无肝素血液透析Kt/V值的影响因素分析

素血液透析是目前高危出血患者血液透析常用的一种抗凝方法,可有效减少或避免患者出血,然而其透析效率较低.本研究采用Kt/V值作为透析效率的衡量指标,通过检测Kt/V值,探讨无肝素血液透析溶质清除效率的影响因素.     

应用便移式血液透析机进行床边无肝素透析

我们报告应用新型使移式血液透析机进行床边无肝素血液透析的资料与方法，供同道们参考。     

无肝素血液透析的临床观察与护理

血液透析是急、慢性肾衰竭患者得以维持生命的治疗方法之一。常规血液透析需应用肝素抗凝建立体外循环,但肝素在达到充分抗凝时也增加了出血的危险。对于一些合并出血（如消化道出血、脑出血、咯血等）及一些存在严重出血倾向、围手术期的病人一般不使用肝素抗凝,目前临床上应用最广泛的是无肝素透析。无肝素透析的优点是无继发性出血,但易发生凝血［1］。虽然无肝素透析过程中有可能发生透析器或管路凝血而丢失一部分血液,但只要护理人员具有高度的责任心,治疗过程中严密观察,及时发现凝血征象,采取相应的护理措施,可以有效消除和减少凝血发生。我们通过对36例出血患者实施236例次无肝素血液透析治疗的临床观察,采取了一系列的护理措施,使本组患者的血液透析能顺利完成,并取得了满意的效果。现报道如下。     

不同冲洗速度对无肝素血液透析患者的影响

目的探讨不同冲洗速度对无肝素血液透析患者的影响。方法将40例无肝素血液透析患者随机分为观察组与对照组各20例。观察组将0.9%氯化钠注射液200mL以250mL/min的速度冲洗滤器及管路,对照组以100mL/min的速度冲洗滤器及管路。比较两组患者透析前后实验室指标、血流动力学指标和滤器凝血情况及使用时间。结果观察组滤器使用时间显著长于对照组,凝血发生率及凝血程度显著低于对照组(P0.05,P0.01)。结论对于无肝素血液透析治疗,250mL/min的冲洗流速可减少治疗中断时间,延长滤器使用时限。     

不同肝素溶媒对血仿膜吸附法无肝素透析吸附稳定性及临床应用效果的影响

目的:在前期研究应用HCHD对高危出血患者行HD基础上,深入探讨不同肝素溶媒对此方法安全性和临床应用效果的影响.材料与方法:急、慢性血透高危出血患者14例.自身交叉对照设计,分别以NS和5%GS为肝素溶媒,患者分别先后经历两次不同方式HCHD治疗.观察指标分三组进行自身和组间对照;还观察了不同溶媒对肝素吸附量和吸附稳定性的影响.结果:1.HCHD期间,14例患者未有加重出血的情况,3例活动性出血患者出血停止.2.肝素平均吸附量:GS组4513±1446U,NS组4011±444U;仅在NS冲洗液中检测到少量肝素的释放.3.血APTT水平,HCHD期间基本无变化,而同期HD组延长了360%,(P＜0.001).其余指标三组间无显著性差异(P＞0.05).结论:极性溶媒NS对HCHD肝素吸附量、体内凝血系统无明显影响,对于高危出血、尤其是活动性出血患者,HCHD是一种简便、安全、有效的无肝素透析方法.     

无肝素血液透析的护理体会

血透机的临床应用,使慢性肾功能衰竭患者延长了生命,生活质量明显提高.但是,随着透析患者的增多,合并出血性疾病的病例时有发生,而血液透析常规需要使用肝素,以防止体外循环发生凝血阻塞透析器,而高危出血或禁忌使用抗凝剂的患者进行血液透析时,使用肝素会加重出血.近年来,我们对合并出血的透析患者,进行无肝素透析、治疗56例,获得满意效果,现将护理体会报告如下.     

无肝素血液透析救治急性肾功能衰竭的疗效观察

目的观察无肝素血液透析(血透)对有出血或有出血倾向的急性肾功能衰竭(ARF)患者，或合并多脏器功能障碍综合征(MODS)患者的临床疗效。方法对24例伴有出血或出血倾向的ARF或合并MODS的患者(观察组)，每天无肝素血透3h；另24例条件相似的患者用低分子肝素抗凝血透作为对照(对照组)。结果观察组患者BUN和SCr均有明显降低，电解质紊乱得到纠正，血流动力学稳定，临床症状能很快控制，出血症状明显好转，治疗有效率为91．7％，与对照组比较，疗效无显著性差异。结论对于高危出血ARF患者，宜选用每天无肝素血透治疗，可改善尿毒症症状、维持血流动力学稳定及避免出血的危险。     

