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.     

Influence of relative hypoparathyroidism on the responsiveness to recombinant human erythropoietin in hemodialysis patients

BACKGROUND/AIM: It has been shown in a few studies examining small patient groups that high levels of intact parathyroid hormone (iPTH) were associated with a less efficient response to recombinant human erythropoietin (rHuEPO). However, the responsiveness to rHuEPO in hemodialysis (HD) patients with relative hypoparathyroidism remains undetermined. This study examines the responsiveness to rHuEPO in HD patients with relative hypoparathyroidism. METHODS: We retrospectively studied 19 nondiabetic patients (mean age 44.3 +/- 8.2 years, age range 29.4-55.6 years) treated with HD for chronic glomerulonephritis. Of the 19 patients, 8 (group A) had iPTH levels <100 pg/ml for the preceding 6 months without administration of 1,25-(OH)(2)-vitamin D(3). Eleven patients had iPTH levels >100 pg/ml (group B). Hematocrit (Hct) and rHuEPO doses were recorded for statistical analysis. RESULTS: In patients of groups A and B, the rHuEPO dose (U/kg/week) was 55.21 +/- 16.23 vs. 84.08 +/- 24.56 (p = 0.01); Hct (%) 33.29 +/- 1.72 vs. 31.43 +/- 2.98 (p = 0.67), and rHuEPO resistance index (weekly rHuEPO dose/Hct) 81.38 +/- 16.64 vs. 155.63 +/- 42.22 (p < 0.001). Furthermore, weekly rHuEPO dose and rHuEPO resistance index correlated positively with serum iPTH levels (R = 0.765, p < 0.001; R = 0.764, p < 0.001), whereas the Hct correlated negatively with serum iPTH levels (R = -0.400, p = 0.045). The alkaline phosphatase level (IU/l) was lower (50.46 +/- 12.87 vs. 69.61 +/- 20.68, p = 0.17) in group A. CONCLUSION: Our observations suggest that the lower the iPTH levels of chronic HD patients, even with relative hypoparathyroidism, the better the responsiveness to rHuEPO.     

Correlates of urea kinetic modeling during hemodialysis in patients with acute renal failure

The current guidelines on dialysis adequacy in acute renal failure (ARF) are loosely defined and have been extrapolated from patients with end-stage renal disease. The objectives of this study were (1) to compare three methods of urea kinetic modeling measurement in patients with ARF receiving intermittent hemodialysis, (2) to compare prescribed to delivered dose of dialysis, and (3) to explore the factors that are associated with dialysis delivery. 'Single-pool' urea kinetic modeling was assessed by the Ureakin) software and the second-generation equation which uses a logarithmic estimate of spKt/V. 'Equilibrated' Kt/V (eKt/V) was calculated using the rate adjustment equation. The prescribed dose was derived using the manufacturer's specifications of the dialyzer clearance, prescribed time, actual delivered blood and dialysate flow, and estimates of volume of urea distribution. A total of 78 consecutive spKt/V measurements were obtained in 24 patients. The mean urea reduction ratio was 51 +/- 1%. The delivered spKt/V was significantly lower than that prescribed (0.87 +/- 0.03 or 0.83 +/- 0.03 vs. 1.28 +/- 0.05; p = 0.0001). The equilibrated Kt/V was markedly lower than the delivered spKt/V (0.73 +/- 0.03 vs. 0.83 +/- 0.03; p = 0.0001). Univariate analyses demonstrated that female gender, low body mass index, low predialysis weight, use of cellulose acetate dialyzers, and increased prescribed time were associated with increased odds of prescribed spKt/V > or =1.2. Similarly, old age, increased delivered time, and high cytokine production were associated with increased odds of delivered spKt/V > or =1.2. In summary, while the impact of delivered intermittent hemodialysis on the survival of patients with ARF remains to be determined, these results indicate that dialysis delivery is suboptimal in ARF, and empiric dosing should strongly consider factors related to lean body mass, including age and gender.     

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.     

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.     

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.     

