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.     

ULTRA VIOLET ABSORBANCE ON‐LINE MEASUREMENT UTILIZED TO MONITOR CLINICAL EVENTS DURING HAEMODIALYSIS

Background — On‐line monitoring systems of spent dialysate, used to estimate dialysis dose, have been developed with different instrumentation during the last two decades. The routine use of an on‐line monitoring system has been suggested to provide an adequate dialysis dose to the haemodialysis (HD) patient. The aim of this study was to show that monitoring the spent dialysate using UV‐absorbance might bring new information about the clearance process. Methods — 108 HD treatments distributed among 16 clinical stable patients were monitored on‐line using ultra violet (UV) absorbance. For the measurement of UV‐absorbance a spectrophotometer was connected to the fluid outlet of the dialysis machine with all spent dialysate passing through a flow cuvette. The UV‐absorbance curves were examined in combination with the recorded observations of events that occurred during the studied treatments. Results — The study demonstrates that UV‐absorbance visualizes different kinds of events such as hypotension, conductivity alarms and restricted flow in artery needle blood pump stops that often occur during dialysis treatment. Conclusion — An on‐line UV‐monitoring system with a high sampling rate makes it possible to identify variations in dialysis clearance of different origin and gives feedback after performing interventions during a dialysis session.     

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.     

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.     

Ionic dialysance to control the dose of dialysis. One year experience

The Diascan equipment (Hospal) measures ionic dialysane which it derives the K and the Kt. If we divide the Kt obtained with Diascan between the Kt/V obtained by a simplified formula, it result a value of V for every patient. Entering this V in the Diascan software we can obtain a Kt/V (Diascan Kt/V), similar in theory to the simplified Kt/V. In the year 2002 we have controlled the delivered dialysis in our unit with the Diascan Kt/V. The aim of the present study was to study the agreement between de Diascan Kt/V and the Lowrie Kt/V. During the year 2002, 63 patients have been dialyzed in monitors with Diascan equipment. We calculated the V of each patient by dividing the Kt Diascan between the Lowrie Kt/V in the same dialysis session. The mea of the two consecutive measurements was considered the V value. Throughout the year 2002, 7 agreement studies were realized. The inter-method variability was assessed by the relative difference (absolute difference Diascan Kt/V-Lowrie Kt/V, divided by the average of both tests). A good agreement was considered when the relative difference was equal or lower than 10%. In the 7 agreement studies realized, the mean of the relative difference oscilled between 5.2 and 6.6%, and the percentage of patients with a relative difference equal or lower than 10% oscilled between 83 and 91%. During a month, the Diascan Kt/V was controlled in all dialysis sessions in 41 patients (554 sessions in total). Failure in the lecture of Kt/V Diascan was observed in 41 sessions (7%). A Diascan Kt/V greater than 1 (the minimum delivered dialysis considered in our unit) was obtained in 93% of the valid sessions. 38 of 41 patients had a mean monthly Diascan Kt/V greater than 1. The coefficient of variability of any patient oscilled between 2.1 and 12.4% (mean 5.1%). Diascan Kt/V is good procedure for the monitoring the delivered dialysis without blood sampling or any additional costs.     

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.     

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     

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.     

Monitoring parameters of dialysis dose

In order to deliver a specific dialysis dose (Kt/V) to all patients, their product Kt (urea clearance K multiplied by dialysis time t) should be individually adjusted according to total body water (V) of each patient. With dialysis time being fixed in most centres for organisational reasons, such individualization can be accomplished by individually set blood flow (QB). For a given t, the value of QB also defines the magnitude of the cumulative blood volume (VB = QB*t), i.e. the volume of blood perfused through the dialyser during the whole dialysis time. VB is displayed by every contemporary dialysis machine but not used. The aim of this work was to derive an easy to use approach to QB individualization based on patient's body weight and dialysis time to obtain a desired Kt/V value which would also be easy to check after dialysis by looking at the obtained VB value. Statistically significant correlation was found between the QB-based Kt/V estimation and Kt/V determined by the other two methods demonstrating practical feasibility of the novel approach. Kt/V values obtained with the QB prescribed according to patient's body weight tended to be better in females and patients with higher body mass index.     

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.     

Bedeutung von PET und Kt/V für die Peritonealdialyse

PET should be monitored 4 weeks after the start of peritoneal dialysis (PD) and then yearly, and Kt/V every 3 months. PET makes it possible to determine different velocities of glucose absorption (from the dialysate) and of the transport of such low-molecular-weight substances as creatinine and urea (from blood to dialysate), and in particular to calculate the prognosis of the long-term ultrafiltration capacity of the peritoneum in each PD patient. Kt/V is a measure of the urea clearance both of the peritoneum and of the actual kidneys; it seems that preservation of any residual renal function has a more significant positive influence on patient survival and on the technical course than does an increase of the dialysis dose. It is accepted that PD is working efficiently when Kt/V is over 1.7. Besides PET and Kt/V clinical (well-being, eating behaviour, whether body weight is steady, functional capacity) and other (blood pressure, neurological status, degree of anaemia, calcium/phosphate ratio) criteria are also important in the evaluation of whether PD treatment is adequate.     

