Evaluation of pre- and postdilutional on-line hemodiafiltration adequacy by partial dialysate quantification and on-line urea monitor.

On-line highflux hemodiafiltration (HDF) is a clinically interesting and effective mode of renal replacement therapy, which offers the possibility to obtain an increased removal of both small and large solutes. The fundamental role of urea kinetic monitoring to assess dialysis adequacy in conventional hemodialysis has been widely studied. Both direct measurement of the urea removed by the modified direct dialysate quantitation (mDDQ) based on partial dialysate collection (PDC) and dialysate-based urea kinetic modeling (DUKM) using urea monitor have been advocated. The validity of this assessment tool in the patients with on-line HDF remained unclear. The aims of this investigation were (1) to compare the delivered Kt/V, urea mass removal (UMR), solute removal index (SRI) and normalized protein catabolic rate (nPCR) between pre- and postdilutional high-flux HDF; (2) to verify and compare the efficiency of pre- and postdilutional HDF using DUKM with on-line dialysate urea sensor, and mDDQ with partial dialysate collection. During both mode of HDF, the paired analysis urea removed and Kt/V showed no significant difference. Using mDDQ, mean values for predilutional mode were as follows: Kt/V 1.53 +/- 0.01 UMR, 16.8 +/- 0.3 g/session; urea clearance 178 +/- 18 ml/min; SRI 75.5 +/- 7.7%; urea distribution volume (V) 28.3 +/- 1.2 liters; nPCR 1.34 +/- 0.18 g/kg/day; on the other hand, mean values for postdilutional mode were Kt/V 1.58 +/- 0.01; UMR 17.10 +/- 0.28 g/session; urea clearance 184 +/- 21 ml/min; SRI 77.2 +/- 3.5%; urea distribution volume, 27.8 +/- 1.5 liters; nPCR 1.34 +/- 0.19 g/kg/day. The mean value of urea generation rate was 5.82 +/- 1.12 mg/min during HDF. Our results showed that dialysis adequacy was achieved with both high-volume predilutional HDF and postdilutional HDF. These two modes of HDF provided similar and adequate small solute clearance. In addition, we found that on-line analysis of urea kinetics is a reliable tool for quantifying and assuring delivery of adequate dialysis.     

透析液流量对血液透析充分性的影响

目的：观察增加透析液流量（Qd）对维持性血液透析（MHD）患者透析充分性的影响。方法：随机选择稳定透析6个月以上的MHD患者38例。血透透析液流量定于500ml／min和800ml／min各透析4周，其他透析参数[透析时间，血流量（Qb），超滤量和透析器型号与面积]不变。每种Qd量于第3周和第4周分别测定透析前后血尿素氮（BUN）、血肌酐（SCr）水平，记录每次透析的透析时间、超滤量及透析后体重（W），并根据Kt／V的自然对数公式计算Kt／V、尿素下降率（URR），取2次测定值的平均值作为患者该透析液流量的Kt／V。同时检测第4周及第8周透析前的血红蛋白（Hb）和红细胞压积（Hct）水平。采用成对t检验和卡方检验进行统计学分析。结果：本研究中每例患者构成自身对照，研究前后一般情况完全一致。Qd为800ml／min时URR及Kt／V值均较Qd流量为500ml／min时增加，具有统计学意义（P〈0．05），而SCr下降率、Hb和Hct水平略有增加趋势，无显著性差异。Qd为800ml／min时透析后URR〉65％的百分数明显高于Qd为500ml／min时，具有显著统计学意义（P〈0．001）。结论：将Qd从500ml／min增加至800ml／min，可显著增加URR、增加Kt／V，提高透析充分性达标率。800ml／min透析液流量的MHD可选择性用于不便于延长治疗时间和提高血流量达到透析充分性的患者。     

Ionic dialysance and quality control in hemodialysis

Quantification of dialysis is based on the measurement of effective urea clearance (K), dialysis dose (Kt) or normalized dialysis dose (Kt/V). During the last 20 years, Kt/V was the single parameter actually useful for quantifying dialysis efficiency, because it can be calculated from just blood or dialysate urea concentrations at the beginning and at the end of the dialysis session. However the calculation of the normalized dialysis dose (Kt/V) actually delivered to the patient cannot be performed during each dialysis session, because of the need of urea concentration measurements. Ionic dialysance is a new parameter easily measured on-line, non-invasively, automatically and without any cost during each dialysis session by a conductivity method. Because ionic dialysance has been proved equal to the effective urea clearance taking into account cardiopulmonary and access recirculation, it is becoming an actual quality-assurance parameter of the dialysis efficiency.     

