Treatment of Acute Kidney Injury: A Review of Current Approaches and Emerging Innovations

Acute kidney injury (AKI) is a complex and life-threatening condition with multifactorial etiologies, ranging from ischemic injury to nephrotoxic exposures. Management is founded on treating the underlying cause of AKI, but supportive care-via fluid management, vasopressor therapy, kidney replacement therapy (KRT), and more-is also crucial. Blood pressure targets are often higher in AKI, and these can be achieved with fluids and vasopressors, some of which may be more kidney-protective than others. Initiation of KRT is controversial, and studies have not consistently demonstrated any benefit to early start dialysis. There are no targeted pharmacotherapies for AKI itself, but some do exist for complications of AKI; additionally, medications become a key aspect of AKI management because changes in renal function and dialysis support can lead to issues with both toxicities and underdosing. This review will cover existing literature on these and other aspects of AKI treatment. Additionally, this review aims to identify gaps and challenges and to offer recommendations for future research and clinical practice.

The value of the ACEF II score in Chinese patients with elective and non-elective cardiac surgery

OBJECTIVE

To evaluate the value of the ACEF II score in predicting postoperative hospital death and acute kidney injury requiring dialysis (AKI-D) in Chinese patients.

METHODS

This retrospective study included adult patients who underwent cardiopulmonary bypass open heart surgery between January 2010 and December 2015 at Guangdong Provincial People's Hospital. ACEF II was evaluated to predict in-hospital death and AKI-D using the Hosmer-Lemeshow goodness of fit test for calibration and area under the receiver operating characteristic (ROC) curve for discrimination in non-elective and elective cardiac surgery.

RESULTS

A total of 9748 patients were included. Among them, 1080 underwent non-elective surgery, and 8615 underwent elective surgery. Mortality was 1.8% (177/9748). In elective surgery, the area under the ROC (AUC) of the ACEF II score was 0.704 (95% CI: 0.648-0.759), similar to the ACEF score of 0.709 (95% CI: 0.654-0.763). In non-elective surgery, the AUC of the ACEF II score was 0.725 (95% CI: 0.663-0.787), higher than the ACEF score (AUC = 0.625, 95% CI: 0.553-0.697). The incidence of AKI-D was 3.5% (345/9748). The AUC of the ACEF II score was 0.718 (95% CI: 0.687-0.749), higher than the ACEF score (AUC = 0.626, 95% CI: 0.594-0.658).

CONCLUSION

ACEF and ACEF II have poor discrimination ability in predicting AKI-D in non-elective surgery. The ACEF II and ACEF scores have the same ability to predict in-hospital death in elective cardiac surgery, and the ACEF II score is better in non-elective surgery. The ACEF II score can be used to assess the risk of AKI-D in elective surgery in Chinese adults.

Timely renal replacement therapy linked to better outcome in patients with sepsis-associated acute kidney injury

Background

Recent studies suggest that acute kidney injury (AKI) can be treated with renal replacement therapy (RRT). However, its benefits to patients with sepsis-associated AKI (SA-AKI), which is linked to high mortality and morbidity rates, remain under debate. The aim of this study was to compare the outcomes of different RRT strategies for patients with SA-AKI.

Methods

This retrospective study evaluated patients who were admitted to the hospital with sepsis and developed SA-AKI during hospitalization from 1st January 2014 to 31st January 2019. Mortality, renal recovery, and systemic organ function at 90 days following admission were compared between the RRT group (RG) and non-RRT group (NRG), as well as the early-RRT group (EG) and delayed-RRT group (DG). The groups were defined according to the time from admission to RRT initiation (criterion 1, EG1 and DG1) and Kidney Disease Improving Global Outcomes (KDIGO) classification (criterion 2, EG2 and DG2). Categorical and continuous variables were compared using the chi-squared test or Fisher's exact test and Student's t-test or Wilcoxon test. Kaplan-Meier curves were constructed to determine the unadjusted survival rates for the different subgroups.

Results

A total of 116 patients were included in this study; of those, 38 received RRT and 46 expired within 90 days. Among different strategies of RRT, there were no significant differences found in 90-day mortality (RG vs. NRG: χ²=0.610, P=0.435; EG1 vs. DG1: χ² =0.835, P=0.360; EG2 vs. DG2: χ²=0.022, P=0.899) and renal recovery. However, the values of change in sequential organ failure assessment (ΔSOFA)_max-min of patients in the EG and RG were significantly higher than those recorded in the NRG (ΔSOFA_RG=7.0, ΔSOFA_NRG=3.60, ΔSOFA_EG1=9.00, ΔSOFA_EG2=6.30; P<0.050). Also, the 90-day renal recovery in the EG was better than that noted in the DG with criterion 1 (87.5% vs. 38.5%, respectively, χ²=10.425, P=0.032), suggesting that RRT (especially timely RRT) may be beneficial to the restoration of systemic organ function in patients with SA-AKI.

