Long thrice weekly hemodialysis: the Tassin experience.
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Adult↗
Biomedical subjects
G Jean
Publications and source records attributed to G Jean.
Role of sodium in dialysis.
The total amount of sodium present in the body conditions the extracellular compartment volume. In advanced renal failure and in dialysis the sodium balance becomes positive and the extracellular volume inflates. This leads to hypertension and to direct cardiac and vascular changes that explain for a large part the excessive cardiovascular morbidity and mortality in dialysis patients. Controlling body sodium content and extracellular volume allows to reduce hypertension, cardiovascular changes and to improve dialysis patients survival. This can be achieved by reducing the sodium input (low sodium diet and reasonably low sodium dialysate) and/or by increasing sodium output (ultrafiltration by convection in hemodialysis or hemofiltration and osmotic drive in peritoneal dialysis). The intermittent nature of hemodialysis (and hemofiltration) conditions the saw-tooth volume fluctuations that drove to conceiving and implementing the concept of a dry weight, corresponding to normal extracellular volume and blood pressure.
Blood Pressure↗
Nutritional effects of carnitine supplementation in hemodialysis patients.
AIMS: Carnitine is involved in fatty acid metabolism and it is cleared by dialysis. As it plays a role in energy utilization and because malnutrition is a frequent complication of HD treatment, we studied the effects of carnitine supplementation on several nutritional parameters in HD patients. MATERIAL AND METHODS: The main selection criterion was a body mass index (BMI; body weight/(height)2) < 22 kg/m2. Fifty-three patients were enrolled to participate in this open and randomized study. For 6 months, 28 patients received 15 mg/kg of intravenous L-carnitine at the end of each hemodialysis (HD) treatment (Group A), the remaining 25 patients were controls (Group B). The measured parameters were the post-dialysis body weight, serum albumin concentration (nephelemetry), food intake assessed by a 3-day food questionnaire, nPNA (normalized protein equivalent of nitrogen appearance), creatinine generation, and anthropometry. RESULTS: Forty-five patients completed the study (Group A: 14 F/9 M, 66.7 years old; Group B: 11 F/11 M, 65.2 years old). At the beginning of the study, there were no differences between the groups for age, gender, HD duration, BMI, diabetes prevalence, plasma carnitine levels and measured nutritional parameters. 65.2% and 77.3% in each group were carnitine-deficient (plasma total carnitine level < 35 micromol/l). After 6 months of L-carnitine supplementation, none of the nutritional parameters had changed in either group, except that serum albumin concentration decreased in both groups. Dividing each group according to their respective median serum albumin concentrations, daily energy and protein intakes, creatinine generation or triceps skinfold thickness did not show any difference in the various nutritional parameters with or without carnitine supplementation. CONCLUSION: Carnitine supplementation, despite normalization of plasma carnitine levels, has no effect on the nutritional status of HD patients.
Adult↗
Risk factor analysis for long-term tunneled dialysis catheter-related bacteremias.
Infection, mainly related to vascular access, is one of the main causes of morbidity and a preventable cause of death in hemodialysis patients. From January 1994 to April 1998 we conducted a prospective study to assess the incidence and risk factors of catheter-related bacteremia. One hundred and twenty-nine tunneled dual-lumen hemodialysis catheters were inserted percutaneously into the internal jugular vein in 89 patients. Bacteremia (n = 56) occurred at least once with 37 (29%) of the catheters (an incidence of 1.1/1,000 catheter-days); local infection (n = 45, 1/1,000 catheter-days) was associated with bacteremia in 18 cases. Death in 1 case was directly related to Staphylococcus aureus (SA) septic shock, and septicemia contributed to deaths in 2 additional cases. Catheters were removed in 48% of the bacteremic episodes. Treatment comprised intravenous double antimicrobial therapy for 15-20 days. Bacteriological data of bacteremia showed 55% involvement of SA. Nasal carriage of SA was observed in 35% of the patients with catheters. Bacteremic catheters were more frequently observed in patients with diabetes mellitus (p = 0.03), peripheral atherosclerosis (p = 0.001), a previous history of bacteremia (p = 0.05), nasal carriage of SA (p = 0.0001), longer catheter survival time (p = 0.001), higher total intravenous iron dose (p = 0.001), more frequent urokinase catheter infusion (p < 0.01), and local infection (p < 0.001) compared with non-bacteremic catheters. Monovariate survival analysis showed that significant initial risk factors for bacteremia were nasal carriage of SA (p = 0.00001), previous bacteremia (p = 0.0001), peripheral atherosclerosis (p = 0.005), and diabetes (p = 0.04). This study confirms the relatively high incidence of bacteremia with tunneled double-lumen silicone catheters and its potential complications. Possible preventive actions are discussed according to the risk factors.