Monitoring hemodialysis dose with ionic dialisance in on-line hemodiafiltration

Until now, with the ionic dialysance measurement, it has been possible to determine hemodialysis dose in each session of hemodialysis (HD) and in the conventional hemofiltration (HDF) but not in the modality of on-line HDF. Recently it is possible with a new biosensor that allows to measure the dose in on-line HDF. The aim of this study was to evaluate the value of this biosensor in different dialysis situations comparing the dialysis dose measured in blood in comparison with the values obtained from the sensor. We have analysed 192 hemodialysis sessions performed in 24 patients, 15 male and 9 female, mean age of 70.2 +/- 12 years, included in on-line HDF. All treatments were done using 4008H (Fresenius) monitor equipped with on-line clearance monitoring (OCM), that measure, with non invasive monitoring, the effective ionic dialysance equivalent to urea clearance. Every patient received eight dialysis sessions: one with dialysate flow (Qd) 500 ml/min, two with HD and Qd 800 ml/min and five with on-line HDF. Other habitual haemodialysis parameters were no changed, dialysis time 200 +/- 63 min (135-300) and blood flow 421 +/- 29 ml/min (350-450). Initial and final ionic dialysance values (K), final Kt, Kt/V measured with OCM using V of Watson, and Kt/V determined in blood pre and postdialysis concentrations of urea (Daugirdas second generation), were measured. The mean of initial K was 251 +/- 21 ml/min and the final K was 234 +/- 24 ml/min. The Kt measured with OCM was 50.6 +/- 17 L, 51.2 +/- 17 in men and 49.7 +/- 16 in women. The V (Watson) was 34.5 +/- 6 L. The Kt/V measured with the Kt of OCM and V was 1,499 +/- 0.54 and Kt/V measured in blood samples was 1,742 +/- 0.58. The correlation between both values was 0.956. The Kt was different according to dialysis modality used: in HD and Qd 500 was 44.7 +/- 15 L, in HD and Qd 800 was 50.7 +/- 17 and in on-line HDF (22.1 +/- 7 L of reposition volume), was 51.8 +/- 17 L. The Kt/V from blood samples also shows variation: in HD and QD 500 was 1.60 +/- 0.55, in HD and Qd 800 was 1,726 +/- 0.56 and in on-line HDF was 1,776 +/- 0.59. In this study has been observed a close correlation between the new biosensor OCM with the measures obtained from the blood samples. For this reason this sensor it is useful in all modalities of dialysis treatment, included on-line HDF. The sensor was able to discriminate the efficacy of different dialysis modalities used in this study.     

Is the correlation between adequate dialysis in peritoneal dialysis and nutritional parameters mathematical or biological? Influence of residual renal function and comorbidity

The relationship between urea Kt/V and nPCR (nPNA) is partly due to a mathematical coupling and greatly depends on the residual renal function (RRF). On the other hand, albumin could be just a comorbidity marker. Our objective in this study was to verify whether dialysis dose in peritoneal dialysis (PD) is biologically related to the nutritional state measured by the mean values of several parameters not mathematically related while analyzing the influence of RRF and comorbidity (C). 101 stable PD patients, 60M and 41F with a mean age of 59.3 +/- 14.3 years, were studied and followed up every six months for a mean time of 35.8 +/- 22.3 months (8-112). The variables studied were initial comorbidity, plasma albumin, normalized protein nitrogen appearance (nPNA), lean body weight % (LBW%) and fat-free mass index (FFMI) derived from creatinine, and RRF. In every study (n = 471) the 24 hours dialysate and urine volumes were collected and the total (T), dialytic (P) and renal (R) urea KT/V and normalized creatinine clearance (CCR) were determined and compared with the nutritional parameters. When starting PD 48 patients (47.5%) had some C and 34 (33.7%) were already anuric. The correlations of nPNA with T-KT/V and T-CCR (n = 101) were r = 0.67 and 0.50 (p < 0.0005) while the correlations of LBW% with T-KT/V and T-CCR were r = 0.36 and 0.40 (p < 0.0005) respectively. The correlations of albumin with T, P and R KT/V and CCR did not reach significance. The nutritional state was better in patients with a higher RRF and albumin showed significant differences when related to morbidity. KT/V and CCR correlations with nutritional variables not mathematically related verify the hypothesis that dialysis dose is biologically associated with the nutritional state.     

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.     

维持性血液透析患者的血压与透析充分性及相关因素分析

目的观察维持性血液透析(MHD)患者血压与透析充分性及其它相关因素间的关系。方法 56例MHD连续12次记录透析前后血压、体重、超滤量(FV),分别计算收缩压(SBP)、舒张压(DBP)和平均动脉压(MAP)的均值,第0、1、2、3个月透析前后测定血液生化值、甲状旁腺激素(PTH)、血红蛋白(Hb)、红细胞压积(Hct),计算尿素清除指数(Kt/V)、尿素下降率(URR)。结果透析充分组(Kt/V≥1.2、URR≥0.65)MHD患者血压明显低于透析不充分组(Kt/V<1.2、URR<0.65)差异有统计学意义(P<0.05);Hct≥0.22组与Hct<0.22组比较MAP差异有统计学意义(P<0.05);Logistic回归分析显示透析间期体重增加量、体重增加率、透析不充分及血清PTH水平与透析前收缩压密切相关(OR=1.98~3.50,P<0.05)。结论充分透析、减少容量负荷是控制MHD患者高血压的关键,透析不充分、透析间期体重增长过多、高血清甲状旁腺激素水平与透析前收缩压升高有密切关系。     

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.     