Conclusion

RRT did not reduce the 90-day mortality among patients with SA-AKI. However, timely RRT may benefit the restoration of systemic organ function, thereby improving the quality of life of patients.

Accelerated versus watchful waiting strategy of kidney replacement therapy for acute kidney injury: a systematic review and meta-analysis of randomized clinical trials

Background

Critically ill patients with severe acute kidney injury (AKI) requiring kidney replacement therapy (KRT) have a grim prognosis. Recently, multiple studies focused on the impact of KRT initiation time [i.e., accelerated versus watchful waiting KRT initiation (WWS-KRT)] on patient outcomes. We aim to review the results of all related clinical trials.

Methods

In this systematic review, we searched all relevant randomized clinical trials from January 2000 to April 2021. We assessed the impacts of accelerated versus WWS-KRT on KRT dependence, KRT-free days, mortality and adverse events, including hypotension, infection, arrhythmia and bleeding. We rated the certainty of evidence according to Cochrane methods and the GRADE approach.

Results

A total of 4932 critically ill patients with AKI from 10 randomized clinical trials were included in this analysis. The overall 28-day mortality rate was 38.5%. The 28-day KRT-dependence rate was 13.0%. The overall incident of KRT in the accelerated group was 97.4% and 62.8% in the WWS-KRT group. KRT in the accelerated group started 36.7 h earlier than the WWS-KRT group. The two groups had similar risks of 28-day [pooled log odds ratio (OR) 1.001, P = 0.982] and 90-day (OR 0.999, P = 0.991) mortality rates. The accelerated group had a significantly higher risk of 90-day KRT dependence (OR 1.589, P = 0.007), hypotension (OR 1.687, P < 0.001) and infection (OR 1.38, P = 0.04) compared with the WWS-KRT group.

Conclusions

This meta-analysis revealed that accelerated KRT leads to a higher probability of 90-day KRT dependence and dialysis-related complications without any impact on mortality rate when compared with WWS-KRT. Therefore, we suggest the WWS-KRT strategy for critically ill patients.

Acute kidney injury following adult lung transplantation

BACKGROUND

Acute kidney injury (AKI) is a common and serious complication following lung transplantation (LTx), and it is associated with high mortality and morbidity. This study assessed the incidence of AKI after LTx and analyzed the associated perioperative factors and clinical outcomes.

METHODS

This retrospective study included all adult LTx recipients at the China-Japan Friendship Hospital in Beijing between March 2017 and December 2019. The outcomes were AKI incidence, risk factors, mortality, and kidney recovery. Multivariate analysis was performed to identify independent risk factors. Survival analysis was presented using the Kaplan-Meier curves.

RESULTS

AKI occurred in 137 of the 191 patients (71.7%), with transient AKI in 43 (22.5%) and persistent AKI in 94 (49.2%). AKI stage 1 occurred in 27/191 (14.1%), stage 2 in 46/191 (24.1%), and stage 3 in 64/191 (33.5%) of the AKI patients. Renal replacement therapy (RRT) was administered to 35/191 (18.3%) of the patients. Male sex, older age, mechanical ventilation (MV), severe hypotension, septic shock, multiple organ dysfunction (MODS), prolonged extracorporeal membrane oxygenation (ECMO), reintubation, and nephrotoxic agents were associated with AKI (P < 0.050). Persistent AKI was independently associated with pre-operative pulmonary hypertension, severe hypotension, post-operative MODS, and nephrotoxic agents. Severe hypotension, septic shock, MODS, reintubation, prolonged MV, and ECMO during or after LTx were related to severe AKI (stage 3) (P < 0.050). Patients with persistent and severe AKI had a significantly longer duration of MV, longer duration in the intensive care unit (ICU), worse downstream kidney function, and reduced survival (P < 0.050).

CONCLUSIONS

AKI is common after LTx, but the pathogenic mechanism of AKI is complicated, and prerenal causes are important. Persistent and severe AKI were associated with poor short- and long-term kidney function and reduced survival in LTx patients.

