Bio-impedance spectroscopy added to a fluid management protocol does not improve preservation of residual kidney function in incident hemodialysis patients in a randomized controlled trial.

Avoiding excessive dialysis-associated volume depletion may help preserve residual kidney function (RKF). To establish whether knowledge of the estimated normally hydrated weight from bioimpedance measurements (BI-NHW) when setting the post-hemodialysis target weight (TW) might mitigate rate of loss of RKF, we undertook an open label, randomized controlled trial in incident patients receiving HD, with clinicians and patients blinded to bioimpedance readings in controls. A total of 439 patients with over 500 ml urine/day or residual GFR exceeding 3 ml/min/1.73m2 were recruited from 34 United Kingdom centers and randomized 1:1, stratified by center. Fluid assessments were made for up to 24 months using a standardized proforma in both groups, supplemented by availability of BI-NHW in the intervention group. Primary outcome was time to anuria, analyzed using competing-risk survival models adjusted for baseline characteristics, by intention to treat. Secondary outcomes included rate of RKF decline (mean urea and creatinine clearance), blood pressure and patient-reported outcomes. There were no group differences in cause-specific hazard rates of anuria (0.751; 95% confidence interval (0.459, 1.229)) or sub-distribution hazard rates (0.742 (0.453, 1.215)). RKF decline was markedly slower than anticipated, pooled linear rates in year 1: -0.178 (-0.196, -0.159)), year 2: -0.061 (-0.086, -0.036)) ml/min/1.73m2/month. Blood pressure and patient-reported outcomes did not differ by group. The mean difference agreement between TW and BI-NHW was similar for both groups, Bioimpedance: -0.04 kg; Control: -0.25 kg. Thus, use of a standardized clinical protocol for fluid assessment when setting TW is associated with excellent preservation of RKF. Hence, bioimpedance measurements are not necessary to achieve this.

A randomized controlled trial evaluating the erythropoiesis stimulating agent sparing potential of a vitamin E-bonded polysulfone dialysis membrane.

BACKGROUND: Vitamin E (VE) bonded polysulfone dialysis membranes have putative erythropoiesis stimulating agent (ESA)-sparing and anti-inflammatory properties based on data from a small number of studies. We sought to investigate this in a large, prospective 12-month randomized controlled trial. METHODS: Two-hundred and sixty prevalent haemodialysis (HD) patients were randomized to dialysis with VE-bonded polysulfone membranes or non-VE-bonded equivalents. All ESA-dosing was performed by means of a computer-based anaemia management decision support system. Monthly data were used to calculate the ESA resistance index (ERI) and blood tests were performed at baseline, 6 and 12 months for measurement of C-reactive protein (CRP) levels. RESULTS: Of the 260 patients, 123 were randomized to dialysis with the VE-membrane and 12-month data was available for 220 patients. At the study population level, no beneficial effect of the VE membranes on the ERI or CRP levels was observed. Post hoc analyses indicated that there was a significant fall in ERI for patients with the highest baseline ESA resistance dialysed with the VE (9.28 [7.70-12.5] versus 7.70 [5.34-12.7] IU/week/kg/g/dL Hb, P = 0.01) but not the control membranes (9.45 [7.62-12.3] versus 8.14 [4.44-15.6] IU/week/kg/g/dL Hb, P = 0.41); this was not attributable to changes in CRP levels. CONCLUSIONS: Wholesale switching of all chronic HD patients to dialysis with VE-bonded polysulfone membranes appears not to be associated with improvements in ESA-responsiveness or CRP. These membranes may have utility in patients with heightened ESA resistance.

A predictive algorithm for the management of anaemia in haemodialysis patients based on ESA pharmacodynamics: better results for less work.

BACKGROUND: Many anaemia management algorithms recommend changes to erythropoiesis-stimulating agent (ESA) doses based on frequent measurement of haemoglobin levels in keeping with the ESA datasheets. We designed a predictive anaemia algorithm based on ESA pharmacodynamics, which we hoped would improve compliance with haemoglobin targets and reduce workload. METHODS: A new algorithm was designed which predicted the 3-month steady-state haemoglobin concentration following a change in ESA dose and only recommended a change if it was outside the range 10.5-12.5 g/dL. Data were collected prospectively for 3 months prior and 15 months subsequent to implementing the algorithm. RESULTS: A total of 214 prevalent dialysis patients were included in the audit. After 12 months, the haemoglobin concentration was 11.4 g/dL, near the midpoint of the target range, with a narrowing of the distribution (SD 1.46 to 1.25 g/dL, P < 0.0001). The proportion of patients with a haemoglobin level in the target range increased from 56% to 66% (P < 0.001) principally due to a reduction in the number of patients with high haemoglobin levels. There was no significant change in the ESA dose over the audit period. The number of prescription changes fell from 1/2.5 months to 1/6.1 months after 12 months (P < 0.001). CONCLUSIONS: Switching prevalent haemodialysis patients to a predictive anaemia management algorithm improved compliance with haemoglobin targets, reduced the number of patients with high haemoglobin levels and reduced the number of ESA dose changes required.