Kt as control and follow-up of the dose at a hemodialysis unit

To ensure our patients are receiving an adequate dose in every dialysis session there must be a target to achieve this in the short or medium term. The incorporation during the last years of the ionic dialysance (ID) in the monitors, has provided monitoring of the dialysis dose in real time and in every dialysis session. Lowrie y cols., recommend monitoring the dose with Kt, recommending at least 40 L in women and 45 L in men or individualizing the dose according to the body surface area. The target of this study was to monitor the dose with Kt in every dialysis session for 3 months, and to compare it with the monthly blood test. 51 patients (58% of our hemodialysis unit), 32 men and 19 women, 60.7+/-14 years old, in the hemodialysis programme for 37.7+/-52 months, were dialysed with a monitor with IC. The etiology of their chronic renal failure was: 3 tubulo-interstitial nephropathy, 9 glomerulonephritis, 12 vascular disease, 7 polycystic kidney disease, 7 diabetic nephropathy and 13 unknown. 1,606 sessions were analysed during a 3 month period. Every patient was treated with the usual parameters of dialysis with 2.1 m2 cellulose diacetate (33.3%), 1.9 m2 polisulfone (33.3%) or 1.8 m2 helixone, dialysis time of 263+/-32 minutes, blood flow of 405+/-66, with dialysate flow of 712+/-138 and body weight of 66.7+/-14 kg. Initial ID, final ID and Kt were measured in each session. URR and Kt/V were obtained by means of a monthly blood test. The initial ID was 232+/-41 ml/min, the final ID was 197+/-44 ml/min, the mean of Kt determinations was 56.6+/-14 L, the mean of Kt/V was 1.98+/-0.5 and the mean of URR was 79.2+/-7%. Although all patients were treated with a minimum recommended dose of Kt/V and URR when we used the Kt according to gender, we observed that 31% of patients do not get the minimum dose prescribed (48.1+/-2.4 L), 34.4% of the men and 26.3% of the women. If we use the Kt individualized for the body surface area, we observe that 43.1% of the patients do not get the minimum dose prescribed with 4.6+/-3.4 L less than the dose prescribed. We conclude that the monitoring of dialysis dose with the Kt provides a better discrimination detecting that between 30 and 40% of the patients perhaps do not get an adequate dose for their gender or body surface area.     

Long-term on-line hemodiafiltration reduces predialysis beta-2-microglobulin levels in chronic hemodialysis patients

BACKGROUND: Hemodiafiltration (HDF) is effective in delaying the surgical need for carpal tunnel syndrome in chronic hemodialysis patients, however, predialysis beta(2)-microglobulin levels were not reduced in most short-term studies. The aim of this study was to assess the effect of long-term and differing frequencies of on-line HDF on serum beta(2)-microglobulin levels in comparison to high-flux hemodialysis (HD). METHODS: One hundred and twelve patients in the Chang Gung Memorial Hospital Dialysis Unit were divided into three groups to receive different frequencies of on-line HDF alternating with high-flux HD. Group 1 was treated once with HDF and twice with high-flux HD per week (n = 21). Group 2 was treated twice with HDF and once with high-flux HD per week (n = 33). Group 3 was treated with HDF three times per week (n = 58). Analysis was performed to compare the serum beta(2)-microglobulin levels in these groups and to high-flux HD. RESULTS: After receiving HDF for a mean of 7.9 months, group 3 patients had a reduced predialysis beta(2)-microglobulin level (22.2 +/-5.3 vs. 34.8 +/-6.3 mg/l, p < 0.001), postdialysis beta(2)-microglobulin level (6.3 +/- 2.0 vs. 13.8 +/- 6.8 mg/l, p < 0.001) and an increased beta(2)-microglobulin reduction rate (76.1 +/- 5.6 vs. 61.1 +/- 13.3%, p = 0.03) when compared to high-flux HD. A significant improvement in URR (p = 0.0004), Kt/V (p = 0.0002) and TAC urea levels (p = 0.006) but not nPCR (p = 0.122) was found after patients had been treated with on-line HDF. The beta(2)-microglobulin reduction rate was positively correlated with the overall volume of the replacement solution per session (p < 0.0001). Patients in group 3 had lower predialysis beta(2)-microglobulin levels than those in group 1 and group 2 (22.2 +/- 5.3 vs. 25.2 +/- 7.2 vs. 26.0 +/- 4.2 mg/l, p = 0.02). Furthermore, an inverse correlation was found between the predialysis beta(2)-microglobulin level and the duration of HDF, if patients were treated for more than 12 months (p = 0.031). CONCLUSION: On-line HDF has an increased dialysis efficiency compared to high-flux dialysis. Long-term HDF further reduced predialysis beta(2)-microglobulin levels, thus, it may provide an improved modality for renal replacement therapy.     

