Importance of early dialysis for acute renal failure after an open-heart surgery

Disease Severity Determines Timing of Initiating Continuous Renal Replacement Therapies: A Systematic Review and Meta-Analysis

Background: Timing of initiating continuous renal replacement therapies (CRRTs) among the patients with acute kidney injury (AKI) in intensive care units (ICU) has been discussed over decades, but the definition of early and late CRRT initiation is still unclear. Methods: The English language randomized controlled trials (RCTs) and cohort studies were searched through MEDLINE, EMBASE, and Cochrane Library on July 19, 2019, by the two researchers independently. The study characteristics; early and late definitions; outcomes, such as all-cause, in-hospital, 28- or 30-, 60-, 90-day mortality; and renal recovery were extracted from the 18 eligible studies. Pooled relative risk ratios (RRs) and 95% CIs were estimated with the fixed effects model and random effects model as appropriate. This study is registered with PROSPERO (CRD 42020158653). Results: Eighteen studies including 3,914 patients showed benefit in earlier CRRT (n = 1,882) over later CRRT (n = 2,032) in all-cause mortality (RR 0.78, 95% CI 0.66-0.92), in-hospital mortality (RR 0.81, 95% CI 0.67-0.99), and 28- or 30-day mortality (RR 0.81, 95% CI 0.74-0.88), but in 60- and 90-day mortalities, no significant benefit was observed. The subgroup analysis showed significant benefit in the disease-severity-based subgroups on early CRRT initiation in terms of in-hospital mortality and 28- or 30-day mortality rather than the time-based subgroups. Moreover, early CRRT was found to have beneficial effects on renal recovery after CRRT (RR 1.21, 95% CI 1.01-1.45). Conclusions: Overall, compared with late CRRT, early CRRT is beneficial for short-term survival and renal recovery, especially when the timing was defined based on the disease severity. CRRT initiation on Acute Kidney Injury Network (AKIN) stage 1 or Risk, Injury, Failure, Loss of kidney function, and End-stage kidney disease (RIFLE)-Risk or less may lead to a better prognosis.

Comparison between watchful waiting strategy and early initiation of renal replacement therapy in the critically ill acute kidney injury population: an updated systematic review and meta-analysis

BACKGROUND

The optimal timing of renal replacement therapy (RRT) initiation is debatable. Many articles in this field enrolled trials not based on acute kidney injury. The safety of the watchful waiting strategy has not been fully discussed, and late RRT initiation criteria vary across studies. The effect of early RRT initiation in the AKI population with high plasma neutrophil gelatinase-associated lipocalin (NGAL) has not been examined yet.

METHODS

In accordance with PRISMA guidelines, the PubMed, Embase, and Cochrane databases were systemically searched for randomized controlled trials (RCTs). Trials not conducted in the AKI population were excluded. Data of study characteristics, primary outcome (all-cause mortality), and related secondary outcomes [mechanical ventilation (MV) days, length of hospital stay, RRT days, and length of ICU stay] were extracted. The outcomes were compared between early and late RRT groups by estimating the pooled odds ratio (OR) for binary outcomes and the weighted mean difference for continuous outcomes. Prospective trials were also examined and analyzed using the same method.

RESULTS

Nine RCTs with 1938 patients were included. Early RRT did not provide a survival benefit (pooled OR, 0.88; 95% confidence interval [CI] 0.62-1.27). However, the early RRT group had significantly fewer MV days (pooled mean difference, - 3.98 days; 95% CI - 7.81 to - 0.15 days). Subgroup analysis showed that RCTs enrolling the surgical population (P = .001) and the AKI population with high plasma NGAL (P = .031) had favorable outcomes regarding RRT days in the early initiation group. Moreover, 6 of 9 RCTs were selected for examining the safety of the watchful waiting strategy, and no significant differences were found in primary and secondary outcomes between the early and late RRT groups.

CONCLUSIONS

Overall, early RRT initiation did not provide a survival benefit, but a possible benefit of fewer MV days was detected. Early RRT might also provide the benefit of shorter MV or RRT support in the surgical population and in AKI patients with high plasma NGAL. Depending on the conventional indication for RRT initiation, the watchful waiting strategy is safe on the basis of all primary and secondary outcomes.

External validation of predictive models for acute kidney injury following cardiac surgery: A prospective multicentre cohort study

BACKGROUND

Four predictive models for acute kidney injury associated with cardiac surgery were developed by Demirjian in the United States in 2012. However, the usefulness of these models in clinical practice needs to be established in different populations independent of that used to develop the models.

OBJECTIVES

Our aim was to evaluate the predictive performance of these models in a Spanish population.

DESIGN

A multicentre, prospective observational study.

DATA SOURCES

Twenty-three Spanish hospitals in 2012 and 2013.

ELIGIBILITY CRITERIA

Of 1067 consecutive cardiac patients recruited for the study, 1014 patients remained suitable for the final analysis.

MAIN OUTCOME MEASURES

Dialysis therapy, and a composite outcome of either a doubling of the serum creatinine level or dialysis therapy, in the 2 weeks (or until discharge, if sooner) after cardiac surgery.

RESULTS

Of the 1014 patients analysed, 34 (3.4%) required dialysis and 95 (9.4%) had either dialysis or doubled their serum creatinine level. The areas under the receiver operating characteristic curves of the two predictive models for dialysis therapy, which include either presurgical variables only, or combined presurgical and intrasurgical variables, were 0.79 and 0.80, respectively. The model for the composite endpoint that combined presurgical and intrasurgical variables showed better discriminatory ability than the model that included only presurgical variables: the areas under the receiver operating characteristic curves were 0.76 and 0.70, respectively. All four models lacked calibration for their respective outcomes in our Spanish population.

