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Background Green nephrology encompasses all initiatives in kidney care that have a positive impact on climate and environment. To prepare the dialysate, at least 120 L of water are needed for one 4-h session with a dialysate flow (Qd) set at 500 mL/min. A lower dialysate flow rate is associated with a significant reduction in the amount of water used. The aim of this study was to check whether change of Qd from 500 mL/min to 300 mL/min has a significant impact on dialysis adequacy. Methods The study was a retrospective analysis. Due to administrative issues, a satellite dialysis center reduced their dialysate flow to 300 mL/min for a month. The center then increased Qd to 500 mL/min again. We analyzed laboratory data from 3 months before dialysate flow reduction, in the month with Qd reduced to 300 mL/min, and from 3 months thereafter with Qd set at 500 mL/min. Results Twenty-four people were included in the final analysis. There were no significant changes in urea reduction ratio caused by lower rate of Qd [64.50 (61.75–71.00) vs 67.00 (63.00–72.25) vs 69.00 (63.75–72.25), analysis of variance F(2,46) = 0.71, P = .50]. Similarly, hemodialysis adequacy expressed by Kt/V did not differ at any Qd [1.23 (1.12–1.41) vs 1.25 (1.18–1.40) vs 1.35 (1.19–1.48), ANOVA F(2,46) = 2.51, P = .09]. There was a small but statistically significant increase in mean predialysis potassium with lower Qd [potassium = 5.18 (95% confidence interval, 95% CI, 4.96–5.44) vs 5.46 (95% CI 5.23–5.69) vs 5.23 (95% CI 4.99–5.47) mmol/L at Qd = 500, 300 and 500 mL/min, respectively, P = .039]. Conclusion Reduction in dialysate flow rate to 300 mL/min seems safe and does not cause any short-term negative effects in this small study. Thus, we might be able to achieve a similar therapeutic effect while saving water consumption. Larger, long-term studies incorporating patient-reported outcome measures are needed to confirm the efficacy of this approach. [ABSTRACT FROM AUTHOR]

Background Patients with kidney failure treated with maintenance haemodialysis (HD) require appropriate small molecule clearance. Historically, a component of measuring 'dialysis adequacy' has been quantified using urea kinetic modelling that is dependent on the HD prescription. However, the impact of dialysate flow rate on urea clearance remains poorly described in vivo and its influence on other patient-important outcomes of adequacy is uncertain. Methods We searched Embase, MEDLINE and the Cochrane Library from inception until April 2022 for randomized controlled trials and observational trials comparing a higher dialysate flow rate (800 ml/min) and lower dialysate flow rate (300 ml/min) with a standard dialysis flow rate (500 ml/min) in adults (age ≥18 years) treated with maintenance HD (>90 consecutive days). We conducted a random effects meta-analysis to estimate the pooled mean difference in dialysis adequacy as measured by Kt/V or urea reduction ratio (URR). Results A total of 3118 studies were identified. Of those, nine met eligibility criteria and four were included in the meta-analysis. A higher dialysate flow rate (800 ml/min) increased single-pool Kt/V by 0.08 [95% confidence interval (CI) 0.05–0.10, P  < .00001] and URR by 3.38 (95% CI 1.97–4.78, P  < .00001) compared with a dialysate flow rate of 500 ml/min. Clinically relevant outcomes including symptoms, cognition, physical function and mortality were lacking and studies were generally at a moderate risk of bias due to issues with randomization sequence generation, allocation concealment and blinding. Conclusion A higher dialysate flow increased urea-based markers of dialysis adequacy. Additional high-quality research is needed to determine the clinical, economic and environmental impacts of higher dialysate flow rates. [ABSTRACT FROM AUTHOR]

