The Acute Dialysis Quality Initiative II: the Vicenza conference

A large number of patients develop acute renal failure in the intensive care unit and nephrology wards, and mortality remains high. In recent years, there have been considerable advances in our understanding and technical capabilities, but consensus over the optimal way to diagnose and treat acute renal failure does not exist. Consequently, a consensus conference under the auspices of the Acute Dialysis Quality Initiative (ADQI) has been held in Vicenza in the year 2002 after the previous conference held in New York in the year 2000. The ADQI aims at establishing an evidence-based appraisal and set of consensus recommendations to standardize care and direct further research. The first of these conferences held in June 2000 in New York focused on continuous renal replacement therapy (CRRT). The reports from this first consensus conference are now available online at www.ADQI.net and are also published in part in this issue. However, there remains a need for consensus in several other areas of acute renal failure. Acute renal failure has no accepted definition or rather there are over 30 definitions used in the literature and no consensus as to which one should be used. Studies designed to prevent or treat acute renal failure often use clinical and physiologic endpoints that are not comparable to other studies making it difficult to compare the results of one study to another. Finally, the success of multicentered clinical trials in supportive care in the intensive care unit (transfusion thresholds and ventilator management) have intensified and renewed interest in the study of supportive care methods as a major target for future research. These developments have set the stage for the first conference and have now driven the spirit of the second. Once again, the final objectives are the development of evidence-based guidelines and directions for future research.     

The first international consensus conference on continuous renal replacement therapy

BACKGROUND: Management of acute renal failure (ARF) in the critically ill is extremely variable and there are no published standards for the provision of renal replacement therapy in this population. We sought to review the available evidence, make evidence-based practice recommendations, and delineate key questions for future study. METHODS: We undertook an evidence-based review of the literature on continuous renal replacement therapy (CRRT) using MEDLINE searches. We determined a list of key questions and convened a 2-day consensus conference to develop summary statements via a series of alternating breakout and plenary sessions. In these sessions, we identified supporting evidence and generated practice guidelines and/or directions for future research. RESULTS: Of the 46 questions considered, we found consensus for 20. We found inadequate evidence for 21 questions and for the remaining five we found data but no consensus. Full versions of workgroup findings are available on the Internet at http://www.ADQI.net. CONCLUSIONS: Despite limited data, broad areas of consensus exist for use of CRRT and guideline development appears feasible. Equally broad areas of disagreement also exist and additional basic and applied research in acute renal failure is needed.     

Renal replacement therapy in acute renal failure

Acute renal failure (ARF) is a common condition in hospitalized patients. The aetiology and physiological characteristics differ from those of chronic renal failure (CRF) and both conditions should be approached differently. At present, the approach to the management of ARF is very heterogeneous. Attempts have therefore been made to improve consensus and to standardize treatment in the Acute Dialysis Quality Initiative (ADQI). Technology for the treatment of ARF is expanding. Traditional intermittent haemodialysis (IHD) is still a major treatment modality but continuous renal replacement therapies (CRRT) and slow, low-efficiency daily dialysis (SLEDD) are commonly used alternatives. Each modality has advantages and disadvantages, but to date no evidence exists for the superiority of one over the other. On the other hand, the availability of multiple options allows us to provide tailor-made treatment: the best modality is chosen depending on local expertise and the individual clinical scenario. Practice guidelines based on the best available evidence and the author's opinion are suggested.     