CONCLUSION

Overall, the lack of calibration of these models and the difficulty in using the models clinically because of the large number of variables limit their applicability.

Sex differences in acute kidney injury requiring dialysis

Background

Female sex has been included as a risk factor in models developed to predict the risk of acute kidney injury (AKI) associated with cardiac surgery, aminoglycoside nephrotoxicity and contrast-induced nephropathy. The commentary acompanying the Kidney Disease Improving Global Outcomes Clinical Practice Guideline for Acute Kidney Injury concludes that female sex is a shared susceptibility factor for acute kidney injury based on observations that female sex is associated with the development of hospital-acquired acute kidney injury. In contrast, female sex is reno-protective in animal models. In this context, we sought to examine the role of sex in hospital-associated acute kidney injury in greater detail.

Methods

We utilized the Hospital Episode Statistics database to calculate the sex-stratified incidence of AKI requiring renal replacement therapy (AKI-D) among 194,157,726 hospital discharges reported for the years 1998–2013. In addition, we conducted a systematic review of the English literature to evaluate dialysis practices among men versus women with AKI.

Results

Hospitalized men were more likely to develop AKI-D than hospitalized women (OR 2.19 (2.15, 2.22) p < 0.0001). We found no evidence in the published literature that dialysis practices differ between men and women with AKI.

Conclusions

Based on a population of hospitalized patients which is more than 3 times larger than all previously published cohorts reporting sex-stratified AKI data combined, we conclude that male sex is associated with an increased incidence of hospital-associated AKI-D. Our study is among the first reports to highlight the protective role of female gender in AKI.

Issues of Acute Kidney Injury Staging and Management in Sepsis and Critical Illness: A Narrative Review

Acute kidney injury (AKI) has a high incidence on intensive care units around the world and is a major complication in critically ill patients suffering from sepsis or septic shock. The short- and long-term complications are thereby devastating and impair the quality of life. Especially in terms of AKI staging, the determination of kidney function and the timing of dialytic AKI management outside of life-threatening indications are ongoing matters of debate. Despite several studies, a major problem remains in distinguishing between beneficial and unnecessary "early" or even harmful renal replacement therapy (RRT). The latter might prolong disease course and renal recovery. AKI scores, however, provide an insufficient outcome-predicting ability and the related estimation of kidney function via serum creatinine or blood urea nitrogen (BUN)/urea is not reliable in AKI and critical illness. Kidney independent alterations of creatinine- and BUN/urea-levels further complicate the situation. This review critically assesses the current AKI staging, issues and pitfalls of the determination of kidney function and RRT timing, as well as the potential harm reflected by unnecessary RRT. A better understanding is mandatory to improve future study designs and avoid unnecessary RRT for higher patient safety and lower health care costs.

Early versus late initiation of renal replacement therapy impacts mortality in patients with acute kidney injury post cardiac surgery: a meta-analysis

Background

Acute kidney injury (AKI) is a common clinical complication of cardiac surgery and increases mortality and hospitalization. We aimed to explore and perform an updated meta-analysis of qualitative and quantitative evaluations of the relationship between early renal replacement therapy (RRT) and mortality.

Methods

We searched the Chinese Biomedical Database, the Cochrane Library, EMBASE, Global Health, MEDLINE and PubMed.

Results

Fifteen studies (five randomized controlled trials (RCTs), one prospective cohort and nine retrospective cohorts) including 1479 patients were identified for detailed evaluation. The meta-analysis suggested that early RRT initiation reduced 28-day mortality (odds ratio (OR) 0.36; 95% confidence interval (CI) 0.23 to 0.57; I² 60%), and shortened intensive care unit (ICU) length of stay (LOS) (mean difference (MD) -2.50; 95% CI -3.53 to -1.47; I² 88%) and hospital LOS (MD -0.69; 95% CI -1.13 to -0.25; I² 88%), and also reduced the duration of RRT (MD -1.18; 95% CI -2.26 to -0.11; I² 69%), especially when RRT was initiated early within 12 hours (OR 0.23; 95% CI 0.08 to 0.63; I² 73%) and within 24 hours (OR 0.52; 95% CI 0.28 to 0.95; I² 58%) in patients with AKI after cardiac surgery.

Conclusions

Early RRT initiation decreased 28-day mortality, especially when it was started within 24 hours after cardiac surgery in patients with AKI.

The optimal time of initiation of renal replacement therapy in acute kidney injury: A meta-analysis

Background

The impact on the timing of renal replacement therapy (RRT) initiation on clinical outcomes for patients with acute kidney injury (AKI) remains controversial.

Materials and methods

We searched the Cochrane Library, EMBASE, Global Health, MEDLINE, PubMed, the International Clinical Trials Registry Platform, and Web of Science.

Results

We included 49 studies involving 9698 patients. Pooled analysis of 5408 critically ill patients with AKI showed that early RRT was significantly associated with reduced mortality compared to late RRT [odds ratio (OR), 0.40; 95% confidential intervals (CI), 0.32 - 0.48; I², 50.2%]. For 4290 non-critically ill patients with AKI, there was no statistically significant difference in the risk of mortality between early and late RRT (OR, 1.07; 95% CI, 0.79 - 1.45; I², 73.0%). Early RRT was markedly associated with shortened intensive care units (ICU) length of stay (LOS) and hospital LOS compared to late RRT in both critically ill and non-critically ill patients with AKI.

Conclusions

Early RRT probably reduce the mortality, ICU and hospital LOS in critically ill patients with AKI. Inversely, early RRT in non-critically ill patients with AKI did not decrease the mortality, but shortened the ICU and hospital LOS.

