDx treatments were statistically significantly higher than those with HD. The highest GRS was obtained with the helixone dialyzer in HDF. CONCLUSIONS: The new MCO dialyzer, Elisio HX, performs with excellent behavior and tolerance. It represents an upgrade compared to their predecessor and is very close to the removal capacity of HDF treatment.

Distinct Solute Removal Patterns by Similar Surface High-Flux Membranes in Haemodiafiltration: The Adsorption Point of View.

INTRODUCTION: Haemodialysis (HD) allow depuration of uraemic toxins by diffusion, convection, and adsorption. Online haemodiafiltration (HDF) treatments add high convection to enhance removal. There are no prior studies on the relationship between convection and adsorption in HD membranes. The possible benefits conferred by intrinsic adsorption on protein-bound uraemic toxins (PBUTs) removal are unknown. METHODS: Twenty-two patients underwent their second 3-days per week HD sessions with randomly selected haemodialysers (polysulfone, polymethylmethacrylate, cellulose triacetate, and polyamide copolymer) in high-flux HD and HDF. Blood samples were taken at the beginning and at the end of the treatment to assess the reduction ratio (RR) in a wide range of molecular weight uraemic toxins. A mid-range removal score (GRS) was also calculated. An elution protocol was implemented to quantify the amount of adsorbed mass (Mads) for each molecule in every dialyser. RESULTS: All synthetic membranes achieved higher RR for all toxins when used in HDF, specially the polysulfone haemodialyser, resulting in a GRS = 0.66 ± 0.06 (p < 0.001 vs. cellulose triacetate and polyamide membranes). Adsorption was slightly enhanced by convection for all membranes. The polymethylmethacrylate membrane showed expected substantial adsorption of ß2-microglobulin (MadsHDF = 3.5 ± 2.1 mg vs. MadsHD = 2.1 ± 0.9 mg, p = 0.511), whereas total protein adsorption was pronounced in the cellulose triacetate membrane (MadsHDF = 427.2 ± 207.9 mg vs. MadsHD = 274.7 ± 138.3 mg, p = 0.586) without enhanced PBUT removal. DISCUSSION/CONCLUSION: Convection improves removal and slightly increases adsorption. Adsorbed proteins do not lead to enhanced PBUTs depuration and limit membrane efficiency due to fouling. Selection of the correct membrane for convective therapies is mandatory to optimize removal efficiency.

Planarian organizers.

An organizer is defined as a group of cells that secrete specific factors and can change the fate of adjacent cells and instruct a specific pattern. Spemann and Mangold were the first to use the term, when in 1938 they discovered that the dorsal blastopore lip of a salamander embryo induced a secondary axis after transplantation. Since then, several such regions have been identified in the embryos of many animal species. However, little is known about the presence of organizers at the adult stage, although some organizing activity must be required during regenerative processes to pattern the new tissue. In this study we review the current knowledge on planarians, flatworms that can regenerate any lost body parts, including their heads, within a few days. We will summarize the current data that made it possible to identify planarian anterior and posterior tips as regenerative organizers. We will present the current knowledge about the molecular networks that define each organizer, and we will discuss the presence of organizers in planarians during normal homeostasis. We will propose some unanswered questions concerning both planarian regeneration and regenerative medicine, and examine future research prospects in this field.

Evaluation and comparison of polysulfone TS-UL and PMMA NF-U dialyzers versus expanded hemodialysis and postdilution hemodiafiltration.