Incidence- and In-hospital Mortality-Related Risk Factors of Acute Kidney Injury Requiring Continuous Renal Replacement Therapy in Patients Undergoing Surgery for Acute Type a Aortic Dissection

Background: Few studies on the risk factors for postoperative continuous renal replacement therapy (CRRT) in a homogeneous population of patients with acute type A aortic dissection (AAAD). This retrospective analysis aimed to investigate the risk factors for CRRT and in-hospital mortality in the patients undergoing AAAD surgery and to discuss the perioperative comorbidities and short-term outcomes. Methods: The study collected electronic medical records and laboratory data from 432 patients undergoing surgery for AAAD between March 2009 and June 2021. All the patients were divided into CRRT and non-CRRT groups; those in the CRRT group were divided into the survivor and non-survivor groups. The univariable and multivariable analyses were used to identify the independent risk factors for CRRT and in-hospital mortality. Results: The proportion of requiring CRRT and in-hospital mortality in the patients with CRRT was 14.6 and 46.0%, respectively. Baseline serum creatinine (SCr) [odds ratio (OR), 1.006], cystatin C (OR, 1.438), lung infection (OR, 2.292), second thoracotomy (OR, 5.185), diabetes mellitus (OR, 6.868), AKI stage 2-3 (OR, 22.901) were the independent risk factors for receiving CRRT. In-hospital mortality in the CRRT group (46%) was 4.6 times higher than in the non-CRRT group (10%). In the non-survivor (n = 29) and survivor (n = 34) groups, New York Heart Association (NYHA) class III-IV (OR, 10.272, P = 0.019), lactic acidosis (OR, 10.224, P = 0.019) were the independent risk factors for in-hospital mortality in patients receiving CRRT. Conclusion: There was a high rate of CRRT requirement and high in-hospital mortality after AAAD surgery. The risk factors for CRRT and in-hospital mortality in the patients undergoing AAAD surgery were determined to help identify the high-risk patients and make appropriate clinical decisions. Further randomized controlled studies are urgently needed to establish the risk factors for CRRT and in-hospital mortality.

Prediction of cardiac surgery associated - acute kidney injury (CSA-AKI) by healthcare professionals and urine cell cycle arrest AKI biomarkers [TIMP-2]*[IGFBP7]: A single center prospective study (the PREDICTAKI trial)

PURPOSE

Cardiac surgery associated acute kidney injury (CSA-AKI) is a contributor to adverse outcomes. Preventive measures reduce AKI incidence in high risk patients, identified by biomarkers [TIMP-2]*[IGFBP7] (Nephrocheck®). This study investigate clinical AKI risk assessment by healthcare professionals and the added value of the biomarker result.

MATERIALS AND METHODS

Adult patients were prospectively included. Healthcare professionals predicted CSA-AKI, with and without biomarker result knowledge. Predicted outcomes were AKI based on creatinine, AKI stage 3 on urine output, anuria and use of kidney replacement therapy (KRT).

RESULTS

One-hundred patients were included. Consultant and ICU residents were best in AKI prediction, respectively AUROC 0.769 (95% CI, 0.672-0.850) and 0.702 (95% CI, 0.599-0.791). AUROC of NephroCheck® was 0.541 (95% CI, 0.438-0.642). AKI 3 occurred in only 4 patients; there was no anuria or use of KRT. ICU nurses and ICU residents had an AUROC for prediction of AKI 3 of respectively 0.867 (95% CI, 0.780-0.929) and 0.809 (95% CI, 0.716-0.883); for NephroCheck® this was 0.838 (95% CI, 0.750-0.904).

CONCLUSIONS

Healthcare professionals performed poor or fair in predicting CSA-AKI and knowledge of Nephrocheck® result did not improved prediction. No conclusions could be made for prediction of severe AKI, due to limited number of events.

Comparison of two delayed strategies for renal replacement therapy initiation for severe acute kidney injury (AKIKI 2): a multicentre, open-label, randomised, controlled trial

BACKGROUND

Delaying renal replacement therapy (RRT) for some time in critically ill patients with severe acute kidney injury and no severe complication is safe and allows optimisation of the use of medical devices. Major uncertainty remains concerning the duration for which RRT can be postponed without risk. Our aim was to test the hypothesis that a more-delayed initiation strategy would result in more RRT-free days, compared with a delayed strategy.