Nierenersatzverfahren auf der Intensivstation

Acute renal failure is a common complication in intensive care medicine. While the incidence of acute renal failure increases, mortality still remains at a high level. In Europe continuous renal replacement therapy (CRRT) has become the standard treatment for acute renal failure. Continuous renal replacement therapy has the advantage of achieving a more stable haemodynamic situation and an easier volume management compared to intermittent haemodialysis (IHD). Until now there has been no evidence to suggest that either classical IHD or CRRT is superior in reducing mortality. Using CRRT in patients with acute renal failure, an ultrafiltration rate adjusted to the patient's bodyweight at 35 ml/kg x h is recommended. A new approach in renal replacement therapy is the slow extended daily dialysis (SLEDD), which combines the advantages of CRRT and IHD. First results are promising, but further investigations are needed to show whether outcome can be improved. A final evidence-based recommendation on the dosing of CRRT or a definitive answer to the question whether daily IHD is better than CRRT, can probably only be possible after two running multicentre studies, the VA/NIH Acute Renal Failure Trial Network (ATN) study and the Augmented Versus Normal Renal Replacement Therapy in Severe Acute Renal Failure Study (ANZICS 2005) Australia and New Zealand Intensive Care Group.     

A comparison of continuous renal replacement therapy to intermittent dialysis in the management of renal insufficiency in the acutely III surgical patient

Acute renal failure (ARF) occurs in 10 per cent to 23 per cent of intensive care unit patients with mortality ranging from 50 per cent to 90 per cent. ARF is characterized by an acute decline in renal function as measured by urine output (UOP), serum creatinine, and blood urea nitrogen (BUN). Causes may be prerenal, intrarenal, or postrenal. Treatment consists of renal replacement therapy (RRT), either intermittent (ID) or continuous (CRRT). Indications for initiation of dialysis include oliguria, acidemia, azotemia, hyperkalemia, uremic complications, or significant edema. Overall, the literature comparing CRRT to ID is poor. No studies of only surgical/trauma patients have been published. We hypothesize that renal function and hemodynamic stability in trauma/ surgical critical care patients are better preserved by CRRT than by ID. We performed a retrospective review of trauma/surgical critical care patients requiring renal supportive therapy. Thirty patients received CRRT and 27 patients received ID. The study was controlled for severity of illness and demographics. Outcomes assessed were survival, renal function, acid-base balance, hemodynamic stability, and oxygenation/ventilation parameters. Populations were similar across demographics and severity of illness. Renal function, measured by creatinine clearance, was statistically greater with CRRT (P = 0.035). There was better control of azotemia with CRRT: BUN was lower (P = 0.000) and creatinine was lower (P = 0.000). Mean arterial blood pressure was greater (P = 0.021) with CRRT. No difference in oxygenation/ventilation parameters or pH was found between groups. CRRT results in an enhancement of renal function with improved creatinine clearance at the time of dialysis discontinuation. CRRT provides better control of azotemia while preserving hemodynamic stability in patients undergoing renal replacement therapy. Prospective randomized controlled studies and larger sample sizes are needed to further evaluate these modalities.     

The Acute Dialysis Quality Initiative--part V: operational characteristics of CRRT

This report represents the consensus statement of the ADQI workgroup addressing the operational characteristics of continuous renal replacement therapy (CRRT). Issues addressed included the specific operational characteristics of continuous hemofiltration (HF), continuous hemodialysis (HD), and continuous hemodiafiltration (HDF) and the impact of these different modalities on solute removal. The relative roles of arteriovenous (AV) and venovenous (VV) modalities of therapy were also evaluated. The workgroup also addressed the optimal components of a CRRT system from an operational standpoint.     

Dose of dialysis in acute renal failure

Acute renal failure (ARF) is a cause of significant morbidity and mortality. Despite advances in supportive care, outcomes in ARF have improved little over the past decades. The primary goals in management of patients with ARF are to optimize hemodynamic and volume status, minimize further renal injury, correct metabolic abnormalities, and permit adequate nutrition. Renal replacement therapy (RRT) is often required to achieve these goals while awaiting renal recovery, but the optimal dose of dialysis in patients with ARF is not known. Extrapolation of required dialysis dose from recommendations in chronic dialysis is unlikely to be appropriate because of the lack of a steady state and differences in distribution volume of urea that are intrinsic to ARF. The prescribed dialysis dose in ARF is often low, and actual delivered dose is often even less than prescribed. Delivery of dialysis in ARF is often hampered by the patient's hypercatabolic state, hemodynamic instability, and volume status, as well as suboptimal vascular access with temporary venous catheters. The impact of intermittent hemodialysis (IHD) versus continuous renal replacement therapy (CRRT) on outcomes in ARF is also not clear. Patient disease severity impacts more than dialysis modality in patient outcome, but when patients are stratified for equal disease severity, CRRT may have potential benefits over IHD in terms of patient survival, fluid and metabolic control, and renal recovery. Strategies associated with improved outcomes that have emerged thus far in ARF are to aim for a time-averaged blood urea nitrogen (BUN) of less than 60 mg/dl with IHD, varying IHD frequency as necessary, or to achieve a minimum ultrafiltration rate of 35 ml/kg/hr with CRRT.     

