Online Hemodiafiltration Research Articles

Effectiveness of sucroferric oxyhydroxide in patients on on-line hemodiafiltration in real-world clinical practice: A retrospective study.

Introduction:Hyperphosphatemia is a serious consequence of chronic kidney disease and has been associated with an increased risk for cardiovascular disease. Controlling serum phosphorus levels in patients on dialysis is a challenge for the clinicians and implies, in most cases, the use of phosphate binders (PB). Part of the reason for this challenge is poor adherence to treatment because of the high pill burden in this patient group.Objective:To assess the real-world effectiveness of sucroferric oxyhydroxide (SO) in controlling serum phosphorus levels and determine the associated pill burden.Methods:A multicenter, quantitative, retrospective, before-after study was conducted with patients receiving online hemodiafiltration. Patients who switched to SO as a part of routine care were included in the study. PB treatment, number of pills, serum phosphorus levels, and intravenous iron medication and dosage were collected monthly during the six months of treatment with either PB or SO.Results:A total of 42 patients were included in the study. After switching from a PB to SO, the prescribed pills/day was reduced 67% from 6 pills/day to 2 pills/day (p < 0.001) and the frequency of pill intake was lowered from 3 times/day to 2 times/day (p < 0.001). During the treatment with SO, the proportion of patients with serum phosphorus ≤ 5.5 mg/dL increased from 33.3% at baseline to 45% after six months of treatment.Conclusion:During the six-month follow-up with SO, serum phosphorus levels were controlled with one third of the pills/day compared to other PB.

Influence of Hemofiltration on Intradialytic Plasma Volume Decrease

Background/Aims: Compared with hemodialysis (HD), hemodiafiltration (HDF) reduces the frequency of episodes of intradialytic hypotension. Intradialytic plasma volume decrease (IPVD) induced by ultrafiltration is a leading cause of the episodes, and hemofiltration might have a preventive effect on IPVD. This study examined whether online HDF (ol-HDF) prevented IPVD compared with HD. Methods: Online HDF of pre-dilution mode (pre-ol-HDF) and post-dilution mode (post-ol-HDF) and HD were performed in 22 patients on maintenance dialysis. In each session, IPVD was calculated by using an intradialytic change in hematocrit, and IPVD in pre-ol-HDF and post-ol-HDF was compared with that in HD in a crossover manner. Results: While the ratios of intradialytic body weight loss to post-dialysis BW (IBWL/BW) in ol-HDF were generally smaller than those in HD, the levels of IPVD and IPVD/IBWL/BW were generally larger than those in HD; the IPVD levels were 0.108 ± 0.058, 0.113 ± 0.053, and 0.101 ± 0.057 (P = 0.67), and those of IPVD/IWL/BW were 2.21 ± 0.97, 2.32 ± 0.91, and 1.98 ± 1.14 (P = 0.21) in pre-ol-HDF, post-ol-HDF, and HD, respectively. Conclusion: Online mode hemofiltration, in either pre-dilution mode or post-dilution mode, performed in combination with hemodialysis has no preventive effect on IPVD.

Significant Fluctuations in Total Complement Hemolytic Activity as a Nutritional Parameter After Transition from Hemodialysis to Online Hemodiafiltration

Significant Fluctuations in Total Complement Hemolytic Activity as a Nutritional Parameter After Transition from Hemodialysis to Online Hemodiafiltration

A case of severe carbamazepine overdose treated successfully with pre-dilution online hemodiafiltration

A case of severe carbamazepine overdose treated successfully with pre-dilution online hemodiafiltration

Middle molecule elimination in expanded haemodialysis: only convective transport?

