Development of a continuous renal replacement program in critically ill patients

BACKGROUND: Critically ill patients encounter many obstacles, such as acute renal failure, that increases length of stay as well as hospital cost. Dialysis in these patients is often ineffective thereby prolonging the inevitable and significantly increasing the cost of care. A dialysis program that could improve patient care, potentially improve outcome and be "revenue neutral" would be ideal. METHODS: A continuous renal replacement therapy (CRRT) program was developed to significantly impact the care of critically ill patients Using the latest CRRT equipment along with an innovative hands-on CRRT training program, a specialized CRRT team was created. Working in conjunction with the hospital business office, new revenue charge codes were created and existing codes were updated. Patients who underwent CRRT had their financial records reviewed for: hospital cost to perform CRRT, total hospital billing to the payer, CRRT revenue 881 (billing units) charged to the payer, total charges and reimbursement for the account, percentage of reimbursement, collected revenue, and payer. RESULTS: From April 2000 to February 2002, 39 critically ill patients underwent CRRT. Initial set-up cost was US$79,622.80 and the cost of CRRT was US$222,323.98. The hospital billed for US$656,090.63 and assuming 100% reimbursement, the potential profit was US$427,678.50. However, loss of revenue, mainly from noncompliance with charge capture resulted in the hospital billing only US$386,794.32 with a total reimbursement of US$165,779.86. The 21 burn patients who underwent CRRT yielded a net profit of US$10,294.12, with the highest reimbursement from workman's compensation and private payers. The overall mortality rate was 59% and 65% for the burn patients; significantly lower than published national averages. CONCLUSIONS: An in-house CRRT program improved patient care by providing dialysis in patients who normally would not tolerate the procedure. Although there was a loss of revenue, CRRT in the burn patients appeared "revenue neutral." Although not specifically studied in this review, based on published data, mortality rates in this population were lower than expected especially in critically ill burn patients.     

Prognosis in critically ill children requiring continuous renal replacement therapy

We performed an observational prospective study in 53 critically ill children to analyze the prognostic factors of children requiring continuous renal replacement therapy. Pediatric index of mortality (PIM), pediatric risk of mortality score (PRISM), multi-organ failure score, serum lactate levels, blood pressure, vasoactive drugs, renal function and characteristics of renal replacement therapy were analyzed. The mortality was 32.1%, with multi-organ failure being the most frequent cause of death (59%). The children who died presented a significantly lower blood pressure and required more doses of vasoactive drugs, dopamine and epinephrine than did the survivors. The PRISM and PIM scores and the serum lactate levels and the number of organs suffering failure were significantly higher in the patients who died than in the survivors. However, the PRISM and PIM scores underestimated the risk of mortality. The age, sex, urea and creatinine levels, type of pump and volume of ultrafiltrate did not affect the prognosis. The association of a mean BP<55 mmHg and epinephrine dose >0.6 g/kg/min was predictive of mortality in 76% of the patients. We conclude that the prognosis in children requiring renal replacement therapy depends on the severity of the clinical state at the time of starting therapy, principally on the hemodynamic situation.     

Norepinephrine and hospital mortality in critically ill patients undergoing continuous renal replacement therapy

High-dose vasopressor use is associated with increasing mortality in patients with septic shock. We conducted this study to determine if the high-dose of vasopressor used before the initiation of continuous renal replacement therapy (CRRT) is associated with increasing mortality in critically ill patients. We retrospectively reviewed all patients who underwent CRRT in the medical intensive care unit of China Medical University Hospital between 2003 and 2007. The association between mortality and highest vasopressors (dopamine and norepinephrine [NE]) dose used were analyzed using Kaplan-Meier analysis and multivariate Cox regression. A total of 279 patients (170 men and 109 women) treated with CRRT in medical intensive care were reviewed and 237 (84.9%) died. In Kaplan-Meier analysis with log-rank test, dopamine dose of ≥20 μg/kg/min and NE dose of ≥0.3 μg/kg/min were significantly linked to mortality (P = 0.007 and <0.001). In multivariate Cox proportional hazards regression, NE dose of ≥0.3 μg/kg/min, Acute Physiology and Chronic Health Evaluation II score, and low platelet count were independently linked to mortality. The hazard ratios and 95% confidence interval (CI) were 1.771 (95% CI: 1.247-2.516, P = 0.001), 1.035 (95% CI: 1.012-1.058, P = 0.003), and 0.997 (95% CI: 0.996-0.999, P = 0.003), respectively. Critically ill patients treated with very high dose of NE before the initiation of CRRT have a very high mortality rate regardless of the acute kidney injury stage.     