在线尿素清除率监测不同透析液流量对血透充分性的相关性研究

血液透析是治疗终末期肾脏病患者最有效的措施之一［1］,充分透析可以提高患者的长期生存率,降低死亡率,改善生活质量。透析充分性是评价透析效果及决定维持性血液透析患者预后的重要指标［2］。临床上用来评价透析充分性的指标［3］很多,但最常用和公认的是尿素清除指数（ Kt／V ）,Kt／V值越高,说明透析越充分。而在线尿素清除率监测器（ on - line clearance monitoring,OCM［4］）是德国Fresenius公司为临床应用而开发的在线血液透析充分性监测方法,该方法具有实时监测、简单可操作并且无创经济等优点。提高透析液流量是通过改变膜两侧溶质的浓度及传递的速度而提高透析的效率。2013年开始我们采用不同透析液流量透析,同时利用费森尤斯4008S的OCM,即实时监测其Kt／V值,以评价其对血透充分性的相关性效果,现将结果报告如下。     

Estimating Dialysis Adequacy Using Ionic Dialysance

The aim of this study was to determine the efficacy and feasibility of estimating dialysis adequacy using ionic dialysance (ID). We retrospectively reviewed the medical records of patients receiving thrice weekly dialysis for an eight-month period at a single-center Veterans Affairs hospital. Dialysis adequacy was determined monthly using pre- and post-treatment BUN measurements to calculate the single pool Kt/V (spKt/V) with the formula set forth by Daugirdas. On the same treatment day, K_IDt was determined by multiplying the average ID times the time (t) of the treatment. A surrogate volume, V_ID, was estimated by dividing K_IDt by spKt/V using data from the first six months. During the subsequent two months, we compared dialysis adequacy estimated by urea-based spKt/V to ionic dialysance based K_IDt/V_ID utilizing V_ID. In the first month, K_IDt/V_ID estimations and the simultaneous spKt/V determinations averaged 1.55 ± 0.36 and 1.59 ± 0.42, respectively. In the second month, K_IDt/V_ID and spKt/V averaged 1.52 ± 0.33 and 1.54 ± 0.35, respectively. K_IDt/V_ID correlated well with spKt/V, as the slope was 0.85 (r = 0.95, p < 0.001). There was considerable intra-patient variability of K_ID, time, and K_IDt/V_ID with coefficient of variations (CV) of 8.4 ± 4.3, 9.0 ± 5.3, and 15.8 ± 9.2, respectively. However, the CV for K_IDt/V_ID was similar to the CV for spKt/V (15.3 ± 7.4). These results suggest that it is possible to estimate dialysis adequacy during every treatment using K_IDt/V_ID. Furthermore, there is considerable variability in the delivered dialysis adequacy, suggesting that many sessions result in sub-optimal dialysis.     

联机在线尿素清除率监测对高通量血透充分性评价的研究

目的：通过血液透析机的在线尿素清除率监测系统（OCM）动态监测以比较高通量血液透析和低通量血液透析对维持性血液透析（MHD）患者的透析充分性以及对中分子物质清除的疗效.方法：80例患者随机分为高通量血液透析组（HFHD组）和低通量血液透析组（LFHD组）,HFHD组使用FX60高通量聚砜膜透析器,LFHD组使用F7低通量聚砜膜透析器,同时使用OCM进行动态监测,比较两组到达设定的Kt/V目标值所需的时间及透析结束时的Kt/V值,同时检测治疗前后血磷（P3＋）、甲状旁腺激素（PTH）、β2微球蛋白（β2-MG）等指标,透析治疗1年后复测并比较上述指标.结果：HFHD组对P3＋、PTH和β2-MG清除明显高于LFHD组（P＜0.01）,一年以后两组比较差异有统计意义（P＜0.01）.结论：HFHD行维持治疗的透析充分性与LFHD差异无统计学意义,但HFHD组对P3＋、PTH和β2-MG的清除效果较LFHD组效果好,HFHD优于LFHD.     

Hemodialysis Urea Rebound and Membrane Biocompatibility: Accuracy of Kt/V Estimations

Abstract: To date, the magnitude, causes, and factors that govern urea rebound are not clearly defined. This study was undertaken to determine the possible influence of the biocompatibility of dialyzer membrane on urea rebound and to assess the participation of rebound in the calculation of Kt/V-urea by different methods. Blood urea samples were obtained before, and at 2, 30, and 60 min posthemodialysis in 8 patients undergoing dialysis with 2 different membranes, Cuprophan and polyacrylonitrile (24 sessions with each membrane). Urea rebound was documented in all patients. The degree of rebound was large,20%, and it was achieved within 30 min after the end of dialysis. Urea rebound was observed with both Cuprophan and polyacrylonitrile membranes, without significant differences. Kt/V-urea significantly decreased (p < 0.001) by all methods when urea rebound was incorporated. We conclude that urea rebound is clinically very important and is not influenced by the biocompatibility of the dialyzer membrane. This phenomenon must be taken into account in the calculation of Kt/V; otherwise, it might be overestimated.     