Phosphate kinetics during different dialysis modalities

BACKGROUND: An abnormal serum phosphate concentration is common in acute renal failure patients, with a reported incidence of 65-80%. Phosphate removal and kinetics during intermittent hemodialysis (IHD) have been investigated, but there is no information on its kinetics during slow low-efficiency dialysis (SLED) and continuous renal replacement therapy (CRRT). METHODS: Eight IHD, 8 SLED, and 10 continuous venovenous hemofiltration (CVVH) patients with a residual renal clearance of <4.0 ml/min were studied during a single treatment to evaluate phosphate removal and kinetics. CVVH was studied the first 24 h after initiation. Dialysis/replacement fluid contained no phosphate. Kt/V, clearance of urea (Ku), inorganic phosphate (Kp) and solute removal was determined by direct dialysate quantification (DDQ). RESULTS: Kp recorded with the three techniques were: IHD, 126.9 +/- 18.4 ml/min; SLED, 58.0 +/- 15.8 ml/min, and CVVH, 31.5 +/- 6.0 ml/min. However, in shorter dialysis treatment the total removal of phosphate was significantly lower than in longer dialysis (IHD, 29.9 +/- 7.7 mmol; SLED, 37.6 +/- 9.6 mmol; CVVH, 66.7 +/- 18.9 mmol, p = 0.001). The duration of treatment is the only factor determining phosphate removal (r = 0.7, p < 0.0001 by linear correlation model). Like IHD, phosphate kinetics during SLED could not be explained by the two-pool kinetic model, and the rebound of phosphate extended beyond 1 h after dialysis. Rebound, however, is less marked than in short dialysis. CONCLUSION: These results are reliable evidence about amount of phosphate removal and behavior of intradialytic phosphate kinetics in renal failure patients undergoing different dialysis modalities. These data will help clinicians plan phosphate supplementation and treatment intensity.     

Acetate-free hemodialysis: a feasibility study on a technical alternative to bicarbonate dialysis

This study aimed at evaluating the feasibility of an acetate-free hemodialysis (AFHD) technique, comparing it with acetate-free biofiltration (AFB) and bicarbonate dialysis (BD). The assessment of the parameters concerned: electrolyte kinetics (Na+, K+), acid-base balance (HCO3-, pH), dialysis efficiency (Kt/V), serum beta2-microglobulin reduction ratio, nutritional status (normalized protein catabolic rate, serum albumin and total proteins, body mass index), hemopoietic status (hemoglobin, hematocrit), and some clinical parameters (systolic and diastolic blood pressures, heart rate, percent blood volume reduction measured by Hemoscan). Nine patients participated in this study which was conducted using a Latin square randomized experimental design. The results of the last week of each month of the study (1 month for each technique) were analyzed by means of Anova for repeated measures. The different treatments were comparable with regard to the main dialysis parameters such as blood flow (320 ml/min) and weight loss rate (0.6 +/- 0.1 kg/h), while dialysis length and dialysate conductivities were different, depending on the dialysis technique. Electrolyte kinetics and acid-base balance were similar during the three periods. The dialysis efficiency for small molecules (Kt/V of urea) was similar (between 1.4 and 1.6); however, AFB seemed to show a higher beta2-microglobulin reduction rate (47.6 +/- 4 vs. 4.3 +/- 10% for AFHD and vs. 9.9 +/- 5% for BD; p < 0.001). The nutritional and hemopoietic status maintained stable, and the hemodynamic parameters were comparable during all periods. The percent blood volume reduction at the end of the treatments was not statistically different (-14.9 +/- 9.4% in AFB, -12.1 +/- 5.1% in AFHD, and -12.2 +/- 4.4% in BD), and these results could explain the similar hemodynamic behavior during the three periods. In conclusion, AFHD appears to be a safe technique which has all positive effects of AFB and the low costs of BD. In our opinion, it could be used in patients with few clinical impairments, usually treated with hemodialysis, in whom a biocompatible treatment is indicated.     