Adult↗
Biological evolution of renal osteodystrophy after decreasing dialysate calcium from 1.75 to 1.6 mmol/l.
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Adult↗
Diabetes mellitus in Tassin, France: remarkable transformation in incidence and outcome of ESRD in diabetes.
The incidence and prevalence of diabetes mellitus (DM) in the dialysis population in Europe, and more especially in France, have been lagging behind the impressive United States and Japanese rates. For a decade, things have been changing, and the incidence of DM in hemodialysis (HD) reached almost 40 in Tassin, France in 1999. The prevalence has followed the same trend but increased more slowly. The increase in incidence and prevalence is almost totally accounted for by type 2 DM explosive outbreak and development. The morbidity on dialysis (hypotensive episodes, hospitalization number, and duration) was significantly worse in diabetic patients (without difference between type 1 and 2) than in nondiabetic patients. The mortality rate was higher in diabetic patients than in nondiabetic patients (mean half-life 3 and 13 years, respectively), even after adjustment for age and comorbidity. The mortality rate was higher in type 2 than in type 1 (mean half-life 2.7 and 5.2 years, respectively), a difference which disappears when adjusting for age and comorbidity. Specific causes of death were different in diabetic and nondiabetic HD patients; in diabetics there was a six-fold higher cardiovascular (CV) and three-fold higher infectious mortality, but there was the same mortality from cancer. A strong difference was observed between type 1 and type 2 DM: in type 1 there was no increased infectious mortality and a moderately increased CV mortality compared with nondiabetic patients. Type 2 diabetic patients had a four-fold increased infectious and an eight-fold increased CV mortality. Altogether, the eruption of DM in our unit over the last decade has drastically increased the crude mortality, but the standardized mortality ratio using the USRDS mortality table remained unchanged, about 45 of expected mortality.
Adult↗
Malnutrition in long-term haemodialysis survivors.