BackgroundNew high-retention onset dialysers have shown improved efficacy in the elimination of uraemic toxins, and their depurative capacity has been compared with high convective volumes of online haemodiafiltration. Haemodialysis (HD) using high-flux membranes leads to convective transport by internal filtration [direct filtration (DF)/backfiltration (BF)] and allows the removal of middle molecules (MMs). The aim of this study was to assess solute transport mechanisms in expanded HD (HDx).MethodsIn 14 4-h HDx sessions with Theranova-500 dialysers under similar dialysis conditions (blood flow 400 mL/min, dialysate flow 700 mL/min, dialysate temperature 35.5°C), pressures at the inlet and outlet of both dialyser compartments (Pbi, Pbo, Pdi and Pdo) were collected hourly to estimate DF/BF volumes by semi-empirical methods. Uraemic toxins with various molecular weights were measured pre-dialysis, at 1 h (pre-filter and post-filter) and post-dialysis to calculate molecules’ reduction over time and dialyser in vivo clearances.ResultsUltrafiltration was 1.47 ± 0.9 L and Kt/V 1.74 ± 0.3. Hydrodynamic data (Pbi: 259 ± 39, Pbo: 155 ± 27, Pdi: 271 ± 30, Pdo: 145 ± 29 mmHg and oncotic pressure 22.0 ± 3.5 mmHg) allowed the estimation of DF/BF rates. DF flow ranged from 29.5 ± 4.2 to 31.3 ± 3.9 mL/min and BF flow ranged from 25.1 ± 2.3 to 23.4 ± 2.6 mL/min. The highest calculated DF volume was 7506.8 ± 935.3 mL/session. Diffusive clearances (Kd) of all solutes were higher than their convective transport (all P < 0.001) except for prolactin (23 kDa) clearances, which showed no differences. Total clearances of all solutes were correlated with their Kd (ρ = 0.899–0.987, all P < 0.001) and Kt/V correlated with all reduction rates (ρ = 0.661–0.941, P = 0.010 to <0.001). DF flow was only associated with urea (ρ = −0.793, P = 0.001), creatinine (ρ = −0.675, P = 0.008) and myoglobin clearance (ρ = 0.653, P = 0.011).ConclusionResults suggest that diffusive transport is a main mechanism of MM elimination in HDx. HDx offers an efficient depuration of MM without the need for high convective volumes.

Current treatment methods for sarcopenia in patients undergoing hemodialysis

Aim. To evaluate the effectiveness of combined post-dilution online hemodiafiltration therapy and ketoanalogue amino acid medications at a dose of 0.2 g/kg of ideal body weight/day for sarcopenia-correcting interventions in patients on hemodialysis with adequate intake of essential nutrients. Materials and methods. In total, 645 patients undergoing hemodialysis were examined. Nutritional status of all patients was evaluated to identify pre-sarcopenia and sarcopenia. In addition, leptin and interleukin-6 serum levels were determined. The patients with signs of sarcopenia were divided into three groups depending on the treatment method. Results. We demonstrated the effectiveness of combined post-dilution online hemodiafiltration therapy and ketoanalogue amino acids at a dose of 0.2 g/kg of ideal body weight/day for correction of sarcopenia in patients on hemodialysis. Conclusion. Combined therapy with post-dilution online hemodiafiltration therapy and ketoanalogue amino acids at a dose of 0.2 g/kg of ideal body weight/day is regarded as a pathogenetically grounded method for correction of sarcopenia in patients on hemodialysis with adequate intake of essential nutrients. (For citation: Jakovenko AA. Current treatment methods for sarcopenia in patients undergoing hemodialysis. Urologicheskie vedomosti. 2018;8(2):36-42. doi: 10.17816/uroved8236-42).

High recovery rate of consciousness by high-volume filtrate hemodiafiltration for fulminant hepatitis.