The effect of early versus late initiation of renal replacement therapy in patients with acute kidney injury: A meta-analysis with trial sequential analysis of randomized controlled trials

BACKGROUND

The optimal timing for initiating renal replacement therapy (RRT) in patients with acute kidney injury (AKI) remains controversial.

METHODS

We conducted a meta-analysis with trial sequential analysis (TSA) of randomized controlled trials (RCTs) using PUBMED, Cochrane Library databases, and Web of Science (from January 1, 1985, to August 21, 2016). Adult patients with AKI who received RRT with different timing were included. The primary outcome was mortality. The secondary outcomes were intensive care unit (ICU) length of stay (LOS) and hospital LOS.

RESULTS

We included 9 RCTs with a total of 1636 participants. No differences between the early RRT group and the late RRT group were found with respect to mortality (38% vs 41.4%; relative risk, 0.93; 95% confidence interval [CI], 0.74-1.18). However, TSA showed that the cumulative Z-curve did not cross either the conventional boundary for benefit or the trial sequential monitoring boundary, indicating insufficient evidence. Similarity, there were no findings of benefits in terms of reduction in the ICU LOS (standard difference in the means, -0.32 days; 95% CI, -0.71 to 0.07 days) and hospital LOS (standard difference in the means, -1.11 days; 95% CI, -2.28 to 0.06 days). Meanwhile, the results of TSA did not confirm this conclusion.

CONCLUSIONS

Although conventional meta-analysis showed that early initiation of RRT in patients with AKI was not associated with decreased mortality, ICU LOS and hospital LOS, TSA indicated that the data were far too sparse to make any conclusions. Therefore, well-designed, large RCTs are needed.

Initiation time of renal replacement therapy on patients with acute kidney injury: A systematic review and meta-analysis of 8179 participants

The early initiation of renal replacement therapy has been recommended for patients with acute renal failure by some studies, but its effects on mortality and renal recovery are unknown. We conducted an updated meta-analysis to provide quantitative evaluations of the association between the early initiation of renal replacement therapy and mortality for patients with acute kidney injury. After applying inclusion/exclusion criteria, 51 studies, including 10 randomized controlled trials, with a total of 8179 patients were analyzed. Analysis of the included trials showed that patients receiving early renal replacement therapy had a 25% reduction in all-cause mortality compared to those receiving late renal replacement therapy (risk ratio [RR] 0.75, 95% CI [0.69, 0.82]). We also noted a 30% increase in renal recovery (RR 1.30, 95% CI [1.07, 1.56]), a reduction in hospitalization of 5.84 days (mean difference [MD], 95% CI [-10.27, -1.41]) and a reduction in the duration of mechanical ventilation of 2.33 days (MD, 95% CI [-3.40, -1.26]) in patients assigned to early renal replacement therapy. The early initiation of renal replacement therapy was associated with a decreased risk of all-cause mortality compared with the late initiation of RRT in patients with acute kidney injury. These findings should be interpreted with caution given the heterogeneity between studies. Further studies are needed to identify the causes of mortality and to assess whether mortality differs by dialysis dose.

Prophylactic furosemide infusion decreasing early major postoperative renal dysfunction in on-pump adult cardiac surgery: a randomized clinical trial

INTRODUCTION

Acute renal dysfunction is a common complication of cardiac surgery. Furosemide is used in prevention, or treatment, of acute renal dysfunction. This study was conducted to evaluate the protective effects of intra- and early postoperative furosemide infusion on preventing acute renal dysfunction in elective adult cardiac surgery.

METHODS

Eighty-one patients, candidates of elective cardiac surgery, were enrolled in this study in either the furosemide (n=41) or placebo (n=40) group. Furosemide (2 mg/h) or 0.9% saline was administered and continued up to 12 hours postoperatively. We measured serum creatinine (Scr) at preoperative and on the second and fifth postoperative days. Then calculated estimated glomerular filtration rate (eGFR) at these times. An increase in Scr of >0.5 mg/dL and/or >25%-50%, compared to preoperative values, was considered as acute kidney injury (AKI). In contrast, an increase in Scr by >50% and/or the need for hemodialysis was regarded as acute renal failure (ARF). At the end we compared the AKI or ARF incidence between the two groups.

RESULTS

On the second and fifth postoperative days, Scr was lower, and the eGFR was higher in the furosemide group. AKI incidence was similar in the two groups (11 vs 12 cases; P-value 0.622); however, ARF rate was lower in furosemide group (1 vs 6 cases; P-value 0.044). During the study period, Scr was more stable in the furosemide group, however in the placebo group, Scr initially increased and then decreased to its preoperative value after a few days.

CONCLUSION

This study showed that intra- and early postoperative furosemide infusion has a renal protective effect in adult cardiac surgery with cardiopulmonary bypass. Although this protective effect cannot be discovered in mild renal dysfunctions, it apparently reduces the rate of the more severe renal dysfunctions. A more multidisciplinary strategy may be needed in reducing the milder renal damage.

Renal Replacement Therapy in Acute Kidney Injury: Controversies and Consensus

Acute kidney injury (AKI) is a common complication among critically ill patents, and 5% of intensive care unit (ICU) patients require initiation of renal replacement therapy (RRT). In recent years, clinical trials have provided evidence-based guidance for some important aspects of RRT management in patients with AKI, such as dialysis dosing and approaches to anticoagulation in patients undergoing continuous RRT. However, there remain many areas of uncertainty, and delivery of RRT in the ICU requires clinical judgment, flexibility, and an understanding of dialysis principles. This article reviews the components of RRT prescription and provides an update on best practices.