Reducing sodium intake in hemodialysis patients.

A low salt diet is beneficial for the whole population but has particular advantages for hemodialyis patients because of the role of salt restriction in the management of hypertension and interdialytic weight gain (IDWG). Education on dietary salt intake based on general healthy eating guidelines, such as the "DASH-sodium" diet, should be provided for staff, families, and carers as well as patients. Anuric hemodialysis patients will need to take in approximately 1 l of water for every 8 g salt consumed. Patients who restrict salt intake to <6 g/day, and drink only when thirsty, should gain no more than 0.8 kg/day. Those with significantly greater weight gains, but predialysis serum sodium close to or higher than the dialysate sodium, need further review of their salt intake. Attempts to restrict fluid intake in these patients will be futile. Patients with high interdialytic weight gain (IDWG) and low predialysis sodium should be assessed for other reasons for fluid intake, such as high blood glucose or social drinking. For patients with poor tolerance of fluid removal during dialysis, and those who are hypertensive in the absence of fluid overload, a salt intake 5 g/day or less may be required. Dietary advice for these patients should be customized to ensure that they do not become malnourished.

Should dialysate calcium concentration be standardised or individualised?

The 2003 K/DOQI bone metabolism guidelines recommend a standard dialysate calcium concentration of 1.25 mmol/l. Studies of calcium balance that take ultrafiltration, as well as changes in ionised calcium, into account show that patients lose calcium when treated with this dialysate Ca. Compensation for negative calcium balance will usually be required in patients with normal or high bone turnover, but may be impossible if the recommendations to restrict intake of calcium, and hold vitamin D therapy if serum phosphate is high, are followed. A literature review suggests that conversion to 1.25 mmol/l dialysate Ca is beneficial in selected, but not all, patients. Conversion to higher dialysate Ca levels has been shown to improve control of calcium, phosphate and PTH, again in selected patients. Given the important role that dialysate calcium concentration plays in the management of renal bone disease, it should be prescribed on an individual basis like other medications.

A comparison of methods for determining urea distribution volume for routine use in on-line monitoring of haemodialysis adequacy.

BACKGROUND: The availability of haemodialysis machines equipped with on-line clearance monitoring (OCM) allows frequent assessment of dialysis efficiency and adequacy without the need for blood samples. Accurate estimation of the urea distribution volume 'V' is required for Kt/V calculated from OCM to be consistent with conventional blood sample-based methods. METHODS: Ten stable HD patients were monitored monthly for 6 months. Time-averaged OCM clearance (K(OCM)) and pre- and post-dialysis blood samples were collected at each monitored session. The second generation Daugirdas formula was used to calculate the single-pool variable volume Kt/V, (Kt/V)(D). Values of V to allow comparison between OCM and blood-based Kt/V were determined from Watson's formula (V(Watson)), bioimpedance spectroscopy (V(BIS)), classical urea kinetic modelling (V(UKM_C)) and a simple computation of V (V(UKM_S)) from the blood-based Kt/V and K(OCM)t. RESULTS: Comparison of K(OCM)t/V with (Kt/V)(D) shows that using V(Watson) leads to significant systematic underestimation of dialysis dose. K(OCM)t/V(BIS) agrees with (Kt/V)(D) to within +/- 10%. K(OCM)t/V(UKM_S) is, by definition, identical to (Kt/V)(D) when initially calculated. However, if a historical value of V is used, agreement between K(OCM)t/V and (Kt/V)(D) over 6 months varies by 5% for V(BIS) and 10% for V(UKM_S). CONCLUSIONS: When investigating the effect of different treatment strategies on dialysis efficiency, any estimate of V can be used provided it is constant, as K is the relevant parameter. When frequent supervision of actual dialysis dose is required, the greatest consistency between K(OCM)t/V and the reference, Kt/V(D), over time is achieved with V(BIS).

Venous needle dislodgement: how to minimise the risks.

Although haemodialysis (HD) has become a routine treatment, adverse side effects, and occasionally life threatening clinical complications, still happen. Venous needle dislodgment (VND) is one of the most serious accidents that can occur during HD. If the blood pump is not stopped, either by activation of the protective system of the dialysis machine or manually, the patient can bleed to death within minutes. Fatal and near-fatal blood loss due to VND have been described in the literature (ECRI 1998; Sandroni 2005; Mactier & Worth 2007), but published reports represent only the tip of the ice berg, as such incidents are normally handled at a local or national level. The European Dialysis and Transplant Nurses Association/European Renal Care Association (EDTNA/ERCA) has produced 12 practice recommendations to help reduce the risk of VND and detect blood leakage as early as possible. A poster summarising these recommendations has been created (Van Waeleghem et al. 2008).