METHODS

This was an unmasked, multicentre, prospective, open-label, randomised, controlled trial done in 39 intensive care units in France. We monitored critically ill patients with severe acute kidney injury (defined as Kidney Disease: Improving Global Outcomes stage 3) until they had oliguria for more than 72 h or a blood urea nitrogen concentration higher than 112 mg/dL. Patients were then randomly assigned (1:1) to either a strategy (delayed strategy) in which RRT was started just after randomisation or to a more-delayed strategy. With the more-delayed strategy, RRT initiation was postponed until mandatory indication (noticeable hyperkalaemia or metabolic acidosis or pulmonary oedema) or until blood urea nitrogen concentration reached 140 mg/dL. The primary outcome was the number of days alive and free of RRT between randomisation and day 28 and was done in the intention-to-treat population. The study is registered with ClinicalTrial.gov, NCT03396757 and is completed.

FINDINGS

Between May 7, 2018, and Oct 11, 2019, of 5336 patients assessed, 278 patients underwent randomisation; 137 were assigned to the delayed strategy and 141 to the more-delayed strategy. The number of complications potentially related to acute kidney injury or to RRT were similar between groups. The median number of RRT-free days was 12 days (IQR 0-25) in the delayed strategy and 10 days (IQR 0-24) in the more-delayed strategy (p=0·93). In a multivariable analysis, the hazard ratio for death at 60 days was 1·65 (95% CI 1·09-2·50, p=0·018) with the more-delayed versus the delayed strategy. The number of complications potentially related to acute kidney injury or renal replacement therapy did not differ between groups.

INTERPRETATION

In severe acute kidney injury patients with oliguria for more than 72 h or blood urea nitrogen concentration higher than 112 mg/dL and no severe complication that would mandate immediate RRT, longer postponing of RRT initiation did not confer additional benefit and was associated with potential harm.

FUNDING

Programme Hospitalier de Recherche Clinique.

Prevention and Therapy of AKI in Asia: A Big Challenge

Asia is the largest and most populous continent and has huge differences in socioeconomic status, development, and health care between the different countries and regions within each country. This manifests in the varied causes of acute kidney injury (AKI), particularly higher rates of community-acquired AKI and in the differential access to health care for the population. Because of resource limitations, prevention and treatment of AKI is a difficult challenge. This review highlights the differences in AKI in Asia compared with the developed world and discusses prevention and treatment of AKI within the context of resource limitations.

Effect of initiation of renal replacement therapy on mortality in acute pancreatitis patients

This study aims to explore effect of initiation of renal replacement therapy (RRT) on mortality in acute pancreatitis (AP) patients. In this study, a total of 92 patients from the surgical intensive care unit (SICU) of the Second Affiliated Hospital of Harbin Medical University who were diagnosed with AP and underwent RRT or not between January 2014 and December 2018 were included in this retrospective study. Demographic and clinical data were obtained on admission to SICU. Patients were divided into early initiation of RRT group (n = 44) and delayed initiation of RRT group (n = 48). Duration of mechanical ventilation (MV), intra-peritoneal pressure, vasopressors infusion, body temperature, procalcitonin, creatinine, platelet counts, length of hospital stay and prognosis were recorded during hospitalization, and then compared between groups. Patients with delayed initiation of RRT exhibited significantly higher APACHE II score, SOFA score and lower GCS score than those with early initiation of RRT (P < 0.001, <0.001,  = 0.04, respectively). No difference in the rest of the baseline data and vasopressors infusion was found. Dose of Norepinephrine, maximum and mean PCT, maximum and mean creatinine, maximum and mean intra-peritoneal pressure, length of hospital stay, prognosis of ICU and hospitalization showed significant difference between groups. Early initiation of RRT may be beneficial for AP patients, which can provide some insight and support for patients' treatment in clinic.

Renal replacement therapy is independently associated with a lower risk of death in patients with severe acute kidney injury treated with targeted temperature management after out-of-hospital cardiac arrest

BACKGROUND

The effect of renal replacement therapy (RRT) on the outcomes of severe acute kidney injury (AKI) after out-of-hospital cardiac arrest (OHCA) is uncertain. This study aimed to evaluate the association of RRT with 6-month mortality in patients with severe AKI treated with targeted temperature management (TTM) after OHCA.

METHODS

This was a retrospective analysis of a prospectively collected multicentre observational cohort study that included adult OHCA patients treated with TTM across 22 hospitals in South Korea between October 2015 and December 2018. AKI was diagnosed using the Kidney Disease: Improving Global Outcomes criteria. The primary outcome was 6-month mortality and the secondary outcome was cerebral performance category (CPC) at 6 months. Multivariate Cox regression analysis was performed to define the role of RRT in stage 3 AKI.