BACKGROUND: Long survival is now common in patients with end-stage renal disease owing to improvement in dialysis techniques and kidney transplantation. As malnutrition is commonly reported in dialysis patients, we evaluated the nutritional status of patients treated with haemodialysis (HD) for more than 20 years. METHODS: Ten patients (59.5 years old; 4F/6M; HD treatment for 304 months; group A) underwent an extensive nutritional examination and were compared to a control group of 10 patients treated with HD for an average of 51 months and strictly matched for age (58.6 years old), gender, and height (group B). The patients were treated on a similar basis (long-duration HD, cellulosic membranes, Daugirdas index >2). RESULTS: The body weight (BW) in group A had decreased gradually from the 11th year of HD treatment, whereas it had increased by an average of 1.9+/-4.4% since the beginning of the HD treatment in group B. The body mass index (BMI) was lower in group A (19.3 +/- 2.3 vs 21.4 +/- 2.8 kg/m(2); P = 0.05). The arm-muscle circumference (AMC), the arm-muscle area (AMA), and triceps skinfold (TSF) were lower in group A than in group B. The fat mass assessed with anthropometry (10.8 +/- 4.0 vs 14.8 +/- 4.2 kg) was significantly lower in group A. The deviation of actual BW from ideal BW (IBW) was significantly lower in group A than in group B (80.6 +/- 10.7% vs 89.6 +/- 9.0%; P = 0.028); The deviations of actual BW, TSF, and AMA from standard values of the NHANES II study were more marked in group A than in group B. On the other hand, daily energy and protein intakes (DEI and DPI) were identical in both groups and met the recommendations for dialysis patients when normalized to the actual BW. When normalized to the IBW, the DEI appeared low. Energy expenditure was not different between groups, and not different from the resting metabolism calculated from the Harris and Benedict formula. Average albumin, prealbumin, and IgF-1 were normal and not different between groups. Branched-chain amino acids (BCAA), and especially leucine, were correlated with BMI in group A but not in group B. Serum total and free carnitine were low in both groups. Three patients had ascorbic acid deficiency in group A but none in group B. CONCLUSIONS: Hence, despite adequate dialysis dose and protein intake, patients treated with HD for a long period of time became malnourished, whereas the classical nutritional markers remained in normal ranges. Among the potential causes leading to malnutrition, inadequate energy intake and micronutrient deficiencies were found in these patients.
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Long-term outcome of permanent hemodialysis catheters: a controlled study.
AIMS: Hemodialysis tunneled catheters are widely used nowadays. However, their complications, infection and dysfunction, remain much too frequent. Different types of tunneled silicone hemodialysis catheters are available. We prospectively compared the long-term outcome of the two most popular devices, Permcath cuffed double catheter and TwinCath uncuffed twin catheter, both inserted percutaneously. METHODS: From January 1994 to April 1998, 125 tunneled catheters were inserted in the internal jugular vein of 86 chronic hemodialysis patients, 63 TwinCath MedComp (TC) and 62 Permcath Quinton (PC). They were prospectively followed looking for technical patency, infection and dysfunction rate. RESULTS: TC were used more often for iterative access (52 vs. 25%, p = 0.01) and were inserted more frequently in the left internal jugular vein (59 vs. 16% p < 0.001). Their median technical survival rate was longer (869 vs. 433 days for PC, p < 0.01) with a 1-year patency rate of 80 vs. 53% (p = 0.002). Total catheter extrusion was also slightly less frequent with TC (4.7 vs. 9.6%), but partial extrusion happened more frequently (43 vs. 16%, p = 0.02). No significant difference in infection rate was observed, 0.77 for TC vs. 1.3 local infection/1,000 catheter days; 1.08 vs. 1.30 bacteremia/1,000 catheter days. A persistent catheter thrombosis was observed in 7.9 vs. 20.9% in PC (p = 0.04), the number of dysfunction was 10.5 vs. 24/1,000 days in use (p = 0.0001) and the number of urokinase infusion was 4.4 vs. 12/1,000 days (p = 0.001). PC needed more radiological interventions for dysfunction with endolumenal brushes (4 vs. 0) or fibrin sleeve removal (4 vs. 0). The vena cava thrombosis incidence was not different (2 vs. 3). CONCLUSION: Although the study was not randomized, TC appears more efficient allowing for a longer patency with a lower dysfunction rate than PC. This was reinforced by less favorable conditions of TC including more left jugular side and more iterative catheters. The cuff does not offer a better bacteriological barrier or protection against extrusion, and the TC seems at a less risk of fibrin sleeves. However, a large randomized study is needed to definitively conclude.
Adult↗
[Incidence and risk factors for infections from hemodialysis catheters].
