Hemodialysis Dose Research Articles

Factors Influencing Vancomycin Loading Dose for Hospitalized Hemodialysis Patients: Prospective Observational Cohort Study

The increasing use of vancomycin to treat methicillin-resistant Staphylococcus aureus (MRSA) has resulted in reduced susceptibility of MRSA to this drug. It is important to optimize vancomycin dosing in patients who are undergoing hemodialysis to attain a pre-hemodialysis serum concentration sufficient to eradicate MRSA, in accordance with recent guideline recommendations. To establish the optimal strategy for vancomycin loading dose in patients undergoing hemodialysis and to explore the determinants of pre-hemodialysis serum concentration of vancomycin measured in these patients. A prospective observational cohort study was conducted between January and June 2010. Eligible participants were adults with established stage 5 chronic kidney disease who were undergoing inpatient hemodialysis. Data were collected on loading dose administered, body weight, serum concentration of vancomycin before the subsequent hemodialysis session (pre-hemodialysis concentration), and time between end of vancomycin infusion and measurement of pre-hemodialysis serum concentration. Multivariate stepwise linear regression was performed to examine independent associations between variables and measured pre-hemodialysis serum concentration of vancomycin. Eighty-one patients were included in the study. Of 24 patients who achieved the recommended pre-hemodialysis serum concentration of vancomycin (15-20 mg/L), 14 had a loading dose between 15 and 20 mg/kg. Further analysis suggested that the pre-hemodialysis serum concentration of vancomycin was independently associated with weight-based loading dose (mg/kg) (ß = 0.293, p = 0.003), age (ß = -0.358, p < 0.001), and time between administration of the loading dose and initiation of hemodialysis (ß = -0.247, p = 0.011). The findings of this study indicate that a loading dose of 15-20 mg/kg (actual body weight) is likely to yield an optimal pre-hemodialysis serum concentration at a median elapsed time of 24 h. In addition to loading dose, patient age and time between administration of the loading dose and initiation of hemodialysis also influenced the pre-hemodialysis serum concentration of the drug.

Daptomycin Pharmacokinetics and Pharmacodynamics in a Pooled Sample of Patients Receiving Thrice-Weekly Hemodialysis

While the pharmacokinetic (PK) properties of daptomycin in hemodialysis (HD) patients have been evaluated previously by three groups, resultant dosing recommendations have varied. To address this clinical conundrum, this study combined concentration-time data from these PK evaluations and derived uniform dosing recommendations among patients on HD receiving daptomycin. A two-compartment model with separate HD and non-HD clearance terms was fit to the PK data from these studies by using BigNPAG. Embedded with PK parameters from the population PK analysis, 5,000-subject Monte Carlo simulations (MCS) were performed to identify HD dosing schemes that provided efficacy (cumulative and daily area under the concentration-time curve [AUC] values) and toxicity (trough concentrations of ≥ 24.3 mg/liter) profiles comparable to those from simulations employing the daptomycin PK model derived from the Staphylococcus aureus bacteremia-infective endocarditis (SAB-IE) study. Separate HD dosing schemes were sought for the two weekly interdialytic periods (48 and 72 h). For the 48-h interdialytic period, intra- and post-HD dosing provided the most isometric cumulative and daily AUCs. For the 72-h interdialytic period, all HD dosing schemes provided noncumulative AUC values from 48 to 72 h (AUC(48-72)) that were <50% of the SAB-IE AUC(48-72) values. Increasing the parent dose by 50% intra- or post-HD provided comparable AUC(48-72) values, while maintaining acceptable trough concentration (C(min)) values. When efficacy and toxicity profiles were evaluated for each individual study, higher probabilities for C(min) reaching ≥ 24.3 mg/liter were observed in one of the three studies. Given the high probability of C(min) being ≥ 24.3 mg/liter in one of the three studies, more intensive creatine phosphokinase (CPK) monitoring may be warranted in HD patients receiving daptomycin.