Early initiation of renal replacement treatment in patients with acute kidney injury: A systematic review and meta-analysis

BACKGROUND

Acute kidney injury (AKI) is associated with a substantially increased risk of mortality for many hospitalized patients. It has been suggested that early initiation of renal replacement treatment has a favorable outcome in critically ill patients complicated with AKI. However, results of studies evaluating the effect of early initiation strategy of renal replacement treatment on AKI have been controversial and contradictory. The aim of this meta-analysis is to examine the effect of early initiation of renal replacement treatment on patients with AKI.

METHODS

The authors searched relevant studies in PubMed, EMBASE, and the Cochrane Library through August 2016. We searched for all eligible randomized controlled trials with regard to the role of early initiation of renal replacement treatment in mortality among patients with AKI. We extracted the following information from each study: mortality, length of stay in intensive care unit (ICU), and length of stay in hospital. Random and fixed effect models were used for pooling data.

RESULTS

Twelve trials including 1756 patients were included. The results of this meta-analysis showed that there was no significant difference between the mortality of early and delayed strategy for the initiation of renal replacement treatment using the random effect model (odds ratio = 0.78; 95% confidence interval [CI], 0.52-1.19; P = 0.25), with wild heterogeneity (chi = 33.50; I = 67%). Analyses from subgroup sepsis and postsurgery came to similar results. In addition, compared with delayed initiation strategy, early initiation showed no significant advantage in length of stay in ICU (mean difference = -0.80; 95% CI, -2.59 to 0.99; P = 0.56) and length of stay in hospital (mean difference = -7.69; 95% CI, -16.14 to 0.76; P = 0.07).

CONCLUSION

According to the results from present meta-analysis, early initiation of renal replacement treatment showed no survival benefits in patients with AKI. To achieve optimal timing of renal replacement treatment, further large multicenter randomized trials, with widely accepted and standardized definition of early initiation, are still needed.

A comparison of preemptive versus standard renal replacement therapy for acute kidney injury after cardiac surgery

BACKGROUND

The optimal timing of renal replacement therapy (RRT) initiation in patients undergoing cardiac surgery remains controversial. This study aimed to determine whether preemptive RRT or standard RRT was associated with hospital mortality in cardiac surgical patients with acute kidney injury (AKI).

METHODS

Data were retrospectively collected from patients who underwent cardiac surgery and experienced postoperative AKI requiring RRT at Zhongshan Hospital of Fudan University from September 1, 2006 to December 31, 2013. The patients were divided into two groups according to the RRT strategy applied.

RESULTS

A total of 213 patients were enrolled in this study; 59 patients were categorized into the preemptive RRT group and 154 into the standard RRT group. The preemptive RRT group exhibited significantly lower mortality (33.90% versus 51.95%, P = 0.018) and time to recovery of renal function than the standard RRT group (15.34 ± 14.46 versus 22.88 ± 14.08 d, P = 0.022). Moreover, the preemptive RRT group showed significantly lower serum creatinine levels and higher proportions of recovery of renal function and weaning from RRT at death or discharge than the standard RRT group. There was no significant difference in the duration of mechanical ventilation, RRT, intensive care unit stay, or hospital stay between the two groups.

CONCLUSIONS

In patients after cardiac surgery, preemptive RRT was associated with lower hospital mortality and faster and more frequent recovery of renal function than standard RRT. However, preemptive RRT did not affect other patient-centered outcomes including mechanical ventilation time, RRT time, or length of intensive care unit or hospital stay.

The impact of "early" versus "late" initiation of renal replacement therapy in critical care patients with acute kidney injury: a systematic review and evidence synthesis

BACKGROUND

The optimal timing of initiating renal replacement therapy (RRT) in critical illness complicated by acute kidney injury (AKI) is not clearly established. Trials completed on this topic have been marked by contradictory findings as well as quality and heterogeneity issues. Our goal was to perform a synthesis of the evidence regarding the impact of "early" versus "late" RRT in critically ill patients with AKI, focusing on the highest-quality research on this topic.

METHODS

A literature search using the PubMed and Embase databases was completed to identify studies involving critically ill adult patients with AKI who received hemodialysis according to "early" versus "late"/"standard" criteria. The highest-quality studies were selected for meta-analysis. The primary outcome of interest was mortality at 1 month (composite of 28- and 30-day mortality). Secondary outcomes evaluated included intensive care unit (ICU) and hospital length of stay (LOS).

RESULTS

Thirty-six studies (seven randomized controlled trials, ten prospective cohorts, and nineteen retrospective cohorts) were identified for detailed evaluation. Nine studies involving 1042 patients were considered to be of high quality and were included for quantitative analysis. No survival advantage was found with "early" RRT among high-quality studies with an OR of 0.665 (95 % CI 0.384-1.153, p = 0.146). Subgroup analysis by reason for ICU admission (surgical/medical) or definition of "early" (time/biochemical) showed no evidence of survival advantage. No significant differences were observed in ICU or hospital LOS among high-quality studies.

CONCLUSIONS

Our conclusion based on this evidence synthesis is that "early" initiation of RRT in critical illness complicated by AKI does not improve patient survival or confer reductions in ICU or hospital LOS.

Contrast-induced nephropathy in CT: incidence, risk factors and strategies for prevention

In the past, a high percentage of hospital-acquired renal failure was attributed to contrast media. That position is now very controversial. Recently, doubts have been raised regarding the real relationship between acute kidney injury and intravenous contrast media administration. Similarly, statements about specific methods of preventing contrast-inducing nephropathy have been challenged. This review article addresses the controversies of incidence, causation, and prevention in an attempt to help the practicing radiologist adopt methods for their own department.