Background The guidelines recommended target and minimum single-pool Kt / V urea are 1.4 and 1.2, respectively, in hemodialysis patients. However, the optimal hemodialysis dose remains controversial. We investigated the effects of Kt / V urea on patient outcomes according to age, with a focus on older patients. Methods This study used the hemodialysis quality assessment program and claims datasets. Patients were divided into four subgroups according to age (<65, 65–74, 75–84, and ≥85 years). Each group was divided into three subgroups according to Kt / V urea : reference (ref) (1.2 ≤  Kt / V urea ≤ 1.4), low (< 1.2), and high (> 1.4). Results The low, ref, and high Kt / V urea groups included 1668, 8156, and 16   546 (< 65 years); 474, 3058, and 7646 (65–74 years); 225, 1362, and 4194 (75–84 years); and 14, 126, and 455 (≥85 years) patients, respectively. The low Kt / V urea group had higher mortality rates than the ref Kt / V urea group irrespective of age [adjusted hazard ratio (aHR), 95% confidence interval (CI): 1.23, 1.11–1.36; 1.14, 1.00–1.30; 1.28, 1.09–1.52; and 2.10, 1.16–3.98, in patients aged <65, 65–74, 75–84, and ≥85 years, respectively]. The high Kt / V urea group had lower mortality rates than the ref Kt / V urea group in patients aged <65 and 65–74 years (aHR, 95% Cl: 0.87, 0.82–0.92 and 0.93, 0.87–0.99 in patients aged <65 and 65–74 years, respectively). Conclusions These results support the current recommendations of a minimum Kt / V urea of 1.2 even in patients age ≥85 years. In young patients, Kt / V urea above the recommended threshold can be beneficial for survival. [ABSTRACT FROM AUTHOR]

Background Dialysis adequacy, as measured by single pool Kt/V , is an important parameter for assessing hemodialysis (HD) patients' health. Guidelines have recommended Kt/V of 1.2 as the minimum dose for thrice-weekly HD. We describe Kt/V achievement, its predictors and its relationship with mortality in the Gulf Cooperation Council (GCC) (Bahrain, Kuwait, Oman, Qatar, Saudi Arabia and the United Arab Emirates). Methods We analyzed data (2012–18) from the prospective cohort Dialysis Outcomes and Practice Patterns Study for 1544 GCC patients ≥18 years old and on dialysis >180 days. Results Thirty-four percent of GCC HD patients had low Kt/V (<1.2) versus 5%–17% in Canada, Europe, Japan and the USA. Across the GCC countries, low Kt/V prevalence ranged from 10% to 54%. In multivariable logistic regression, low Kt/V was more common (P < 0.05) with larger body weight and height, being male, shorter treatment time (TT), lower blood flow rate (BFR), greater comorbidity burden and using HD versus hemodiafiltration. In adjusted Cox models, low Kt/V was strongly related to higher mortality in women [hazard ratio (HR) = 1.91, 95% confidence interval (CI) 1.09–3.34] but not in men (HR = 1.16, 95% CI 0.70–1.92). Low BFR (<350 mL/min) and TT (<4 h) were common; 41% of low Kt/V cases were attributable to low BFR or TT (52% for women and 36% for men). Conclusion Relatively large proportions of GCC HD patients have low Kt/V. Increasing BFR to ≥350 mL/min and TT to ≥4 h thrice weekly will reduce low Kt/V prevalence and may improve survival in GCC HD patients—particularly among women. [ABSTRACT FROM AUTHOR]

Background The Dt/V obtained by using ionic dialysance (D) as a surrogate for urea clearance (K) is a well-validated adjunct measure of hemodialysis adequacy, with a variable level of correlation with urea-based Kt/V. However, this correlation has not been examined based on patients' body size and ultrafiltration (UF) volume during the dialysis session. Methods Simultaneous evaluations of online Dt/V and single-pool variable-volume urea Kt/V were made. Patients were categorized into three subgroups based on their weight (<60, 60–80 and ≥80 kg), body mass index (<25, 25–30 and >30 kg/m2) and UF volume (<1.5, 1.5–3 and >3 L). The correlation between Dt/V and Kt/V was evaluated for the entire cohort per dialysis session in each subgroup. Results Mean Kt/V was greater than the mean Dt/V (1.72 versus 1.50, P < 0.001), with an overall correlation r value of 0.602. This correlation was stronger in the medium weight group versus lower and higher weights. The correlation between Dt/V and Kt/V was inversely related to the UF volume (r  = 0.698, 0.621 and 0.558 for those with UF volume of <1.5, 1.5–3.0 and >3 L, respectively). A total of 99.3% of patients with Dt/V of >1.2 also had Kt/V >1.2 and 9.5% of those with Dt/V <1.2 had their Kt/V <1.2. Conclusions There is a moderate degree of correlation between Dt/V and Kt/V in African-American hemodialysis patients, which is impacted by body size and UF volume. A Dt/V of >1.2 strongly predicts adequate dialysis as defined by Kt/V of >1.2. [ABSTRACT FROM AUTHOR]