RESULTS

Among 10,426 patients with OHCA, 1373 were treated with TTM. After excluding those who died within 48 h of return of spontaneous circulation (ROSC) and those with pre-arrest chronic kidney disease, our study cohort comprised 1063 patients. AKI developed in 590 (55.5%) patients and 223 (21.0%) had stage 3 AKI. Among them, 115 (51.6%) were treated with RRT. The most common treatment modality among RRT patients was continuous renal replacement therapy (111 [96.5%]), followed by intermittent haemodialysis (4 [3.5%]). The distributions of CPC (1-5) at 6 months for the non-RRT vs. the RRT group were 3/108 (2.8%) vs. 12/115 (10.4%) for CPC 1, 0/108 (0.0%) vs. 1/115 (0.9%) for CPC 2, 1/108 (0.9%) vs. 3/115 (2.6%) for CPC 3, 6/108 (5.6%) vs. 6/115 (5.2%) for CPC 4, and 98/108 (90.7%) vs. 93/115 (80.9%) for CPC 5, respectively (P = 0.01). The RRT group had significantly lower 6-month mortality than the non-RRT group (93/115 [81%] vs. 98/108 [91%], P = 0.04). Multivariate Cox regression analyses showed that RRT was independently associated with a lower risk of death in patients with stage 3 AKI (hazard ratio, 0.569 [95% confidence interval, 0.377-0.857, P = 0.01]).

CONCLUSION

Dialysis interventions were independently associated with a lower risk of death in patients with stage 3 AKI treated with TTM after OHCA.

Timing of Renal Replacement Therapy for Severe Acute Kidney Injury in Critically Ill Patients

Acute kidney injury (AKI) affects many ICU patients and is responsible for increased morbidity and mortality. Although lifesaving in many situations, renal replacement therapy (RRT) may be associated with complications, and the appropriate timing of its initiation is still the subject of intense debate. An early initiation strategy can prevent some metabolic complications, whereas a delayed one may allow for renal function recovery in some patients without need for this costly and potentially dangerous technique. For years, most of the knowledge on this issue stemmed from observational studies or small randomized controlled trials. Recent randomized controlled trials have indicated that a watchful waiting strategy (in the absence of life-threatening conditions such as severe hyperkalemia or pulmonary edema) during severe AKI allowed many patients to escape RRT and did not seem to adversely affect survival compared with a strategy of immediate RRT. In addition, data suggest that a delayed strategy may reduce the rate of complications (such as catheter infection) and favor renal function recovery. Ongoing studies will have to both confirm these conclusions and clarify to what extent the delay in initiating RRT can be prolonged. Pending those results, the bulk of evidence suggests that, in the absence of potential severe complications of AKI, delaying RRT is a valid and safe strategy that may also allow for considerable cost savings.

Furosemide Stress Test in Predicting Acute Kidney Injury Outcomes

How to cite this article: Rajasekaran KK, Venkataraman R. Furosemide Stress Test in Predicting Acute Kidney Injury Outcomes. Indian J Crit Care Med 2020;24(Suppl 3):S100–S101.

Early initiation renal replacement therapy for fluid management to reduce central venous pressure is more conducive to renal function recovery in patients with acute kidney injury

Background:

Acute kidney injury (AKI) is a serious complication in critically ill patients with septic shock treated in the intensive care unit. Renal replacement therapy (RRT) is a treatment for severe AKI; however, the time of initiation of RRT and factors that affect the recovery of kidney function remains unclear. This study was to explore whether early initiation of RRT treatment for fluid management to reduce central venous pressure (CVP) can help to improve patients’ kidney function recovery.

Methods:

A retrospective analysis of septic patients who had received RRT treatment was conducted. Patients received RRT either within 12 h after they met the diagnostic criteria of renal failure (early initiation) or after a delay of 48 h if renal recovery had not occurred (delayed initiation). Parameters such as patients’ renal function recovery at discharge, fluid balance, and levels of CVP were assessed.

Results:

A total of 141 patients were eligible for enrolment: 40.4% of the patients were in the early initiation group (57 of 141 patients), and 59.6% were in the delayed initiation group (84 of 141 patients). There were no significant differences in the characteristics at baseline between the two groups, and there were no differences in 28-day mortality between the two groups (χ² = 2.142, P = 0.143); however, there was a significant difference in the recovery rate of renal function between the two groups at discharge (χ² = 4.730, P < 0.001). More importantly, early initiation of RRT treatment and dehydration to reduce CVP are more conducive to the recovery of renal function in patients with AKI.

Conclusion:

Compared with those who received delayed initiation RRT, patients who received early-initiation RRT for dehydration to reduce CVP have enhanced kidney function recovery.