Toray has created a new generation of dialyzers, the polysulphone (TS) UL series, and polymethylmethacrylate (PMMA) NF-U series, which offer enhanced efficacy over the previous TS-S series and NF-H series. The aim of this study was to evaluate the safety and efficacy of these dialyzer series versus contrasted expanded hemodialysis (HDx) and postdilution hemodiafiltration (HDF). We conducted a prospective study in 12 patients. Each patient underwent six dialysis sessions: FX80 Cordiax in HD, Toraysulfone TS-1.8 UL in HD, Theranova 400 in HDx, polymethylmethacrylate (PMMA) NF-2.1 U in HDF, Toraysulfone TS-2.1 UL in HDF, and FX80 Cordiax in HDF. The removal ratios (RRs) of urea, creatinine, ß2 -microglobulin, myoglobin, prolactin, α1 -microglobulin, α1 -acid glycoprotein, and albumin were compared intraindividually. Dialysate albumin loss was also measured. The RRs for ß2 -microglobulin, myoglobin, prolactin, α1 -microglobulin, and α1 -acid glycoprotein were higher with the TS-2.1 UL and FX80 Cordiax dialyzers in HDF than those obtained with HD treatments and NF-2.1 U in HDF. The ß2 -microglobulin, myoglobin, and prolactin RRs were also higher with HDx than those obtained with HD treatments. The myoglobin and prolactin RRs were higher with TS-1.8 UL in HD than those obtained with helixone dialyzers in HD. Dialysate albumin loss was less than 3 g in all situations except in TS-2.1 UL in HDF. The highest global removal score values were obtained with the TS-2.1 UL and helixone dialyzers in HDF. Significant differences were found between all study situations. In conclusion, the new generation dialyzers, Toraysulfone TS Series UL and PMMA NF-U series, show excellent behaviour and tolerance in HD and HDF, representing an upgrade versus their predecessor series. The higher permeability of the TS UL series has been proven with higher efficiency in HD and maximum performance in HDF. The new PMMA NF-U series allows the use of HDF with good efficiency and complete safety.

Efficacy and safety of the Clearum dialyzer.

The Clearum dialyzer, built by Medtronic, became commercially available in several European countries in 2020, but there are still no reports of in vivo data. The aim of this study was to evaluate the efficacy and risk of hypoalbuminemia of this dialyzer compared with previously evaluated hemodialysis (HD), expanded hemodialysis (HDx), and postdilution hemodiafiltration (HDF) treatments. A prospective study was carried out in 15 patients. Each patient underwent seven dialysis sessions: FX80 Cordiax in HD, Clearum HS17 in HD, Phylther 17-SD in HDx, Theranova 400 in HDx, Phylther 17-G in postdilution HDF, Clearum HS17 in postdilution HDF, and FX80 Cordiax in postdilution HDF. The reduction ratios of urea, creatinine, ß2 -microglobulin, myoglobin, prolactin, α1 -microglobulin, α1 -acid glycoprotein, and albumin were compared intraindividually. Dialysate albumin loss was also measured. Comparison of dialysis techniques revealed no differences between small molecules, but HDx and HDF were significantly higher than HD with medium and large molecular weights. The Clearum dialyzer in HDF obtained similar results to FX80 Cordiax in HDF, was slightly superior to Phylther 17-G in HDF, and was statistically superior to both dialyzers in HDx. Albumin losses with the Clearum dialyzer were among the lowest, both in HD and HDF treatments. The highest global removal score (GRS) values were obtained with the helixone and Clearum dialyzers in HDF, with similar results both in HD and HDF. In addition, the GRS values with HDx treatments were statistically significantly higher than those with HD. The new Clearum dialyzer has excellent behavior and tolerance in HD and HDF. Its adequate permeability has been proven with its maximal performance in HDF, which could represent an upgrade versus its predecessor polyphenylene dialyzers.

Study of Biocompatibility of Membranes in Online Hemodiafiltration.

BACKGROUND: The biocompatibility of dialysis membranes is a determining factor in avoiding chronic microinflammation in patients under haemodialysis. Lower biocompatibility has been related to increased inflammatory status, which is known to be associated with cardiovascular events. Classically, cellulose membranes have been considered bioincompatible. A new-generation of asymmetric cellulose triacetate (CTA) membranes allows the performance of high convective transport techniques, but there have been no studies of their biocompatibility. The aim of the present study was to analyze and compare the biocompatibility characteristics of 4 membranes, including CTA, in online hemodiafiltration (OL-HDF) patients. METHODS: We included 15 patients in -OL-HDF. After a 2-week washout period with helixone membrane, each patient was treated with the 4 membranes (polyamide, polynephron, helixone and CTA) for 4 weeks in a randomized order. The other dialysis parameters were kept stable throughout the study. We studied changes in markers of the activation of the complement system, monocytes, platelets, and adhesion molecules with the 4 membranes, as well as inflammatory parameters. RESULTS: Biocompatibility was similar among the membranes. There were no sustained differences in complement activation, measured by C3a and C5a levels, or in platelet activation, determined by levels of P-selectin and platelet-derived microparticles (CD41a+). No differences were observed in activated monocyte levels (CD14+/CD16+) or in plasma levels of interleukin (IL)-1, IL-6, IL-10 or high-sensitivity C-reactive protein, although tumour necrosis factor-α levels decreased when the patients were dialyzed with CTA. No significant differences were found in markers of endothelial damage, assessed by levels of plasminogen activator inhibitor-1 and adhesion molecules (intercellular adhesion molecule-1 and vascular cell adhesion molecule-1). CONCLUSION: The 4 membranes evaluated in this study in stable patients on OL-HDF, including the new-generation CTA, show similar biocompatibility with the methods applied.