Background The monitoring of dialysate ultraviolet (UV) absorbance is a validated technology to measure hemodialysis adequacy and allows for continuous and real-time tracking every session as opposed to the typical once-monthly assessments. Clinical care guidelines are needed to interpret the findings so as to troubleshoot problematic absorbance patterns and intervene during an individual treatment as needed. Methods When paired with highly structured clinical care protocols that allow autonomous nursing actions, this technology has the potential to improve treatment outcomes. These devices measure the UV absorbance of dialysate solutes to calculate and then display the delivered as well as predicted clearance for that session. Various technical factors can affect the course of dialysate absorbance, confound the device's readout of clearance results and thus lead to challenges for the dialysis unit staff to properly monitor dialysis adequacy. We analyze optimal and problematic patterns to the device's 'clearance' display (e.g. due to thrombosis of hollow fibers, inadequate access blood flow or recirculation) and provide specific interventions to ensure delivery of an adequate dialysis dose. A rigorous algorithm is presented with representative device monitor display profiles from actual hemodialysis sessions. Procedural rationale and interventions are described for each individual scenario. Conclusion Real-time hemodialysate UV absorbance patterns can be used for protocol-based intradialytic interventions to optimize solute clearance. [ABSTRACT FROM AUTHOR]

Current guidelines for dialysis specify a minimum Kt/V. For haemodialysis (HD) patients, minimum treatment time and frequency is also specified. The guidelines allow for modification to take account of renal function. The guidelines are not specifically aimed at the elderly and may not be appropriate for all patients in this group. Increasing age is accompanied by physiological and pathological changes that may modify the patient's response to uraemia and dialysis. Frailty and multi-morbidity are likely, but to a variable extent. Elderly patients could be more susceptible to the effects of uraemia and require a higher dose of dialysis. Conversely, the generation rate of uraemic toxins is lower in elderly patients, potentially reducing the need for dialysis. In the elderly, quality of life may be more adversely affected by multimorbidity than uraemic symptoms, thus the dose of dialysis may be less relevant. Higher doses of dialysis may be more difficult to achieve in the elderly and may be less well tolerated. We conclude that the prescription of dialysis in the elderly should be individualized, taking multiple factors into account. An individualized Kt/V may be useful in controlling dialysis dose and detecting problems in delivery. However, achievement of a specified Kt/V may not result in any benefit to an elderly patient and could be counterproductive. [ABSTRACT FROM AUTHOR]

Thrice-weekly haemodialysis schedules have become the standard default haemodialysis prescription worldwide. Whereas the measurement of residual renal function is accepted practice for peritoneal dialysis patients and the importance of residual renal function in determining technique success is well established, few centres routinely assess residual renal function in haemodialysis patients. Although intradialytic hypotension and episodes of acute kidney injury may predispose to an earlier loss of residual renal function, a significant proportion of haemodialysis patients maintain some residual function long after dialysis initiation. As such, an incremental approach to the initiation of dialysis with careful monitoring of residual renal function may potentially provide some haemodialysis patients with an improved quality of life and greater preservation of residual renal function whilst fewer dialysis sessions may reduce health care costs. Prospective trials are required to determine the optimum approach to the initiation of haemodialysis for the oliguric patient. Once residual renal function has been lost, then dialysis prescriptions should be re-examined to consider the use of longer or more frequent treatment sessions and switching from low-flux to high-flux dialysis or haemodiafiltration to offset retention of middle sized molecules and protein-bound azotaemic solutes. [ABSTRACT FROM AUTHOR]

Background. 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. Methods. 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. Results. Kt/V and K+ were significantly different between Monday and Wednesday (P = 0.013 and P = 0.047, respectively). Conclusion. 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. [ABSTRACT FROM AUTHOR]