Long-term renal and overall survival of critically ill patients with acute renal injury who received continuous renal replacement therapy

Background: Acute kidney injury (AKI) is associated with the increased short-term mortality of critically ill patients on continuous renal replacement therapy (CRRT). The aim of this research was to evaluate the association of kidney function at discharge with the long-term renal and overall survival of critically ill patients with AKI who were on CRRT in an intensive care unit (ICU).

Methods: We retrospectively collected data for critically ill patients with AKI who were admitted to ICU on CRRT at a tertiary metropolitan hospital in China between 2008 and 2013. The patients were followed up to their death or to 30 September 2016 by telephone.

Results: A total of 403 patients were enrolled in this study. The 1-, 3- and 5-year patient survival rates were 64.3?±?2.4, 55.8?±?2.5 and 46.3?±?2.7%, respectively. In multivariate analysis, age, sepsis, decreased renal perfusion (including volume contraction, congestive heart failure, hypotension and cardiac arrest), preexisting kidney disease, Apache II score, Saps II score, vasopressors and eGFR <45?mL/min/1.73?m² at discharge were independent factors for worse long-term patient survival. And age, preexisting kidney disease, Apache II score, mechanical ventilation (MV) and eGFR <45?mL/min/1.73?m² at discharge were also associated with worse renal survival.

Conclusions: This study showed that impaired kidney function at discharge was shown to be an important risk factor affecting the long-term renal survival rates of critically ill patients with AKI. An eGFR <45?mL/min/1.73?m² was an independent risk factor for decreased overall survival and renal survival.     

持续肾替代治疗在肝移植术后急性肾损伤的应用

目的 探讨持续肾替代治疗(CRRT)对肝移植术后急性肾损伤的治疗效果.方法 回顾性分析82例肝移植围手术期应用CRRT患者的肾功能情况,对其治疗前后的主要指标进行检测.结果 与治疗前比较,治疗后患者丙氨酸氨基转移酶(ALT)、总胆红素(TBil)、血尿素氮(BUN)、肌酐(Cr)、肌酸磷酸激酶(CPK)、C反应蛋白(CPR)、肌酐下降,差异均有统计学意义(P＜0.05).与治疗前比较,CRRT治疗后患者血K+、Na+、Cl-、HCO3-、中心静脉压(CVP)显著好转,差异亦具有统计学意义(P＜0.05).其他生化指标与治疗前比较变化不大,差异无统计学意义(P＞0.05).对开始血滤治疗的时机进行研究显示,在急性肾损伤RIFLE分级Ⅰ级开始血滤治疗的患者肾功能恢复的比例明显高于在F级开始血滤治疗的患者(P＜0.05).结论 CRRT治疗能明显改善肝移植术后急性肾损伤患者的预后.     

连续性肾脏替代治疗多脏器功能衰竭的疗效

目的 分析连续性肾脏替代治疗(continuous renal replacement therapy,CRRT)对多脏器功能衰竭患者的疗效.方法 回顾性分析30例多脏器功能衰竭患者的临床资料,探讨CRRT治疗多脏器功能衰竭的疗效.结果 30例多脏器功能衰竭患者中15例痊愈,5例存活,10例死亡.结论 多脏器功能衰竭是临床上的急危重症,发病凶险,死亡率高,CRRT对多脏器功能衰竭患者有很好的疗效.     