A C-terminally truncated form of ß-catenin acts as a novel regulator of Wnt/ß-catenin signaling in planarians.

ß-Catenin, the core element of the Wnt/ß-catenin pathway, is a multifunctional and evolutionarily conserved protein which performs essential roles in a variety of developmental and homeostatic processes. Despite its crucial roles, the mechanisms that control its context-specific functions in time and space remain largely unknown. The Wnt/ß-catenin pathway has been extensively studied in planarians, flatworms with the ability to regenerate and remodel the whole body, providing a 'whole animal' developmental framework to approach this question. Here we identify a C-terminally truncated ß-catenin (ß-catenin4), generated by gene duplication, that is required for planarian photoreceptor cell specification. Our results indicate that the role of ß-catenin4 is to modulate the activity of ß-catenin1, the planarian ß-catenin involved in Wnt signal transduction in the nucleus, mediated by the transcription factor TCF-2. This inhibitory form of ß-catenin, expressed in specific cell types, would provide a novel mechanism to modulate nuclear ß-catenin signaling levels. Genomic searches and in vitro analysis suggest that the existence of a C-terminally truncated form of ß-catenin could be an evolutionarily conserved mechanism to achieve a fine-tuned regulation of Wnt/ß-catenin signaling in specific cellular contexts.

Localization of planarian ß-CATENIN-1 reveals multiple roles during anterior-posterior regeneration and organogenesis.

The ß-catenin-dependent Wnt pathway exerts multiple context-dependent roles in embryonic and adult tissues. In planarians, ß-catenin-1 is thought to specify posterior identities through the generation of an anteroposterior gradient. However, the existence of such a gradient has not been directly demonstrated. Here, we use a specific polyclonal antibody to demonstrate that nuclear ß-CATENIN-1 exists as an anteroposterior gradient from the pre-pharyngeal region to the tail of the planarian Schmidtea polychroa High levels in the posterior region steadily decrease towards the pre-pharyngeal region but then increase again in the head region. During regeneration, ß-CATENIN-1 is nuclearized in both anterior and posterior blastemas, but the canonical WNT1 ligand only influences posterior nuclearization. Additionally, ß-catenin-1 is required for proper anterior morphogenesis, consistent with the high levels of nuclear ß-CATENIN-1 observed in this region. We further demonstrate that ß-CATENIN-1 is abundant in developing and differentiated organs, and is particularly required for the specification of the germline. Altogether, our findings provide the first direct evidence of an anteroposterior nuclear ß-CATENIN-1 gradient in adult planarians and uncover novel, context-dependent roles for ß-catenin-1 during anterior regeneration and organogenesis.

Anthracycline-induced cardiotoxicity in diffuse large B-cell lymphoma: NT-proBNP and cardiovascular score for risk stratification.

