Early High-Volume Hemofiltration versus Standard Care for Post-Cardiac Surgery Shock. The HEROICS Study

Impact of Early versus Late Initiation of Renal Replacement Therapy in Patients with Cardiac Surgery-Associated Acute Kidney Injury: Meta-Analysis with Trial Sequential Analysis of Randomized Controlled Trials

Background

Previous studies have examined the effect of the initiation time of renal replacement therapy (RRT) in patients with cardiac surgery-associated acute kidney injury (CSA-AKI), but the findings remain controversial. The aim of this meta-analysis was to systematically and quantitatively compare the impact of early versus late initiation of RRT on the outcome of patients with CSA-AKI.

Methods

Four databases (PubMed, the Cochrane Library, ISI Web of Knowledge, and Embase) were systematically searched from inception to June 2018 for randomized clinical trials (RCTs). Two investigators independently performed the literature search, study selection, data extraction, and quality evaluation. Meta-analysis and trial sequential analysis (TSA) were used to examine the impact of RRT initiation time on all-cause mortality (primary outcome). The Grading of Recommendations Assessment Development and Evaluation (GRADE) was used to evaluate the level of evidence.

Results

We identified 4 RCTs with 355 patients that were eligible for inclusion. Pooled analyses indicated no difference in mortality for patients receiving early and late initiation of RRT (relative risk [RR] = 0.61, 95% confidence interval [CI] = 0.33 to 1.12). However, the results were not confirmed by TSA. Similarly, early RRT did not reduce the length of stay (LOS) in the intensive care unit (ICU) (mean difference [MD] = -1.04; 95% CI = -3.34 to 1.27) or the LOS in the hospital (MD = -1.57; 95% CI = -4.62 to 1.48). Analysis using GRADE indicated the certainty of the body of evidence was very low for a benefit from early initiation of RRT.

Conclusion

Early initiation of RRT had no beneficial impacts on outcomes in patients with CSA-AKI. Future larger and more adequately powered prospective RCTs are needed to verify the benefit of reduced mortality associated with early initiation of RRT.

Trial Registration

This trial is registered with PROSPERO registration number CRD42018084465, registered on 11 February 2018.

The Japanese clinical practice guideline for acute kidney injury 2016

Acute kidney injury (AKI) is a syndrome which has a broad range of etiologic factors depending on different clinical settings. Because AKI has significant impacts on prognosis in any clinical settings, early detection and intervention is necessary to improve the outcomes of AKI patients. This clinical guideline for AKI was developed by a multidisciplinary approach with nephrology, intensive care medicine, blood purification, and pediatrics. Of note, clinical practice for AKI management which was widely performed in Japan was also evaluated with comprehensive literature search.

Timing for initiation of sequential continuous renal replacement therapy in patients on extracorporeal membrane oxygenation

Background

Extracorporeal membrane oxygenation (ECMO) is a lifesaving therapy used in critically ill patients with severe cardiopulmonary dysfunction. Continuous renal replacement therapy (CRRT) is supplemented to treat fluid overload, acute kidney injury, and electrolyte disturbances during ECMO. However, the best time to initiate CRRT is not well-defined. We performed this study to identify the optimal timing of CRRT for ECMO.

Methods

We conducted a multicenter retrospective cohort study of 296 patients over 12 years. Patients received CRRT during ECMO at Seoul National University Hospital, Seoul National University Bundang Hospital, or Yonsei University Hospital. We assigned patients to an early or late CRRT group depending on the CRRT initiation time. We considered early CRRT to be CRRT instituted within 72 hours of ECMO initiation.

Results

Among 296 patients, 212 patients (71.6%) received early CRRT. After using a propensity score matching method, 47 patients were included in each group. The time from ECMO initiation to CRRT initiation was 1.1 ± 0.9 days in the early CRRT group and 14.6 ± 18.6 days in the late CRRT group. No difference in patients' mortality (P = 0.834) or hospital stay (P = 0.627) between the early and late CRRT groups was found. After adjusting all covariables, there was no significant difference in mortality between the early and late CRRT groups (hazard ratio, 0.697; 95% confidence interval, 0.410-1.184; P = 0.182).