Two-point normalized protein catabolic rate overestimates nPCR in pediatric hemodialysis patients

Normalized protein catabolic rate (nPCR) calculation depends on estimating the urea generation between consecutive hemodialysis (HD) treatments. Two-point nPCR using blood urea nitrogen (BUN) before and after the same HD treatment has not been validated in pediatric patients, who typically receive a more intense HD dose than adults. This study aimed to compare nPCR calculated with a two-point vs. a three-point nPCR model in pediatric HD patients. Pediatric patients receiving HD at 2 units were enrolled. Three BUN measurements were obtained around a midweek HD treatment: one prior to HD (preBUN1), one 30s after HD (30sBUN), and one prior to the subsequent HD (preBUN2). The two-point nPCR model was calculated using preBUN1 and 30sBUN and the three-point nPCR model was calculated using preBUN2 and 30sBUN. Seventy-six BUN sets from 35 patients were analyzed. Mean age was 16.4 ± 3.5years. Mean dry weight was 51.4 ± 17.1kg. Mean spKt/V was 1.54 ± 0.23. Mean preBUN2 was significantly lower than mean preBUN1 (60.2 ± 18.6 vs. 64.0 ± 18.9mg/dl, p = 0.0001). nPCR obtained from the three-point model was significantly lower than nPCR obtained from the two-point model (1.07 ± 0.31 vs. 1.17 ± 0.31g/kg/day, p = 0.00001). Seven of 76 (9.2%) paired comparisons yielded three-point nPCR <1 vs. two-point nPCR >1. Our data show that in pediatric patients receiving HD, the ((1) two-point and three-point models lead to significantly different nPCRs, and (2) inaccurate protein intake assessment may result from reliance on a two-point model for nPCR estimates.

Urea concentration and haemodialysis dose.

Background. Dialysis dose is commonly defined as a clearance scaled to some measure of body size, but the toxicity of uraemic solutes is probably associated more to their concentrations than to their clearance. Methods. 619 dialysis sessions of 35 patients were modified by computer simulations targeting a constant urea clearance or a constant urea concentration. Results. Urea generation rate G varied widely in dialysis patients, rather independently of body size. Dialysing to eKt/V 1.2 in an unselected patient population resulted in great variations in time-averaged concentration (TAC) and average predialysis concentration (PAC) of urea (5.9–40.2 and 8.6–55.8 mmol/L, resp.). Dialysing to equal clearance targets scaled to urea distribution volume resulted in higher concentrations in women. Dialysing to the mean HEMO-equivalent TAC or PAC (17.7 and 25.4 mmol/L) required extremely short or long treatment times in about half of the sessions. Conclusions. The relation between G and V varies greatly and seems to be different in women and men. Dialysing to a constant urea concentration may result in unexpected concentrations of other uraemic toxins and is not recommended, but high concentrations may justify increasing the dose despite adequate eKt/V, std EKR, or std K/V.

Dialysis dose scaled to body surface area and size-adjusted, sex-specific patient mortality.

When hemodialysis dose is scaled to body water (V), women typically receive a greater dose than men, but their survival is not better given a similar dose. This study sought to determine whether rescaling dose to body surface area (SA) might reveal different associations among dose, sex, and mortality. Single-pool Kt/V (spKt/V), equilibrated Kt/V, and standard Kt/V (stdKt/V) were computed using urea kinetic modeling on a prevalent cohort of 7229 patients undergoing thrice-weekly hemodialysis. Data were obtained from the Centers for Medicare & Medicaid Services 2008 ESRD Clinical Performance Measures Project. SA-normalized stdKt/V (SAN-stdKt/V) was calculated as stdKt/V × ratio of anthropometric volume to SA/17.5. Patients were grouped into sex-specific dose quintiles (reference: quintile 1 for men). Adjusted hazard ratios (HRs) for 1-year mortality were calculated using Cox regression. spKt/V was higher in women (1.7 ± 0.3) than in men (1.5 ± 0.2; P<0.001), but SAN-stdKt/V was lower (women: 2.3 ± 0.2; men: 2.5 ± 0.3; P<0.001). For both sexes, mortality decreased as spKt/V increased, until spKt/V was 1.6-1.7 (quintile 4 for men: HR, 0.62; quintile 3 for women: HR, 0.64); no benefit was observed with higher spKt/V. HR for mortality decreased further at higher SAN-stdKt/V in both sexes (quintile 5 for men: HR, 0.69; quintile 5 for women: HR, 0.60). SA-based dialysis dose results in dose-mortality relationships substantially different from those with volume-based dosing. SAN-stdKt/V analyses suggest women may be relatively underdosed when treated by V-based dosing. SAN-stdKt/V as a measure for dialysis dose may warrant further study.