Background. Depression may be associated with activation of pro-inflammatory cytokines and increased long-term mortality in patients on maintenance haemodialysis (MHD). There are numerous reports regarding the association of depression with inflammatory status, co-morbidities and nutritional condition, but few of these studies have explored the possible correlations between depression, age and economic status. The study explores the possible correlations between depression and demographic, socio-economic, clinical and laboratory variables.Methods. One hundred and forty-six MHD patients (65 males and 81 females, mean age: 63.8 ± 15.2 years) were enrolled in this cross-sectional study. Demographic and socio-economic status as well as clinical and laboratory variables including co-morbidities were obtained. The self-administered Beck Depression Inventory (BDI) was used to determine the presence or absence of depression symptoms. Biochemical parameters (serum albumin, triglyceride, cholesterol, etc.) and dialysis dosage delivery (Kt/V and urea reduction rate or URR) were examined. All the patients were on high-flux biocompatible dialysers for MHD. The presence of an inflammatory state was assessed by determinations of plasma interleukin-6 (IL-6) levels.Results. The prevalence of depression (BDI ≥14) was 45.9%. In patients found to have symptoms of depression, no statistically significant difference was shown with respect to age, gender, smoking habits or clinical characteristics. However, these patients were more likely to have a number of co-morbidities. They also had higher levels of serum IL-6 and total cholesterol as well as lower serum albumin and Kt/V values. The BDI correlated significantly with Kt/V values (r = −0.19; P < 0.05), levels of serum albumin (r = −0.28; P < 0.005) and serum IL-6 (r = 0.47; P < 0.001). Multivariate stepwise forward logistic regression analysis showed a direct correlation between BDI and IL-6 levels (P = 0.001; OR = 1.537) and between BDI and co-morbidities (P = 0.037; OR = 3.584). There was an inverse correlation between BDI and serum albumin levels (P = 0.006; OR = 0.145) and between BDI and age (P = 0.007; OR = 0.96). The rate of depression was significantly lower for the elderly patients (age ≥75 years) compared with those below 64 years of age. The percentage of personal monthly disposable income at or above Taiwan dollar (TWD) >10 000 was similar in patients aged ≥75 and those below 64 years old.Conclusions. Maintenance haemodialysis patients with symptoms of depression may have higher serum IL-6 and lower serum albumin levels. The prevalence of depression was lower in elderly patients at or above 75 years old, and no correlation was found with socio-economic status. Factors including co-morbid conditions, serum IL-6, albumin and age may help predict which patients may be predisposed to develop symptoms of depression. [ABSTRACT FROM AUTHOR]

Background. Haemodialysis dose has been shown to have a distinct impact upon the morbidity and mortality rate in patients on regular dialysis therapy. Accordingly, the adequacy of dialysis treatment should be guaranteed. [ABSTRACT FROM PUBLISHER]

Background. The achievement of dialysis adequacy targets in peritoneal dialysis (PD) is assessed by the calculation of the Kt/V and creatinine clearance (CCr) obtained by collecting dialysate and urine, usually two or three times a year. Prescription decisions are based on such adequacy assessments, regardless of any variability in the single measurements. The aim of our study was to assess the day-to-day variability of common dialysis adequacy parameters and to evaluate its impact on the adequacy indexes in PD. [ABSTRACT FROM PUBLISHER]

Introduction.In Europe, especially in Germany, little is currently known about the relationship between delivered and predicted haemodialysis doses for patients on maintenance haemodialysis. We compared delivered and predicted Kt/V in patients of an outpatient dialysis centre in Berlin by calculating the ratio of delivered and predicted Kt/V, resulting in the efficacy quotient, QE. Moreover, we studied the influence of technical and anthropometric parameters on both delivered Kt/V and QE under routine clinical conditions. [ABSTRACT FROM PUBLISHER]

Background. Currently the total (dialytic plus renal) urea clearance (KT) is computed as Kt/V plus the equivalent Kt/V (KT/VKR) provided by the renal urea clearance (KR). However, KT/VKR is computed with two different formulae, by Gotch and Keshaviah respectively. Moreover Teschan suggested a weekly KT, that is a multiple of Keshaviah's KT. We suggest the equivalent renal urea clearance (EKR), that kinetically quantifies the ‘time-averaged KT’ and is independent of treatment type and schedule. Methods. Computer simulation has been used to analyse the relationship between EKR, as corrected for urea volume (EKRc), and Kt/V. Data from 66 HD patients, of whom eight were on once-weekly and 11 on twice-weekly HD, had been used to compare EKR with current KTs. Results. For each individual schedule, the relationship between EKRc and Kt/V is linear and each ml/min of KR increases EKR by the same amount. For instance, for thrice-weekly HD patients, EKRc=1+10×Kt/V: so that, the critical Kt/V values of 0.8 and 1.0 correspond to EKRc values of 9.0 and 11 ml/min respectively, independently from treatment type and schedule. As to the clinical data, all once- and twice-weekly patients had a significant KR and excellent clinical status, but most of them had 9≤EKRc<11 ml/min. After appropriate reconciliation of units, it has been found that kinetic KT was overestimated by about 10–12% (range, 2–23%) by Keshaviah and Teschan's KT, and by about 2–7% (range, 0.3–15%) by Gotch's KT. Conclusions. EKRc can account for KR and provide guidelines for all types of dialysis treatments: as far as urea is concerned, dialysis adequacy should require EKRc≥11 ml/min. However, it is likely that EKRc≥9 ml/min could suffice for patients with a substantial residual renal function. [ABSTRACT FROM PUBLISHER]