Conclusion

This study showed that early CRRT may not be superior to late CRRT in ECMO patients. Further clinical trials are warranted.

Effect of high-volume hemofiltration on mortality in critically ill patients: A PRISMA-compliant systematic review and meta-analysis

BACKGROUND

High-volume hemofiltration (HVHF) is widely used for blood purification in critically ill patients with systemic inflammatory syndromes. The purpose of this study was to evaluate the effect of HVHF on mortality at different follow-up periods in critically ill patients.

METHODS

We systematically searched PubMed, Embase, and the Cochrane Library through April 2017 to identify trials that evaluated the effect of HVHF on mortality in critically ill patients. Summary relative risks (RRs) and 95% confidence intervals (CIs) were employed to calculate the treatment effect using a random effects model. Eleven trials involving 1048 critically ill patients were included in this study.

RESULTS

The summary results indicated no significant differences between HVHF and usual care for the incidence of 28-day mortality (RR: 0.93; 95%CI: 0.80-1.08; P = .321), 7-day mortality (RR: 0.72; 95%CI: 0.50-1.03; P = .072), 60-day mortality (RR: 1.00; 95%CI: 0.86-1.16; P = .997), and 90-day mortality (RR: 1.01; 95%CI: 0.88-1.16; P = .927). Subgroup analysis suggested HVHF significantly reduced the risk of 28-day mortality (RR: 0.64; 95%CI: 0.42-0.97; P = .035) if pooled the study sample size < 100.

CONCLUSION

Our findings suggest HVHF significantly reduced the incidence of 28-day mortality when pooled the study sample size < 100. Further, HVHF had a marginal effect on the incidence of 7-day mortality.

The Japanese Clinical Practice Guideline for acute kidney injury 2016

Acute kidney injury (AKI) is a syndrome which has a broad range of etiologic factors depending on different clinical settings. Because AKI has significant impacts on prognosis in any clinical settings, early detection and intervention are necessary to improve the outcomes of AKI patients. This clinical guideline for AKI was developed by a multidisciplinary approach with nephrology, intensive care medicine, blood purification, and pediatrics. Of note, clinical practice for AKI management which was widely performed in Japan was also evaluated with comprehensive literature search.

Timing of Renal Replacement Therapy for Acute Kidney Injury

Acute kidney injury (AKI) is common in critically ill patients and associated with increased morbidity and mortality. With the increased use of renal replacement therapy (RRT) for severe AKI, the optimal time for initiation of RRT has become one of the most probed and debated topic in the field of nephrology and critical care. There appears to be an increased trend toward earlier initiation of RRT to avoid life-threatening complications associated with AKI. Despite the presence of a plethora of studies in this field, the lack of uniformity in study design, patient population types, definition of early and late initiation, modality of RRT, and results, the optimal time for starting RRT in AKI still remains unknown. The beneficial effects reported in observational studies have not been supported by clinical trials. Recently, 2 of the largest randomized control trials evaluating the timing of RRT in critically ill patients with AKI showed differing results. We provide an in-depth review of the available data on the timing of dialysis in patients with AKI.