OBJECTIVE: To evaluate the role of N-terminal pro-brain-type natriuretic peptide (NT-proBNP) and a cardiovascular (CV) risk score named FRESCO for predicting anthracycline-induced cardiotoxicity (AIC) in diffuse large B-cell lymphoma (DLBCL). METHODS: A total of 130 consecutive DLBCL patients treated in first-line with anthracycline-containing immunochemotherapy. Competitive risk between NT-proBNP, FRESCO, and time to AIC was considered. RESULTS: Cumulative incidence of AIC was 12.2% and 17.5% at 1 and 5 years, respectively. Median time to development cardiotoxicity was 6.4 months, with half of the cases showing heart failure and the other half silent AIC. Both NT-proBNP levels and FRESCO score were independently associated with higher risk of AIC (P = 0.001 and P = 0.03, respectively). Patients with NT-proBNP ≥600 pg/mL or those with FRESCO ≥4.5% had 3.97 or 2.54 times higher risk of AIC than those with lower values (P = 0.001 and P = 0.048, respectively). According to the previous cutoffs, three groups of patients with a significantly different risk of AIC could be identified (P < 0.0001). CONCLUSIONS: Doxorubicin-containing chemotherapy is associated with increased risk of silent and overt AIC. Baseline NT-proBNP levels and FRESCO CV risk score are accurate predictors of AIC and can identify groups of patients at different risk, in which personalized cardiologic evaluation should be offered.

Vancomycin hemodialysis: Clearance differences between high-flux hemodialysis and on-line hemodiafiltration.

The aim of this study was to analyze the differences between vancomycin clearance (Kd) with high-flux hemodialysis (HFHD) and on-line hemodiafiltration (OL-HDF). The OL-HDF therapy combined the diffusion and convective transport of solutes. To compare the Kd, a vancomycin loading dose of 1 g was administered intravenously post-dialysis to 11 chronic and anuric (<100 mL/24 h) hemodialysis patients, undergoing HFHD and post-dilutional OL-HDF in consecutive therapies. Additional doses of 0.5 g were administered after 45 minutes at the end of each dialysis therapy during antibiotic treatment. Blood samples were drawn from arterial and venous lines at the start of hemodialysis sessions and at the first, second, third, and fourth hours. Additional samples were drawn at 15, 30, and 45 minutes after the end of dialysis therapy. Vancomycin plasma concentration, blood urea nitrogen (BUN), creatinine, and ß2 -microglobulin were measured. The patients' hydration status was evaluated by bioimpedance analysis. The mean of vancomycin dialyzer clearance (Kddc ) calculated was 110.8 ± 15 mL/min with HFHD and 146.8 ± 13.8 mL/min with OL-HDF (P = 0.025). Significant differences were also obtained for ß2 -microglobulin clearance, Kddc 72.6 ± 15.4 mL/min with HFHD and 113.4 ± 24.2 mL/min with OL-HDF (P = 0.012), whereas no differences were found for BUN or creatinine. Additionally, to analyze differences between HFHD and OL-HDF, a variable volume dual pool mathematical model was developed to estimate the body clearance (Kdbc ), extraction mass (Me ), and inter-compartment mass-transfer coefficient (K12 ) of each molecule. A higher vancomycin Kddc with OL-HDF produced by convection improved removal of antibiotic; this can compromise achieving a therapeutic concentration target. We recommended evaluating increased loading doses of vancomycin and avoiding administration during OL-HDF to assure adequate treatment.

Medium Cut-Off Dialyzer versus Eight Hemodiafiltration Dialyzers: Comparison Using a Global Removal Score.

BACKGROUND: A novel class of membranes, medium cut-off (MCO) membranes, has recently been designed to achieve interesting removal capacities for middle and large middle molecules in hemodialysis (HD) treatments. The few studies published to date have reported contradictory results regarding middle-sized molecules when comparing MCO dialyzers versus dialyzers used in online hemodiafiltration (OL-HDF). METHODS: A prospective, single-center study was carried out in 22 patients. Each patient underwent 9 dialysis sessions with routine dialysis parameters, one with an MCO dialyzer in HD and the other 8 with different dialyzers in OL-HDF. The removal ratio (RR) of urea, creatinine, ß2-microglobulin, myoglobin, prolactin, α1-microglobulin, α1-acid glycoprotein, and albumin was intraindividually compared. Albumin loss in dialysate was measured. We propose a global removal score ([ureaRR + ß2-microglobulinRR + myoglobinRR + prolactinRR + α1-microglobulinRR + α1-acid glycoproteinRR]/6 - albuminRR) as a new tool for measuring dialyzer effectiveness. RESULTS: No significant differences in the RRs of small and middle molecular range molecules were observed between the MCO vs. OL-HDF dialyzers (range 60-80%). Lower RRs were found for α1-microglobulin and α1-acid glycoprotein without significant differences. The albumin RR was < 11% and dialysate albumin loss was < 3.5 g in all situations without significant differences. The global removal score was 54.9 ± 4.8% with the MCO dialyzer without significant differences. CONCLUSIONS: Removal of a wide range of molecular weights, calculated with the proposed global removal score, was almost equal with the MCO dialyzer in HD treatment compared with 8 high-flux dialyzers in high-volume OL-HDF without relevant changes in albumin loss. The global removal score could be a new tool to evaluate the effectiveness of dialyzers and/or different treatment modalities.