Effect of hemodialysis and hemodiafiltration on uremic neuropathy.

This study was undertaken to compare the effect of 1 year hemodialysis (HD) or hemodiafiltration (HDF) treatment on peripheral neuropathy. Thus 21 of 42 patients on chronic HD (1-1.3 m2 cuprophane dialyzer, Qb 300 ml/min) were switched to HDF (1.3 m2 polysulfone dialyzer, Qb 400 ml/min, substitution volume 9-13 liters, ultrafiltration rate 60-70 ml/min), while the remaining patients were considered as a control group. Treatment time was scheduled both in HD and HDF to maintain adequate BUN levels in relation to protein catabolic rate. However, HDF provided a significantly greater weekly inulin (MW 5,000) clearance than HD (5.8 +/- 1.2 vs. 1.6 +/- 0.2 ml/min; p less than 0.001). HD and HDF groups were comparable for age, time on dialysis and starting electroneurographic parameters, which were on average within the normal range. After 1 year follow-up, creatinine, hematocrit, calcium, phosphate, PTH, BUN, protein catabolic rate and residual GFR were comparable in the two groups, whereas beta 2-microglobulin was significantly reduced in HDF patients (29 +/- 6.7 vs. 38.8 +/- 13.9 mg/l in HD patients, p less than 0.01). During the 1-year treatment, electroneurographic parameters did not change in HDF patients, whereas a significant decrease of ulnar motor nerve conduction velocity, ulnar muscle action potential amplitudes, median sensory nerve conduction velocity and peroneal muscle action potential amplitudes was detected in HD patients. We conclude that HDF might prevent the worsening of the electroneurographic indices occurring during chronic HD treatment, as it provides a more effective removal of middle and larger molecules than HD. The use of a more biocompatible membrane in HDF might further contribute to this favorable effect on uremic neuropathy.     

Mathematical analysis of urea rebound in long-term hemodialysis patients

Quantifying hemodialysis (HD) treatment requires knowledge of the equilibrated concentrations of the post-HD small molecule rebounds. However, measurement of the equilibrated concentrations is only possible after resting in bed after HD for at least 30 min, and this is often impractical. Therefore, we have analyzed mathematically the time course of post-HD urea rebound, and from this, have derived a new formula for predicting its equilibrated concentration. The blood urea nitrogen (BUN) was measured at 10 time points (immediately following HD, and 0.5, 2.5, 5, 7.5, 10, 15, 20, 25, and 30 min post-HD) in 12 anuric HD patients. The absolute change in the urea rebound (DeltaeqBUN) was approximated (DeltaestBUN) using the equation: DeltaestBUN = b -[1-exp x (-c x time (min))] + a x time (min). After the good correlation between DeltaeqBUN and DeltaestBUN, we compared the value of DeltaeqBUN measured at 30 min (DeltaeqBUN(30)) with that calculated (DeltaestBUN(30)) using only four sample points (immediately following HD, and 2.5, 5 and 10 min post-HD). Based on this result, we tried to predict post-HD BUN at 30 min (estBUN(30)). This study was undertaken to determine whether estBUN(30) may be representative of the equilibrated BUN (eqBUN(30)), and to compare with Kt/V using estBUN(30) and eqBUN(30). There was a significant correlation between DeltaeqBUN and DeltaestBUN (0.97 < r < 0.99, P < 0.001). Thus, there was a significant positive linear correlation between eqBUN(30) and estBUN(30) (eqBUN(30): 25.7 +/- 2.25 mg/dL, estBUN(30): 26.3 +/- 2.31 mg/dL; r(2) = 0.99, P < 0.001). A Kt/V measurement was obtained with single pool model using BUN just after HD (Kt/V(sp)), eqBUN(30) (Kt/V(eq)), and estBUN(30) (Kt/V(est)), and with double pool model using Kt/V(sp) (Kt/V(dp)) and was compared with them. Though Kt/V(sp) was significantly higher than Kt/V(eq) (1.26 +/- 0.08 vs. 1.09 +/- 0.07, P < 0.001), there were no differences among Kt/V(eq), Kt/V(est) and Kt/V(dp) (Kt/V(est): 1.06 +/- 0.07, Kt/V(dp): 1.10 +/- 0.07) and all values were clinically acceptable. Furthermore, there was a significant positive linear correlation between Kt/V(eq) and Kt/V(est) (r(2) = 0.98, P < 0.001). In conclusion, we have devised the method to predict equilibrated BUN and calculate double pool Kt/V, which requires samples up to 10 min post-HD.     

