Effect of Dialysate Sodium Reduction on Body Water Volume,Blood Pressure,and Inflammatory Markers in Hemodialysis Patients — A Prospective Randomized Controlled Study

Accumulating evidence suggests an association between body volume overload and inflammation in chronic kidney diseases. The purpose of this study was to evaluate the effect of dialysate sodium concentration reduction on extracellular water volume, blood pressure (BP), and inflammatory state in hemodialysis (HD) patients. In this prospective controlled study, adult patients on HD for at least 90 days and those with C-reactive protein (CRP) levels ≥ 0.7 mg/dL were randomly allocated into two groups: group A, which included 29 patients treated with reduction of dialysate sodium concentration from 138 to 135 mEq/L; and group B, which included 23 HD patients not receiving dialysate sodium reduction (controls). Of these, 20 patients in group A and 18 in group B completed the protocol study. Inflammatory, biochemical, hematological, and nutritional markers were assessed at baseline and after 8 and 16 weeks. Baseline characteristics were not significantly different between the two groups. Group A showed a significant reduction in serum concentrations of tumor necrosis factor-α, and interleukin-6 over the study period, while the BP and extracellular water (ECW) did not change. In Group B, there were no changes in serum concentrations of inflammatory markers, BP, and ECW. Dialysate sodium reduction is associated with attenuation of the inflammatory state, without changes in the BP and ECW, suggesting inhibition of a salt-induced inflammatory response.     

人工肾系统的安全防护技术及传感器校正方法

本文介绍了人工肾系统的组成，全面解析了人工肾系统的安全防护技术，并以费森尤斯4008S机型为例说明常用传感器的校正方法。     

Do Only Small Uremic Toxins,Chromophores, Contribute to the Online Dialysis Dose Monitoring by UV Absorbance?

The aim of this work was to evaluate the contributions of the main chromophores to the total UV absorbance of the spent dialysate and to assess removal dynamics of these solutes during optical on-line dialysis dose monitoring. High performance chromatography was used to separate and quantify UV-absorbing solutes in the spent dialysate sampled at the start and at the end of dialysis sessions. Chromatograms were monitored at 210, 254 and 280 nm routinely and full absorption spectra were registered between 200 and 400 nm. Nearly 95% of UV absorbance originates from solutes with high removal ratio, such as uric acid. The contributions of different solute groups vary at different wavelengths and there are dynamical changes in contributions during the single dialysis session. However, large standard deviation of the average contribution values within a series of sessions indicates remarkable differences between individual treatments. A noteworthy contribution of Paracetamol and its metabolites to the total UV absorbance was determined at all three wavelengths. Contribution of slowly dialyzed uremic solutes, such as indoxyl sulfate, was negligible.     

高通量血液透析联合超纯透析液对尿毒症贫血的影响

目的探讨高通量血液透析联合超纯透析液在尿毒症贫血治疗中的意义。方法选取50例血液透析半年以上病情稳定的尿毒症患者,自2008年12月1日开始接受高通量透析联合超纯透析液治疗,观察14个月。每个月定期上机前取血标本,查血常规、血生化、透析后肾功能、甲状旁腺激素等,通过前后对照的前瞻性队列研究,采用非参数检验和秩和相关分析进行评价和比较。结果经过高通量联合超纯透析液治疗,至观察结束,患者血红蛋白、血细胞比容、血浆清蛋白增加,治疗前后差异有统计学意义,分别为P〈0.001,P〈0.001,P〈0.05;而促红素剂量、KT/V差异无统计学意义。结论高通量血液透析联合超纯透析液对于尿毒症贫血的治疗具有积极作用,长期治疗可以改善尿毒症贫血,增加血浆清蛋白。高通量透析可能对甲状旁腺激素清除较差,机制尚需进一步研究。     

Festschrift for Professor Claude Jacobs. Recent developments in conductivity monitoring of haemodialysis session.