Clinical value of ankle-brachial index in asymptomatic aortic stenosis patients.

BACKGROUND AND AIM OF THE STUDY: The study aim was to assess the prevalence and clinical value of the pathological ankle-brachial index (ABI) in asymptomatic aortic stenosis (AS) patients. METHODS: This prospective study included 203 asymptomatic AS patients, with a mean follow up of 18 ± 10.6 months. Six-minute walk tests (6MWT) and ABI measurements were performed when patients were included in the study. Study events were defined as death, hospital admission due to related symptoms, or a need for surgery. RESULTS: A total of 198 patients (95 females, 103 males; mean age 74.6 ± 9.5 years) completed the study. An abnormal ABI was found in 35.8%. Mean (± SD) values were: peak velocity Vmax 4.1 ± 0.8 m/s; maximum/mean gradient 70.5 ± 25.1/43.3 ± 16.3 mmHg; aortic valve area 0.8 ± 0.7 cm2; indexed aortic valve area 0.4 ± 0.1 cm2/m2. A pathological ABI was associated with diabetes (p = 0.01), previous peripheral vascular disease (p = 0.04) and previous stroke (p = 0.04). In multivariate analyses, diabetes was an independent factor related to pathological ABI (relative risk 1.71, 95% CI 1.22-2.19). Patients with a pathological ABI walked less in the 6MWT (263.9 m versus 328.3; p = 0.002), but did not present a worse prognosis at follow up (p = NS). CONCLUSION: Among asymptomatic AS patients, 35.8% had an abnormal ABI and this was related to previous diabetes. These patients walked less in the 6MWT but did not have a worse prognosis at follow up.

Mathematical Modeling of Different Molecule Removal on On-Line Haemodiafiltration: Influence of Dialysis Duration and Infusion Flow.

BACKGROUND: In a previous study on a nocturnal, every-other-day online haemodiafiltration scheme, different removal patterns were observed for urea, creatinine, ß2-​microglobulin, myoglobin and prolactin. The aim of this study was to evaluate the influence of dialysis duration and infusion flow (Qi) on the removal of different molecular weight (MW) solutes, and to quantify the effect of the different treatments on the kinetics of the solutes by using a classical two-compartment model. METHODS: This prospective, in-center study was carried out in 10 patients on a nocturnal, every-other-day online post-dilution haemodiafiltration program. Each patient received four dialysis sessions with different conditions, two 4-h sessions (with infusion flows of 50 or 100 ml/min) and two 8-h sessions (with infusion flows of 50 or 100 ml/min). To analyze the solute kinetics, blood samples were obtained hourly during the dialysis treatments and in the first 3 h post-dialysis. RESULTS: Removal patterns differed in the molecules studied, which were quantified by means of the two-compartment mathematical model. The main results show the impact of dialysis duration on the removal of low molecular weight molecules (urea and creatinine), while the impact of Qi is clearly shown for high molecular weight molecules (myoglobin and prolactin). For middle molecular weight solutes, such as ß2-microglobulin, both factors (duration and Qi) enhance the removal efficiency of the dialyzer. CONCLUSIONS: Our study evaluates experimentally and mathematically how treatment time and infusion flow affect the filtration of solutes of different MW during post-dilution haemodiafiltration. The results provided by the present study should help physicians to select and individualise the most appropriate schedules to deliver an optimum diffusive and convective dialysis dose for each patient.

Posterior Wnts Have Distinct Roles in Specification and Patterning of the Planarian Posterior Region.