Conventional blood sampling versus On-Line Clearance Monitoring

On-line Clearance Monitoring (OCM) calculates the Kt/V during a dialysis session using a module incorporated into the Fresenius 4008 H/S haemodialysis machine (1). The method is based on repeated increments in dialysate sodium concentrations followed by measuring the change of dialysate sodium concentration after the dialysate has passed through the kidney. OCM is a patient friendly, non-invasive and easy method for measuring Kt/V. Kt/V calculated on single-pool urea kinetics according to Daugirdas was compared to Kt/V measured by OCM in thirty stable patients on chronic haemodialysis. Patients were dialysed using a dialyser with either a high-flux polysulfone or a haemophane membrane. In four patients OCM was measured in ten consecutive sessions to assess the intra-individual variation in OCM. The calculated Kt/V was compared to Kt/Vocm in three patients at five consecutive dialysis sessions to measure the intra-individual correlation. A linear correlation was present between Kt/Vocal and Kt/Vac for both the polysulfone and haemophane membrane. Intra-individual Kt/Vocm showed very stable values with an average variation of less than 5%. Intra-individual correlation between calculated Kt/V and Kt/Vocm was high.     

Improved iron utilization and reduced erythropoietin resistance by on-line hemodiafiltration

BACKGROUND: Recent investigation has shown that on-line hemodiafiltration (HDF) can reduce the amount of recombinant human erythropoietin (rhEPO) deemed necessary to reach the target hematocrit. The aim of this study was to analyze the potential effect of on-line HDF on rhEPO resistance in relation to iron utilization and anemia-related parameters, when compared to conventional hemodialysis (HD). METHODS: Ninety-two chronic uremic patients were treated with conventional HD and then shifted to on-line HDF. Measurements of various erythropoiesis-related parameters were collected during HD and on-line HDF periods for statistical analysis for erythropoietin resistance. RESULTS: Patients treated with on-line HDF switching from conventional HD significantly contributed to the reduction of EPO dose to reach a higher mean hematocrit level (31.8 +/- 4.4% vs. 29.5 +/- 3.9%, p < 0.001) and a reduction of the serum ferritin level (322.5 +/- 268.4 vs. 544.9 +/- 642.4, p < 0.001). The median EPO/Hct ratio was greater in the HD period (504.6 +/- 310.1) than in the on-line HDF period (307.6 +/- 334.4) (p < 0.001). These results indicated a reduced EPO resistance and improved iron utilization by on-line HDF. By multiple regression analysis, the significant predictors of EPO resistance are ferritin, transferrin, albumin, and TACurea (Time average concentration of urea) in HD treatment. In on-line HDF modality, in addition to ferritin and albumin, the duration of on-line HDF is a negative predictor in EPO resistance. CONCLUSION: When on-line HDF is recommended to chronic dialysis patients, long-term use of this technique provides an efficient means of achieving the goal of an elevated hemoglobulin by reducing EPO resistance, improved iron utilization and may further improve the quality of life.     