/ urea (u) has been used as a measure of adequacy of haemodialysis (HD). However, the accurate assessment of its components is difficult and subject to error in a clinical setting. This study was designed to evaluate different forms of dialyser clearance () measurements and their influence on . Sixteen patients on high-flux HD were studied at blood flow () rates of 250 and 350 ml/min and at constant dialysate flow rates. of urea was measured by the arteriovenous blood sampling technique (), corrected for access recirculation () and compared with as determined by dialysate collection () using a new sampling device. At 250 and 350 ml/min, as based on dialysate collection was significantly lower than and as based on arteriovenous blood sampling: at 250, 169.0± 13.3, 191.2±11.5, and 203.0±9.3 ml/min (P<0.0005); at 350, 196.5±17.3, 227.7±15.5, and 243.6±12.7 ml/min (<0.0005). At 250 ml/min (1.33±0.17) overestimated (1.11±0.13) by 16.8%, at 350 ml/min by 19.3% (1.58 ± 0.19 versus 1.27±0.15). Dialyser clearances based on arteriovenous differences in blood overestimate true clearances (and therefore ) as measured by dialysate collection. This overestimation is more marked with higher blood flow rates. [ABSTRACT FROM PUBLISHER]

Urea kinetic modelling (UKM) was used to assess adequacy of dialysis in 50 CAPD patients. Nutritional status was assessed from the measurement of visceral protein status (total protein, albumin, transferrin, immunoglobulins, complement), somatic protein status (anthropometry), and dietary intake (1 week weighed dietary inventory and normalized protein catabolic rate (NPCR) from UKM). Morbidity was assessed from the peritonitis and admission history. Mean Kt/V (corrected to ×3 weekly dialysis) was 0.66 ± 0.02. Dietary protein intake estimated from the NPCR (1.08±0.03 g kg day) correlated well (=0.72, <0.001) with that estimated from the dietary inventory (1.10±0.04 g kg day). There was a strong correlation between Kt/V and NPCR corrected for actual weight (=0.65, <0.001), but when NPCR was corrected for IBW this correlation was weaker (=0.35, <0.05). Patients were divided by Kt/V into two groups (>0.65, =22 and <0.65, =28). There were no significant differences in the indices of visceral protein status between the two groups. Weight, height, BMI, fat free mass and arm muscle area were significantly greater in the group Kt/V<0.65. Residual renal function (creatinine clearance) was higher in the group Kt/V>0.65 (3.8±0.7 versus 1.9±0.5 1/24 h, <0.05) and plasma creatinine less (913±51 versus 1265±51 µmol/l, <0.001). Hb, potassium, bicarbonate, phosphate, alkaline phosphatase, PTH, and blood pressure were not different. Neither was there any difference between the two groups in any of the indices of morbidity. [ABSTRACT FROM PUBLISHER]

To test the validity of the assumption that the protein catabolic rate (PCRn g/kg/day) is dependent on the normalized dose of dialysis (Kt/V urea), and to try to define the charactenstics of the patients in the undefined domain A of the mechanistic map of the National Cooperative Dialysis Study (NCDS), which should include patients with adequate amount of dialysis but inadequate PCRn, urea kinetic model ling was performed over 12 months on 85 patients undergoing haemodialysis All the patients were man aged to maintain a Kt/V urea ≥0.9. During the entire period of study the total number of hospitalizations and the number of days of hospitalization were recorded. Total serum proteins and serum albumin concentrations were measured at the start and at the end of the study. The results of the study show that there was no correlation between Kt/V and PCRn nor between Kt/V and patient's age, but there was a strong inverse correlation between age and PCRn (r=0.578; P <0.0001). Further division of the patients into four groups according to age showed that the lowest values of PCRn were for the group of patients ≥75 years old. Twelve patients with PCRn≤0.8 and Kt/V≤0.9 were included in domain A of the mechanistic map. Eleven (92%) of these 12 patients were ≥ years old. No correlations were found between the total number of hospitalizations, the total days of hospitalization, Kt/V, time on HD, body weight and PCRn by multiple regression analysis, while the inverse correlation between PCRn and age was confirmed. Body weight, total serum proteins and serum albumin concentration remained stable throughout the study. However, the basal serum albumin was less in the group of patients ≥ 75 years old. We conclude that if an adequate amount of dialysis is delivered, the protein intake becomes independent of the quantity of dialysis and dependent on other factors not yet known. In this situation, the age of the patients exerts a great negative influence on PCRn, particularly in patients ≥75 years old. In the 12 patients from the whole group with Kt/V ≥0.9 and PCRn ≤0.8g/kg/day (domain A of the mechanistic map), we could find no differences in death, hospitalization rate, or duration of hospitaliza flon compared to the others. The reduced PCRn in the oldest patients does not affect body weight, total serum protein, and serum albumin concentrations over time. This suggests that these patients might do well even with less protein intake. [ABSTRACT FROM PUBLISHER]