Hemodialysis Adequacy and the Hospitalized End‐Stage Renal Disease Patient—Raising Awareness

Assessment of hemodialysis adequacy may require different approaches for the stable, outpatient with end-stage renal disease (ESRD) and for the sick, inpatient with acute kidney injury (AKI). Variability of urea distribution volume, urea generation, and treatment schedule, for instance, complicates dialysis dosing in the latter group although progress has been made in our understanding of their needs. There is a third population, however, for whom hemodialysis dosing requirements remain unclear--the hospitalized ESRD patient. This commentary discusses the key urea kinetic differences between stable ESRD and AKI to give the context to where, on the intervening spectrum, the hospitalized ESRD patient might lie. The limited literature examining hemodialysis dosing in this population is discussed along with those outstanding questions that might form the basis of a future research agenda.

Shortened Red Blood Cell Lifespan Is Related to the Dose of Erythropoiesis‐Stimulating Agents Requirement in Patients on Hemodialysis

Renal anemia is an important complication of chronic kidney disease (CKD). One of the most important complications of renal anemia is reduced red blood cell (RBC) lifespan, but there has been little research conducted into the causes of and treatments for this anemia. We measured alveolar carbon monoxide (CO) and then estimated RBC lifespan in patients on hemodialysis (HD). We also examined their requirement for erythropoiesis-stimulating agents (ESA), HD dose, nutrition factors, iron metabolism factor, reticulocyte counts and % reticulocytes. We enrolled 140 patients undergoing intermittent HD; among this group, 31 were not administered ESA and the others were on ESA therapy. Twelve healthy volunteers served as controls. The RBC lifespans in the healthy volunteers and in the HD patients were 128 ± 28 and 89 ± 28 days (mean ± SD), respectively. The RBC lifespan significantly and negatively correlated with ESA requirement (r = -0.489, P < 0.0001) in the HD patients. Other factors suspected to influence the RBC lifespan did not significantly correlate with the RBC lifespan in HD patients, in contrast to the correlation observed for S-Cr, BUN, S-ALB and total cholesterol vs. RBC lifespan. A shortened RBC lifespan seems to rather significantly affect the ESA requirement. Better nutritional status or active HD patients also seem to have longer RBC lifespans and lower ESA requirement.

Can Delivery Dialysis Dose Affect Survival of Acute Kidney Injury Patients?

Intensity of dialysis dose in acute kidney injury (AKI) might benefit critically ill patients. The aim of this study was to evaluate the effect of intermittent hemodialysis (IHD) dose on mortality in patients with AKI. Methods: Prospective observational study was performed on AKI patients treated with IHD. The delivered dialysis dose per session was calculated based on single-pool Kt/V urea. Patients were allocated in two groups according to the weekly delivered median Kt/V: higher intensity dialysis dose (HID: Kt/V higher than median) and lower intensity dialysis dose (LID: Kt/V lower than median). Thereafter, AKI patients were divided according to the presence or absence of sepsis and urine output. Clinical and lab characteristics and survival of AKI patients were compared. Results: A total of 121 AKI patients were evaluated. Forty-two patients did not present with sepsis and 45 did not present with oliguria. Mortality rate after 30 days was lower in the HID group without sepsis (14.3% × 47.6%; p = 0.045) and without oliguria (31.8% × 69.5%; p = 0.025). Survival curves also showed that the HID group had higher survival rate when compared with the LID group in non-septic and non-oliguric patients (p = 0.007 and p = 0.003, respectively). Conclusion: Higher dialysis doses can be associated with better survival of less seriously ill AKI patients.