The effect of timing of initiation of renal replacement therapy on mortality: A retrospective case-control study

Purpose

To determine if earlier initiation of renal replacement therapy (RRT) is associated with improved survival in patients with severe acute kidney injury.

Methods

We performed a retrospective case-control study of propensity-matched groups with multivariable logistic regression using Akaike Information Criteria to adjust for non-matched variables in a surgical ICU in a tertiary care hospital.

Results

We matched 169 of 205 (82%) patients with new initiation of RRT (EARLY group) to 169 similar patients who did not initiate RRT on that day (DEFERRED group). Eighteen (11%) of DEFERRED eventually received RRT before discharge. By univariate analysis, ICU mortality was higher in EARLY (n = 60 (36%) vs. n = 23 (14%), p < 0.001) as was hospital mortality (n = 73 (43%) vs. n = 44 (26%), p = 0.001). Of the 18 RRT patients in DEFERRED, 12 (67%) died in ICU and 13 (72%) in hospital. After propensity matching and logistic regression, we found that EARLY initiation of RRT was associated with a more than doubling of ICU mortality (aOR = 2.310, 95% confidence interval = 1.254-4.257, p = 0.007). However, after similar adjustment, there was no difference in hospital mortality (aOR = 1.283, 95% CI = 0.753-2.186, p = 0.360).

Conclusions

While ICU mortality was increased in the EARLY group, there was no difference in hospital mortality between EARLY and DEFERRED groups.

Effects of early dialysis on the outcomes of critically ill patients with acute kidney injury: a systematic review and meta-analysis of randomized controlled trials

The appropriate timing for initiating renal replacement therapy (RRT) in critically ill patients with acute kidney injury (AKI) remains unknown. This meta-analysis aims to assess the efficacy of early initiation of RRT in critically ill patients with AKI. The Pubmed, Embase and Cochrane databases were searched up to August 13, 2019. Only randomized controlled trials (RCTs) comparing the effects of early and late RRT on AKI patients were included. The primary outcome was 28-day mortality. Eleven RCTs including 1131 and 1111 AKI patients assigned to early and late RRT strategies, respectively, were enrolled in this meta-analysis. The pooled 28-day mortality was 38.1% (431/1131) and 40.7% (453/1111) in the patients assigned to early and late RRT, respectively, with no significant difference between groups (risk ratio (RR), 0.95; 95% CI, 0.78-1.15, I2 = 63%). No significant difference was found between groups in terms of RRT dependence in survivors on day 28 (RR, 0.90; 95% CI, 0.67-1.25, I2 = 0%), and recovery of renal function (RR, 1.03; 95% CI, 0.89-1.19, I2 = 56%). The early RRT group had higher risks of catheter-related infection (RR, 1.7, 95% CI, 1.01-2.97, I2 = 0%) and hypophosphatemia (RR, 2.5, 95% CI, 1.25-4.99, I2 = 77%) than the late RRT group. In conclusion, an early RRT strategy does not improve survival, RRT dependence, or renal function recovery in critically ill patients with AKI in comparison with a late RRT strategy. However, clinicians should be vigilant because early RRT can carry higher risks of catheter-related infection and hypophosphatemia during dialysis than late RRT.

Timing of Renal Support and Outcome of Septic Shock and Acute Respiratory Distress Syndrome. A Post Hoc Analysis of the AKIKI Randomized Clinical Trial

RATIONALE

The optimal strategy for initiation of renal replacement therapy (RRT) in patients with severe acute kidney injury in the context of septic shock and acute respiratory distress syndrome (ARDS) is unknown.

OBJECTIVES

To examine the effect of an early compared with a delayed RRT initiation strategy on 60-day mortality according to baseline sepsis status, ARDS status, and severity.

METHODS

Post hoc analysis of the AKIKI (Artificial Kidney Initiation in Kidney Injury) trial.

MEASUREMENTS AND MAIN RESULTS

Subgroups were defined according to baseline characteristics: sepsis status (Sepsis-3 definition), ARDS status (Berlin definition), Simplified Acute Physiology Score 3 (SAPS 3), and Sepsis-related Organ Failure Assessment (SOFA). Of 619 patients, 348 (56%) had septic shock and 207 (33%) had ARDS. We found no significant influence of the baseline sepsis status (P = 0.28), baseline ARDS status (P = 0.94), and baseline severity scores (P = 0.77 and P = 0.46 for SAPS 3 and SOFA, respectively) on the comparison of 60-day mortality according to RRT initiation strategy. A delayed RRT initiation strategy allowed 45% of patients with septic shock and 46% of patients with ARDS to escape RRT. Urine output was higher in the delayed group. Renal function recovery occurred earlier with the delayed RRT strategy in patients with septic shock or ARDS (P < 0.001 and P = 0.003, respectively). Time to successful extubation in patients with ARDS was not affected by RRT strategy (P = 0.43).