ON‐LINE CLEARANCE MONITORING FOR BLOOD ACCESS MANAGEMENT

On‐line Clearance Monitoring (OCM) provides frequent and precise information about urea clearance values during haemodialysis. In the case of blood access recirculation, it is presumed that urea clearance values on OCM would be lower and suspect to blood access malfunction. In order to check the relation between significantly lower urea clearance values and blood access recirculation, the Kt value (Clearance × time/min) for fifteen patients on OCM, including the patients with a low Kt/V in spite of their small urea distribution volume (V) was observed. Average urea clearance was calculated indirectly using Kt value (Kt/time in minutes = average clearance ml/min) and blood access recirculation tests performed using slow/stop flow two‐needle, three samples method (urea method). After comparison of the recirculation percentage to clearance value, positive correlation between high recirculation and clearance reduction was noted. OCM alongside detection of haemodialysis inefficiency is also a practical instrument for blood access management between regular monitoring. Lower OCM urea clearance values demonstrate a possible blood access problem that can be confirmed with another method. When an OCM urea clearance reading is decreased by more than 25%, undiscovered access recirculation can be suspected.     

On-line clearance monitoring for blood access management

On-line Clearance Monitoring (OCM) provides frequent and precise information about urea clearance values during haemodialysis. In the case of blood access recirculation, it is presumed that urea clearance values on OCM would be lower and suspect to blood access malfunction. In order to check the relation between significantly lower urea clearance values and blood access recirculation, the Kt value (Clearance x time/min) for fifteen patients on OCM, including the patients with a low Kt/V in spite of their small urea distribution volume (V) was observed. Average urea clearance was calculated indirectly using Kt value (Kt/time in minutes = average clearance ml/min) and blood access recirculation tests performed using slow/stop flow two-needle, three samples method (urea method). After comparison of the recirculation percentage to clearance value, positive correlation between high recirculation and clearance reduction was noted. OCM alongside detection of haemodialysis inefficiency is also a practical instrument for blood access management between regular monitoring. Lower OCM urea clearance values demonstrate a possible blood access problem that can be confirmed with another method. When an OCM urea clearance reading is decreased by more than 25%, undiscovered access recirculation can be suspected.     

Evaluation of methods to calculate dialysis dose in daily hemodialysis

Daily dialysis has shown excellent clinical results because a higher frequency of dialysis is more physiological. Different methods have been described to calculate dialysis dose which take into consideration change in frequency. The aim of this study was to calculate all dialysis dose possibilities and evaluate the better and practical options. Eight patients, 6 males and 2 females, on standard 4 to 5 hours thrice weekly on-line hemodiafiltration (S-OL-HDF) were switched to daily on-line hemodiafiltration (D-OL-HDF) 2 to 2.5 hours six times per week. Dialysis parameters were identical during both periods and only frequency and dialysis time of each session were changed. Time average concentration (TAC), time average deviation (TAD), normalized protein catabolic rate (nPCR), Kt/V, equilibrated Kt/V (eKt/V), equivalent renal urea clearance (EKR), standard Kt/V (stdKt/V), urea reduction ratio (URR), hemodialysis product and time off dialysis were measured. Daily on-line hemodiafiltration was well accepted and tolerated. Patients maintained the same TAC although TAD decreased from 9.7 +/- 2 in baseline to a 6.2 +/- 2 mg/dl after six months, p < 0.01. No significant changes were observed in weekly Kt/V and eKt/V throughout the study. However EKR, stdKt/V and weekly URR were increased during D-OL-HDF in 24-34%, 46% and 50%, respectively. Hemodialysis product was raised in a 95% and time off dialysis was reduced to half. CONCLUSION: Dialysis frequency is an important urea kinetic parameter which there are to take in consideration. It's necessary to use EKR, stdKt/V or weekly URR to calculate dialysis dose for an adequate comparison between different frequency dialysis schedules.     