Pericardial effusion as a crucial presentation of Erdheim-Chester disease in a hemodialysis patient: an overlooked diagnosis

Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocytosis whose hallmark is tissue infiltration by CD68-positive, CD1a-negative and usually S-100 protein-positive foamy non-Langerhans histiocytes and mononuclear cells. Here, we report a hemodialysis (HD) patient who presented with fever and pericardial effusion. We performed pericardiocentesis with pericardial biopsy and the histological findings indicated ECD. We administered intravenous methylprednisolone pulse therapy (250 mg/d) followed by oral prednisolone (50 mg/d). The patient's fever gradually subsided and there was no recurrence of pericardial effusion. This is the first report of an HD patient with ECD. We suggest that ECD be considered in the differential diagnosis of new HD patients who present with pericardial effusion, especially when this did not improve following increased dose of HD.

Intima media thickness in children undergoing dialysis

Uremic vasculopathy, including vascular calcification, increases the risk for cardiovascular disease and mortality in chronic kidney disease (CKD) patients. We have investigated the prevalence and factors associated with vasculopathy in children undergoing peritoneal dialysis (PD) or hemodialysis (HD) in a single center. Common carotid intima media thickness (cIMT) and its relation with demographics, biochemical parameters and medication was analyzed in 60 patients (mean age 12.9 ± 3.4 years; 27 girls) treated with PD (n = 31) or HD (n = 29) for 34 ± 34 months. Patients were divided into two groups: normal cIMT and increased cIMT. Mean levels of calcium, phosphate and calcium/phosphate product were in the normal range, the but parathyroid hormone level, 729 ± 670 pg/mL, was higher than the National Kidney Foundation Kidney Disease Outcome Quality Iniative (K/DOQI) recommendations. Twenty-nine patients had increased cIMT, which was associated with time on dialysis of >2 years, hypercalcemia, higher daily dose of calcitriol and HD (vs. PD). In the multivariate analysis, accounting for time on dialysis, HD persisted as a risk for increased cIMT. The prevalence of increased cIMT in children on dialysis is similar to that reported in adults with CKD and increased with time on dialysis. HD was associated with increased cIMT, independently of time on dialysis; however, the results should be interpreted with caution due to the possible impact of confounding factors. These results underline the need to monitor and, if possible, prevent and treat increased cIMT in children on dialysis.

Factors determining a low dose of haemodialysis as measured by ionic dialysance in critical patients with acute kidney injury.

Estimating the dialysis dose is a requirement commonly used to assess the quality of renal replacement therapy (RRT) in patients with chronic kidney disease (CKD). In patients with acute kidney injury (AKI), this value is not always evaluated and it has been estimated that the prescribed dose is seldom obtained. Reports addressing this issue in AKI individuals are scarce and most have not included an adequate number of patients or treatments, nor were patients treated with extended therapies. Kt values obtained by the ionic dialysance method have been validated for the evaluation of the dialysis dose and it has also been shown that, compared with Kt/V, this is the most sensitive strategy for revealing inadequate dialysis treatment in critically ill AKI individuals. The main aim of this study was to assess the difference between the prescribed and the administered dialysis dose in critically ill AKI patients, and to evaluate what factors determine this gap using Kt values assessed through ionic dialisance. Data from 394 sessions of renal replacement therapy in 105 adult haemodialysis (HD) patients with oliguric acute kidney injury and admitted to ICU were included in this analysis. RRT was carried out with Fresenius 4008E dialysis machines equipped with on-line clearance monitoring (OCM® Fresenius), which use non-invasive techniques to monitor the effective ionic dialysance, equivalent to urea clearance. The baseline characteristics of the study population as well as the prescription and outcome of RRT were analysed. These variables were included in a multivariate model in which the dependent variable was the failure to obtain the threshold dose (TD). The main baseline characteristics of the study population/treatments were: age 66 ± 15 years, 37% female, most frequent cause of AKI: sepsis (70%). Low BP and/or vasoactive drug requirement (71%), mechanical ventilation (70%) and average individual severity index: 0.7 ± 0.26. Two hundred and one intermittent HD (IHD) and 193 extended HD (EHD) sessions were performed; the most frequently used temporary vascular access was the femoral vein catheter (79%). Prescribed Kt was 53.5 ± 14L and 21% of prescriptions fell below the TD. Sixty-one percent of treatments did not fulfill the TD (31 ± 8L) compared with 56 ± 12L obtained in the subgroup that achieved the target. Compared to IHD, EHD provided a significantly larger Kt (46 ± 16L vs 33L ± 9L). Univariate analysis showed that inadequate compliance was associated with age (>65y), male gender, intra-dialytic hypotension, low Qb, catheter line reversal, and IHD. The same variables with the exception of age and gender were independently associated in the multivariate analysis. The dialysis dose obtained was significantly lower than that prescribed. EHD achieved values closer to the prescribed KT and significantly higher than in IHD. Ionic Kt measurement facilitates monitoring and allows HD treatments to be extended based upon a previously established TD. Besides the chosen strategy to dispense the dose of dialysis, a well-functioning vascular access allowing for optimal blood flow and other approaches aimed at avoiding hemodynamic instability during RRT are the most important factors to achieve TD, mainly in elderly male patients. The dialysis dose should be prescribed and monitored for all critically ill AKI patients.