The estimation of Kt/V by utilization of the pre- and postdialysis urea concentrations (per cent reduction in urea and In(U/U,)) provides a simple, quick technique that can be applied at the bedside. However, the accuracy of such techniques has been questioned. One possible reason for this inaccuracy may be the frequently observed postdialysis rebound in serum urea. We assessed the urea rebound at 30 min postdialysis in 34 haemodiafiltered patients and compared the calculation of Kt/V using this urea concentration with that using the immediate postdialysis concentration. These results were then compared to the Kt/V calculated by urea kinetic modelling (UKM), also utilizing the delayed serum urea concentration. The degree of urea rebound observed was large, 21.4%, being a reflection of the short-duration, rapid-flux dialysis. The formulae for calculation of Kt/V all significantly correlated with Kt/V by UKM but all gave results significantly different from Kt/V by UKM (P<0.001 by paired t test). For assessment of Kt/V by these formulae or by UKM, the urea rebound is too large to ignore in the setting of short-duration, rapid-flux dialysis. [ABSTRACT FROM PUBLISHER]

Urea Kt/V, calculated according to the variable volume single pool urea kinetic model (UKM), has been accepted as the yardstick reflecting the adequacy of haemodialysis therapy. However, the classical algorithm of UKM requires great care in dialyser urea clearance (K) measurement in order to avoid major inaccuracies in estimating the urea distribution volume (V). Thus, we suggest a modified algorithm of UKM which avoids the measurement of K. It assumes an arbitrary V value and then calculates kinetically K as a function of the assumed V value. The rationale of the modified algorithm can be derived from the knowledge that the classical algorithm imposes a proportionality ratio between K and V: given a particular set of data, a change in the attributed value of K leads to a proportional change in the calculated V value, so that the ratio K/V remains nearly constant.Aims of the study were (1) to validate the modified algorithm by comparing the resulting Kt/V and normalised protein catabolic rate (NPCR) values with the homologous ones obtained using the classical algorithm in a group of 33 patients on thrice-weekly haemodialysis; plasma water urea concentrations were used with the classical algorithm (CApw) and the modified algorithm (MApw); and (2) to verify the possibility of using plasma urea concentrations with the modified algorithm (MAp) instead of the more rigorous plasma water concentrations.NPCR (g/kg per day) was 1.33±0.05 in CApw, 1.29±0.05 in MApw and 1.28±0.04 in MAp. Kt/V was 1.27±0.03 in CApw, 1.25±0.03 in MApw and 1.26±0.03 in MAp. Statistical analysis showed no significant difference and an excellent correlation (r=0.98) of MApw and MAp vs CApw data.In conclusion, MApw and MAp are valid substitutes for CApw and allow an easy and very accurate routine monitoring of Kt/V and NPCR even in very busy haemodialysis units. [ABSTRACT FROM PUBLISHER]

The well-being and survival of dialysis patients not only depend on the removal of waste products and excess fluid, but also on the prevention of cardiovascular complications by maintaining normovolaemia and adequate blood pressure and avoidance of ectopic calcification. Also, the maintenance of nutritional status and adequate removal of middle molecules are amongst the most important issues in long-term renal replacement therapy. In this review, attention is given to optimal peritoneal small solute clearance and Kt/V and to the evidence concerning the role of residual renal function. In addition, factors that can influence this residual function are also discussed. [ABSTRACT FROM PUBLISHER]