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

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

Determination of the dose of dialysis with integrated modules in the same monitor

The "gold standard" method to measure the mass balance achieved during dialysis for a given solute is based on the total dialysate collection. This procedure is unfeasible and too cumbersome. For this reason, alternative methods have been proposed including the urea kinetic modelling (Kt/V), the measurement of effective ionic dialysance (Diascan), and the continuous spent sampling of dialysate (Quantiscan). The aim of this study was to compare the reliability and agreement of these two methods with the formulas proposed by the urea kinetic modelling for measuring the dialysis dose and others haemodialysis parameters. We studied 20 stable patients (16 men/4 women) dialyzed with a monitor equipped with the modules Diascan (DC) and Quantiscan (QC) (Integra. Hospal). The urea distribution volume (VD) was determined using anthropometric data (Watson equation) and QC data. Kt/V value was calculated according to Daurgidas 2nd generation formula corrected for the rebound (eKt/V), and using DC (Kt/VDC) and QC (Kt/VQC) data. The total mass of urea removed was calculated as 37,93 +/- 16 g/session. The VD calculated using Watson equation was 35.7 +/- 6.6 and the VDQC was 35.06 +/- 9.9. And they showed an significative correlation (r:0,82 p < 0.001). The (VDQC-VDWatson) difference was -0.64 +/- 5.8L (ns). Kt/VDC was equivalent to those of eKt/V (1.64 +/- 0.33 and 1.61 +/- 0.26, mean difference -0.02 +/- 0.29). However, Kt/VQC value was higher than eKt/V (1.67 +/- 0.22 and 1.61 +/- 0.26 mean difference 0.06 +/- 0.07 p < 0.01). Both values correlated highly (R2: 0.92 p < 0.001). Urea generation (C) calculated using UCM was 8.75 +/- 3.4 g/24 h and those calculated using QC was 8.64 +/- 3.21 g/24 h. Mean difference 0.10 +/- 1.14 (ns). G calculated by UCM correlated highly with that derived from QC (R2: 0.88 p < 0.001). In conclusion, Kt/VDC and Kt/VQC should be considered as valid measures for dialysis efficiency. However, the limits of agreement between Kt/VQC and eKt/V were closer than Kt/VDC.     

On-line hemodiafiltration and high-flux hemodialysis: comparison of efficiency and cost analysis

With on-line hemodiafiltration (HDF), low molecular weight substances are predominantly cleared by diffusion while middle molecules such as ß2-microglobulin (ß2M), an amyloidogenic factor, are removed mainly by convection. The objectives of this study are to evaluate the cost-effectiveness and safety of on-line HDF with dialyzer reuse, and to compare HDF and high-flux hemodialysis (HD) with respect to ß2M removal, urea kinetics (Kt/V) and symptom relief in those patients having dialysis-related amyloidosis. Ten chronic HD patients were put on post-dilution HDF for a period of 14.2 ±7.1 months. The AK 100 ULTRA system was used for on-line preparation of substitution fluid. These patients were then switched over to high-flux HD for a period of 4.6 ±3 months. Dialyzers were reused up to 30 times to reduce the cost of HDF. All the patients were hemodynamically stable during both HDF and high-flux HD treatments. No febrile reactions were reported. The percentage reduction of ß2M during HDF was significantly higher when compared with high-flux HD (75 ±4% vs 51 ±7%, p < 0.001). After 14.2 ±7.1 months of HDF, the patients had significant reduction of both the pre-dialysis ß2M level (47.4 ±7.9 μg/mL vs 28.2 ±4.9 μg/mL, p < 0.01) and post-dialysis ß2M level (11.4 ±2.8 μg/mL vs 6.8 ±1.0 μg/mL, p < 0.01). eKt/V achieved by HDF was significantly higher than that achieved by high-flux HD (1.94 ±0.26 vs 1.75 ±0.23, p < 0.01). Those patients with dialysis arthropathy and carpal tunnel syndrome had decreased joint pain and hand numbness respectively after putting on HDF but symptoms recurred while on high-flux HD. There were no statistical significant differences in the percentage reduction of ß2M, ß2M clearance, urea clearance and eKt/V with dialyzer reuse, and no adverse patient reactions had been recorded.ConclusionOn-line HDF has been proven to be a safe and reliable treatment. The clearance of ß2M and urea are significantly increased by HDF when compared with high-flux HD, and the increase in clearance of ß2M is sustained throughout the HDF treatment period. Symptoms of dialysis-related amyloidosis are improved by HDF. Dialyzer reuse, which reduces the cost of HDF by 30%, is feasible and safe.     