An artificial liver support (ALS) system sustaining patients with acute liver failure (ALF) in good condition until recovery of the native liver or performance of liver transplantation (LT), is essential for the improvement of the poor prognosis of ALF despite the lack of survival benefit. We aimed to investigate the efficacy of various ALS systems for fulminant hepatitis (FH) carried out in our liver unit so far, focusing on the restoration of consciousness from hepatic encephalopathy. One hundred and ten consecutive adult Japanese patients with FH admitted to Chiba University Hospital (Chiba, Japan) between 1988 and 2016 who received ALS were analyzed. Recovery rate of consciousness improved with the increased dialysate flow rate and filtrate rate: 37.5% by plasma exchange (PE), 51.9% by PE + continuous hemodiafiltration (CHDF), 57.7% by slow PE (sPE) + high-flow CHDF (HFCHDF) (QD = 300mL/min), 88.6% by HFCHDF (QD = 500mL/min) (+ sPE), and 92.9% by on-line HDF (OLHDF) (+ sPE). All patients except one, who could not be fully treated because of circulatory failure, recovered consciousness by OLHDF, including those whose liver function were completely abolished. Superiority of HFCHDF (QD = 500mL/min) and OLHDF was also shown in patients who died without LT or received LT. More effective ALS should be recognized considering the extremely high recovery rate of consciousness. In particular, OLHDF with predilution reduces the cost of substitution fluid by supplying an unlimited amount of dialysate as substitution fluid prepared using an on-line system, and simplifies the procedure for the management.

Comparison of intradialytic plasma volume change between online hemodiafiltration and standard hemodialysis

BackgroundIntradialytic plasma volume change (IPVC) owing to ultrafiltration is a dominant cause of intradialytic hypotension (IDH). Lower occurrence of IDH in hemodiafiltration (HDF) than in standard hemodialysis (std-HD) indicates that HDF has preventive effect on IPVC. This study examined whether online HDF (ol-HDF) prevented IPVC compared with std-HD.MethodsIn 115 std-HD, 59 push-pull ol-HDF (pp-ol-HDF), 39 pre-dilution ol-HDF (pre-ol-HDF), and 33 post-dilution ol-HDF (post-ol-HDF) sessions, we calculated IPVC using intradialytic change of hemoglobin (IPVCHb) and also using the change of hematocrit (IPVCHt), and compared them in association with intradialytic body weight loss (IBWL) between the dialysis modes.ResultsBoth IPVCHb and IPVCHt were not different between the modes; in std-HD, pp-ol-HDF, pre-ol-HDF, and post-ol-HDF, IPVCHb were 0.10 ± 0.06, 0.11 ± 0.07, 0.10 ± 0.05, and 0.10 ± 0.06, respectively, and IPVCHt were 0.10 ± 0.07, 0.11 ± 0.07, 0.10 ± 0.06, and 0.10 ± 0.06, respectively. IPVCs divided by relative IBWL to DW (IBWL/DW) were also not different between the modes; in std-HD, pp-ol-HDF, pre-ol-HDF, and post-ol-HDF, IPVCHb/IBWL/DW were 1.9 ± 2.0, 1.7 ± 4.6, 2.1 ± 0.9, and 2.1 ± 1.8, respectively, and IPVCHt/IBWL/DW were 1.9 ± 2.2, 1.9 ± 3.7, 2.1 ± 1.1, and 2.1 ± 2.0, respectively.ConclusionIrrespective of the modes, ol-HDF has the same level of IPVC as std-HD.

Removal capacity of different high‐flux dialyzers during postdilution online hemodiafiltration

The aim of this study is to compare molecule removal and albumin leakage in postdilution online hemodiafiltration with different high-flux dialyzers. We studied seven high-flux dialyzers (Polyflux 210H®, Evodial 2.2®, FxCordiax1000®, Elisio21H®, TS-2.1SL®, XevontaHi20®, VitaPES 210-HF®) in 6 patients. The reduction ratio (RR) of small- and middle-sized molecules was calculated. Dialysate samples were collected to estimate the albumin leakage. Global differences between dialyzers were observed in the RR of ß2 microglobulin (P =0.003) and prolactin (P =0.013). The mean loss of albumin in the dialysate per session varied between 114 ± 67 mg (with Evodial 2.2) and 2621 ± 1363 mg per session (with XevontaHi20). We found global differences between dialyzers in total albumin loss (P = 0.05). We demonstrated that the performance of high-flux dialyzers was different among the types and that not all high-flux dialyzers should be considered equal.