Regional citrate anticoagulation during hemodialysis: a simplified procedure using Duocart biofiltration

BACKGROUND: Regional citrate anticoagulation during hemodialysis is promising, but its clinical implementation is routinely cumbersome because a continuous adjustment of calcium infusion at the dialyzer outlet is needed. Duocart biofiltration (DCB) is a new hemodialysis method using a calcium and magnesium-free dialysate containing only sodium chloride and bicarbonate combined with the infusion into the venous line of a solution containing the ionic complement (K, Ca, Mg) and glucose. Since the dialysate is calcium- and magnesium-free and infusion rate of the solution containing calcium is automatically determined by the dialysis delivery system according to the on-line measured value of ionic dialysance, DCB seems a technique especially suitable for citrate anticoagulation procedure. METHODS: Thirty DCB sessions were performed in 10 patients with increased risk of bleeding. A commercially available mixture of trisodium citrate, citric acid and glucose was infused into the arterial line at a rate equal to 3% of dialyzer blood flow. The ionic complement (K: 48 mM, Ca: 42 mM, Mg: 14 mM, glucose: 110 mM) was infused at a rate equal to 1/24 ionic dialysance value automatically determined each 15 min by the dialysis monitor. DCB sessions were compared to 21 conventional bicarbonate hemodialysis (BHD) sessions with low-molecular-weight heparin anticoagulation. RESULTS: Whole blood activated clotting time (WBACT) measured in the venous line (before infusion of ionic complement) was 200% of the WBACT value in the arterial line. Clotting and citrate-related adverse events were not observed. Postdialysis compression time of the arteriovenous access is significantly (p<0.001) shorter after DCB sessions (3.9+/-1.1 min) compared with BHD sessions (8.7+/-4.6 min). CONCLUSION: Citrate anticoagulation during Duocart biofiltration is effective, safe and suitable for routine use because calcium infusion rate is automatically adjusted without the need of monitoring degree of anticoagulation and level of ionized calcium.     

Inflamación y adecuación de la hemodiálisis: ¿están los niveles de proteína C reactiva influidos por la dosis de diálisis recibida?

IntroductionChronic inflammation and the underlying cardiovascular comorbidity are still current problems in chronic hemodialysis patients. There are few studies comparing the “dialysis dose” (Kt/V) with the degree of inflammation in the patient. Our main objective was to determine whether there is a relationship between serum C-reactive protein (CRP) levels and the Kt/V using ionic dialysance.MethodsMulticenter cross-sectional study. A total of 536 prevalent chronic hemodialysis patients were included. CRP levels, neutrophil-lymphocyte ratio and platelet-lymphocyte ratio were collected. Kt was obtained by ionic dialysance and urea distribution volume was calculated from the Watson's formula. The sample was divided into 2 groups, taking the median CRP as the cut-off point. Dialysis adequacy obtained in each group was compared. Finally, a logistic regression model was carried out to determine the variables with the greatest influence.ResultsMedian CRP was 4.10 mg/L (q25-q75: 1.67-10) and mean Kt/V was 1.48 ± 0.308. Kt/V was lower in the patients included in the high inflammation group (P = .01). In the multivariate logistic regression, the “high” levels of CRP were directly correlated with the Log neutrophil-lymphocyte ratio (P < .001) and inversely proportional with serum albumin values (P = .014), Kt/V (P = .037) and serum iron (P < .001).ConclusionThe poorer adequacy in terms of dialysis doses (lower Kt/V values) may contribute to a higher degree of inflammation in chronic hemodialysis patients.     

Estimate of the dialysis dose using ionic dialysance

The Diascan equipment (Hospal) measures ionic dialysance from which it derives the Kt/V. It is automatic, does not need blood samples and displays the results in real time. The aim of the present study was to compare the Diascan Kt/V with the Kt/V obtained with four simple formulas: two based on a single pool model of urea kinetics (Lowrie 1983 and Daugirdas 1993) and the other based on the two pool model (Maduell formulation applied to Lowrie Kt/V and that proposed by Daugirdas 1995). We have analyzed the inter-method variability, the degree of relationship among the different procedures for Kt/V calculation and the intra-individual variability. The intermethod variability between Kt/V Diascan and Kt/V calculated by the four simple formulas were studied in one hemodialysis session in 19 patients. The Kt/V Diascan was statistically different from that calculated by the four formulas (1,021 +/- 0.140 Diascan vs 1,147 +/- 0.124 for Lowrie-83; vs 1,373 +/- 0.164 for Daugirdas-93; vs 0.963 +/- 0.105 for Maduell and vs 1,173 +/- 0.143 for Daugirdas-95, p < 0.01). The lowest inter-method variability was obtained with the Maduell's Kt/V (relative difference 9%) but even in this case 37% of patients had a variability above 10%. The correlation coefficient was not high enough to allow an estimation of the different Kt/V measurements from the Diascan Kt/V by a regression equation. To study the individual relationship between the Diascan Kt/V and the Kt/V calculated by the four formulations, we have determined the Kt/V every 30 minutes in one hemodialysis session in 30 patients. In all patients we observed a good relationship between the Diascan Kt/V and the other four (correlation coefficient of 0.9952 for Lowrie-83, 0.9976 for Daugirdas-93, 0.9961 for Maduell and 0.9971 for Daugirdas-95); with these correlation coefficientes it was possible to derive regression equations and to obtain an estimation of the four Kt/V's from the Diascan Kt/V. To study the individual variability of each procedure used in the Kt/V calculations we determined the coefficient of variation of the different methods in 5 consecutive hemodialysis sessions performed under identical conditions in 19 patients. The coefficient of variation was 3.7 +/- 1.8% for the Diascan Kt/V; 6.0 +/- 2.8 for the Lowrie-83 Kt/V; 5.8 +/- 2.4 for the Daugirdas-93 Kt/V; 6.5 +/- 2.6% for the Maduell Kt/V; and 5.7 +/- 2.2% for the Daugirdas-95 Kt/V (p < 0.01 between the Diascan Kt/V and the other four). CONCLUSIONS: Although the Diascan Kt/V was statistically different from the other four Kt/V's calculated by the usual formulas, the Diascan Kt/V has an excellent correlation with all of them and showed a lower intra-individual variability. It is possible to obtain an estimation of the calculated Kt/V for each patient by linear regression equation.     

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.     

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。     

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。