[Renal replacement therapy for acute kidney injury in the intensive care unit]

Renal replacement therapy for acute kidney injury has been used for more than 60 years. Except when life-threatening metabolic complications such as severe hyperkalaemia are present, renal replacement therapy initiation criteria are the subject of intense debate. Significant progress has been made with the publication of the AKIKI multicenter trial, which showed that a delayed renal replacement therapy initiation strategy (in the absence of life-threatening metabolic complications) was not associated with a difference in mortality compared to an early renal replacement therapy initiation strategy. In addition, this delayed strategy obviated the need for renal replacement therapy in almost 50% of cases was associated with a more rapid renal function recovery and with a lower incidence of catheter-bloodstream related infections. Research on renal replacement therapy modalities (continuous vs. intermittent renal replacement therapy, citrate vs. heparin anticoagulation, jugular vs. femoral catheterization) did not show any obvious superiority of one modality over another. Thus, the choice depends mainly on local considerations (patient recruitment, availability of modalities, staff experience). The criteria for renal replacement therapy discontinuation are still unclear due to difficulties in assessing renal function recovery. Urine output remains the main criteria in the decision to wean from renal replacement therapy. Pending the confirmation of AKIKI trial by similar studies in progress, it seems reasonable to choose a delayed renal replacement therapy initiation strategy under watchful surveillance in case of severe acute kidney injury in the absence of life-threatening metabolic complications.

Haste makes waste-Should current guideline recommendations for initiation of renal replacement therapy for acute kidney injury be changed?

There is broad consensus among guideline organizations that renal replacement therapy (RRT) should not be delayed in case of life-threatening conditions. However, in case of severe acute kidney injury (AKI) without these conditions, it is unclear whether immediate RRT has an advantage over delayed RRT. Two recently published randomized controlled trials (AKIKI and ELAIN) with seemingly opposite results have reignited the discussion whether guideline recommendations on initiation strategies in severe AKI should be adapted. This editorial discusses RRT initiation strategies in severe AKI, based on recent literature and highlights the potential advantages and disadvantages of immediate vs delayed start. Overall, evidence in favor of immediate compared to delayed strategies is sparse and there is wide heterogeneity across studies making it difficult to draw firm conclusions. RRT should not be delayed in case of refractory hyperkalemia, severe metabolic acidosis or pulmonary edema resistant to diuretics. In all other cases, a delayed strategy seems justified and might enhance renal recovery. RRT is not a "it doesn't hurt to try" technique and can expose the patient to a higher risk of bleeding, hemodynamic problems, under-dosing of antibiotics, loss of nutrients, catheter-related complications and the uncertain effects of blood-membrane interactions. There is no compelling reason to change current guideline recommendations and research focus should shift toward the development of algorithms as a decision aid tool for RRT initiation in severe AKI.

An isolated elevation in blood urea level is not 'uraemia' and not an indication for renal replacement therapy in the ICU

The decision to initiate renal replacement therapy (RRT) and the optimal timing for commencement is a difficult decision faced by clinicians when treating acute kidney injury (AKI) in the intensive care setting. Without clinically significant ureamic symptoms or emergent indications (electrolyte abnormalities, volume overload) the timing of RRT initiation remains contentious and inconsistent across health providers. Current trends of initiating RRT in the ICU are often based on isolated blood urea levels without clear guidelines demonstrating an upper limit for treatment. Although the appropriate upper limit remains unclear, it is reasonable to conclude that a blood urea level less than 40 mmol/L is not in itself an indication for RRT, especially in the absence of supporting evidence of kidney impairment (anuria, elevated serum creatinine), presenting a welcome reminder to treat the patient and not a number.

A comparison of early versus late initiation of renal replacement therapy for acute kidney injury in critically ill patients: an updated systematic review and meta-analysis of randomized controlled trials

BACKGROUND

To investigate the impact of timing the initiation of renal replacement therapy (RRT) on clinical outcomes in critically ill patients with acute kidney injury (AKI), focusing on the randomized controlled trials (RCTs) in this field.

METHODS

The PubMed, EMBASE and Cochrane databases were searched between January 1, 1985, and June 30, 2016, to identify randomized trials that assessed the timing of initiation of RRT in patients with AKI.