We report here a revue of hemodialysis catheter-related infections data published since 1985. The reported prevalence of bacteremia is 1 to 20% of catheters, and incidence is 0.72 to 9/1000 catheter-days. Local infection is reported in 6 to 63% of catheters and in 1 to 5/1000 catheter-days. Tunneled catheters and implantables chambers reported less infection rate. The most severe complication is endocarditis (4% rate). Death occurs in 8 to 20% of cases. Reported microbial data show that Staphylococcus aureus (SA) is responsible for most infections ahead of non-aureus Staphylococcus. SA skin colonisation is a risk factor for catheter colonisation and the first step of infection. On the other hand, the host immunity impairment in hemodialysis patients seems a significant risk factor. Iron overload, specially after blood transfusions, older age, diabetes mellitus, low serum albumin level, previous history of bacteremia and immunosuppressive treatment have been frequently involved. Other catheter-related factors are time of use, absence of tunnel and use for parenteral nutrition. Nurses plans, dressing type and frequency, nurses work experience are also important. In spite of recent progress in risk factor understanding, hemodialysis-related infection remains frequent. Multicentre studies are necessary to better evaluated care protocols and new catheter material.
Bacteremia↗
[Prevalence of stenosis and thrombosis of central veins in hemodialysis after a tunneled jugular catheter].
Central venous stenosis (ST) and thrombosis (TB) related to catheter (KT) had been reported mostly for the subclavian vein. We performed a systematic cavographic study to evaluate the prevalence of these complications in 51 hemodialysis patients with present or previous history of tunneled internal jugular catheter. Each of them had used one or several KT (1.8 +/- 1.4 KT) for a mean 28 +/- 26 month cumulative time (i.e. 43,584 days total exposure time). Fifty percent of the KT were PermCath Quinton and 50% were Twincath (uncuffed) or CS 100 (cuffed) Medcomp. Twenty-seven had no ST (53%, group I), 24 had one or several significant ST (47%, group II) of superior Vena Cava (SVC, n = 4), inferior Vena Cava (IVC, n = 1), Brachio-cephalic Vein (BCV, n = 5) and subclavian vein (SC, n = 10), or a TB of SVC (n = 1), IVC (n = 3), BCV (n = 3), SC (n = 2). This accounts for an incidence of 0.55 ST or TB/1000 patient-days. Five of the twelve subclavian ST and TB had no history of previous subclavian catheter. Comparison between the two groups showed no differences according to age, time on dialysis, diabetes, hematocrit, CRP, cumulative time with catheter, catheter-related infections, type of catheter and anticoagulant treatment. IVC catheter tip's position is an important risk factor for TB and ST (4/6). Twelve group II patients had ST or TB-related symptoms, with a functional AV fistula in 9 cases. Eleven patients underwent repeated percutaneous angioplasty with 4 additional Wallstents and in 2 cases an AV fistula need to be closed. Central venous ST and TB after a jugular KT is extremely frequent, mostly without any symptoms. Consequences on peripheral or central vascular access, cost and poor long-term patency rate of angioplasty are of major importance. These results incite us to further reduce the catheter use in dialysis patients.
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Quest for postdialysis urea rebound-equilibrated Kt/V with only intradialytic urea samples.