连续性肾脏替代治疗剂量对急性肾衰竭患者预后影响的荟萃分析

目的 通过荟萃分析评价连续性肾脏替代治疗（CRRT）剂量对急性肾衰竭（ARF）患者预后的影响。 方法 制定原始文献的纳入标准和检索策略,在Medline、EMBASE及Cochrane 图书馆内进行相关的检索。比较标准剂量和低剂量CRRT对ARF患者预后影响的随机对照试验（RCT）纳入分析。应用随机或固定效应模型处理预后指标的相对危险度（RR）。 结果 6项研究符合纳入标准。与低剂量比较,标准剂量CRRT未能降低病死率（RR 0.87,95%CI 0.70~1.07,P = 0.19）和联合终点事件（死亡和依赖透析）的发生率（RR 0.87,95%CI 0.69~1.09,P = 0.21）,但有增加依赖透析率的趋势（RR 1.43,95%CI 0.94~2.18,P = 0.09）。由于研究间存在异质性,亚组分析显示,实际治疗剂量达标（标准剂量>35 ml&#8226;kg-1&#8226;min-1）、治疗模式以连续性静脉-静脉血液滤过（CVVH）为主（置换液量大于透析液量）、非脓毒症为ARF主要原因（脓毒血症发病率<50%）的研究中,经标准剂量CRRT后病死率显著下降（P < 0.01）。 结论 尽管标准剂量CRRT未能降低ARF患者的病死率、依赖透析率和联合终点事件的发生率,但可改善实际治疗剂量达标、治疗模式以CVVH为主及非脓毒症ARF患者的存活率。     

连续肾脏替代治疗在肝移植围手术期的应用

目的探讨连续肾脏替代治疗(continuousrenalreplacementtherapy,CRRT)对肝移植围手术期患者肾功能衰竭的预防作用。方法回顾性分析21例肝移植围手术期应用CRRT的患者的肾功能情况。结果所有行CRRT的患者血清肌酐值均有不同程度下降,21例患者中存活13例,死亡8例(38.1%)。其中有12例患者肾功能恢复,9例患者肾功能未恢复。肾功能恢复患者死亡率8.3%,未恢复患者死亡率77.8%,两者相比差异有统计学意义(χ2=5.838,P<0.05)。治疗期间无严重的并发症。结论CRRT是肝移植术后患者的肾脏替代治疗的首选,尽管如此在围手术期应用CRRT治疗的患者仍有较高的死亡率。     

ICU脓毒血症患者接受连续肾脏替代治疗中抗凝剂使用后凝血功能的变化及护理

【摘要】 目的 探讨ICU脓毒血症患者接受连续肾脏替代治疗中枸橼酸钠体外局部抗凝后凝血功能的变化和护理重点。方法〓回顾性分析2012年3月至2015年6月符合本研究76例行CRRT治疗的ICU脓毒血症患者,40例患者采用枸橼酸钠抗凝(RCA),36例患者采用低分子肝素抗凝。对比两组患者治疗前和治疗后3天凝血功能、血气、生化、出血及滤器使用等指标变化。结果〓两组患者治疗后尿素氮(BUN)、肌酐(Cr)、乳酸(Lac)均明显降低(P<0.05),代谢性酸中毒纠正,但两组间比较无统计学差异;治疗后RCA组凝血酶原时间(PT)、活化部分凝血活酶时间(APTT)、血小板总数(PLT)无明显变化,而低分子肝素组PT、APTT明显延长,PLT数量减少,两组间比较具有统计学差异(P<0.05),同时,RCA组出血发生率明显减少,且滤器使用时间明显延长,差异均有统计学意义(P<0.05)。结论〓枸橼酸钠体外局部抗凝连续肾脏替代治疗ICU脓毒血症对患者凝血功能无影响,同时能减少血小板的消耗、降低出血发生率、延长滤器使用寿命。     

心血管手术相关急性肾损伤患者行连续性肾脏替代治疗后的预后因素分析

目的探讨心血管手术相关急性肾损伤患者行连续性肾脏替代治疗后不同预后的相关因素。 方法本研究纳入2015年1月至2018年12月在南京医科大学第一附属医院住院行心血管手术治疗且接受连续性肾脏替代治疗的患者,按90 d是否死亡和90 d内RRT治疗天数(≤14 d,15～90 d,>90 d)将患者分为4组,分析90 d死亡、90 d透析依赖、90 d延迟摆脱透析的相关影响因素。 结果本研究共纳入210例患者,平均随访400 d。其中90 d死亡114例,90 d生存且14 d内摆脱透析37例,90 d生存15～90 d内摆脱透析46例,90 d生存且透析依赖13例。多因素Cox回归显示：90 d死亡的独立危险因素包括高龄(HR＝1.029,95%CI: 1.013～1.045,P<0.001)、术前血清肌酐低(HR＝0.993,95%CI: 0.987～0.998,P＝0.008)、CRRT前APACHE Ⅱ高评分(HR＝1.043, 95%CI: 1.004～1.084,P＝0.028)、CRRT前SOFA评分高(HR＝1.130, 95%CI: 1.052～1.213,P<0.001)、CRRT前脓毒症(HR＝2.327, 95%CI: 1.591～3.403,P<0.001)、CRRT前过低的舒张压(HR＝0.979,95%CI: 0.963～0.996,P＝0.013)。90 d存活患者透析依赖的独立危险因素包括术前较低的eGFR(HR＝0.962,95%CI: 0.940～0.984,P<0.001)。90 d存活患者中延迟摆脱透析的危险因素有血清白蛋白低(OR＝0.837,95%CI: 0.717～0.977,P＝0.024)、机械通气时间长(OR＝1.434,95%CI: 1.175～1.749,P<0.001)、CRRT前尿量少(OR＝0.739,95%CI: 0.623～0.876,P<0.001)。 结论心血管手术相关急性肾损伤并行连续性肾脏替代治疗患者中,90 d死亡与高龄、CRRT前疾病的严重程度、脓毒症和过低的舒张压有关;90 d存活患者透析依赖与患者术前较差的肾功能有关;90 d存活患者延迟摆脱透析与血清白蛋白低、机械通气时间长、CRRT前尿量少有关。     