RESULTS

Nine RCTs, with a total of 1636 patients, were enrolled in this meta-analysis. A pooled analysis of the studies indicated no mortality benefit with "early" RRT, with an RR of 0.98 (95% CI 0.78 to 1.23, P = 0.84). There was no significant difference in intensive care unit (ICU) length of stay (LOS) or hospital LOS between the early and late RRT groups for survivors or nonsurvivors. Pooled analysis also demonstrated no significant change in renal function recovery (RR 1.02, 95% CI 0.88 to 1.19, I2 = 59%), RRT dependence (RR 0.76, 95% CI 0.42 to 1.37, I2 = 0%), duration of RRT (Mean difference 1.43, 95% CI -1.75 to 4.61, I2 = 78%), renal recovery time (Mean difference 0.73, 95% CI -2.09 to 3.56, I2 = 70%) or mechanical ventilation time (Mean difference - 0.95, 95% CI -3.54 to 1.64, I2 = 64%) between the early and late RRT groups. We found no significant differences in complications between the groups.

CONCLUSIONS

Our meta-analysis revealed that the "early" initiation of RRT in critically ill patients did not result in reduced mortality. Pooled analysis of secondary outcomes also showed no significant difference between the early and late RRT groups. More well-designed and large-scale trials are expected to confirm the result of this meta-analysis.

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.

Early Versus Late Initiation of Renal Replacement Therapy in Critically Ill Patients: Systematic Review and Meta-Analysis

OBJECTIVE

Early initiation of renal replacement therapy (RRT) effect on survival and renal recovery of critically ill patients is still uncertain. We aimed to systematically review current evidence comparing outcomes of early versus late initiation of RRT in critically ill patients.

METHODS

We searched the Medline (via Pubmed), LILACS, Science Direct, and CENTRAL databases from inception until November 2016 for randomized clinical trials (RCTs) or observational studies comparing early versus late initiation of RRT in critically ill patients. The primary outcome was mortality. Duration of mechanical ventilation, intensive care unit (ICU) length of stay (LOS), hospital LOS, and renal function recovery were secondary outcomes. Meta-analysis and trial sequential analysis (TSA) were used for the primary outcome.

RESULTS

Sixty-two studies were retrieved and analyzed, including 11 RCTs. There was no difference in mortality between early and late initiation of RRT among RCTs (odds ratio [OR] = 0.78; 95% confidence interval [CI]: 0.52-1.19; I² = 63.1%). Trial sequential analysis of mortality across all RCTs achieved futility boundaries at both 1% and 5% type I error rates, although a subgroup analysis of studies including only acute kidney injury patients was not conclusive. There was also no difference in time on mechanical ventilation, ICU and hospital LOS, or renal recovery among studies. Early initiation of RRT was associated with reduced mortality among prospective (OR = 0.69; 95% CI: 0.49-0.96; I² = 85.9%) and retrospective (OR = 0.61; 95% CI: 0.41-0.92; I² = 90.9%) observational studies, both with substantial heterogeneity. However, subgroup analysis excluding low-quality observational studies did not achieve statistical significance.

CONCLUSION

Pooled analysis of randomized trials indicates early initiation of RRT is not associated with lower mortality rates. The potential benefit of reduced mortality associated with early initiation of RRT was limited to low-quality observational studies.

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.

Earlier versus later initiation of renal replacement therapy among critically ill patients with acute kidney injury: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Although the optimal timing of initiation of renal replacement therapy (RRT) in critically ill patients with acute kidney injury has been extensively studied in the past, it is still unclear.

METHODS

In this systematic review, we searched all related randomized controlled trials (RCTs) that directly compared earlier and later RRT published prior to June 25, 2016, from PubMed, MEDLINE, and EMBASE. We extracted the study characteristics and outcomes of all-cause mortality, RRT dependence, and intensive care unit (ICU) and hospital length of stay (LOS).