BACKGROUND: Postdialysis urea rebound (PDUR) is a cause of Kt/V overestimation when it is calculated from predialysis and the immediate postdialysis blood urea collections. Measuring PDUR requires a 30- or 60-minute postdialysis sampling, which is inconvenient. Several methods had been devised for a reasonable approach to determine PDUR-equilibrated Kt/V in short dialysis without the need for a delayed sample. The aim of our study was to compare these different Kt/V methods during the longer eight-hour hemodialysis sessions, and to determine the optimum intradialytic urea sample time that fits best with PDUR. METHODS: The study included 21 patients (mean age 71.9 years) who were hemodialyzed for 60+/-60 months at three times eight hours weekly, using bicarbonate dialysate and cellulosic membranes. Blood urea samples were obtained at onset, and then at 17, 33, 50, 66, 75, 80, 85, and 100% of the dialysis session times, after 30 seconds of low flow, and then at 60-minutes postdialysis. All patients had a meal during dialysis. We compared four different formulas of Kt/V [(a) Kt/V-Smye with a 33% dialysis time urea sample, (b) two-pool equilibrated eKt/V, (c) Kt/V-std (Daugirdas-2) obtained with an immediate postdialytic sample, and (d) the different intradialytic urea samples for Kt/V (50, 66, 75, 80, and 85% of dialysis time)] with the equilibrated 60-minute PDUR Kt/V (Kt/V-r-60) formula as the reference method. RESULTS: The mean PDUR was 17.2+/-9%, leading to an overestimation of Kt/V-std by 12.2%. Kt/V-r-60 was 1.68+/-0.34. Kt/V-std was 1.88+/-0.36 (Delta = 12.2+/-4.8%, r = 0.8). eKt/V was 1.77+/-0.3 (Delta = 5+/-5%, r = 0.96), and Kt/V-Smye was 1.79+/-0.47 (Delta = 5.2+/-14%, r = 0.9). The best time for the intradialytic sampling was 80% (that is, at 6 hr and 24 min). The Kt/V-80 was 1.64+/-0.3 and was best fitted with Kt/V-r-60 (Delta = -1.8+/-8%, r = 0.91). The mean intradialytic urea evolution showed a three-exponential rate, in discrepancy with the two-exponential rate theoretical model. CONCLUSIONS: These results confirm that a significant postdialysis rebound exists in an eight-hour dialysis. An intradialytic urea sample taken at 80% of the total session time permits an estimation of the 60-minute Kt/V-rebound without the necessity of taking a delayed sample, with better accuracy than eKt/V or especially Kt/V-Smye. This may be related to a particular urea kinetics curve on the longer dialysis duration, which needs to be studied further.
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Molecular characterization of CTNS deletions in nephropathic cystinosis: development of a PCR-based detection assay.
Nephropathic cystinosis is an autosomal recessive disorder that is characterized by accumulation of intralysosomal cystine and is caused by a defect in the transport of cystine across the lysosomal membrane. Using a positional cloning strategy, we recently cloned the causative gene, CTNS, and identified pathogenic mutations, including deletions, that span the cystinosis locus. Two types of deletions were detected-one of 9.5-16 kb, which was seen in a single family, and one of approximately 65 kb, which is the most frequent mutation found in the homozygous state in nearly one-third of cystinotic individuals. We present here characterization of the deletion breakpoints and demonstrate that, although both deletions occur in regions of repetitive sequences, they are the result of nonhomologous recombination. This type of mechanism suggests that the approximately 65-kb deletion is not a recurrent mutation, and our results confirm that it is identical in all patients. Haplotype analysis shows that this large deletion is due to a founder effect that occurred in a white individual and that probably arose in the middle of the first millenium. We also describe a rapid PCR-based assay that will accurately detect both homozygous and heterozygous deletions, and we use it to show that the approximately 65-kb deletion is present in either the homozygous or the heterozygous state in 76% of cystinotic patients of European origin.
Alleles↗
Severity of phenotype in cystinosis varies with mutations in the CTNS gene: predicted effect on the model of cystinosin.
Infantile nephropathic cystinosis is a rare, autosomal recessive disease caused by a defect in the transport of cystine across the lysosomal membrane and characterized by early onset of renal proximal tubular dysfunction. Late-onset cystinosis, a rarer form of the disorder, is characterized by onset of symptoms between 12 and 15 years of age. We previously characterized the cystinosis gene, CTNS, and identified pathogenic mutations in patients with infantile nephropathic cystinosis, including a common, approximately 65 kb deletion which encompasses exons 1-10. Structure predictions suggested that the gene product, cystinosin, is a novel integral lysosomal membrane protein. We now examine the predicted effect of mutations on this model of cystinosin. In this study, we screened patients with infantile nephropathic cystinosis, those with late-onset cystinosis and patients whose phenotype does not fit the classical definitions. We found 23 different mutations in CTNS; 14 are novel mutations. Out of 25 patients with infantile nephropathic cystinosis, 12 have two severely truncating mutations, which is consistent with a loss of functional protein, and 13 have missense or in-frame deletions, which would result in disruption of transmembrane domains and loss of protein function. Mutations found in two late-onset patients affect functionally unimportant regions of cystinosin, which accounts for their milder phenotype. For three patients, the age of onset of cystinosis was <7 years but the course of the disease was milder than the infantile nephropathic form. This suggests that the missense mutations found in these individuals allow production of functional protein and may also indicate regions of cystinosin which are not functionally important.