The Acute Dialysis Quality Initiative--part IV: membranes for CRRT

The extracorporeal membrane used in a continuous renal replacement therapy (CRRT) for the treatment of a critically ill patient with acute renal failure (ARF) is vitally important for several reasons, including its influence on biocompatibility and filter performance. The clinical relevance of membrane-related biocompatibility markers traditionally used in chronic hemodialysis remains unclear in CRRT. Numerous approaches may be used to assess membrane and filter performance in CRRT, but no specific methodology is accepted widely at present. Although a potential benefit of certain membranes used for CRRT is adsorptive removal of inflammatory mediators, this issue has not been assessed carefully in well-designed clinical trials. These and other issues should be the subject of future clinical research efforts.     

Quality of pharmacokinetic studies in critically ill patients receiving continuous renal replacement therapy

Continuous renal replacement therapy (CRRT) is the preferred renal replacement therapy modality in the critically ill. We aimed to reveal the literature on the pharmacokinetic studies in critically ill patients receiving CRRT with special reference to quality assessment of these studies and the CRRT dose. We conducted a systematic review by searching the MEDLINE, EMBASE, and the Cochrane databases to December 2009 and bibliographies of relevant review articles. We included original studies reporting from critically ill adult subjects receiving CRRT because of acute kidney injury with a special emphasis on drug pharmacokinetics. We used the minimum reporting criteria for CRRT studies by Acute Dialysis Quality Initiative (ADQI) and, second, the Downs and Black checklist to assess the quality of the studies. We calculated the CRRT dose per study. We included pharmacokinetic parameters, residual renal function, and recommendations on drug dosing. Of 182 publications, 95 were considered relevant and 49 met the inclusion criteria. The median [interquartile range (IQR)] number of reported criteria by ADQI was 7.0 (5.0-8.0) of 12. The median (IQR) Downs and Black quality score was 15 (14-16) of 32. None of the publications reported CRRT dose directly. The median (IQR) weighted CRRT dose was 23.7 (18.8-27.9) ml/kg/h. More attention should be paid both to standardizing the CRRT dose and reporting of the CRRT parameters in pharmacokinetic studies. The general quality of the studies during CRRT in the critically ill was only moderate and would be greatly improved by reports in concordant with the ADQI recommendations.     

Dialysis membrane and modality in acute renal failure: understanding discordant meta-analyses

Meta-analyses of the published literature are increasingly being used, allowing similar clinical trials to be combined quantitatively, thereby increasing the precision of the estimation of treatment effect. Four meta-analyses were recently published comparing the impact of dialysis membranes or dialysis modality on clinical outcomes of patients with acute renal failure (ARF) requiring renal replacement therapy. Two studies compared dialysis membranes in intermittent hemodialysis (IHD) and two studies compared continuous renal replacement therapy (CRRT) to IHD. The findings between each pair of meta-analyses were discordant. This was due in part to the differences among meta-analyses in inclusion and exclusion criteria, the paucity of randomized controlled trials, variation in individual study quality, and heterogeneity in the study populations and settings. Understanding these issues is important to properly interpret results from these meta-analyses.     