Assessment of dialysis adequacy guidelines implementation in a developing country

Dialysis adequacy has been shown to have a significant impact on patient survival, but there are few data concerning the adequacy of the delivered hemodialysis dose in developing countries. To describe the level of implementation of dialysis practice guidelines in a dialysis center in Morocco, we retrospectively reviewed our 1-year experience of managing chronic hemodialysis patients (CHP), from May 2009 to May 2010. Demographic and biochemical data were collected, and the percentage of patients achieving targets recommended by the NKF-KDOQI guidelines were calculated. Our data suggests that dialysis units in a developing country can achieve current guidelines targets for dialysis adequacy, however, our results are not generalizable to all dialysis centers in Morocco.

Mortality Associated with Dose Response of Erythropoiesis-Stimulating Agents in Hemodialysis versus Peritoneal Dialysis Patients

Background: Several studies have shown an association between erythropoietin-stimulating agent (ESA) responsiveness and mortality in chronic kidney disease (CKD) patients. In our present study, we examined the association between prescribed ESA dose and mortality in peritoneal dialysis (PD) and hemodialysis (HD) patients. We hypothesized that PD patients received lower ESA dose for the same achieved hemoglobin compared to HD patients and that ESA dose-mortality associations were different between PD and HD patients. Methods: We compared the prescribed doses of ESA between 139,103 HD and 10,527 PD patients treated in DaVita dialysis clinics from 7/2001 through 6/2006 using adjusted Poisson regression and examined mortality-predictability of prescribed ESA dose and ESA responsiveness index (ESA/hemoglobin) in PD and HD with follow-up through 6/2007 using Cox regression models. Results: Poisson adjusted ratio of ESA dose of HD to PD was 3.6 (95% CI 3.5–3.7). In PD patients, adjusted all-cause death hazard ratios (HR) for ESA doses of 3,000–5,999, 6,000–8,999 and ≧9,000 U/week (reference <3,000 U/week) were 0.97 (0.87–1.07), 0.85 (0.76–0.95) and 1.08 (0.98–1.18), respectively; whereas in HD patients across commensurate ESA dose increments of 10,000–19,999, 20,000–29,999 and ≧30,000 U/week (reference <10,000 U/week) were 1.14 (1.11–1.17), 1.54 (1.50–1.58) and 2.15 (2.10–2.21), respectively. In PD and HD patients, the adjusted death HR of the 4th to 1st quartile of ESA responsiveness index were 1.14 (1.04–1.26) and 2.37 (2.31–2.43), respectively. Conclusions: Between 2001 and 2006, most PD patients received substantially lower ESA dose for same achieved hemoglobin levels, and low ESA responsiveness was associated with higher mortality in both HD and PD patients.