KEY POINTS

• The reported CIN incidence ranges from 2-12 % following contrast-enhanced CT. • Studies without a non-contrast CT control group may overestimate CIN incidence. • Development and application of a comprehensive CIN prevention strategy is recommended.

Renal replacement therapy in adult and pediatric intensive care : Recommendations by an expert panel from the French Intensive Care Society (SRLF) with the French Society of Anesthesia Intensive Care (SFAR) French Group for Pediatric Intensive Care Emergencies (GFRUP) the French Dialysis Society (SFD)

Acute renal failure (ARF) in critically ill patients is currently very frequent and requires renal replacement therapy (RRT) in many patients. During the last 15 years, several studies have considered important issues regarding the use of RRT in ARF, like the time to initiate the therapy, the dialysis dose, the types of catheter, the choice of technique, and anticoagulation. However, despite an abundant literature, conflicting results do not provide evidence on RRT implementation. We present herein recommendations for the use of RRT in adult and pediatric intensive care developed with the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system by an expert group of French Intensive Care Society (SRLF), with the participation of the French Society of Anesthesia and Intensive Care (SFAR), the French Group for Pediatric Intensive Care and Emergencies (GFRUP), and the French Dialysis Society (SFD). The recommendations cover 4 fields: criteria for RRT initiation, technical aspects (access routes, membranes, anticoagulation, reverse osmosis water), practical aspects (choice of the method, peritoneal dialysis, dialysis dose, adjustments), and safety (procedures and training, dialysis catheter management, extracorporeal circuit set-up). These recommendations have been designed on a practical point of view to provide guidance for intensivists in their daily practice.

Effects of renal replacement therapy on renal recovery after acute kidney injury

Recovery of kidney function following an episode of acute kidney injury (AKI) is now acknowledged as a vital patient-centered outcome with clear health economic implications. In approximately 5-8% of critically ill patients with more severe forms of AKI, support with renal replacement therapy (RRT) is provided. Recent data have suggested that rates of RRT utilization in AKI are increasing. Despite advances in our understanding of how best to prescribe acute RRT in critically ill patients with AKI, additional aspects remain uncertain, predisposing to suboptimal delivery and variation in practice. Importantly, if, when, how, and by what principles we apply acute RRT for AKI are all treatment decision-related factors that are modifiable and may interact with recovery of kidney function. Limited data, mostly from observational studies and secondary analyses, have explored the specific association between acute RRT and recovery. Available data are not able to clarify whether providing any RRT in otherwise eligible patients with AKI impacts recovery. They are also unable to inform whether the timing or circumstance under which RRT is started impacts recovery. No studies have evaluated whether there is an optimal time to start RRT to maximize the probability of recovery. Accumulated evidence, mostly derived from observational studies, suggests initial therapy in critically ill patients with AKI with continuous RRT, compared with intermittent modalities, improves the probability of recovery to dialysis independence. Evidence from high-quality randomized trials failed to show any association between delivered dose intensity of RRT and recovery. The use of biocompatible membranes for acute RRT may improve recovery in AKI; however, data are inconsistent. Limited data have evaluated the impact of membrane flux properties on recovery. Preliminary data have suggested that circuit anticoagulation with citrate, which results in a reduction in membrane-induced oxidative stress and leukocyte activation, may be associated with improved recovery; however, further corroborative data are needed. Additional evidence, ideally from randomized trials, is clearly needed to inform best practice in the delivery of acute RRT to optimize probability of recovery of kidney function for survivors of AKI.

Timing of continuous renal replacement therapy and mortality in critically ill children*

OBJECTIVES

Acute kidney injury and fluid overload frequently necessitate initiation of continuous renal replacement therapy in critically ill patients admitted to the ICU. In this study, our primary objective was to determine the effect of timing of initiation of continuous renal replacement therapy on ICU mortality in children requiring renal support for management of acute kidney injury and/or fluid overload.

DESIGN

Retrospective cohort study.

SETTING

Tertiary level, multidisciplinary PICU.

PATIENTS

Children who received continuous renal replacement therapy for management of acute kidney injury and/or fluid overload from January 2000 through July 2009 were included in the study. Patients requiring extracorporeal life support and patients initiated on continuous renal replacement therapy for indications other than acute kidney injury and/or fluid overload were excluded.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Timing of initiation was defined chronologically as time from ICU admission to continuous renal replacement therapy initiation. Three hundred eighty treatments were performed during the study period, of which 190 were eligible and included in the study. Overall ICU mortality was 47% among the study population. Median timing of initiation was higher among nonsurvivors compared with survivors (3.4 vs 2.0 d, p = 0.001). Multivariable logistic regression analysis identified timing of initiation as an independent predictor of mortality with an adjusted odds ratio of 1.05 (95% CI, 1.01, 1.11). Fluid overload, indication for continuous renal replacement therapy initiation, severity of illness at ICU admission, and active oncologic diagnosis were the other independent predictors of mortality that were identified in the final regression model. In the survival analysis, late initiators (> 5 d) had higher mortality than early initiators (≤ 5 d) with a hazard ratio of 1.56 (95% CI, 1.02, 2.37).

CONCLUSIONS

Earlier initiation of continuous renal replacement therapy was associated with lower mortality in this cohort of critically ill children. Future studies should focus on early identification of such children who may benefit from early continuous renal replacement therapy initiation.

Early versus late initiation of renal replacement therapy in critically ill patients with acute kidney injury after cardiac surgery: a systematic review and meta-analysis

OBJECTIVE

To investigate the impact of early versus late renal replacement therapy (RRT) on mortality in patients with acute kidney injury (AKI) after cardiac surgery.