Anticoagulation and continuous renal replacement therapy

More than half of patients with acute renal failure in the intensive care unit require dialysis, and the majority of them have significant hemodynamic instability. Continuous renal replacement therapy (CRRT) is often the preferred dialysis modality in these patients. One requirement for CRRT is anticoagulation, which can expose patients to the risk of bleeding. However, absence of effective anticoagulation may result in clotting of the CRRT circuit and subsequently less effective treatment. While heparins are widely used for anticoagulation, because of potential side effects such as bleeding and heparin-induced thrombocytopenia, alternative anticoagulation protocols should be considered. Citrate anticoagulation, regional heparin/protamine, predilution, r-hirudin, prostacyclin, and nafamostat are among these methods.     

Financial aspects of renal replacement therapy in acute kidney injury

Acute kidney injury (AKI) is associated with high morbidity and mortality and consumes substantial health-care resources, particularly when renal replacement therapy is required. Randomized controlled trials (RCTs) have not identified the optimal mode of renal replacement for AKI in terms of clinically relevant endpoints such as patient survival or recovery of renal function. As for other complex health interventions, the costs and consequences of AKI treatment are relevant to health-care providers and decision makers aiming to maximize health outcomes despite fixed health resources. Studies from several different centers suggest that continuous renal replacement therapy (CRRT) is more costly than intermittent hemodialysis and less economically attractive than even intensive intermittent dialysis. On the other hand, while the incremental costs of providing CRRT are significant, they remain relatively small compared with the projected costs of providing chronic dialysis to survivors who do not recover renal function. Even small differences in the risk of chronic dialysis in survivors are likely to determine the economic attractiveness of the different types of renal replacement therapies. To clarify the true incremental cost-effectiveness of these therapies, future RCTs should collect data on long-term survival, the need for chronic dialysis, and detailed information on costs.     

Overview of pediatric renal replacement therapy in acute renal failure

The disease spectrum leading to pediatric renal replacement therapy (RRT) provision has broadened over the last decade. In the 1980s, intrinsic renal disease and burns constituted the most common pediatric acute renal failure etiologies. More recent data demonstrate that pediatric acute renal failure (ARF) most often results from complications of other systemic diseases, resulting from advancements in congenital heart surgery, neonatal care, and bone marrow and solid organ transplantation. In addition, RRT modality preferences to treat critically ill children have shifted from peritoneal dialysis to continuous renal replacement therapy (CRRT) as a result of improvements in CRRT technologies. Currently, multicenter prospective outcome studies for critically ill children with ARF are sorely lacking. The aims of this article are to review the pediatric specific causes necessitating renal replacement therapy provision, with an emphasis on emerging practice patterns with respect to modality and the timing of treatment, and to focus upon the application of the different renal replacement therapy modalities and assessment of the outcome of children with ARF who receive renal replacement therapy.     

In Good Conscience—Safely Withholding Dialysis in the Elderly

Across the world, the incidence of end‐stage kidney disease is increasing in the elderly. However, they do not always fare very well on renal replacement therapy. Age at the start of dialysis, multiple comorbidities (especially if ischemic heart disease is one of them), diabetes, functional dependence, poor intellectual capacity, low serum albumin, peripheral vascular disease, and late referral have been associated with increased mortality on dialysis in various studies. Moreover, renal failure is only one of the many problems affecting the elderly and dialysis can potentially impair their quality of life tremendously. Therefore, it is often a challenge for the nephrologist to decide whether starting dialysis is in the best interest of the elderly patient. Is it sometimes nobler to provide supportive care without dialysis to an elderly patient with renal failure? Can dialysis be safely delayed where the nephrologist is uncertain of the prognosis or the patient is unsure whether or not to have dialysis? How robust is the evidence base to help inform discussion between the nephrologist and the patient/carer? What are the limitations in carrying out further research in this area? What does conservative management, which is better termed nondialytic supportive care, entail and how should it be delivered? This article aims to answer these fundamental questions confronting the nephrologist in day to day clinical practice.     