Age of Onset↗
The Janus-faced aspect of 'dry weight'.
BACKGROUND: The goal of haemodialysis treatment in end-stage renal disease (ESRD) patients is to correct the complications of the uraemic condition. Among the main complications are fluid overload and subsequent hypertension that are corrected by achievement of 'dry weight'. We report in this study the evolution of post-dialysis body-weight and blood pressure in patients who began their HD treatment in our unit. METHODS: We studied the monthly evolution of post-dialysis body-weight (expressed as a percentage of pre-dialysis body-weight at the first HD treatment) and predialysis mean arterial pressure (MAP) over 24 months in 61 patients (21 females, mean age 59.8 years; 20% diabetic), treated with cellulosic membranes for 8 h, 3 times a week. RESULTS: The post-dialysis body-weight decreased between the onset of HD and month 2 (M2) (-4.40+/-0.52%). Then it went up, reaching -1.56+/-0.96% at M6, +0.3+/-1.27% at M12, +1.27+/-1.38% at M18 and +1.64+/-1.33% at M24. The post-dialysis body-weight increased by 6% between M2 and M24. The mean arterial pressure (MAP) decreased from 111.3+/-2.5 mmHg at M0 to 94.4+/-1.7 at M6, and then remained stable after M6. Between M2 and M6 the post-dialysis body-weight increased, whereas the predialysis MAP continued to decline. The incidence of hypotension episodes was maximal during the first 4 months of HD treatment. CONCLUSIONS: After the second month of dialysis treatment, the simultaneous increase of post-dialysis body-weight and decrease of pre-dialysis MAP are related to the effects of two processes, i.e. increased weight as the result of anabolism induced by the HD treatment on the one hand and normalization of blood pressure by fluid removal on the other. Continuous clinical assessment of the patient is necessary to provide adequate prescription of post-dialysis body-weight. During the first months of HD treatment, the nephrologist, like Janus, is a double-faced gatekeeper: he must be willing to decrease post-dialysis weight to achieve 'dry weight' and to normalize blood pressure, but he must also be prepared to increase it to compensate for anabolism and to avoid episodes of hypotension.
Analysis of Variance↗
Hemodialysis trends in time, 1989 to 1998, independent of dose and outcome.
The 1989 Morbidity, Mortality, and Prescription of Dialysis Symposium (Dallas, TX) deeply modified the way of prescribing and delivering hemodialysis (HD) in the United States, as elsewhere. Among strategies emerging for end-stage renal disease treatment improvement, increasing the delivered dose has been the central issue, whereas the session time effect has remained an unsettled question. The purpose of this article is to analyze the trends in HD session time over the last decade in Tassin, France, and elsewhere and their relationship to outcome, independent of dialysis dose. The published data indicate that in the United States, there has been an increase in session time. Outside the United States, where session time had been somewhat longer, there has been either no change or a decrease in time without apparent ill effects. The dialysis dose, as measured by the urea Kt/V, has increased everywhere because improved technology allows for efficient toxin removal within a very short dialysis session. In Tassin, a recent limited experience of high-dose shortened dialysis did not show a significant short-term survival difference, but an impaired control of blood pressure (BP) and nutrition. Thus far, the highest HD long-term survival rates have been reported by the groups that used the largest doses and the longer times of HD. Effects of dose and time are, at this point, impossible to disentangle. A longer dialysis time improves extracellular volume (ECV) and BP control and decreases cardiovascular mortality. Shortening the HD session leads to impaired control of BP and increasing cardiovascular morbidity (by far the first cause of mortality on HD). In the future, the length of dialysis session should be governed by the demand of BP control.