Influence of post haemodialysis sampling on Kt/V result

The recommended Kt/V is 1.2. Unfortunately there is no written policy for nurses on the procedure for taking blood urea nitrogen samples post haemodialysis. The aim of this study was to establish the Kt/V variability of haemodialysis patients depending on the method of collection of post-haemodialysis blood urea nitrogen. Twenty-two patients were analysed. A Kt/V was performed every 15 days during a period of 2 months. It was taken five times on each patient: 30 minutes before the end of a haemodialysis session (Kt/V30), at the end of haemodialysis (Kt/V1), after slowing flows (50 ml/min) for 2 minutes (Kt/V2) and after the blood circuit had been returned to the patient at 5 and 15 minutes respectively. (Kt/V5, Kt/V15). The Kt/V results were: Kt/V1 1.23 +/- 0.2 Vs Kt/V2 1.14 +/- 0.19 (p < 0.003); Kt/V5- 1.05 +/- 0.19 (p < 0.002 Vs Kt/V2); Kt/V15 1 +/- 0.16 (p < 0.05 Vs Kt/V5); Kt/V30 1.12 +/- 0.21 (pNS Vs Kt/V2). In conclusion, there was a large variability in the Kt/V depending on the method of collection of the blood urea nitrogen sample post-haemodialysis.     

The circadian blood pressure rhythm in non-diabetic hemodialysis patients.

This study investigates the circadian blood pressure variation of non-diabetic chronic hemodialysis (HD) patients on both HD and non-HD days as well as the factors affecting diurnal BP variation. Forty-nine HD patients aged 61.8 +/- 12.9 years who were on daytime HD for 97 +/- 68 months were studied. No significant difference was found in every daytime and nighttime BP between the first (HD) and the second (non-HD) day. However, the ratio nighttime/daytime BP was significantly higher on the second day. Each BP diurnal variability pattern was classified as either Dipper (D: the ratio nighttime/daytime mean BP 0.8-0.9), non-dipper (0.9 < ND < 1.0), or inverted dipper (ID > 1.0). More than 75% of the cases were classified as ND (26 cases) or ID (11 cases). The ultrafiltration rate in D was significantly less than that in ND and ID. The difference of plasma renin activity between pre- and post-HD (dRen) was significantly higher in ID than in D and ND. The amount of dialysis (Kt/V) was found to be significantly correlated with nighttime BP fall. Ultrafiltration, dRen and Kt/V were independent factors for the abnormal BP diurnal variability. In conclusion, the decreased nocturnal BP fall seen in non-diabetic HD patients is associated with increased extracellular fluid even in the patients without overt overhydration, whereas relatively insufficient amount of dialysis (low Kt/V) may be another possible cause. The increased dRen observed only in ID patients may reflect occult cardiovascular damage or functional disturbances in aortic and carotid baroreflexes caused by arterial structural changes.     

Effect of hemodiafiltration against radical stress in the course of blood purification

The involvement of radical stress has been suggested as a cause for complications in patients on dialysis, such as arteriosclerosis, dialysis-related amyloidosis, etc. It has been reported that the increase in radical stress is not only seen in renal failure, but that its amplified effect is also seen in the process of blood purification. Our group has reported on the radical stress-reducing effect of HDF. We performed four types of blood purification (HD; on-line HDF; pre, on-line HDF; post, P/P HDF) in patients on maintenance dialysis using the polysulfone (APS) dialyzer. The change in radical related markers such as pentosidine (total, free) and CML (total, free), and the CTL/Cr ratio, and the hydroperoxide radicals were studied. In HDF (post, pre), the amplification rate of hydroperoxide radicals was significantly low, whereas the reduction rate of CTL/Cr ratio as index for hydroxy radicals was significantly higher in on-line HDF than in HD. Both the total CML and T-pentosidine increased in HD but showed a decrease in HDF. As HDF uses large amounts of replacement solution, the following effects can be expected: (a) suppression of the amplification of hydroperoxide radicals and suppression of the amplification of hydroxy radicals, and (b) suppression of fat oxidation by AGEs themselves. These antiradical stress effects are presumed to be exerted by effective removal of radical carrier protein, denatured protein, and complement protein in HDF, by dilution of radicals by massive use of replacement solution, and by the sequential reduction of the excitation and amplification effects.