Outcome in critically ill medical patients treated with renal replacement therapy for acute renal failure: comparison between patients with and those without haematological malignancies.

BACKGROUND: Starting renal replacement therapy (RRT) for acute renal failure in critically ill patients with haematological malignancies is controversial because of the poor outcome and high costs. The aim of this study was to compare the outcome between critically ill medical patients with and without haematological malignancies who received RRT for acute renal failure. METHODS: We retrospectively collected data on all consecutive patients who received RRT for acute renal failure at the Medical Intensive Care Unit (ICU) of a University Hospital between 1997 and 2002, and assessed the impact of the presence of a haematological malignancy on the survival within 6 months after ICU admission by Cox proportional hazard models. RESULTS: Fifty of the 222 (22.5%) consecutive patients with haematological malignancies admitted to the ICU over the study period received RRT for acute renal failure compared with 248 of the 4293 (5.8%) patients without haematological malignancies (P<0.001). Among patients who received RRT, those with haematological malignancies had higher crude ICU (79.6 vs 55.7%, P=0.002) and in-hospital (83.7 vs 66.1%, P=0.016) mortality rates, and a higher mortality at 6 months (86 vs 72%, P=0.018) by Kaplan-Meier estimates compared with those without haematological malignancies. However, after adjustment for the severity of illness and the duration of hospitalization before ICU admission, haematological malignancy by itself was no longer associated with a higher risk of death (hazard ratio 1.04; 95% confidence interval, 0.73-1.54, P=0.78). CONCLUSIONS: Medical ICU patients with haematological malignancies have a higher rate of occurrence of acute renal failure treated with RRT and a higher mortality, compared with those without haematological malignancies. However, the presence of a haematological malignancy by itself is not a reason to withhold RRT in medical ICU patients with acute renal failure.     

重度肾功能损害患者行不停跳冠脉搭桥术后持续肾脏替代治疗影响因素分析

目的探讨重度肾功能损害患者行非体外循环冠状动脉旁路移植术(off-pump coronary artery bypass grafting,OPCABG)术后应用持续肾脏替代治疗(continuous renal replacement therapy,CRRT)的术前独立危险因素。方法访问首都医科大学附属北京安贞医院麻醉科OPCABG围术期数据库,收集2012年2月至2016年7月术前血清肌酐(Cr)重度升高(血清Cr值≥正常值1.5倍)患者行OPCABG的临床资料,统计术后CRRT发生情况,采用Logistic回归分析CRRT的术前独立危险因素。结果共纳入45例患者,术后应用CRRT有9例(20%)。与非CRRT患者比较,CRRT患者术前血清Cr和尿素氮(BUN)浓度明显升高,术中尿量明显减少,术后12、24h血清Cr浓度明显升高,术后ICU时间明显延长,院内死亡率明显升高(P0.05或P0.01)。Logistic回归分析显示,术前血清Cr浓度升高为术后CRRT的独立危险因素(OR=1.05,95%CI 1.05~1.10,P=0.046)。当术后12h血清Cr浓度166μmol/L时,每升高1μmol/L,术后CRRT治疗率增加5%(OR=1.05,95%CI 1.01~1.08,P=0.013),但在血清Cr浓度350μmol/L时,达到封顶效应。结论术前血清Cr重度升高患者OPCABG术后CRRT治疗率为20%,而术前血清Cr浓度升高是OPCABG患者术后CRRT的独立危险因素。     

连续性肾脏替代治疗在危重病中的应用

近年来，连续性肾脏替代治疗（CRRT）技术日趋成熟，在复杂性急性肾功能衰竭（ARF）中的应用已达成共识。而其临床应用范围已远远超过肾脏替代治疗领域，拓展至非肾脏病邻域已成为重症监护病房（ICU）各种危重病救治中多器官功能支持（MOST）的重要手段之一。     

Sustained low-efficiency daily diafiltration (SLEDD-f) for critically ill patients requiring renal replacement therapy: towards an adequate therapy.