On-line monitoring of dialysate conductivity is now a standard equipment (called 'Diascan') of the dialysis monitor Integra (Hospal, Italy). From the record of the dialysate conductivity at the dialyser inlet and outlet, the Diascan calculates the values of patient's plasma conductivity and of ionic dialysance which is a weighed average of the dialysances of all ions of quantitative importance in plasma and dialysate. Because there is an equivalence between the transfer characteristics of urea and electrolytes, the ionic dialysance reflects the urea clearance corrected for recirculation. Because the conductivity of a solution is related to the concentrations of the ions and thus to the effective osmolality, the plasma conductivity is a reflection of the plasma sodium concentration. The determination of ionic dialysance and plasma conductivity by the Diascan module is fully automatic and totally inexpensive, does not require any blood or dialysate sampling and therefore can be repeated every 15 or 30 min during each dialysis session. Some clinical applications of conductivity modelling are presented: (i) the repeated measurement of ionic dialysance allows the quantification of the dialysis dose actually delivered to the patient from the beginning of the session; (ii) the measurement of ionic dialysance with blood lines in normal and reversed positions permits the easy estimation of the blood flow rate in the vascular access of the haemodialysed patient; (iii) the on-line monitoring of ionic dialysance allows the development of new methods of haemodialysis with simultaneous infusion of ions; (iv) the on-line monitoring of ionic dialysance and patient's plasma conductivity facilitates the automatic optimization of the dialysate conductivity for each individual patient.     

透析液钾浓度对血液透析患者QT间期及QT离散度的影响

目的探讨透析液钾浓度变化对血液透析患者QT间期及QT离散度的影响。方法选择南通大学附属南通第三医院血液净化中心60例慢性肾衰竭长期维持性血液透析患者先后应用钾浓度为2．0 mmol/L,3．0mmol/L的透析液各进行1次血液透析,分别记录临床及实验室指标,采用12导联同步记录透析中（透析至4h）心电图测量并计算QT间期（QT）及QT离散度（QTd）。结果采用钾浓度3．0mmol/L透析液血液透析时,QT间期由钾浓度2．0mmol/L透析时（595．51±39．01）ms缩短为（540．61±44．63）ms,QTd由（63．27±8．46）ms缩短为（53．46±8．83）ms,两者差异均有统计学意义;心律失常的发生率明显降低（P〈0．01）．差异有统计学意义。采用相同钾浓度透析液透析时透析前血钾浓度〈3．5mmol/L患者QTd较血钾浓度≥3．5mmol/L患者长,差异有统计学意义（P〈0．05）。结论QTd反映心室复极的不均一性和电不稳定性，采用钾浓度3．0mmol/L透析液进行透析可缩短QT间期及QTd,降低心律失常的发生率。防治透析前低血钾也可缩短QTd,减少透析中心律失常的发生率。     

Machine-generated bicarbonate dialysate for continuous therapy: a prospective, observational cohort study.

BACKGROUND: In 1995, we described the technique of adapting a haemodialysis (HD) machine to produce a composition-adjustable, bicarbonate-based fluid (as our primary source for dialysate) for continuous HD in intensive care unit (ICU) patients with acute renal failure (ARF). The following studies the clinical effects, biochemical changes and economic costs of this practice in a large cohort of patients at a single centre over the last 10 years. METHODS: The CCF-ARF Support Registry (1995-2001) was used to identify 405 patients initially supported with bicarbonate continuous HD. The registry is a prospective, observational cohort database that captures demographic, dialysis therapy, laboratory and outcome data. All supported ARF patients were recorded from 1995-98, and then one in five patients from 1999 to 2001. We also reviewed records of the individual dialysis procedures, dialysate disposal, dialysate monitoring tests and specific costs. RESULTS: Continuous HD was performed for 1292 +/- 587 days from 1994 to 2004. Demographics [age 59.57 +/- 14.41 years, weight 84.2 +/- 24 kg, male 65%, chronic kidney disease (CKD) 34%] and ICU mortality (60.5%) were comparable to other reported series. Day 4 solute [BUN 52.3 mg/dl (95% CI 49.6-54.9), creatinine 2.79 mg/dl (95% CI 2.64-2.95)], electrolyte and acid-base balance [bicarbonate 24.12 mmol/l (95% CI 23.7-24.6)] were well controlled. Dialysate monitoring revealed no positive cultures or elevated endotoxin levels. Variable-composition dialysate was achieved and delivered to all patients without adverse consequences. The cost of dialysate actually declined over time (1995 = $0.91/l, 2005 = $0.67/l). CONCLUSION: We have demonstrated that ICU ARF patients can be safely, effectively and economically supported with continuous HD using this source.     

Temperature and concentration distribution within the Genius dialysate container.