On line UV-adsorbance measurements. Summary of the EDTNA/ERCA journal club discussion. Summer 2006.

The discussion was initiated by a paper comparing the measurement of dialysis dose (Kt/V) and solute clearance using on-line ultra-violet absorbance, blood and dialysate urea and ionic dialysance by Uhlin et al (NDT 2006). Participants from 14 countries discussed the theory behind the UV absorbance technique and the potential for its use in routine practice, the correlation between Kt/V measured using different methods, the use of ionic dialysance and the optimisation of dose monitoring. The 'take-home' messages from the discussion were that UV-absorbance could help ensure the delivery of dialysis dose as it provides real time feedback on the effect interventions such as repositioning of needles. The technology is relatively inexpensive and requires no consumables but changes in the dialysis machine settings could lead to misleading measurements if not communicated to the UV monitor. Session-to-session variation in dialysis dose can be measured using on-line clearance monitoring. If it is already on the machine and costs nothing, why not use it? Alternatively, regular access recirculation checks and a record of the total blood volume processed at each session allow problems with delivered dialysis dose to be picked up between routine blood tests.

Merits and limitations of continuous blood volume monitoring during haemodialysis. Summary of the EDTNA/ERCA Journal Club discussion: Winter 2005.

The discussion explored and expanded on the issues raised by Dasselaar et al in their review of the measurement of relative blood volume (RBV) changes during dialysis (NDT 2005). Dialysis machines incorporating blood volume monitoring and control are widely available in Europe. The use of continuous blood volume monitoring (CBVM) to help establish dry weight; problems with CBVM due to connection and use of single needle dialysis; the physiological processes that cause RBV changes during eating, exercise and posture changes; and the application of blood volume based biofeedback control were discussed by participants from ten countries. The 'take-home' messages from the discussion were that CBVM can assist in setting target weight, but must be used together with traditional measures and experience. Biofeedback control may help to achieve symptom-free dialysis, but staff should be prepared to monitor patients systematically for several weeks to obtain individualised settings. Users of CBVM should be aware of factors that can alter the central haematocrit leading to apparent changes in RBV. Practical guidelines should be developed to help staff interpret CBVM data effectively.

A randomized, controlled study of the consequences of hemodialysis membrane composition on erythropoietic response.

BACKGROUND: Membrane biocompatibility has long been thought to be relevant to hemodialysis outcomes and, possibly, renal anemia. METHODS: We performed a randomized, controlled, single-center study comparing the consequences on renal anemia of 2 dialyzers of equivalent performance, but different composition, during 7 months. Two hundred eleven patients of an unselected dialysis population of 235 patients gave informed consent to undergo random assignment to either group A (SF170E; modified cellulose triacetate/midflux membrane; Nipro, Osaka, Japan) or group B (HF80LS; polysulfone/high-flux membrane; Fresenius, Bad Homburg, Germany). Anemia management was identical in both treatment groups and followed strict clinical protocols managed by computer algorithms. Dialysis adequacy, hemoglobin (Hb) level, ferritin level, percentage of red blood cell hypochromicity, C-reactive protein (CRP) level, and intravenous iron and epoetin doses were monitored monthly. RESULTS: One hundred seventy-seven patients completed the 7-month study. Equilibrated Kt/V increased in both groups. Hb outcome improved overall, but did not differ between the 2 study groups. Epoetin dose was not significantly different after 7 months compared with baseline in either group. Hb level, epoetin dose, iron status, CRP level, dialysis Kt/V, and residual renal function did not differ between the 2 groups. A slight but significant negative correlation was identified between dialysis Kt/V and Hb level in the population as a whole (Spearman's correlation, -0.16; P = 0.04). CONCLUSION: No significant epoetin-sparing effect was identified through the use of the high-flux polysulfone HF80LS membrane over the modified cellulose triacetate SF170E membrane. Although not a primary outcome for this study, there was a suggestion of benefit of improved Hb level, without increased need for epoetin, through increasing delivered dialysis dose.

Information and counselling for patients approaching end-stage renal failure in selected centres across Europe.

The EDTNA/ERCA survey of the provision of pre-ESRF information, education and counselling in renal care was the third project organised through the Collaborative Research Programme (CRP). Data was collected from 35 participating centres in 10 countries. The majority of participating centres had a structured pre-ESRF programme. Advice and education received by patients in these centres was usually provided by a multidisciplinary team and was coordinated by nurses in half of the centres. Programmes in all countries had similar content in that normal kidney function, medication, diet, haemodialysis, peritoneal dialysis and transplantation were routinely discussed and that issues such as employment, importance of leisure activities, holidays and Kidney Patient Associations were also on the agenda for discussion. Educational material produced by companies was widely used. Policy differences did emerge in attitudes to discussing the "no-treatment" option with patients accepted for dialysis and in the treatment that would be offered to patients with specific co-morbidities and life-style.