BACKGROUND: Sustained low-efficiency daily dialysis (SLEDD) is an increasingly popular renal replacement therapy for intensive care unit (ICU) patients. SLEDD has been previously reported to provide good solute control and haemodynamic stability. However, continuous renal replacement therapy (CRRT) is considered superior by many ICU practitioners, due first to the large amounts of convective clearance achieved and second to the ability to deliver treatment independently of nephrology services. We report on a program of sustained low-efficiency daily diafiltration (SLEDD-f) delivered autonomously by ICU nursing personnel, and benchmark solute clearance data with recently published reports that have provided dose-outcome relationships for renal replacement therapy in this population. METHODS: SLEDD-f treatments were delivered using countercurrent dialysate flow at 200 ml/min and on-line haemofiltration at 100 ml/min for 8 h on a daily or at least alternate day basis. All aspects of SLEDD-f were managed by ICU nursing personnel. Clinical parameters, patient outcomes and solute levels were monitored. Kt/V, corrected equivalent renal urea clearance (EKRc) and theoretical Kt/V(B12) were calculated. RESULTS: Fifty-six SLEDD-f treatments in 24 critically ill acute renal failure patients were studied. There were no episodes of intradialytic hypotension or other complications. Observed hospital mortality was 46%, not significantly different from the expected mortality as determined from the APACHE II illness severity scoring system. Electrolyte control was excellent. Kt/V per completed treatment was 1.43+/-0.28 (0.96-2.0). Kt/V(B12) per completed treatment was 1.02+/-0.21 (0.6-1.38). EKRc for patients was 35.7+/-6.4 ml/min (25.0-48.2). CONCLUSION: SLEDD-f provides stable renal replacement therapy and good clinical outcomes. Logistic elements of SLEDD-f delivery by ICU nursing personnel are satisfactory. Small solute clearance is adequate by available standards for CRRT and intermittent haemodialysis, and larger solute clearance considerable. SLEDD-f is a viable alternative to CRRT in this setting.     

连续性肾脏替代治疗与间歇性血液透析治疗多器官功能障碍综合征的疗效比较

目的比较连续性肾脏替代治疗(CRRT)与间歇性血液透析(IHD)治疗伴急性肾功能衰竭(ARF)的多器官功能障碍综合征(MODS)患者的疗效.方法49例伴ARF的MODS患者,23例接受CRRT,26例接受每周3次或隔日1次的IHD.所有患者血液净化治疗前及治疗后记录液体摄人量,每日晨检查血肌酐、尿素氮、血钾、血碳酸氢根浓度,动脉血pH值.结果CRRT组和IHD组每日液体摄入量分别为(5128±103)ml、(2207±97)ml(P＜0.05).IHD组21例次出现透析相关低血压、17例次透析间期发生容量依赖性心功能衰竭,高于CRRT组的3例次及2例次(P＜0.05).IHD组每日晨血尿素氮、血肌酐、碳酸氢根、pH值组内比较差异有显著性意义(P＜0.05),而CRRT组组内比较差异没有显著性意义(P＞0.05);IHD组每日晨平均血肌酐、尿素氮高于CRRT组(P＜0.05);IHD组和CRRT组存活率分别为65.4%(17/26)、34.8%(8/23),但在APACHEⅡ评分27以上、衰竭器官数在3个以上的患者中,CRRT组和IHD组存活率分别为26.7%、14.3%(P＞005).结论CRRT控制伴ARF的MODS患者酸碱平衡、液体平衡及氮质血症优于IHD.     