残余肾功能状态对腹膜透析效能的影响

目的:前瞻性观察终末期肾衰(ESRF)患者在腹膜透析(PD)治疗后残余肾功能(RRF)对透析效能及相关临床指标之间的影响。方法:所有患者按残余肾小球滤过率(rGFR)水平将其分为A组(GFR0~2ml/min)、B组(GFR2·1~4ml/min)和C组(GFR>4ml/min)。每3个月进行一次临床随访,全面评估患者的全身情况及透析状态,包括血压、身高、体重、体重指数(BMI)、尿量(UV)、残余肾肌酐清除率(Ccr)、每周总尿素氮表现率(Kt/Vtotal)、每周肌酐总清除率(WCcrtotal)、蛋白氮呈现率(nPNA)、残余肾尿素及Ccr。对比观察不同RRF状态患者透析状况和部分临床及生化指标变化。尿量<100ml/d或Ccr<1·0ml/min视为无尿。结果:三组不同残肾状态患者Kt/vtotal和Ccr分别为1·75±0·35、2·07±0·54、2·46±0·50和53·4±11·2、66·6±11·2、97·6±22·1(L/Wks),各组之间差异非常显著(P<0·001)。三组不同残余肾Kt/v和Ccr分别占总体kt/v的12·4%、27%、45·7%及总体Ccr的18·3%、47·3%和65·3%,三组间相比差异亦显著(P<0·01)。此外,三组间高血压发生率、心胸比例及左心室肥厚(LVH)亦存在一定差异,C组心脏增大的病例明显低于A、B两组。RRF状态与透析效能呈正相关。本组患者除2例在透析治疗时即无尿,128例患者中有31例(24·2%)发生无尿,其中原发病为血管炎综合征及糖尿病肾病各占4例和7例,其无尿发生率分别占本病种的66·7%及25·9%;另20例无尿患者为肾小球肾炎或其它疾病,占此类疾病的20·6%。此外,发生无尿患者中有5例(16·1%)透析时尿量<300ml/d。结论:PD患者的残余肾仍然是清除体内代谢产物的重要途径,同时也影响血压及心血管系统并发症。     

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。     

Lactose digestion by human jejunal biopsies: the relationship between hydrolysis and absorption.

The relationship between lactose hydrolysis and absorption of released glucose was investigated by determining the kinetics of lactose digestion by jejunal biopsies incubated in vitro. Lactase activity in intact biopsies correlated with conventional assay of tissue homogenates (r = 0.85, p less than 0.001), and glucose uptake from 28 mM lactose was directly proportional to lactase activity (r = 0.95, p less than 0.001) in 21 subjects with normal lactase levels, six with hypolactasia (primary or secondary to coeliac disease) and two with lactose intolerance but normal lactase activity. Kinetic analysis at 0.56-56 mM lactose in five normal subjects showed saturable kinetics for hydrolysis (app Km = 33.9 +/- 2.2 mM; app Vmax = 26.5 +/- 1.1 nmol/min/mg dry weight) but glucose uptake could be fitted to a model either of saturable uptake (app Kt = 47.2 +/- 0.3 mM; app Jmax = 14.1 +/- 0.2 nmol/min/mg) or saturable uptake plus a linear component (app Kt = 21.3 +/- 1.15; app Jmax = 4.59 +/- 0.12; app Kd = 0.093 +/- 0.010 nmol/min/mg/mM). The proportion of glucose taken into the tissue did not significantly exceed 50% of the total released at any lactose concentration suggesting the lack of an efficient capture mechanism for the released glucose. The results suggest that lactose hydrolysis is the rate limiting step in the overall absorption of glucose from lactose in vitro, and that the relationship between hydrolysis and absorption is the same in normal subjects and in hypolactasic subjects.     

Improvement of anemia in hemodialysis patients treated by hemodiafiltration with high-volume on-line-prepared substitution fluid