RESULTS

We identified 51 published relevant studies from 13,468 screened abstracts. Nine RCTs with 1627 participants were included in this meta-analysis. Earlier RRT was not associated with benefits in terms of mortality [relative risk (RR) 0.88, 95% confidence interval (CI) 0.68-1.14, p = 0.33] and RRT dependence (RR 0.81, 95% CI 0.46-1.42, p = 0.46). There were also no significant differences in the ICU and hospital LOS between patients who underwent earlier versus later RRT [standard means difference -0.08 (95% CI -0.26 to 0.09) and -0.11 (95% CI -0.37 to 0.16) day, respectively]. In subgroup analysis, earlier RRT was associated with a reduction in the in-hospital mortality among surgical patients (RR 0.78, 95% CI 0.64-0.96) and patients who underwent continuous renal replacement therapy (CRRT) (RR 0.80, 95% CI 0.67-0.96).

CONCLUSIONS

Compared with later RRT, earlier initiation of RRT did not show beneficial impacts on patient outcomes. However, a lower rate of death was observed among surgical patients and in those who underwent CRRT. The included literature is highly heterogeneous and, therefore, potentially subject to bias. Further high-quality RCT studies are warranted.

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.

Early Renal Replacement Therapy Versus Standard Care in the ICU: A Systematic Review, Meta-Analysis, and Cost Analysis

OBJECTIVE:

Renal replacement therapy (RRT) is the treatment of choice for severe acute kidney injury, but there are no firm guidelines as to the time of initiation of RRT in the critically ill. The primary objective of this study is to determine 1-month mortality rates of early versus late dialysis in critical care. As secondary end points, we provide a cost analysis of early versus late RRT initiation, intensive care unit (ICU) length of stay (LOS), hospital LOS, and number of patients on dialysis at day 60 postrandomization.

DATA SOURCES:

We identified all randomized controlled trials (RCTs) through EMLINE and MEDBASE that examined adult patients admitted to critical care who were randomized to receiving early dialysis versus standard of care.

STUDY SELECTION:

Inclusion criteria: (1) RCTs conducted after the year 2000, (2) the population evaluated had to be adults admitted to ICU, (3) the intervention had to be early RRT versus standard care, and (4) outcomes had to measure patient mortality.

DATA EXTRACTION:

Two independent investigators reviewed search results and identified appropriate studies. Information was extracted using standardized case report forms.

DATA SYNTHESIS:

Overall, 7 RCTs were included with a total of 1400 patients. Early RRT showed no survival benefit when compared to standard treatment (odds ratio [OR], 0.90 95% confidence interval [95% CI] 0.70-1.15, P = .39). There was no significant difference in length of hospital stay in patients with early RRT (-1.55 days [95% CI -4.75 to 1.65, P = .34]), in length of ICU stay (-0.79 days [95% CI -2.09 to 0.52], P = .24), or proportion of patients on dialysis at day 60 (OR 0.93 [95% CI 0.62 to 1.43], P = .79). Per patient, there is likely a small increase in costs (<US$1000) owing to increased total dialysis.

CONCLUSION:

Across all measured domains, there is no clear benefit to early RRT. Moreover, this intervention may result in increased costs and exposes patients to an invasive therapy with potential harm.

Early versus late initiation of renal replacement therapy in patients with acute kidney injury-a systematic review & meta-analysis of randomized controlled trials

BACKGROUND

Acute kidney injury (AKI) is a common complication in the critically ill patients and associated with a substantial morbidity and mortality. Severe AKI may be associated with up to 60% hospital mortality. Over the years, renal replacement therapy (RRT) has emerged as the mainstay of the treatment for AKI. However, the exact timing of initiation of RRT for better patient outcome is still debatable with conflicting data from randomized controlled trials. Thus, a systematic review and meta-analysis was performed to assess the impact of "early" versus "late" initiation of RRT.

METHODS

All the published literature through the major databases including Medline/Pubmed, Embase, and Google Scholar were searched from 1970 to October 2016. Reference lists from the articles were reviewed to identify additional pertinent articles. Retrieved papers concerning the effect of "early/prophylactic" RRT versus "late/as and when required" RRT were reviewed by the authors, and the data were extracted using a standardized data collection tool. Randomized trials (RCTs) comparing early initiation of RRT or prophylactic RRT with late or as and when required RRT were included. The primary outcome measures were all cause mortality and dialysis dependence on day 90. The secondary outcome measures were: length of ICU stay, length of hospital stay, recovery of renal function and adverse events.