Effect of online hemodiafiltration compared with hemodialysis on quality of life in patients with ESRD: A systematic review and meta-analysis of randomized trials.

BackgroundEnd-stage renal disease (ESRD) is related to high morbidity, mortality, and impaired health-related quality of life. While hemodialysis (HD) is the current life-saving standard of treatment for patients with ESRD, their quality of life (QoL) remains far from desirable. Online HDF (OL-HDF), due to its convenience, could improve the QoL of patients with ESRD, however, this remains uncertain.ObjectiveWe aimed to assess the body of evidence of OL-HDF compared to HD regarding QoL in patients with ESRD.MethodsWe comprehensively searched in multiple data bases from their inception to February 2018. Reviewers working independently and in duplicate appraised the quality and included randomized controlled trials (RCTs) that evaluated, in patients with ESRD and HD or OL-HDF, QoL (Short Form Health Survey with 36 questions (SF-36) with physical component score (PCS) and mental component score (MCS) as well as scores about social activity, fatigue, and emotion). A meta-analysis of each outcome of interest was performed using a random-effects model.ResultsSix moderate quality RCTs met the inclusion criteria. Meta-analysis of 4 RCTs including a total of 1,209 patients showed that OL-HDF was associated with a lower yet non-significant score of PCS: MD (mean difference) -0.77 (95% CI -1.94 to 0.41, p = 0.20), and MCS: MD -1.25 (95% CI -3.10 to 0.59, p = 0.18); indicating a poorer QoL in patients on OL-HDF. Meta-analysis of 4 RCTs including a total of 845 patients showed OL-HDF was associated with a significant increase in the score of social activity compared to HD: SMD (standardized mean difference): 1.95 (95% CI 0.05 to 3.86, p = 0.04), indicating a better QoL in patients on OL-HDF; but regarding fatigue and emotion, there was no significant improvement when compared to HD by meta-analysis of 3 RCTs (133 patients).ConclusionsThe body of evidence suggests that OL-HDF does not improve QoL in patients with ESRD when compared to HD.

Is Expanded Hemodialysis an Option to Online Hemodiafiltration for Small- and Middle-Sized Molecules Clearance?

Background: Recent evidence suggests a better reduction rate of some uremic toxins with expanded hemodialysis (HDx). Methods: Prospective study including 8 hemodialysis patients. We divided the study in 2 phases; within the first one, we assigned 4 patients (group 1) to undergo online hemodiafiltration with a PF 210H dialyzer, and the other 4 patients (group 2) to undergo HDx with the high retention onset Theranova 500 dialyzer during 24 sessions. Later, during the second phase and after a washout period, the same patients were switched to receive HDx (group 1) and HDF (group 2). Results: No differences were found in the Urea and β2-microglobulin reduction ratio. However, in the case of myoglobin, the reduction ratio with HDF was 35 vs. 60% with HDx (p < 0.001). Similarly, in the case of prolactin, the reduction ratio with HDF was 45 and 61% with HDx (p < 0.001). Conclusions: We conclude that HDx is not inferior to online hemodiafiltration in the clearance of small and middle molecules and could be superior in the clearance of larger middle molecules.

Membrane innovation: closer to native kidneys.

Modern methods in analytical biochemistry have established that uraemia is associated with the retention of proteins, both in their native state and post-translationally modified, over a wide range of molecular weights up to 60 kDa. Evidence is accumulating that these higher molecular weight retention solutes are important uraemic toxins, and therapies such as online haemodiafiltration (HDF), which enhance their removal, are associated with improved outcomes. However, HDF has limitations regarding cost, clinical implementation and the need for an external source of sterile substitution solution to maintain fluid balance. New membranes that have a solute removal profile more closely approaching that of the glomerular filtration barrier when used for conventional haemodialysis, while at the same time not allowing the passage of clinically significant amounts of beneficial proteins, are needed to address these limitations. Tighter control of the molecular characteristics of the polymers used for membrane fabrication, along with the introduction of additives and improvements in the manufacturing process, has led to membranes with a tighter pore size distribution that allows the use of an increased absolute pore size without leaking substantial amounts of albumin. At the same time, the wall thickness and internal diameter of membrane fibres have been decreased, enhancing convective transport within the dialyser without the need for an external source of substitution solution. These new expanded range membranes provide a solute removal profile more like that of the native kidney than currently available membranes when used in conventional haemodialysis.