DESIGN

Meta-analysis of 9 retrospective cohort studies and 2 randomized clinical trials extracted from the Medline engine from 1950 to 2013.

SETTING

University medical school.

PARTICIPANTS

841 Patients.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 841 patients were studied. Pooled estimates of the odds ratio with 95% confidence interval using a random-effect model were conducted as well as the heterogeneity, publication bias, and sensitivity analysis. Primary outcome was 28-day mortality, and secondary outcome was the intensive care unit (ICU) length of stay. The 28-days mortality rate was lower in the early RRT group (OR = 0.29, 95% CI, 0.16-0.52, p<0.0001, NNT = 5). Heterogeneity was high (I2 = 56%), and publication bias was low. Secondary outcome suggested 3.9 (1.5-6.3) days shorter ICU stay in the early RRT group, p<0.0001, with extremely high heterogeneity (I(2) = 99%), and low publication bias. Specifically, studies before 2000 and studies with mortality less than 50% in the late RRT group reported significantly higher odds ratio and mean difference than overall value favoring early RRT.

CONCLUSION

Early initiation of RRT for patients with AKI after cardiac surgery revealed lower 28-days mortality and shorter ICU length of stay. However, this was based on 11 studies of various qualities with very high heterogeneity of results. Defining treatment guidelines needs further research with a larger and better database.

Acute renal dysfunction: time from coronary angiography to cardiac surgery

Background

The incidence of acute renal dysfunction has not changed much over the years, despite improvements in perioperative care. Our objectives were to evaluate the impact of timing of cardiac surgery after coronary angiography on acute renal dysfunction, to identify risk factors associated with development of acute renal dysfunction, and to measure the association between acute renal dysfunction and mortality.

Patients and methods

The patients were divided into 3 groups: group A (cardiac surgery 0–3 days after angiography), group B (surgery 4–6 days after angiography), and group C (surgery > 6 days after angiography). Endpoints were acute renal dysfunction, defined as serum creatinine > 25% of baseline on the 3rd postoperative day, and mortality.

Results

In 749 patients, the incidence of acute renal dysfunction was 15%; 5% required dialysis. Hypertension, congestive heart failure, chronic obstructive pulmonary disease, ejection fraction < 40%, prolonged cardiopulmonary bypass time, intraaortic balloon pump use, and urgent surgery were risk factors for acute renal dysfunction after cardiac surgery. Patients in group C had a lower risk of acute renal dysfunction.

Conclusion

Acute renal dysfunction has a definite relationship with the time period between angiography and cardiac surgery. The causative factors for this condition are multiple and also show a consistent association with mortality.

Timing of renal replacement therapy initiation by AKIN classification system

INTRODUCTION

Previous studies using Acute Kidney Injury Network (AKIN)/RIFLE criteria to classify early initiation of renal replacement therapy (RRT) have defined it as the therapy started in less severe AKIN/RIFLE stages. Generally, these studies failed in demonstrating measurable benefits.

METHODS

We compared RRT initiation in critically ill patients and defined early or late RRT in reference to timing after stage 3 AKIN was met: patients beginning RRT within 24 hours after acute kidney injury (AKI) stage 3 were considered early starters. AKIN criteria were evaluated by both urine output (UO) and serum creatinine (sCr) and patients with acute-on-chronic kidney disease were excluded. A propensity score methodology was used to control variables.

RESULTS

A total of 358 critically ill patients were submitted to RRT. Only 150 patients with pure AKI at stage 3 were analyzed. Mortality was lower in the early RRT group (51.5 vs. 77.9%, P=0.001). After achieving balance between the groups using a propensity score, there was a significant 30.5 (95% confidence interval [CI] 14.4 to 45.2%, P=0.002) relative decrease of mortality in the early RRT group. Moreover, patients on the early RRT group had lower duration of mechanical ventilation, time on RRT and a trend to lower intensive care unit (ICU) length of stay.

CONCLUSIONS

For the first time, AKIN was used with UO criterion to evaluate early and late RRT. Using a time-based approach could be a better parameter to access the association between RRT initiation and outcomes in patients with AKI.

Choice of renal replacement therapy modality and dialysis dependence after acute kidney injury: a systematic review and meta-analysis

PURPOSE

Choice of renal replacement therapy (RRT) modality may affect renal recovery after acute kidney injury (AKI). We sought to compare the rate of dialysis dependence among severe AKI survivors according to the choice of initial renal replacement therapy (RRT) modality applied [continuous (CRRT) or intermittent (IRRT)].

METHODS

Systematic searches of peer-reviewed publications in MEDLINE and EMBASE were performed (last update July 2012). All studies published after 2000 reporting dialysis dependence among survivors from severe AKI requiring RRT were included. Data on follow-up duration, sex, age, chronic kidney disease, illness severity score, vasopressors, and mechanical ventilation were extracted when available. Results were pooled using a random-effects model.

RESULTS

We identified 23 studies: seven randomized controlled trials (RCTs) and 16 observational studies involving 472 and 3,499 survivors, respectively. Pooled analyses of RCTs showed no difference in the rate of dialysis dependence among survivors (relative risk, RR 1.15 [95 % confidence interval (CI) 0.78-1.68], I(2) = 0 %). However, pooled analyses of observational studies suggested a higher rate of dialysis dependence among survivors who initially received IRRT as compared with CRRT (RR 1.99 [95 % CI 1.53-2.59], I (2) = 42 %). These findings were consistent with adjusted analyses (performed in 7/16 studies), which found a higher rate of dialysis dependence in IRRT-treated patients [odds ratio (OR) 2.2-25 (5 studies)] or no difference (2 studies).