BACKGROUND: The Genius single-pass batch system, using a closed dialysate container, is increasingly applied for dialysis treatment. Although fluid separation between fresh and spent dialysate is maintained in the container during standard dialysis, dialysate mixing may occur under certain clinical conditions. An in vitro study showed that differences in dialysate temperature and solute content between fresh and spent dialysate determine the occurrence and moment of dialysate mixing. METHODS: To better understand the maintenance of separation of fresh and spent dialysate in the prevention of mixing, a mathematical model of the 75 l Genius container was developed and the general fluid, mass and heat transfer equations were solved, simulating a dialysis session of 300 min with 1 g/l urea as starting 'blood' urea concentration and 36.2 degrees C starting dialysate temperature. Boundary and initial conditions were chosen according to two different strategies applied in previous in vitro tests, with spontaneous cooling of the reservoir on the one hand and heating of the spent dialysate to maintain an equal temperature as the fresh dialysate on the other. RESULTS: Our simulation data show that dialysate inside the container is cooling down near the container wall in both scenarios and near the central glass tube in the setup with spontaneous cooling. In the setup with heating of spent dialysate, the upper layers are heated near the central tube. Since density stratification is maintained at each time point, solutes will rise towards warmer zones. This is halfway between the container axis and wall for spontaneous cooling and, even to a larger extent, near the central tube for simulations with heated spent dialysate. Hence, the contaminated volume in the case of heating is much larger than theoretically supposed. CONCLUSIONS: These computer simulations unravel temperature and concentration distribution inside the container, offering insight into the complicated mixing phenomenon and indicate that temperature is a major impacting factor.     

In vitro and in vivo evaluation of a new dialyzer.

BACKGROUND: Recent dialyzer-related developments have concentrated upon the improvement of performance and biocompatibility. The focus of these developments was predominantly on the membrane itself. A newly developed high-flux dialyzer (FX60) with an advanced Fresenius Polysulfone) membrane (Helixone) overcomes this limitation and has several design-related advantages attributed to the redesign of the individual functional components. For the first time, polypropylene was selected as the material for the dialyzer housing. Both the fibre and the fibre-bundle geometry were refined with the aim of improving overall performance and to reduce dialysate consumption. METHODS: This study aims at investigating the in vitro and in vivo performance of the new FX60 dialyzer with the focus on dialysate flow distribution and dialysate consumption. A new method to analyse dialysate flow distribution, based on local clearances, is suggested. The effect of reducing dialysate flow from 500 to 300 ml/min is investigated in vivo. RESULTS: K(0)A(urea), a common measure to quantify device performance, is found to approach 1000 ml/min for the FX60 with a surface of only 1.4 m(2). Local clearance measurement shows equal performance of the Helixone fibre bundle over the entire cross-section. A dialysate flow reduction by 20% (in vivo) only results in a minor loss in clearance. CONCLUSIONS: The newly developed high-flux dialyzer (FX60) shows a remarkable performance (K(0)A(urea)). The excellent utilization of dialysate could be proven in vivo and is attributed to the superior dialysate flow distribution. A reduction of dialysate flow by 20% could lead to substantial economic savings.     

On-line haemodiafiltration with and without acetate.

BACKGROUND: In patients on on-line convective treatments, given the considerable quantity of dialysis fluid re-infused, the small amount of acetate present in bicarbonate dialysis fluid as a pH stabilizing factor may allow a significant transfer of that anion to the patient, possibly inducing cytokine activation. METHODS: To verify this hypothesis, we performed on-line haemodiafiltration (OL-HDF) with (3 mmol/l) and without acetate in dialysis fluid in a cross-over randomized order on 12 prevalent patients. RESULTS: In comparison with the pre-treatment values, plasma acetate levels were unchanged during and after acetate-free OL-HDF, while they were 5-6 times higher in the course of OL-HDF containing acetate in dialysis fluid; plasma acetate levels returned to basal values 2 h after the end of the procedure. The total increase of bases in the patient attributable to acetate was 36%. Plasma bicarbonate values at the end of treatment were significantly lower in treatments without acetate, as compared to those with acetate. Interleukin-6 plasma levels were super-imposable at the beginning and in the course of the two methods compared, but there was a tendency towards a greater increase at an interval of 2 h following OL-HDF with acetate. CONCLUSIONS: Our preliminary results confirm the assumption that body gain of acetate is particularly high in convective treatments, while acetate-free OL-HDF slows down acetate burden. Clinical advantages due to these effects should be evaluated in properly designed prospective studies.