Clinical evidence on haemodiafiltration.

Haemodiafiltration (HDF) combines diffusive and convective solute removal in a single treatment session. HDF provides a greater removal of higher molecular weight uraemic retention solutes than conventional high-flux haemodialysis (HD). Recently completed randomized clinical trials suggest better patient survival with online HDF. The treatment is mainly used in Europe and Japan. This review gives a brief overview of the presently available evidence of the effects of HDF on clinical end points, it speculates on possible mechanisms of a beneficial effect of HDF as compared with standard HD and ends with some perspectives for the future.

Zero Diffusive Sodium Balance in Hemodialysis Provided by an Algorithm-Based Electrolyte Balancing Controller: A Proof of Principle Clinical Study.

Restoring and controlling fluid volume homeostasis is still a challenge in contemporary end-stage kidney disease patients treated by intermittent hemodialysis (HD) or hemodiafiltration (HDF). This primary target is achieved by ultrafiltration (dry weight probing) and control of intradialytic sodium transfer (dialysate-plasma Na gradient). The latter task is mostly ignored in clinical practice by applying a dialysate sodium prescription uniform for all patients of the dialysis center but unaligned to individual plasma sodium levels. Depending on the patient's natremia, a positive gradient gives rise to intradialytic diffusive sodium load and postdialytic thirst. On the contrary, a negative gradient may cause unwanted diffusive sodium removal and intradialytic symptoms. To overcome these challenges, a new conductivity-based electrolyte balancing algorithm embedded in a hemodialysis machine with the aim to achieve "zero diffusive sodium balance" in HD and online HDF treatments was tested in the form of a prospective clinical trial. The study comprised two phases: a first phase with a conventional fixed-sodium dialysate (standard care phase), followed by a phase with the electrolyte balancing control (EBC) module activated (controlled care phase). The results show a reduction in the variability of the intradialytic plasma sodium concentration shift, but it is overlain by a small but statistically significant increase in the mean plasma sodium levels. However, no clinical manifestations were observed. This sodium load can be explained by the design of the algorithm based on dialysate conductivity instead of sodium concentration. Furthermore, the increase in plasma sodium can be corrected by taking into account the potassium shift during the treatment. This study showed that the EBC module incorporated in the HD machine is able to automatically individualize the dialysate sodium to the patient's plasma sodium without measuring or calculating predialytic plasma levels from previous laboratory tests. This tool has the potential to facilitate fluid management, to control diffusive sodium flux, and to improve intradialytic tolerance in daily clinical practice.

El Kt/V alto, a diferencia del Kt, se asocia a mayor mortalidad: importancia de la V baja

IntroductionKt/V has been used as a synonym for haemodialysis dose. Patient survival improved with a Kt/V>1; this target was subsequently increased to 1.2 and 1.3. The HEMO study revealed no significant relationship between Kt/V and mortality. The relationship between Kt/V and mortality often shows a J-shaped curve. Is V the confounding factor in this relationship? The objective of this study is to determine the relationship between mortality and Kt/V, Kt and body water content (V) and lean mass (bioimpedance). MethodsWe studied a cohort of 127 prevalent haemodialysis patients, who we followed-up for an average of 36 months. Kt was determined by ionic dialysance, and V and nutrition parameters by bioimpedance. Kt/V, Kt corrected for body surface area (Kt/BSA) and target Kt/BSA were calculated. The mean data from 18,998 sessions were used as haemodialysis parameters, with a mean of 155 sessions per patient. ResultsMean age was 70.4±15.3 years and 61% were male; 76 were dialysed via an arteriovenous fistula and 65 were on online haemodiafiltration. Weight was 70.6 (16.8)kg; BSA 1.8 (0.25) m2; total body water (V) 32.2 (7.41) l and lean mass index (LMI) 11.1 (2.7)kg/m2. Mean Kt/V was 1.84 (0.44); Kt 56.1 (7)l and Kt/BSA 52.8 (10.4)l. The mean target Kt/BSA was 49.7 (4.5)l. Mean Kt/BSA–target Kt/BSA +6.4 (7.0)l. Patients with a higher Kt/V had worse survival rates than others; with Kt this is not the case. Higher Kt/V values are due to a lower V, with poorer nutrition parameters. LMI and serum albumin were the parameters that best independently predicted the risk of death and are lower in patients with a higher Kt/V and lower V. ConclusionKt/V is not useful for determining dialysis doses in patients with low or reduced body water. Kt or the Kt/BSA are proposed as an alternative.