RESULTS

Of the 547 citation retrieved, full text of 44 articles was assessed for eligibility. Of these a total of 10 RCTs with 1,636 participants were included. All the trials were open label; six trials have unclear or high risk of bias for allocation concealment while four trials have low risk of bias for allocation concealment. There was a variable definition of early versus late in different studies. Thus, the definition of early or late was taken according to individual study definition. Compared to late RRT, there was no significant benefit of early RRT on day 30 mortality [6 studies; 1301 participants; RR, 0.92;95% CI: 0.76, 1.12); day 60 mortality [3 trials;1075 participants; RR, 0.94; 95% CI: 0.78, 1.14)]; day 90 mortality [3 trials; 555 participants; RR,0.94;95% CI: 0.67, 1.33)]; overall ICU or hospital mortality; dialysis dependence on day 90 [3 trials; (RR, 1.06; 95% CI:0.53, 2.12)]. There was no significant difference between length of ICU or hospital stay or recovery of renal functions. A subgroup analysis based on modality of RRT or mixed medical and surgical vs. surgical or based on severity of illness showed no difference in outcome measure. The trials with high or unclear risk of bias for allocation concealment showed benefit of early RRT (RR, 0.74; 95% CI: 0.59, 0.91) while the trials with low risk of bias for allocation concealment showed no difference in the mortality (RR, 1.02; 95% CI: 0.89, 1.17). Grade evidence generated for most of the outcomes was "low quality".

CONCLUSION

This updated meta-analysis showed no added benefit of early initiation of RRT for patients with AKI. The grade evidence generated was of "low quality" and there was a high heterogeneity in the included trials.

PROSPERO REGISTRATION NUMBER

CRD42016043092 .

Strategies for the optimal timing to start renal replacement therapy in critically ill patients with acute kidney injury

Renal replacement therapy (RRT) is increasingly utilized to support critically ill patients with severe acute kidney injury (AKI). The question of whether and when to start RRT for a critically ill patient with AKI has long troubled clinicians. When severe complications of AKI develop, the need to commence RRT is unambiguous. In the absence of such complications but in the presence of severe AKI, the optimal time and thresholds for starting RRT are uncertain. The majority of existing data have largely been derived from observational studies. These have been limited due to confounding by indication, considerable heterogeneity in case mix and illness severity, and variably applied definitions for both AKI and for how "timing" was anchored relative to starting RRT. It is unclear whether a preemptive or earlier strategy of RRT initiation aimed largely at avoiding complications related to AKI or a more conservative strategy where RRT is started in response to developing complications leads to better patient-centered outcomes and health services use. This question has been the focus of 2 recently completed randomized trials. In this review, we provide an appraisal of available evidence, discuss existing knowledge gaps, and provide perspective on future research that will better inform the optimal timing of RRT initiation in AKI.

High-volume haemofiltration for sepsis in adults

BACKGROUND

Severe sepsis and septic shock are leading causes of death in the intensive care unit (ICU), despite advances in the treatment of patients with severe sepsis and septic shock, including early recognition, appropriate treatment with antibiotics and support of organs that may have been affected by the illness. High-volume haemofiltration (HVHF) is a blood purification technique that may improve outcomes in severe sepsis or septic shock. The technique of HVHF has evolved from renal replacement therapies used in the ICU to treat critically ill patients with acute kidney injury (AKI). This review was first published in 2013 and was updated in 2016.

OBJECTIVES

To investigate whether HVHF improves outcomes in critically ill adults admitted to the intensive care unit with severe sepsis or septic shock. The primary outcome of this systematic review is patient mortality; secondary outcomes include duration of stay, severity of organ dysfunction and adverse events.