CONCLUSIONS

Among AKI survivors, initial treatment with IRRT might be associated with higher rates of dialysis dependence than CRRT. However, this finding largely relies on data from observational trials, potentially subject to allocation bias, hence further high-quality studies are necessary.

Renal replacement therapy in acute kidney injury

Although the use of renal replacement therapy (RRT) to support critically ill patients with acute kidney injury (AKI) has become routine, many of the fundamental questions regarding optimal management of RRT remain. This review summarizes current evidence regarding the timing of initiation of RRT, the selection of the specific modality of RRT, and prescription of the intensity of therapy. Although absolute indications for initiating RRT-such as hyperkalemia and overt uremic symptoms-are well recognized, the optimal timing of therapy in patients without these indications continues to be a subject of debate. There does not appear to be a difference in either mortality or recovery of kidney function associated with the various modalities of RRT. Finally, providing higher doses of RRT is not associated with improved clinical outcomes.

Timing for initiation of continuous renal replacement therapy in patients with septic shock and acute kidney injury

The optimal timing for renal replacement therapy initiation in septic acute kidney injury (AKI) remains controversial. This study investigates the impact of early versus late initiation of continuous renal replacement therapy (CRRT) on organ dysfunction among patients with septic shock and AKI. Patients were dichotomized into "early" (simplified RIFLE Risk) or "late" (simplified RIFLE Injury or Failure) CRRT initiation. Patients with chronic kidney disease stage 5 or those on long-term dialysis were excluded. Organ dysfunction was quantified by Sequential Organ Failure Assessment (SOFA) score. From January 2008 to June 2011, 120 patients fulfilled the inclusion criteria. Thirty-one (26%) underwent "early" while 89 (74%) had "late" CRRT. No significant difference was noted between groups on improvement of total SOFA/non-renal SOFA score or noradrenaline equivalent in the first 24 and 48 h after CRRT initiation. Dialysis requirement and mortality (at 28 days, 3 months and 6 months) did not differ. In conclusion, improvement of non-renal SOFA score 48 h after CRRT correlated with SOFA score on CRRT initiation (P = 0.040) and APACHE IV risk of death (P = 0.000), but not estimated glomerular filtration rate on CRRT initiation (P = 0.377). Improvement of non-renal SOFA score correlated with SOFA score on CRRT initiation and APACHE IV risk of death. However, this retrospective review cannot identify any significant clinical benefit of early CRRT initiation in patients presenting with septic shock and AKI.

U-curve association between timing of renal replacement therapy initiation and in-hospital mortality in postoperative acute kidney injury

Background

Postoperative acute kidney injury (AKI) is associated with poor outcomes in surgical patients. This study aims to evaluate whether the timing of renal replacement therapy (RRT) initiation affects the in-hospital mortality of patients with postoperative AKI.

Methodology

This multicenter retrospective observational study, which was conducted in the intensive care units (ICUs) in a tertiary hospital (National Taiwan University Hospital) and its branch hospitals in Taiwan between January, 2002, and April, 2009, included adult patients with postoperative AKI who underwent RRT for predefined indications. The demographic data, comorbid diseases, types of surgery and RRT, and the indications for RRT were documented. Patients were categorized according to the period of time between the ICU admission and RRT initiation as the early (EG, ≦1 day), intermediate (IG, 2–3 days), and late (LG, ≧4 days) groups. The in-hospital mortality rate censored at 180 day was defined as the endpoint.

Results

Six hundred forty-eight patients (418 men, mean age 63.0±15.9 years) were enrolled, and 379 patients (58.5%) died during the hospitalization. Both the estimated probability of death and the in-hospital mortality rates of the three groups represented U-curves. According to the Cox proportional hazard method, LG (hazard ratio, 1.527; 95% confidence interval, 1.152–2.024; P = 0.003, compared with IG group), age (1.014; 1.006–1.021), diabetes (1.279; 1.022–1.601; P = 0.031), cirrhosis (2.147; 1.421–3.242), extracorporeal membrane oxygenation support (1.811; 1.391–2.359), initial neurological dysfunction (1.448; 1.107–1.894; P = 0.007), pre-RRT mean arterial pressure (0.988; 0.981–0.995), inotropic equivalent (1.006; 1.001–1.012; P = 0.013), APACHE II scores (1.055; 1.037–1.073), and sepsis (1.939; 1.536–2.449) were independent predictors of the in-hospital mortality (All P<0.001 except otherwise stated).

Conclusions

The current study found a U-curve association between the timing of the RRT initiation after the ICU admission and patients’ in-hospital mortalities, and alerts physicians of certain factors affecting the outcome after the RRT initiation.

Timing of initiation of renal replacement therapy in acute kidney injury: a systematic review and meta-analysis

OBJECTIVE

The aim of the study is to summarize the effects of timing of initiation of renal replacement therapy (RRT) on mortality.

METHODS

A systematic search for randomized controlled trials (RCTs) and other clinical studies was performed without language restriction in PubMed, Web of Science, and Embase. We estimated pooled relative risk ratios (RRs) and 95% confidence intervals (CIs) using fixed effects model or random effects model as appropriate. Heterogeneity, publication bias, and subgroup analyses were conducted.