CONCLUSIONS

Early RRT initiation strategy was not associated with any improvement of 60-day mortality in patients with severe acute kidney injury and septic shock or ARDS. Unnecessary and potentially risky procedures might often be avoided in these fragile populations. Clinical trial registered with www.clinicaltrials.gov (NCT 01932190).

Retarder une épuration extrarénale dans l’insuffisance rénale aiguë : la nuit nous appartient

Les indications de l’épuration extrarénale (EER) dans le contexte d’insuffisance rénale aiguë en réanimation sont débattues avec une certaine passion. Il est évident que les situations qui peuvent menacer immédiatement le pronostic vital (hyperkaliémie ou acidose métabolique réfractaire et sévère ou oedème pulmonaire de surcharge chez le patient anurique) nécessitent un recours urgent à l’EER. Hormis ces situations extrêmes, des études de haut niveau de preuve ont récemment montré que retarder l’indication de l’EER n’affecte pas la survie des patients et pourrait même favoriser la récupération de la fonction rénale par comparaison à une EER trop précoce. Cette mise au point se propose de discuter les risques théoriques liés au fait de différer l’EER et s’attache à montrer qu’ils constituent plus des craintes que des réalités.

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.

Association between diuretics and successful discontinuation of continuous renal replacement therapy in critically ill patients with acute kidney injury

BACKGROUND

Despite aggressive application of continuous renal replacement therapy (CRRT) in critically ill patients with acute kidney injury (AKI), there is no consensus on diuretic therapy when discontinuation of CRRT is attempted. The effect of diuretics on discontinuation of CRRT in critically ill patients was evaluated.

METHODS

This retrospective cohort study enrolled 1176 adult patients who survived for more than 3 days after discontinuing CRRT between 2009 and 2014. Patients were categorized depending on the re-initiation of renal replacement therapy within 3 days after discontinuing CRRT or use of diuretics. Changes in urine output (UO) and renal function after discontinuing CRRT were outcomes. Predictive factors for successful discontinuation of CRRT were also analyzed.

RESULTS

The CRRT discontinuation group had a shorter duration of CRRT, more frequent use of diuretics after discontinuing CRRT, and greater UO on the day before CRRT discontinuation [day minus 1 (day - 1)]. The diuretics group had greater increases in UO and serum creatinine elevation after discontinuing CRRT. In the CRRT discontinuation group, continuous infusion of furosemide tended to increase UO more effectively. Multivariable regression analysis identified high day - 1 UO and use of diuretics as significant predictors of successful discontinuation of CRRT. Day - 1 UO of 125 mL/day was the cutoff value for predicting successful discontinuation of CRRT in oliguric patients treated with diuretics following CRRT.

CONCLUSIONS

Day - 1 UO and aggressive diuretic therapy were associated with successful CRRT discontinuation. Diuretic therapy may be helpful when attempting CRRT discontinuation in critically ill patients with AKI, by inducing a favorable fluid balance, especially in oliguric patients.

Continuous Renal Replacement Therapy: Who, When, Why, and How

Continuous renal replacement therapy (CRRT) is commonly used to provide renal support for critically ill patients with acute kidney injury, particularly patients who are hemodynamically unstable. A variety of techniques that differ in their mode of solute clearance may be used, including continuous venovenous hemofiltration with predominantly convective solute clearance, continuous venovenous hemodialysis with predominantly diffusive solute clearance, and continuous venovenous hemodiafiltration, which combines both dialysis and hemofiltration. The present article compares CRRT with other modalities of renal support and reviews indications for initiation of renal replacement therapy, as well as dosing and technical aspects in the management of CRRT.

Response to different furosemide doses predicts AKI progression in ICU patients with elevated plasma NGAL levels

BACKGROUND

Furosemide responsiveness (FR) is determined by urine output after furosemide administration and has recently been evaluated as a furosemide stress test (FST) for predicting severe acute kidney injury (AKI) progression. Although a standardized furosemide dose is required for FST, variable dosing is typically employed based on illness severity, including renal dysfunction in the clinical setting. This study aimed to evaluate whether FR with different furosemide doses can predict AKI progression. We further evaluated the combination of an AKI biomarker, plasma neutrophil gelatinase-associated lipocalin (NGAL), and FR for predicting AKI progression.