SEARCH METHODS

For this updated version, we extended searches of the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, Latin American Caribbean Health Sciences Literature (LILACS), Web of Science and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) to 31 December 2015. The original search was performed in 2011. We also searched trials registers.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) and quasi-randomized trials comparing HVHF or high-volume haemodiafiltration versus standard or usual dialysis therapy, as well as RCTs and quasi-randomized trials comparing HVHF or high-volume haemodiafiltration versus no similar dialysis therapy. These studies involved adults treated in critical care units.

DATA COLLECTION AND ANALYSIS

Three review authors independently extracted data and assessed trial quality. We sought additional information from trialists as required.

MAIN RESULTS

We included four randomized trials involving 200 participants. Owing to small numbers of studies and participants, it was not possible to combine data for all outcomes. Two trials reported 28-day mortality, and one trial reported hospital mortality; in the third trial, the number of deaths stated did not match the quoted mortality rates. The pooled risk ratio (95% confidence interval) for 28-day mortality associated with HVHF was 0.89 (0.60 to 1.32, two trials, 146 participants, low-quality evidence). One study (137 participants, low-quality evidence) reported length of stay in the ICU. Two trials (170 participants, low-quality evidence) reported organ dysfunction, but we could not pool results owing to reporting differences. Three studies (189 participants, low-quality evidence) reported on haemodynamic changes, but we could not pool results owing to reporting differences. Investigators reported no adverse events. Overall, the included studies had low risk of bias.

AUTHORS' CONCLUSIONS

Investigators reported no adverse effects of HVHF (low-quality evidence). The results of this meta-analysis show that very few studies have been conducted to investigate the use of HVHF in critically ill patients with severe sepsis or septic shock (four studies, 201 participants, low-quality evidence). Researchers should consider additional randomized controlled trials that are large and multi-centred and have clinically relevant outcome measures. The cost-effectiveness of HVHF should also be studied. .

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.

Intensity of continuous renal replacement therapy for acute kidney injury

BACKGROUND

Acute kidney injury (AKI) is a common condition among patients in intensive care units (ICU), and is associated with substantial morbidity and mortality. Continuous renal replacement therapy (CRRT) is a blood purification technique used to treat the most severe forms of AKI but its effectiveness remains unclear.

OBJECTIVES

To assess the effects of different intensities (intensive and less intensive) of CRRT on mortality and recovery of kidney function in critically ill AKI patients.

SEARCH METHODS

We searched Cochrane Kidney and Transplant's Specialised Register to 9 February 2016 through contact with the Information Specialist using search terms relevant to this review. Studies contained in the Specialised Register are identified through search strategies specifically designed for CENTRAL, MEDLINE, and EMBASE; handsearching conference proceedings; and searching the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov. We also searched LILACS to 9 February 2016.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs). We included all patients with AKI in ICU regardless of age, comparing intensive (usually a prescribed dose ≥35 mL/kg/h) versus less intensive CRRT (usually a prescribed dose < 35 mL/kg/h). For safety and cost outcomes we planned to include cohort studies and non-RCTs.

DATA COLLECTION AND ANALYSIS

Data were extracted independently by two authors. The random-effects model was used and results were reported as risk ratios (RR) for dichotomous outcomes and mean differences (MD) for continuous outcomes, with 95% confidence intervals (CI).