Hemofiltration compared to hemodialysis for acute kidney injury: systematic review and meta-analysis

IntroductionThe objective of this systematic review and meta-analysis was to determine the effect of renal replacement therapy (RRT), delivered as hemofiltration vs. hemodialysis, on clinical outcomes in patients with acute kidney injury (AKI).MethodsMEDLINE, EMBASE and CENTRAL databases and conference abstracts were searched to June 2012 for parallel-group or crossover randomized and quasi-randomized controlled trials (RCTs) evaluating hemofiltration vs. hemodialysis in patients with AKI. Two authors independently selected studies and abstracted data on study quality and outcomes. Additional information was obtained from trial authors. We pooled data using random-effects models.ResultsOf 6,657 citations, 19 RCTs (10 parallel-group and 9 crossover) met inclusion criteria. Sixteen trials used continuous RRT. Study quality was variable. The primary analysis included three parallel-group trials comparing similar doses of hemofiltration and hemodialysis; sensitivity analyses included trials comparing combined hemofiltration-hemodialysis or dissimilar doses. We found no effect of hemofiltration on mortality (risk ratio (RR) 0.96, 95% confidence interval (CI) 0.73 to 1.25, P = 0.76; three trials, n = 121 (primary analysis); RR 1.10, 95% CI 0.88 to 1.38, P = 0.38; eight trials, n = 540 (sensitivity analysis)) or other clinical outcomes (RRT dependence in survivors, vasopressor use, organ dysfunction) compared to hemodialysis. Hemofiltration appeared to shorten time to filter failure (mean difference (MD) -7 hours, 95% CI (-19,+5), P = 0.24; two trials, n = 50 (primary analysis); MD -5 hours, 95% CI (-10, -1), P = 0.01; three trials, n = 113 (including combined hemofiltration-hemodialysis trials comparing similar doses); MD -6 hours, 95% CI (-10, -1), P = 0.02; five trials, n = 383 (sensitivity analysis)). Data primarily from crossover RCTs suggested that hemofiltration increased clearance of medium to larger molecules, including inflammatory cytokines, compared to hemodialysis, although almost no studies measured changes in serum concentrations. Meta-analyses were based on very limited data.ConclusionsData from small RCTs do not suggest beneficial clinical outcomes from hemofiltration, but confidence intervals were wide. Hemofiltration may increase clearance of medium to larger molecules. Larger trials are required to evaluate effects on clinical outcomes.

Novel Dialysis Modalities: Do We Need New Metrics to Optimize Treatment?

Delivered dose of hemodialysis has long been an important predictor of mortality. The limitations of conventional hemodialysis treatments have led to a renewed interest in more frequent and longer hemodialysis treatments. As alternative hemodialysis schedules have become more prevalent, a need for modified metrics to measure adequacy has emerged. In addition, there is an interest in finding measures of hemodialysis adequacy that are more reliable in certain subgroups of patients, such as women, ethnic minority groups, or people with small body size. Finally, extended hemodialysis schedules suggest a need for metrics that can measure the clearance of solutes other than urea, such as middle-size molecules, and solutes for which clearance depends on intercompartmental transport across membranes. New metrics to quantify clearance in extended and alternate hemodialysis schedules are needed. As new metrics are developed, it is anticipated that they will also contribute to more accurate assessments of associations between clinical outcomes and delivered dose of dialysis in more intensive, nontraditional hemodialysis schedules. This review provides a historical prospective of dialysis dose and adequacy and describes the need for new metrics from both solute type and dialysis dose prospective as alternative hemodialysis schedules have emerged and become more prevalent.