Assessment of Hemodialysis Adequacy by Ionic Dialysance: Comparison to Standard Method of Urea Removal

Background. The hemodialysis adequacy is one of the most important issues influencing the survival of patients on maintenance hemodialysis (HD). Assessment of measuring the delivered dialysis dose using clearance × time/volume (Kt/V) index requires multiple blood sampling. New methods for assessment of dialysis dose based on ionic dialysance (ID) have been suggested. Online conductivity monitoring (using sodium flux as a surrogate for urea) allows the repeated noninvasive measurement of Kt/V on each HD treatment. In this study we have compared this method with the standard method of estimating Kt/V. Methods. We studied 24 established HD patients over a 4 week time period. Patients were dialyzed using Fresenius 4008S dialysis monitors, equipped with modules to measure ID. Data were manually collected and analyzed using the appropriate statistical software. Urea removal (UR) was measured once a week by a two-pool calculation, estimating an eKt/V. Results. The Kt/V measured by ID highly correlated with the one derived from the measurement of the UR (r = 0.8959, p< 0.0001). The ID underestimated UR by the mean of 6%. The ID varied greatly within individual patients with a median of 1.29 ± 0.22. If the eKt/V ≥ 1.2 is considered adequate, 33% of the patients would have been inadequately dialyzed. The mean HD duration to achieve an adequate dialysis was 4 hours and 47 minutes with high interpatient variability. Conclusion. The ID seems to be an easily obtained measure of the delivered dialysis dose, correlating well with standard UR method. Substantial individual variations imply that repeated measures (ideally for all treatments) are necessary to obtain a real answer to the mean treatment dose being delivered to the patients.     

Influence of dialyser clearance measurement accuracy on haemodialysis prescription based onKt/V

Kt/V urea (u) has been used as a measure of adequacy of haemodialysis(HD). However, the accurate assessment of its components isdifficult and subject to error in a clinical setting. This studywas designed to evaluate different forms of dialyser clearance(K) measurements and their influence on Kt/V. Sixteen patientson high-flux HD were studied at blood flow (Q_b) rates of 250and 350 ml/min and at constant dialysate flow rates. K of ureawas measured by the arteriovenous blood sampling technique (K_bu),corrected for access recirculation (K_bru) and compared withK as determined by dialysate collection (K_du) using a new samplingdevice. At Q_b 250 and 350 ml/min, K_bu as based on dialysatecollection was significantly lower than K_bru and K_bu as basedon arteriovenous blood sampling: at Q_b 250, K_du 169.0±13.3, K_bru 191.2±11.5, and K_bu 203.0±9.3 ml/min(P<0.0005); at Q_b 350, K_du 196.5±17.3, K_bru 227.7±15.5,and K_bu 243.6±12.7 ml/min (P<0.0005). At Q_b 250 ml/minK_bu t/V (1.33±0.17) overestimated K_du t/V (1.11±0.13)by 16.8%, at Q_b 350 ml/min by 19.3% (1.58 ± 0.19 versus1.27±0.15). Dialyser clearances based on arteriovenousdifferences in blood overestimate true clearances (and thereforeKt/V) as measured by dialysate collection. This overestimationis more marked with higher blood flow rates.     

Accuracy of Kt/V estimations in high-flux haemodiafiltration using per cent reduction of urea: incorporation of urea rebound

The estimation of Kt/V by utilization of the pre- and postdialysisurea concentrations (per cent reduction in urea and In(U_pre/U_post,))provides a simple, quick technique that can be applied at thebedside. However, the accuracy of such techniques has been questioned.One possible reason for this inaccuracy may be the frequentlyobserved postdialysis rebound in serum urea. We assessed theurea rebound at 30 min postdialysis in 34 haemodiafiltered patientsand compared the calculation of Kt/V using this urea concentrationwith that using the immediate postdialysis concentration. Theseresults were then compared to the Kt/V calculated by urea kineticmodelling (UKM), also utilizing the delayed serum urea concentration.The degree of urea rebound observed was large, 21.4%, beinga reflection of the short-duration, rapid-flux dialysis. Theformulae for calculation of Kt/V all significantly correlatedwith Kt/V by UKM but all gave results significantly differentfrom Kt/V by UKM (P<0.001 by paired t test). For assessmentof Kt/V by these formulae or by UKM, the urea rebound is toolarge to ignore in the setting of short-duration, rapid-fluxdialysis.     