Efficiency of post-dilution online hemodiafiltration therapy in combination with ketoanalogues of amino acid in the correction of protein-energy malnutrition in hemodialysis patients

Purpose of the study. Evaluate the efficiency of permanent post-dilution online hemodiafiltration therapy in combination with the prescription of keto analogues of amino acid at a dose of 0,2 g/kg of ideal body weight/day to correct protein-energy malnutrition in hemodialysis patients with adequate intake of essential nutrients. Patients and methods. A total of 645 patients with terminal renal failure received programmed hemodialysis, of which there were 300 men and 345 women aged 58,8 ± 6,9 years. All patients received treatment with programmed GD for 6,9 ± 2,1 years. All patients underwent a comprehensive assessment of nutritional status. The level of leptin and interleukin-6 serum was determined. Patients with signs of protein-energy malnutritian (PEM) were divided into three groups, depending on the method of PEM correction. Results. The study showed the efficiency of postdilution online hemodiafiltration therapy on an ongoing basis in combination with keto-analogues of amino acids at a dose of 0,2 g/kg of ideal body weight/day for correction of PEM in hemodialysis patients. Conclusion. The post-dilution online hemodiafiltration therapy combined with keto-analogues of amino acid at a dose of 0.2 g /kg of ideal body weight/day can be considered one of the pathogenetically grounded methods for correcting PEM in patients receiving programmed hemodialysis with adequate intake of essential nutrients.

Overcoming glucose delivery by on-line hemodiafiltration: a feasible chimera for diabetics on dialysis.

The increasing number of patients with diabetes undergoing renal replacement therapy has raised interest in the issue of glucose delivery with the substitution fluid-over 20g per session. The ideal situation would be to have a glucose-containing bath to avoid glycemic disarrays and a glucose-free substitution fluid. But this seems a chimera because the substitution fluid is nothing else than an ultrapure dialysis bath. In this technical note, we present a cheap solution to realize the desired mix, using a commercially available glucose-free dialysate and adding glucose in the inlet dialysate compartment of the dialyzer by means of a common pump and a unique handmade T-tube. Our in vitro experiments showed glucose levels in the dialysate (mean ± SD, mg/dl): 99.7 ± 4.6at baseline, 100.7 ± 7.3at mid-session and 100.7 ± 2.1at the end of dialysis, whereas measurements in the substitution fluid always gave a "low" output (p < 0.0001). Similar results were obtained in single 1- and 4-h in vivo experiments carried out in a non-diabetic overweight hemodialysis patient. Our simple, yet unequivocal, results lay the foundation for assembling a hemodialysis machine equipped with an infusion pump to modify the on-line substitution fluid without affecting the dialysate. This would overcome the ethical issue of delivering glucose intravenously in certain groups of patients.

Hemodiafiltration versus conventional hemodialysis: Should "conventional" be redefined?