Uraemic toxins versus volume and water as the major factor that matters with dialysis

In this pro-con debate, we will analyse the relevance of data supporting the prime role of uraemic toxins versus salt and volume overload as the main driver for the impressive mortality and morbidity characteristic of any end-stage re- nal disease patient. Firstly, we are going to review the circumstantial evidence and associated studies/clinical observational data which only weakly suggest that uraemic solutes are indeed linked to damage to the body and its constituents, especially the car- diovascular (CV) system. At the same time, we will equally thoroughly discuss the 'fact' that decreasing salt and fluid load is essential for any dialysed patient. Evidence in favour of a prominent role for uraemic toxins is appealing from a pathophysiological point of view, but unfortunately is mis- leading in real life practice. Evidence in favour of salt and water reduction is overwhelmingly stronger. This difference in apparent evidence strength notwith- standing the weaker support for uraemic toxins does not take away from clinical importance of minimizing uraemic tox- icity load in the large majority of the dialysis population. filtration (HDF) or more frequent/longer dialysis, was only partially associated with better results. Moreover, in the ma- jority of the positive studies, alternative interpretations of the results is possible, including a contribution of better volume control achievable with these particular dialysis techniques. Some 'observational' studies (2-7) showed a beneficial effect of high-flux versus low-flux synthetic dialysis mem- branes on survival, whereas prospective random controlled trials (RCTs) were inconclusive. In the Haemodialysis (HEMO) study, the largest random- ized clinical trial conducted in haemodialysis (HD) so far, patients were randomized to either a high-dialysis dose (achieved eKt/V ¼ 1.53 � 0.09, sp Kt/V ¼ 1.71 � 0.11) or a standard-dose goal (achieved eKt/V ¼ 1.16 � 0.08, sp Kt/V ¼ 1.32 � 0.09) and to dialysis with either high-flux dialysers (b2-microglobulin clearance of > 20 mL/min) or to low-flux dialysers—(b2-microglobulin clearance < 10 mL/ min). The results showed that a higher HD dose was not associated with a lower mortality risk compared with con- ventional HD dose (8). Thus, while a minimumKt/V ,a ccord- ing to the guidelines, is mandatory, the HEMO study clearly demonstrated that there are no advantages in further increas- ing the urea Kt/V, even in the high-flux membrane group. At the same time, each 10 mg/L increase in b2-M level was associated with an 11% increase in mortality, even after ad- justment for years on dialysis and residual kidney function. These results deserve further specifically designed studies in order to clarify if it is a matter of larger molecule removal or better fluid removal. In the other large trial in the field, the Membrane Perme- ability Outcome study, there was no significant difference in survival between high- and low-flux groups when all patients were included in the analysis (9). However, patients with serum albumin � 40 g/L on enrolment and with diabetes had a significantly better survival in the high-flux arm. High-flux dialysis was associated with a significantly lower accumulation of b2-microglobulin. Again, it is important to clarify if the better outcome was related to larger molecule removal or better fluid removal. Compared with conventional HD, HDF could theoretically offer some advantages: better clearance of middle- and

How best to improve survival in hemodialysis patients: solute clearance or volume control?

How much dialysis is required for optimal well-being and long-term survival? The Frequent Hemodialysis Network completed two prospective trials examining the effect of more frequent, short hours and, now, of nocturnal hemodialysis compared with standard thrice-weekly treatments. Whereas the short-hours trial reported benefits with more frequent dialysis, somewhat paradoxically, nocturnal hemodialysis had fewer advantages. However, this trial was probably underpowered, and confounded by the beneficial effects of home hemodialysis in the control group.

Determination of Dialysis Dose: A Clinical Comparison of Methods

Background: Guidelines recommend regular measurements of the delivered hemodialysis dose Kt/V. Nowadays, automatic non-invasive online measurements are available as alternatives to the conventional method with blood sampling, laboratory analysis, and calculation. Methods:In a prospective clinical trial, three different methods determining dialysis dose were simultaneously applied: Kt/V_Dau (conventional method with Daugirdas’ formula), Kt/V_OCM [online clearance measurement (OCM) with urea distribution volume V based on anthropometric estimate], and Kt/V_BCM [OCM measurement with V measured by bioimpedance analysis (Body Composition Monitor)]. Results:1,076 hemodialysis patients were analyzed. The dialysis dose was measured as Kt/V_Dau = 1.74 ± 0.45, Kt/V_OCM = 1.47 ± 0.34, and Kt/V_BCM = 1.65 ± 0.42. The difference between Kt/V_OCM and Kt/V_BCM was due to the difference between anthropometric estimated V_Watson and measured V_BCM. Compared to Kt/V_Dau, Kt/V_OCM was 15% lower and Kt/V_BCM 5% lower. Kt/V_Dau was incidentally prone to falsely high values due to operative errors, whereas in these cases OCM-based measurements Kt/V_OCM and Kt/V_BCM delivered realistic values. Conclusions:The automated OCM Kt/V_OCM with anthropometric estimation of urea distribution volume was the easiest method to use, but Kt/V_BCM with measured urea distribution volume was closer to the conventional method.