Assessment of haemodialysis adequacy by ionic dialysance: intra-patient variability of delivered treatment.

INTRODUCTION: Adequate delivered dose of solute removal (as assessed by urea reduction and calculation of Kt/V) is an important determinant of clinical outcome in chronic haemodialysis (HD) patients. The requirement for multiple blood sampling and efforts taken to minimize the effects of rebound on post-treatment samples ensure Kt/V is measured only intermittently. On-line conductivity monitoring (using sodium flux as a surrogate for urea) allows the repeated non-invasive measurement of Kt/V on each HD treatment. We have studied the accuracy of this method of measuring Kt/V, and the variability of treatment dose delivered to individual patients. METHODS: We prospectively studied 26 established chronic HD patients over 4 weeks (316 treatments). Patients were dialysed using Hospal Integra dialysis monitors, equipped with Diascan modules to measure Kt/V. Data were downloaded automatically to a central computer server. Urea reduction was measured (once a week) by a two-pool calculation using 30 min post-treatment sampling. RESULTS: Treatment time, Q(B) and modality were fully delivered in all treatments analysed (97% of total). Kt/V measured by ionic dialysance (Kt/V(ID)) correlated highly with that derived from measurement of urea reduction (R(2)=0.92, P<0.0001). Kt/V(ID) underestimated urea-based Kt/V by a mean of only 1.5% (95% CI 0.18-2.9%). Kt/V(ID) varied greatly within individual patients with a mean CV of 0.13+/-0.10 (95% CI 0.05-0.3). If a Kt/V(ID) of 1.0 is considered 'adequate', 55% of the patients had variations that would have potentially altered their status as being adequately or inadequately dialysed, as the range of Kt/V readings cross that point during the study period. CONCLUSION: In conclusion, Kt/V(ID) seems to be an accurate and readily obtained measure of adequacy. Substantial variation in Kt/V implies repeated measures (ideally for all treatments) are necessary to gain a true picture of the mean treatment dose being delivered to patients.     

Dialysis dose and frequency.

BACKGROUND: From the beginning of the dialysis era, the issue of optimal dialysis dose and frequency has been a central topic in the delivery of dialysis treatment. METHODS: We undertook a discussion to achieve a consensus on key points relating to dialysis dose and frequency, focusing on the relationships with clinical and patient outcomes. RESULTS: Traditionally, dialysis adequacy has been quantified referring to the kinetics of urea, taken as a paradigm of all uraemic toxins, and applying the principles of pharmacokinetics using either single- or double-pool variable volume models. An index of dialysis dose is the fractional clearance of urea, which is commonly expressed as Kt/V. It can be calculated from blood urea concentration and haemodialysis (HD) parameters, according to the respective urea kinetic model or by means of simplified formulas. Similar principles are applicable to peritoneal dialysis (PD), where weekly Kt/V and creatinine clearance are used. Recommended minimal targets for dialysis adequacy have been defined by both American and European guidelines (DOQI and European Best Practice Guidelines, respectively). The question of how to improve the severe outcome of dialysis patients has recently come back to the fore, since the results of two recent randomized controlled trials led to the conclusion that, in thrice weekly HD and in PD, increasing the dialysis dose well above the minimum requirements of current American guidelines did not improve patient outcome. Daily HD (defined as a minimum of six HD sessions per week), in the form of either short daytime HD or long slow nocturnal HD, is regarded as a possibility to improve dialysis patient outcome. The results of the studies published so far indicate excellent results with respect to all outcomes analysed: optimal blood pressure control, regression of left ventricular hypertrophy and amelioration of left ventricular performance, improvement of renal anaemia, optimal hyperphosphataemia control, improvement of nutritional status, reduction in oxidative stress indices and improvement in quality of life. The basis for these beneficial effects is thought to be a more physiological clearance of solutes and water, with reduced pre- and post-HD solute concentrations and interdialytic oscillation, compared with traditional HD. Apart from concerns regarding reimbursement and organizational issues, no serious adverse effects have been described with daily HD. However, the evidence accumulated is limited mainly to retrospective cohorts, with small patient numbers and no adequate controls in most instances. Therefore, large prospective studies with adequate controls are required to make daily HD accepted by reimbursing authorities and patients. CONCLUSIONS: Given the available observational and interventional body of evidence, there is no reason to reduce arbitrarily dialysis dose, particularly dialysis treatment time in HD patients treated three times weekly. Daily HD represents a very promising tool for improving dialysis outcomes and quality of life, although its impact on patient survival has not yet been proven definitively.