Cooling effect of continuous renal replacement therapy in critically ill patients

Hypothermia is reported to increase intensive care unit (ICU) mortality. The heat loss that occurs during continuous renal replacement therapy (CRRT) favors the development of hypothermia. In an effort to assess the influence of CRRT on body temperature, we reviewed the records of 72 consecutive ICU patients treated with CRRT and further prospectively studied the temperature in the inlet and outlet lines for blood and dialysate of 27 other patients at various flow settings during continuous venovenous hemodialysis (CVVHD). Among the 72 retrospective cases, 36 episodes of hypothermia (core body temperature <35.5 degrees C) occurred and persisted for a mean of 2.6+/-1.8 days. It was more frequent during venovenous than arteriovenous modalities (31 of 67 v5 of 20, respectively); no patients developed hypothermia during arteriovenous slow continuous ultrafiltration (AVSCUS), whereas 48% of the patients undergoing CVVHD became hypothermic, occurring earlier in the therapy course (days 2 to 4). Mean arterial pressure (MAP) tended to increase after CRRT initiation, but absolute changes were not statistically significant. In the prospective arm, the CVVHD circuit temperatures were directly measured. Whereas no attempt was made to change body temperature, stepwise changes in blood (Qb) and dialysate flow rate (Qd) produced venous circuit temperature changes: the higher the Qb, the smaller the arteriovenous temperature differences independent of changes in Qd (P < 0.001). Also, venous circuit temperature varied directly with Qd at fixed Qb (P < 0.001). This relationship also held for temperature conversion to lost energy units per minute. Using room temperature dialysate, CRRT may significantly lower patients' core temperatures. Although the clinical significance of this effect is not clear at this point, energy loss during CVVHD may be important in hemodynamic stability or patient prognosis.     

A systematic review of continuous renal replacement therapy and intermittent haemodialysis in management of patients with acute renal failure

Background: Acute renal failure (ARF) still bears a poor prognosis with mortality rates up to 70% and the ideal form of renal replacement therapy (RRT) remains controversial. The purpose of this study was to conduct a systematic review and meta-analysis of all randomized controlled trials (RCT) to examine the effect of dialysis modality (IHD: Intermittent haemodialysis; CRRT: continuous renal replacement therapy) on survival of patients with ARF and to also study the effect of each modality on dialysis dependence (DD). Methods: Using and combining two comprehensive search themes (ARF and RRT), we searched electronic databases from 1969 through September of 2007, supplemented by a manual review of abstracts from nephrology meetings and reference lists of review articles. All RCT comparing IHD with CRRT in adult patients with ARF and with explicit reporting of mortality were included. The primary outcome was the pooled estimate of the odds ratio (OR) of mortality for patients with ARF treated with CRRT versus IHD. The secondary outcome was OR of DD at time of discharge for surviving patients. Results: A total of 587 studies were identified, 554 of which were excluded on initial screening. Analysis of the nine RCT (1635 patients) showed an OR of 0.89 (0.63–1.24) for survival in patients on CRRT. Limiting the analysis to the seven RCT published after the year 2000, revealed an OR of 0.72 (0.58–0.90). The OR of all the studies before 2000 was 1.06 (95% CI 0.67–1.68), as compared with OR of 0.61 (95% CI 0.50–0.74) for studies post-2000. Four studies showed a significantly lower risk of DD among the CRRT group and none showed higher OR for DD. When analysis was limited to the RCT, the OR for DD was 1.07 (0.47–2.39), suggesting no difference in DD between the modalities. Conclusions: Similar to previously reported meta-analyses, we did not find a significant effect of CRRT on the OR of survival. The progressive reduction in the OR of survival with CRRT relative to IHD might reflect progressive improvements in IHD. The OR of DD was not affected by mode of RRT. In conclusion, compared with IHD, CRRT does not offer an advantage with regards to survival or DD in ARF. Considering its cost and potential disadvantages, it is imperative to identify the subset of patients with ARF that would potentially derive maximum benefit from CRRT. This will require large, adequately powered studies with sufficient follow-up.     

Problems and advantages of continuous renal replacement therapy*

SUMMARY: The continuous replacement of renal function must facilitate fluid and solute homeostasis, nutrition and vital organ function, and, where possible, hasten the recovery of renal function. Difficulties with anticoagulation, biocompatibility, mobility and cost remain obstacles to be overcome. the use of continuous renal replacement therapy (CRRT) to remove systemic inflammatory mediators is yet to be confirmed. Although survival benefits of CRRT over intermittent dialysis remain controversial, the slow continuous removal of fluid, acid and solute has a number of advantages, especially where patients are haemodynamically unstable.