A comparison of laboratory values in pediatric hemodialysis patients: does day of the week matter?

The National Kidney Foundation Dialysis Outcomes Quality Initiative (NKF-K/DOQI) guidelines recommend the delivered dose of hemodialysis (HD) be measured no less than monthly by checking Kt/V (K is effective urea clearance, t is minute and V is urea distribution). To date, no studies have explored whether the day of the week for checking maintenance HD laboratory studies impacts dialysis dosing. Data were collected at two HD facilities on 19 patients, ages ≤ 21 years receiving maintenance HD thrice weekly over a consecutive 6-month period. Data obtained from the Monday and Wednesday of each full third week of the month included dialysis vintage, ultrafiltration volume, serum electrolytes, hemoglobin and clearances. Kt/V and K+ were significantly different between Monday and Wednesday (P = 0.013 and P = 0.047, respectively). Due to variability in values based on the day of laboratory evaluations, the dialysis provider must consider the impact of this on the quality of patient care when prescribing dialysis. Research on a larger scale needs to be conducted to allow for better decision-making capabilities in the chronic HD population.

Value of carotid intimal–medial thickness as independent predictor of endothelial dysfunction in uremic patients

Abstract Background and aim of the work Cardiovascular mortality and morbidity are significantly higher among uremic patients. Although the carotid intimal–medial thickness (C-IMT) as a predictor of endothelial dysfunction (ED) has a prognostic value that has been well demonstrated as an independent predictor of future cardiovascular events, its value in uremic patients need to be re-assisted in our locality. The aim of the work is to investigate a correlation between the brachial artery reactivity test (BART) and the carotid intimal–medial thickening (C-IMT) and their value as independent predictors of endothelial dysfunction in uremic patients. Subjects and methods The study involved 70 uremic patients, 40 men and 30 women, 36–56 years old, 40 of them on regular hemodialysis (HD) and 30 on conservative therapy, in addition to 30 healthy persons as a control group. They were selected from the General Medicine and Nephrology Departments, Al-Azhar Assiut University and Assiut University Hospitals over a period of 2 years. All of them were subjected to detailed history, thorough clinical examination, laboratory investigations including complete blood picture, renal function tests (urine analysis, blood urea, and serum creatinine), lipid profile, serum calcium and serum phosphorus, parathyroid hormone (PTH), fasting blood glucose, electrocardiography (ECG), high resolution B-mode ultra-sonography for C-IMT evaluation and brachial artery reactivity test (BART), and abdominal ultra-sonography. Results The results of the present study showed: (1) uremic patients are at an increased risk for carotid atherosclerotic lesions, with significant increase in C-IMT than controls with more significant increase in HD patients. (2) Uremic patients are characterized by impaired endothelium dependent dilatation of the brachial artery (highly significant reduction in flow-mediated dilatation (FMD%)), an abnormality related to the renal failure severity and to the hemodialysis doses. The endothelial dysfunction in the brachial artery was more pronounced in HD patients than in patients on conservative therapy. (3) Significant positive correlation between increased C-IMT and reduction of the brachial FMD%. (4) Significant relation between C-IMT and plaque prevalence and HD duration, while no relations recorded between brachial FMD with HD duration. Conclusion (1) The study confirmed that carotid IMT and brachial artery FMD can be used in interventional studies in which cardiovascular risk is modified and increased in the uremic patients. (2) There was negative correlation between brachial FMD and C-IMT in the uremic patients.