MAIN RESULTS

We included six studies enrolling 3185 participants. Studies were assessed as being at low or unclear risk of bias. There was no significant difference between intensive versus less intensive CRRT on mortality risk at day 30 (5 studies, 2402 participants: RR 0.88, 95% CI 0.71 to 1.08; I² = 75%; low quality of evidence) or after 30 days post randomisation (5 studies, 2759 participants: RR 0.92, 95% CI 0.80 to 1.06; I² = 65%; low quality of evidence). There were no significant differences between intensive versus less intensive CRRT in the numbers of patients who were free of RRT after CRRT discontinuation (5 studies, 2402 participants: RR 1.12, 95% CI 0.91 to 1.37; I² = 71%; low quality of evidence) or among survivors at day 30 (5 studies, 1415 participants: RR 1.03, 95% CI 0.96 to 1.11; I² = 69%; low quality of evidence) and day 90 (3 studies, 988 participants: RR 0.98, IC 95% 0.94 to 1.01, I² = 0%; moderatequality of evidence). There were no significant differences between intensive and less intensive CRRT on the number of days in hospital (2 studies, 1665 participants): MD -0.23 days, 95% CI -3.35 to 2.89; I² = 8%; low quality of evidence) and the number of days in ICU (2 studies, 1665 participants: MD -0.58 days, 95% CI -3.73 to 2.56, I² = 19%; low quality of evidence). Intensive CRRT increased the risk of hypophosphataemia (1 study, 1441 participants: RR 1.21, 95% CI 1.11 to 1.31; high quality evidence) compared to less intensive CRRT. There was no significant differences between intensive and less intensive CRRT on numbers of patients who experienced adverse events (3 studies, 1753 participants: RR 1.08, 95% CI 0.73 to 1.61; I² = 16%; moderate quality of evidence). In the subgroups analysis by severity of illness and by aetiology of AKI, intensive CRRT would seem to reduce the risk mortality (2 studies, 531 participants: RR 0.73, 95% CI 0.61 to 0.88; I² = 0%; high quality of evidence) only in the subgroup of patients with post-surgical AKI.

AUTHORS' CONCLUSIONS

Based on the current low quality of evidence identified, more intensive CRRT did not demonstrate beneficial effects on mortality or recovery of kidney function in critically ill patients with AKI. There was an increased risk of hypophosphataemia with more intense CRRT. Intensive CRRT reduced the risk of mortality in patients with post-surgical AKI.

The effects of early high-volume hemofiltration on prolonged cardiac arrest in rats with reperfusion by cardiopulmonary bypass: a randomized controlled animal study

Background

It is not yet clear whether hemofiltration can reduce blood cytokine levels sufficiently to benefit patients who suffer prolonged cardiac arrest (CA) treated with cardiopulmonary bypass (CPB). We sought to assess effects of high-volume and standard volume continuous veno-venous hemofiltration (CVVH) on blood cytokine levels and survival in a rat model of prolonged CA treated with CPB.

Methods

Sprague-Dawley male rats were subjected to 12 min of asphyxia to induce CA. CPB was initiated for resuscitation of animals and maintained for 30 min. Twenty-four rats were randomly assigned into three groups: without CVVH treatment (sham); standard volume CVVH at a filtration rate of 35–45 mL/kg/h; and high-volume hemofiltration (HVHF, 105–135 mL/kg/h). Hemofiltration was started simultaneously with CPB and maintained for 6 h. Plasma TNFα and IL-6 levels were measured at baseline, 0.5, 1, 2, 3, and 6 h after reperfusion. Survival time, neurological deficit score, and hemodynamic status were assessed.

Results

All animals survived over 6 h and died within 24 h. There were no significant differences in survival time (log-rank test, sham vs. CVVH; p = 0.49, sham vs. HVHF; p = 0.33) or neurological deficit scores (ANOVA, p = 0.14) between the groups. There were no significant differences in blood cytokine levels between the groups. Mean blood pressure in sham group animals increased to 1.5-fold higher than baseline levels at 30 min. HVHF significantly reduced blood pressure to 0.7-fold of sham group (p < 0.01).

Conclusions

There was no improvement in mortality, neurological dysfunction, TNFα, or IL-6 levels in rats after prolonged CA with CPB on either hemofiltration group when compared to the sham group.

Electronic supplementary material

The online version of this article (doi:10.1186/s40635-016-0101-6) contains supplementary material, which is available to authorized users.

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.