The wnt signaling pathway is an intercellular communication mechanism essential in cell-fate specification, tissue patterning and regional-identity specification. A ßcatenin-dependent signal specifies the AP (Anteroposterior) axis of planarians, both during regeneration of new tissues and during normal homeostasis. Accordingly, four wnts (posterior wnts) are expressed in a nested manner in central and posterior regions of planarians. We have analyzed the specific role of each posterior wnt and the possible cooperation between them in specifying and patterning planarian central and posterior regions. We show that each posterior wnt exerts a distinct role during re-specification and maintenance of the central and posterior planarian regions, and that the integration of the different wnt signals (ßcatenin dependent and independent) underlies the patterning of the AP axis from the central region to the tip of the tail. Based on these findings and data from the literature, we propose a model for patterning the planarian AP axis.

Correlation of plasmatic sodium determined by the laboratory and that determined by the dialysis machine.

INTRODUCTION: Changes in plasma sodium concentration (pNa, expressed in mEq/L) are common in hemodialysis (HD) patients. Hemodialysis monitors can estimate pNa by using an internal algorithm based on ion dialysance measurements. The present study studies the accuracy of the correlation between the pNa estimated by the dialysis monitor and that measured by the biochemistry laboratory at our center. MATERIAL AND METHODS: A single-centre prospective observational study in patients on a chronic HD program with the 6008 CAREsystem monitor and standard sodium (138mmol/L) and bicarbonate (32mmol/L) prescriptions. Venous blood samples were drawn from each patient before and after each HD session to ensure inter- and intra-individual validity. The pNa was measured in the biochemistry laboratory using indirect potentiometry and simultaneously the estimated pNa by the HD monitor was recorded at the beginning and at the end of the HD session. For statistical analysis, a scatterplot was made, and Spearman's correlation quotient was calculated. In addition, the differences between both methods were represented as Bland-Altman diagrams. RESULTS: The pre-dialysis pNa measured in the laboratory was 137.49±3.3, and that of the monitor, 137.96±2.91, with a correlation with R2 value of 0.683 (p<0.001). The post-dialysis pNa measured in the laboratory was 137.08±2.23, and that of the monitor was 138.87±1.88, with an R2 of 0.442 (p<0.001). On the Bland-Altman plots, the pre-dialysis pNa has a systematic error of 0.49, in favor of the monitor-estimated pNa, with a 95% confidence interval (CI) of (-3.24 to a 4.22). In the post-dialysis pNa, a systematic error of 1.79 with a 95% CI of (-1.64 to 5.22) was obtained. CONCLUSION: The correlation between the pNa estimated by Fresnius 6008 CAREsystem HD monitor and that measured by the laboratory is good, especially pre-dialysis measurements. Further studies should verify the external validity of these results.

Comparison of efficacy and safety of the new generation helixone dialyzers.

INTRODUCTION: New generation helixone dialyzers has recently been developed as part of the ongoing effort to improve dialyzer hemocompatibility and avoid adverse reactions to synthetic dialyzers. This study aimed to assess the performance and albumin loss of this new dialyzer series in hemodiafiltration and compare it with the previous generation helixone series. MATERIAL AND METHODS: A prospective study was conducted in 19 patients. Each patient underwent eight dialysis sessions with the same routine dialysis parameters; only the dialyzer varied: FX60 CorDiax, FX CorAL 60, FX600 CorDiax, FX CorAL 600, FX80 CorDiax, FX CorAL 80, FX800 CorDiax, and FX CorAL 800. The reduction ratios (RR) of urea, creatinine, ß2-microglobulin, myoglobin, kappa-free immunoglobulin light chains (κFLC), prolactin, α1-microglobulin, α1-acid glycoprotein, lambda immunoglobulin light chains (λFLC), and albumin were compared intra-individually. Dialysate albumin loss was also measured. RESULTS: All treatments were well tolerated. The mean amount of replacement fluid ranged from 31 to 34 L. Comparison of dialysis treatments showed no differences between small molecules and even up to those the size of ß2-microglobulins. Little differences were found between myoglobin, κFLC, prolactin, α1-microglobulin, and λFLC RRs, and only FX80 CorDiax was slightly superior to the others. Mean dialysate albumin losses were similar, with less than 2.5 g lost in each dialyzer. The FX80 CorDiax showed slightly higher global removal scores than the other dialyzers evaluated, except for FX CorAL 800. CONCLUSION: The new generation helixone dialyzers series has been updated to minimise the risk of adverse reactions, while maintaining the effectiveness and albumin loss achieved by the previous most advanced helixone generation.