BACKGROUND: Hemodiafiltration (HDF) is associated with a lower incidence of neuropathy, carpal tunnel syndrome, joint pain, and partial correction of anemia. HDF with on-line-prepared substitution fluid (OL HDF), as compared with conventional hemodialysis, increases the treatment tolerance and, as compared with standard HDF, avoids storage problems and allows a higher substitution volume at low cost. METHODS: Thirty-two hemodialysis patients treated by OL HDF for at least 9 months were studied. Hemoglobin, hematocrit, iron metabolism, serum albumin, dialysis dose and dry body weight were determined under a settled condition with regular hemodialysis 3 months before the transfer to OL HDF. The same parameters were analyzed 3, 6 and 9 months after the beginning of the new treatment modality. RESULTS: During OL HDF, hemoglobin values significantly increased in patients without addition of recombinant human erythropoietin (rHuEPO): baseline vs. 6 months 11 +/- 1.7 vs. 12 +/- 1.8 g/dl (p < 0.01); baseline vs. 9 months 11 +/- 1.7 vs. 12 +/- 1.6 g/dl (p < 0.05). In patients on a maintenance dose of rhuEPO, this could be significantly reduced, while the target hemoglobin levels were maintained (10.6 +/- 0.9 g/dl): baseline 99.8 +/- 50.4 U/kg/week, 3rd month 76.2 +/- 43 U/kg/week, 6th month 64.3 +/- 37 U/kg/week, and 9th month 59.4 +/- 38.6 U/kg/week (p = 0.007, p = 0.0006, and p = 0.0007, respectively, vs. baseline). Iron metabolism, dialysis dose, dry body weight and serum albumin levels did not significantly change during the follow-up period. Further, a stability of the rHuEPO supplementation was observed in 14 patients followed up for 24 months. CONCLUSIONS: OL HDF influences anemia and rHuEPO dose. It allows considerable anemia correction in patients without rHuEPO treatment, while it significantly reduces rHuEPO doses in those on rHuEPO treatment as compared with standard hemodialysis. The rHuEPO costs are consequently reduced.     

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.     

Nutritional status of peritoneal dialysis patients and parameters of dialysis adequacy

The aim of our study was to evaluate relations between peritoneal dialysis (PD) adequacy and nutritional parameters of PD patients. Patients (n = 124), who finished PD treatment, were separated on 2 groups according to the mean total Kt/V for the entire PD course being below 2.0 (group I) or over 2.0 (group II). Adequacy parameters, daily intake of food products and nutritional indices were evaluated in each patient every 3-6 months during the entire PD course. Mean values of examined parameters were used for comparison of differences observed between both groups. Group I included 63 men, 16 women, age 50.3 +/- 13.8 years, PD duration 13.2 +/- 10.1 months. Group II consisted of 12 men, 33 women, age 49.1 +/- 14.9 years, PD duration 8.8 +/- 6.0 months. Due to a significant difference in sex distribution, dialysis duration and ideal body mass (IBM) between groups, statistical analysis was performed with adjustment of results to these parameters. Absolute amounts of daily intake of food components were higher in group I for animal protein, sodium, retinol, niacin, saturated and polyunsaturated fatty acids and cholesterol. When daily food intake was normalized to IBM, group II showed higher both protein nitrogen appearance (I - 0.92 +/- 0.25, II - 1.12 +/- 0.45 g/kg IBM, p = 0.005) and intake of vegetable protein (I - 0.29 +/- 0.10, II - 0.34 +/- 0.09 g/kg IBM, p = 0.040), carbohydrates (I - 3.30 +/- 1.08, II - 3.80 +/- 1.34 g/kg IBM, p = 0.029), potassium (I - 33.2+/-10.6, II - 38.3 +/- 13.2 mg/kg IBM, p = 0.034), calcium (I - 5.81 +/- 2.46, II - 7.20 +/- 3.54 mg/kg IBM, p = 0.028), magnesium (I - 2.86 +/- 0.86, II - 3.41 +/- 1.36 mg/kg IBM, p = 0.004), beta-carotene (I 22.4 +/- 15.8, II - 34.9 +/- 29.1 mg/kg IBM, p = 0.002) as well as calorie delivered from protein (I - 0.22 +/- 0.04, II - 0.26 +/- 0.07%, p = 0.001) and carbohydrates (I - 0.79 +/- 0.15, II - 0.94 +/- 0.21, p = 0.000) in relation to total amount of ingested calorie. Group I showed significantly lower serum levels of albumin (I - 2.45, 1-3, II - 2.83, 1-3 scores, p = 0.023) and cholesterol (I - 5.54 +/- 1.06, II - 6.35 +/- 1.63 mmol/l, p = 0.009), but higher serum iron (I - 16.7 +/- 4.4, II - 15.8 +/- 5.2 micromol/l, p = 0.042) and ferritin (I - 615, 28-5113, II - 377, 24-3376 ng/ml, p = 0.021) concentrations as well as transferrin saturation (I - 31.1 +/- 9.2, II - 28.5 +/- 9.2%, p = 0.032). We conclude that PD patients with Kt/V over 2.0 as compared to those with Kt/V below 2.0 show tendency for better nutritional indices excluding serum iron parameters.