France↗
A novel gene encoding an integral membrane protein is mutated in nephropathic cystinosis.
Nephropathic cystinosis, an autosomal recessive disorder resulting from defective lysosomal transport of cystine, is the most common inherited cause of renal Fanconi syndrome. The cystinosis gene has been mapped to chromosome 17p13. We found that the locus D17S829 was homozygously deleted in 23 out of 70 patients, and identified a novel gene, CTNS, which mapped to the deletion interval. CTNS encodes an integral membrane protein, cystinosin, with features of a lysosomal membrane protein. Eleven different mutations, all predicted to cause loss of function of the protein, were found to segregate with the disorder.
Amino Acid Sequence↗
Is post-dialysis urea rebound significant with long slow hemodialysis?
BACKGROUND: According to previous studies, postdialysis urea rebound (PDUR) is achieved within 30-90 min, leading to an overestimation of Kt/V of between 15 and 40% in 3- to 5-hour dialysis. The purpose of the study was to assess the impact of PDUR on the urea reduction ratio (URR), Kt/V and normal protein catabolic rate (nPCR) with long 8-hour slow hemodialysis. METHODS: This study was performed in 18 patients (13 males/5 females), 62.5 +/- 11.7 years of age, hemodialyzed for 3-265 months. Initial nephropathies were: 3 diabetes; 2 polycystic kidney disease; 3 interstitial nephritis; 2 nephrosclerosis; 3 chronic glomerulonephritis, and 5 undetermined. Residual renal function was negligible. The dialysis sessions were performed using 1- to 1.8-m2 cellulosic dialyzers during 8 h, 3 times a week. Blood flow was 220 ml/min, dialysate flow 500 ml/min, acetate or bicarbonate buffer was used. Serial measurements of the urea concentration were obtained before dialysis, immediately after dialysis (low flow at t = 0), and at 5, 10, 20, 30, 40, 60, 90 and 120 min, and before the next session. The low-flow method was used to evaluate the access recirculation, second-generation Daugirdas formulas for Kt/V, and Watson formulas for total body water volume estimation. The difference between the expected urea generation (UG) and urea measured after dialysis (global PDUR) defines net PDUR (n-PDUR). RESULTS: The n-PDUR usually became stable after 58 +/- 25 (30-90) min. Its mean value was 17 +/- 10% of the 30-second low-flow postdialysis urea (3.9 +/- 2 mmol/l). This small postdialysis urea value and the importance of UG in comparison with shorter dialysis justify the use of n-PDUR. Ignoring n-PDUR would lead to a significant 4% overestimation (p < 0.001) of the URR (79 +/- 7 vs. 76 +/- 8%), 12% of Kt/V (1.9 +/- 0.4 to 1.7 +/- 0.38) and 4% of the nPCR (1.1 +/- 0.3 to 1.05 +/- 0.3). n-PDUR correlated negatively with postdialysis urea (r = 0.45 p = 0.05), positively with URR (r = 0.31 p = 0.01) and Kt/V (r = 0.3 p = 0.03) but not with K, and negatively with the urea distribution volume (r = 0.33 p = 0.05). Mean total recirculation, ultrafiltration rate, predialysis urea levels and urea clearance did not correlate with n-PDUR. CONCLUSION: We found a significant PDUR in long-slow hemodialysis after a mean of 1 h after dialysis. This PDUR has a less important impact upon dialysis delivery estimation than short 3- to 5-hour hemodialysis, especially for the lower Kt/V or URR ranges. This is explained by the low-flux, high-efficiency, and long-term dialysis. Its inter-individual variability incites us to calculate PDUR on an individual basis.
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