An extended kinetic model-based correction factor equation to account hemodialysis post-treatment hemoconcentration.

The hemoconcentration effect for middle weight solutes in hemodialysis is corrected by oversimplified methods based on hematocrit changes or distribution volume variations. Here we implemented a variable volume dual pool kinetic model targeted at obtaining a precise correction factor equation for extracellularly distributed solutes based on relevant kinetic parameters such as the ultrafiltration to dry weight ratio UF/DW, the dialyzer clearance, Kd, the intercompartment mass-transfer coefficient, Kc, and the central compartment to extracellular volume ratio, α. More than 300,000 solutions of the model were computed, performing a sweep among physiological values of the proposed kinetic parameters, resulting in a linear regression denoted by the expression fcorr = 1.0707 - 5.2246 (UF/DW) - 0.0005 Kd - 0.0004 Kc - 0.0007 α, with an excellent coefficient of determination R2 = 0.983. The presented fcorr provides a substantial extension of the currently implemented methods to estimate the hemoconcentration factor for middle and high molecular weight extracellular distributed solutes in hemodialysis.

Practical implementation and clinical benefits of the new automated dialysate sodium control biosensor.

Background: A key feature of dialysis treatment is the prescription of dialysate sodium (Na). This study aimed to describe the practical implementation of a new automated dialysate Na control biosensor and to assess its tolerance and the beneficial clinical effects of isonatraemic dialysis. Methods: A prospective study was carried out in 86 patients who, along with their usual parameters, received the following five consecutive phases of treatment for 3 weeks each: phase 0: baseline 5008 machine; phases 1 and 2: 6008 machine without activation of the Na control biosensor and the same fixed individualized Na dialysate prescription or adjusted to obtain similar conductivity to phase 0; phases 3 and 4: activated Na control to isonatraemic dialysis (Na dialysate margins 135-141 or 134-142 mmol/L). Results: When the Na control was activated, the few episodes of cramps or hypotension disappeared when the lower dialysate Na margin was increased by 1 or 2 mmol/L. The activated Na control module showed significant differences compared with baseline and the non-activated Na module in final serum Na values, diffusive Na balance, and changes in pre- to postdialysis plasma Na values. The mean predialysis systolic blood pressure value was significantly lower in phase 4 than in phase 1. There were no significant differences in total Na balance in the four 6008 phases evaluated. Conclusions: The implementation of the automated dialysate Na control module is a useful new tool, which reduced the diffusive load of Na with good tolerance. The module had the advantages of reducing thirst, interdialytic weight gain and intradialytic plasma Na changes.

Conductivity variations and changes in serum sodium concentration during dialysis related to monitor switching.

INTRODUCTION: The sodium gradient during hemodialysis sessions is one of the key factors in sodium balance in patients with dialysis-dependent chronic kidney disease; however, until the appearance of the new monitors with sodium modules, the differences between prescribed and measured sodium have been understudied. The present study aimed to compare the impact on the measured conductivity and the initial and final plasma sodium after changing the 5008 Cordiax to the new 6008 Cordiax monitor. MATERIAL AND METHODS: 106 patients on hemodialysis were included. Each patient underwent 2 dialysis sessions in which only the monitor was varied. The variables collected were dialysate, sodium and bicarbonate prescribed, real conductivity, initial and final plasma sodium measured, and the calculated sodium gradient (ΔPNa). RESULTS: The change of dialysis monitor showed small but statistically significant differences in the initial (138.14mmol/L with 5008 vs. 138.81mmol/L with 6008) and final plasma sodium (139.58mmol/L vs. 140.97mmol/L), as well as in the actual conductivity obtained (13.97 vs. 14.1mS/cm). The ΔPNa also increased significantly. CONCLUSION: The change from 5008 to 6008 monitor is associated with increased conductivity, leading the patient to end the sessions with higher plasma sodium and ΔPNa. Knowing and confirming this change will allow us to individualize the sodium prescription and avoid possible undesirable effects. It could be the preliminary study to explore the new sodium biosensor incorporated into the new generation of monitors.