RESULTS

We analyzed the date extracted from 15 studies (3 RCTs, 2 prospective, and 10 retrospective comparative cohort studies) with a total of 2955 patients. Overall, 51.0% (772/1514) patients died in the "early" RRT group compared with 58.0% (836/1441) in the "late" RRT group. The pooled RR was 0.71 (95% CI: 0.59, 0.86), but the heterogeneity existed (p < 0.00001). Subgroup analysis based on modality did not record heterogeneity across trials. In continuous RRT (CRRT) group (n = 607), patients treated with "early" CRRT suggested a significant decrease in mortality compared with those in "late" CRRT group (27.8% vs. 43.0%) and the RR was 0.69 (95% CI: 0.56, 0.84) without evidence of heterogeneity (I2 = 33%, p = 0.18). In intermittent hemodialysis (IHD) group (n = 115), the RR was 0.26 (95% CI: 0.15, 0.45) without evidence of heterogeneity (I2 = 0%, p = 0.50). In the mixed group, heterogeneity existed.

CONCLUSION

"Early" CRRT and "early" IHD both could reduce the mortality of patients with acute kidney injury compared with "late" CRRT or IHD.

Renal replacement therapy in critically ill patients with acute kidney injury--when to start

BACKGROUND

Despite the frequent use of renal replacement therapy (RRT) for patients with acute kidney injury (AKI) in the intensive care unit (ICU), there is no accepted consensus on the optimal indications and timing.

METHODS

The aim of this paper is to identify optimal triggers for RRT in critically ill patients with AKI.

RESULTS

We examined data from 2 randomized controlled trials, 2 prospective studies and 13 retrospective trials and found large variation in the different parameters and cut-offs for initiation of RRT. No single biochemical parameter was adequate to define the optimal indication and time to commence RRT. Degree of fluid overload, oliguria and associated non-renal organ failure appeared to be more appropriate parameters for initiation of RRT. We propose a clinical algorithm based on regular assessment of the patient's condition and trends in these parameters. It is intended to aid the process of deciding when to start RRT in critically ill adult patients with AKI.

CONCLUSION

Available evidence suggests that the decision when to start RRT in critically ill patients with AKI should be based on trends in the patient's severity of illness, presence of oliguria and fluid overload and associated non-renal organ failure rather than specific serum creatinine or urea values.

A comparison of early versus late initiation of renal replacement therapy in critically ill patients with acute kidney injury: a systematic review and meta-analysis

INTRODUCTION

Our aim was to investigate the impact of early versus late initiation of renal replacement therapy (RRT) on clinical outcomes in critically ill patients with acute kidney injury (AKI).

METHODS

Systematic review and meta-analysis were used in this study. PUBMED, EMBASE, SCOPUS, Web of Science and Cochrane Central Registry of Controlled Clinical Trials, and other sources were searched in July 2010. Eligible studies selected were cohort and randomised trials that assessed timing of initiation of RRT in critically ill adults with AKI.

RESULTS

We identified 15 unique studies (2 randomised, 4 prospective cohort, 9 retrospective cohort) out of 1,494 citations. The overall methodological quality was low. Early, compared with late therapy, was associated with a significant improvement in 28-day mortality (odds ratio (OR) 0.45; 95% confidence interval (CI), 0.28 to 0.72). There was significant heterogeneity among the 15 pooled studies (I(2) = 78%). In subgroup analyses, stratifying by patient population (surgical, n = 8 vs. mixed, n = 7) or study design (prospective, n = 10 vs. retrospective, n = 5), there was no impact on the overall summary estimate for mortality. Meta-regression controlling for illness severity (Acute Physiology And Chronic Health Evaluation II (APACHE II)), baseline creatinine and urea did not impact the overall summary estimate for mortality. Of studies reporting secondary outcomes, five studies (out of seven) reported greater renal recovery, seven (out of eight) studies showed decreased duration of RRT and five (out of six) studies showed decreased ICU length of stay in the early, compared with late, RRT group. Early RRT did not; however, significantly affect the odds of dialysis dependence beyond hospitalization (OR 0.62 0.34 to 1.13, I(2) = 69.6%).

CONCLUSIONS

Earlier institution of RRT in critically ill patients with AKI may have a beneficial impact on survival. However, this conclusion is based on heterogeneous studies of variable quality and only two randomised trials. In the absence of new evidence from suitably-designed randomised trials, a definitive treatment recommendation cannot be made.

Risk factors for failure of continuous veno-venous hemodialysis in the treatment of acute renal failure following cardiac surgery

OBJECTIVE

To evaluate the risk factors for failure of continuous veno-venous hemodialysis (CVVHD) in the treatment of acute renal failure (ARF) after cardiac surgery.

METHODS

Adult patients without any prior pre-operative history of chronic renal failure who underwent CVVHD after cardiac surgery in our medical center from January 2005 to December 2008 were divided into a success or a failure group. All selected patients' pre-, intra-, and post-operative data were retrospectively analyzed. ARF was described as post-operative urinary output of less than 0.5ml/kg/h and/or a 50% increase in baseline BUN and serum creatinine levels.

RESULTS

Fifty-two adult patients (accounting for 3.04%) who underwent CVVHD after cardiac surgery were entered into this study. Thirty-six patients survived, with a mortality rate of 30.8%. Pre-operative mean left ventricular ejection fraction (LVEF) in the success group was higher than that in the failure group (46±9% versus 40±7%, p=0.0220). Mean duration of oliguria until dialysis in the failure group was significantly longer than that in the success group (22.1±6.9h versus 11.6±2.5h, p<0.0001). Through univariate analysis and multivariate logistic regression, independent risk factors for failure of CVVHD in the treatment of post-operative ARF included pre-operative LVEF (OR=0.635, 95% CI 0.358-0.852) and duration of oliguria until dialysis (OR=2.442, 95% CI 1.563-5.768).

CONCLUSIONS

Pre-operative impaired left ventricular function is an important risk factor for failure of CVVHD in the treatment of ARF after cardiac surgery. The sooner CVVHD is instituted the better prognosis may be.