In the 1980s, conventional hemodialysis was considered as dialysis with acetate dialysate, dialysis machines without volumetric control, low blood flow and low-flux dialyzers; in the 1990s, the concept of conventional hemodialysis changed due to technological advances in dialysis machines, control of ultrafiltration and the widespread use of bicarbonate dialysate, which allowed an increase in blood flow and the use of synthetic high-flux dialyzers. To avoid backfiltration-induced adverse reactions, exogenous replacement fluid was promoted but its adoption was limited for technical and financial reasons. This scenario changed in 1995 with the development of on-line hemodiafiltration (HDF) techniques using the dialysis fluid itself as a replacement fluid. Dialysis machines were modified to perform on-line HDF, incorporating safety filters to ensure the quality of this replacement fluid (ultrapure dialysate). After more than two decades of clinical experience and technological development with high-volume HDF, the present article discusses whether HDF can currently be considered as the standard conventional treatment for chronic hemodialysis patients. A review of the evidence indicates that the time has come to consider HDF as the conventional hemodialysis treatment for the following reasons: first, technological development in water treatment and advances in dialysis machines, as well as the widespread use of synthetic high-flux dialyzers has made it a feasible proposition. Second, there is an absence of published literature showing any undesirable effects. Finally, scientific evidence is available showing the superiority of HDF over hemodialysis in overall and cardiovascular mortality in both prevalent and incident patients.

Heparin-free renal replacement therapy for chronic hemodialyzed patients at high risk for bleeding: a comparison of on-line predilution hemodiafiltration with conventional hemodialysis.

In chronic hemodialysis patients with high risk of bleeding, optimal anticoagulation of the extracorporeal circuit is challenging. Heparin-free hemodialysis (HD) with heparin-coated AN69ST dialyzer is now considered as a good option and recommended by experts. Predilutional hemodiafiltration (HDF) may represent also a feasible alternative but has been poorly investigated. In this study, our aim was to evaluate the performance of on-line automated predilution heparin-free HDF as compared to conventional heparin-free HD with a heparin-coated membrane. We prospectively studied chronic hemodialysis patients at high risk of bleeding consecutively admitted to hospital who underwent heparin-free renal replacement therapy (RRT) in our nephrology department. During 1 year, we routinely used heparin-free HD and on-line HDF in these settings. By using a propensity score, we compared HDF to HD regarding to session failure and efficiency. One hundred and seventy-nine patients were included in the study. Clotting phenomena necessitating premature termination of RRT sessions were encountered in 19% of them. After propensity score matching, the comparison of 77 HD and 77 HDF sessions showed no significant differences in duration of the sessions and in dialyzer clotting. By multivariate analysis, a blood flow less than 250 mL/min and recent surgery were the only parameters associated with extracorporeal circuit thrombosis. Heparin-free on-line predilutional HDF is a safe and effective technique for chronic hemodialysis patients with increased bleeding risk. The use of an automatic substitution volume that avoids filters hemoconcentration and of a blood flow above 250 mL/min strongly contribute to the observed performance. Further studies are, however, intended to confirm these results.

Haemodialysis membranes.

Haemodialysis is an extracorporeal process in which the blood is cleansed via removal of uraemic retention products by a semipermeable membrane. Traditionally, dialysis membranes have been broadly classified on the basis of their composition (cellulosic or noncellulosic) and water permeability (low flux or high flux). However, advances in materials technology and polymer chemistry have led to the development of membranes with specific characteristics and refined properties that mandate a reconsideration of traditional membrane classification systems. For adequate characterization of these newer types of membranes, additional parameters are now relevant, including new permeability indices, the hydrophilic or hydrophobic nature of membranes, adsorption capacity and electrical potential. In this Review, we provide clinicians with an updated analysis of dialysis membranes and dialysers. We discuss the basic mechanisms that underlie solute and water removal in dialysis (that is, diffusion, convection, adsorption and ultrafiltration) in the context of treatments that use highly permeable membranes. Specifically, we highlight online haemodiafiltration and new therapies (for example, expanded haemodialysis) that utilize membranes designed to produce a high degree of internal filtration. Finally, we discuss the considerations that govern the clinically acceptable balance between large-solute clearance and albumin loss for extracorporeal therapies.