BackgroundThe majority of bicarbonate based dialysis fluids are acidified with acetate. Citrate, a well known anticoagulant and antioxidant, has been suggested as a biocompatible alternative. The objective of this study was to evaluate short term safety and biocompatibility of a citrate containing acetate-free dialysis fluid.MethodsTwenty four (24) patients on maintenance dialysis three times per week, 13 on on-line hemodiafiltration (HDF) and 11 on hemodialysis (HD), were randomly assigned to start with either citrate dialysis fluid (1 mM citrate, 1.5 mM calcium) or control fluid (3 mM acetate, 1.5 mM calcium) in an open-labeled cross-over trial (6 + 6 weeks with 8 treatments wash-out in between). Twenty (20) patients, 11 on HDF and 9 on HD were included in the analyses. Main objective was short term safety assessed by acid–base status, plasma ionized calcium and parathyroid hormone (PTH). In addition, biocompatibility was assessed by markers of inflammation (pentraxin 3 (PTX-3), CRP, IL-6, TNF-α and IL-1β) and thrombogenicity (activated partial thromboplastin time (APTT) and visual clotting scores).ResultsNo differences dependent on randomization order or treatment mode (HD vs. HDF) were detected. Citrate in the dialysis fluid reduced the intra-dialytic shift in pH (+0.04 week 6 vs. +0.06 week 0, p = 0.046) and base excess (+3.9 mM week 6 vs. +5.6 mM week 0, p = 0.006) over the study period. Using the same calcium concentration (1.5 mM), citrate dialysis fluid resulted in lower post-dialysis plasma ionized calcium level (1.10 mM vs. 1.27 mM for control, p < 0.0001) and higher post-dialysis PTH level (28.8 pM vs. 14.7 pM for control, p < 0.0001) while pre-dialysis levels were unaffected. Citrate reduced intra-dialytic induction of PTX-3 (+1.1 ng/ml vs. +1.4 ng/ml for control, p = 0.04) but had no effect on other markers of inflammation or oxidative stress. Citrate reduced visual clotting in the arterial air chamber during HDF (1.0 vs. 1.8 for control, p = 0.03) and caused an intra-dialytic increase in APTT (+6.8 s, p = 0.003) without affecting post-dialysis values compared to control.ConclusionsDuring this small short term study citrate dialysis fluid was apparently safe to use in HD and on-line HDF treatments. Indications of reduced treatment-induced inflammation and thrombogenicity suggest citrate as a biocompatible alternative to acetate in dialysis fluid. However, the results need to be confirmed in long term studies.Trial registrationISRCTN: ISRCTN28536511

An international group of around 50 nephrologists and scientists, including representatives from large dialysis provider organisations, formulated recommendations on how to develop and implement quality assurance measures to improve individual hemodialysis patient care, population health and cost effectiveness. Discussed were methods thought to be of highest priority, those clinical indicators which might be most related to meaningful patient outcomes, tools to control treatment delivery and the role of facilitating computerized expert systems. Emphasis was given to the use of new technologies such as measurement of online dialysance and ways of assessing fluid status. The current evidence linking achievement of quality criteria with patient outcomes was reviewed. This paper summarizes useful processes and quality measures supporting quality assurance that have been agreed across the expert panel. It also notes areas where more understanding is required.

Background/Aims: Radical thinking about the design of industrial processes has greatly improved the quality and efficiency of manufacturing and services. Applying similar methods in healthcare to deliver quality care at lower costs would be valuable. Methods: We have developed and validated a methodology – Treatment Mapping – to analyze the hemodialysis (HD) delivery as an operational process. Results: The methodology was well applicable in the 26 Gambro Healthcare clinics studied (Europe, Taiwan, USA). Monitor process, patient process and dialysis treatment times (mean ± SD) were 324.4 ± 46.0, 272.2 ± 34.5 and 221.6 ± 28.8 min, respectively. In general, significant variability in process cycle times was found in the clinics studied. Conclusion: HD delivery is a complex process influenced by patient characteristics, monitor/disposables design, staff skills and clinic practices and physical layout. The Treatment Mapping methodology is a useful tool to analyze the HD delivery from a process quality and process operational perspective.

In this pilot study, muscle interstitial urea concentrations during hemodialysis (HD) were determined with a microdialysis technique and the results were compared with plasma water urea concentrations. Three patients were investigated during a total of five treatments. Under predialysis steady-state conditions, no difference was observed. During treatment, the muscle interstitial urea concentration was on average 19% higher (range 13-28%, n=4) than the plasma urea concentration after 17+/-3 min, 29% higher (25-31%, n=3) after 53+/-10 min, 40% higher (26-50%, n=3) after 117+/-6 min, 31% higher (26-34%, n= 3) after 179+/-5 min, and 31% higher (27-36%, n=4) after 231+/-5 min. The gradient declined after the conclusion of HD, muscle interstitial concentrations being on average 16% (9-26%, n=4) higher than plasma urea concentrations 9+/-2 min after treatment, and 8% (6-10%, n=3) 25+/-3 min after treatment. Thus, a urea concentration gradient with a higher concentration in muscle interstitium than in plasma, developed during HD, and dissipated gradually after treatment. This is consistent with blood flow-dependent urea sequestration in muscle tissue, causing intercompartment disequilibrium of urea during HD, and its consequent redistribution after treatment contributing to postdialysis urea rebound.

Hydration status has a major impact on hemodialysis (HD) patients. Overhydration is related to hypertension, pulmonary and peripheral edema, and other cardiovascular events; while dehydration is related to hypotension, and other severe ischemic symptoms. All result in increased morbidity and mortality. Bioimpedance has been newly developed to measure the amount of water in the body. Several predictive equations were used, taken from demographic and anthropometric data. The purpose of this study was to evaluate the body composition of HD patients and to propose a hydration index. We performed bioimpedance measures with the Tanita TBF-300 scale, which calculates Total Body Water (TBW). The tool was reliable, with good reproducibility. However, we found significant differences between weight variations (dW) and TBW variations (dTBW) during HD sessions. This paper proposes a hydration index (I=dW-dTBW), with the hypothesis that dry weight is reached when I=0, while I>0 or I<0 indicate overhydrated or dehydrated, respectively. In this study, the changes in the index corresponded to the variations in weight and hydration state. We conclude that impedancemetry is a currently available technique that can be used to estimate TBW in HD patients. Although the index has to be improved by complementary studies, it may be a good guide to assess the dry weight achieved.