Withholding and withdrawing renal support in acute kidney injury

Management of critically ill patients with acute kidney injury (AKI) is mainly limited to supportive therapy, with dialysis as one of the main components. Whether or not to offer dialysis and when to withdraw dialysis is a one of the many choices physicians face in daily clinical practice. Withholding or withdrawing renal replacement therapy is a complex decision and depends on many interacting factors, which are unique for each patient and their families and for the care team. An evidence-based guideline with nine specific recommendations for managing patients has been available however is infrequently employed to help clinical decision making. In this review, we discuss the important issues affecting decisions to withhold or withdraw dialysis in AKI patients and provide an approach for making these decisions for patient management.     

Metabolic disturbances following the use of inadequate solutions for hemofiltration in acute renal failure

Continuous renal replacement therapy (CRRT) has become an important supportive therapy for critically ill children with acute renal failure. In Turkey, commercially available diafiltration and replacement fluids cannot be found on the market. Instead, peritoneal dialysis fluids for dialysis and normal saline as replacement fluid are used. The first objective of this study was to examine metabolic complications due to CRRT treatments. The second objective was to determine demographic characteristics and outcomes of patients who receive CRRT. We did a retrospective chart review of all pediatric patients treated with CRRT between February and December 2004. Thirteen patients received CRRT; seven survived (53.8%). All patients were treated with continuous venovenous hemodiafiltration. Median patient age was 71.8 ± 78.8 (1.5–180) months. Hyperglycemia occurred in 76.9% (n = 10), and metabolic acidosis occurred in 53.8% (n = 7) of patients. Median age was younger (48.8 vs.106.2 months), median urea level (106.2 vs. 71 mg/dl) and percent fluid overload (FO) (17.2% vs. 7.6%, respectively) were higher, and CRRT initiation time was longer (8.6 vs 5.6 days) in nonsurvivors vs. survivors for all patients, although these were not statistically significant. CRRT was stopped in all survivors, and four nonsurvivors (67%) were on renal replacement therapy at the time of death. Hyperglycemia and metabolic acidosis were frequently seen in CRRT patients when commercially available diafiltration fluids were not available. Using peritoneal dialysis fluid as dialysate is not a preferable solution. Early initiation of CRRT offered survival benefits to critically ill pediatric patients. Mortality was associated with the primary disease diagnosis.     

Blood Purification in the Intensive Care Unit: Evolving Concepts

Until relatively recently surgeons were familiar with the concept that some of their patients admitted to the intensive care unit require dialysis to deal with the development of severe acute renal failure. Under such circumstances the nephrology team would then attend the patient and take over that aspect of management. More recently, however, this situation has undergone a significant evolution because of the advent of continuous renal replacement therapy (CRRT). First introduced as "last ditch" therapy in the most critically ill patients who were hemodynamically intolerant of hemodialysis, CRRT has become more and more widely used. It is now the dominant form of artificial renal support in Australia and close to being the dominant treatment of the severe acute renal failure of critical illness in most European countries. The use of CRRT in the United States is rapidly growing. The arrival of CRRT has also renewed interest in the wider concept of blood purification during critical illness. Experimental and preliminary human data suggest that such blood purification therapies may indeed have beneficial immunomodulatory effects. Accordingly, CRRT is now being considered as a potential adjuvant treatment of septic shock and has even moved into the operating room as a tool for antiinflammatory therapy and volume control. The intensivist-surgeon and the general surgeon need to be aware of and understand these developments in extracorporeal therapy if they wish to make the full armamentarium of modern treatment available to their sickest patients.     

急性肾衰竭三种治疗方法的疗效对比观察

目的 :回顾性探讨治疗急性肾衰竭较理想的透析方法。方法 :对 2 3例HD患者和 2 0例PD患者及 17例CRRT患者进行比较 ,观察其治愈率、死亡率及透析后的主要并发症。结果 :HD组、PD组、CRRT组的治愈率分别为 82 .6 %、85 %、76 .5 % ;死亡率分别为 8.7%、0、17.6 %。腹膜透析并发症少。结论 :急性肾衰竭在缺少CRRT条件 ,病情允许情况下可首选腹膜透析治疗 ,严重病例、多器官衰竭还是选择CRRT为宜