RESULTS

We retrospectively analyzed 95 patients who were treated with bolus furosemide in our medical-surgical intensive care unit. Patients who had already developed AKI stage 3 were excluded. A total of 18 patients developed AKI stage 3 within 1 week. Receiver operating curve analysis revealed that the area under the curve (AUC) values of FR and plasma NGAL were 0.87 (0.73-0.94) and 0.80 (0.67-0.88) for AKI progression, respectively. When plasma NGAL level was < 142 ng/mL, only one patient developed stage 3 AKI, indicating that plasma NGAL measurements were sufficient to predict AKI progression. We further evaluated the performance of FR in 51 patients with plasma NGAL levels > 142 ng/mL. FR was associated with AUC of 0.84 (0.67-0.94) for AKI progression in this population with high NGAL levels.

CONCLUSIONS

Although different variable doses of furosemide were administered, FR revealed favorable efficacy for predicting AKI progression even in patients with high plasma NGAL levels. This suggests that a combination of FR and biomarkers can stratify the risk of AKI progression in a clinical setting.

Acute Kidney Injury (AKI)

Kidneys perform a multitude of essential functions within the human body. Of these the most important are (1) maintaining pH through regulation of acid/base levels and (2) excreting end products of metabolism. As for most organ-systems, these functions are especially important for healing following trauma and/or surgery and decline with age. Acute Kidney Injury (AKI) is one of the common forms of organ failures seen in the ICU and elderly patients are more prone to it. The causes maybe classified as Prerenal (inadequate perfusion), renal (inherent kidney disease) and post-renal (urinary obstruction). Preventing AKI should be an important concern in all critically ill patients but especially important in the elderly patients since the development of AKI can significantly increase in-hospital mortality. Once AKI has set in a systematic and step-wise approach of diagnosis and management is key to avoiding adverse outcomes.

Prognostic Factors and Efficacy for Continuous Renal Replacement Therapy in Critically Ill Patients: A Chinese Single-Center Retrospective Study

BACKGROUND

There is controversy about the efficacy and prognostic factors for continuous renal replacement therapy (CRRT) in China due to practice variation. Our aim is to investigate these questions.

METHOD

A total of 613 adult patients receiving CRRT in last 3 years from one Chinese ICU were enrolled. The analysis of demographic data, vital signs, and laboratory tests prior to CRRT and outcomes were performed. The data between pre- and post-CRRT were compared for efficacy analysis.

RESULTS

Prior to CRRT, partial pressure of carbon dioxide (PCO2), systolic blood pressure (SBP), gender, age, bilirubin, cystatin C, and mechanical ventilation were correlated with in-hospital mortality. In a binary logistic regression, PCO2, SBP, age, and gender were significant in predicting mortality. Cox regression analysis demonstrated PCO2 independent association with mortality, and lower SBP worse mortality. CRRT could eliminate the fluid and metabolites.

CONCLUSION

CO2 retention and low SBP prior to CRRT were associated with increased mortality. CRRT significantly improved hemeostasis.

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.

The role of the specialized team in the operation of continuous renal replacement therapy: a single-center experience

Background

The requirement of continuous renal replacement therapy (CRRT) is increasing with the growing incidence of acute kidney injury (AKI). The decision to initiate CRRT is not difficult if an adequate medical history is obtained. However, the handling and maintenance of CRRT constitute a labor-intensive intervention that requires specialized skills. For these reasons, our center organized a specialized CRRT team in March 2013. The aim of this study is to report on the role of a specialized CRRT team and to evaluate the team’s outcome.

Methods

This retrospective single-center study evaluated AKI patients who underwent CRRT in the intensive care unit (ICU) from March 2011 to February 2015. Patients were divided into two groups based on whether they received specialized CRRT team intervention. We collected information on demographic characteristics, laboratory parameters, SOFA score, CRRT initiation time, actual delivered dose and CRRT down-time. In-hospital mortality was defined by medical chart review. Binary logistic regression analysis was used to define factors associated with in-hospital mortality.

Results

A total of 1104 patients were included in this study. The mean patient age was 63.85 ± 14.39 years old, and 62.8% of the patients were male. After the specialized CRRT team intervention, there was a significant reduction in CRRT initiation time (5.30 ± 13.86 vs. 3.60 ± 11.59 days, p = 0.027) and CRRT down-time (1.78 ± 2.23 vs. 1.38 ± 2.08 h/day, p = 0.002). The rate of in-hospital mortality decreased after the specialized CRRT team intervention (57.5 vs. 49.2%, p = 0.007). When the multivariable analysis was adjusted, delayed CRRT initiation (HR 1.054(1.036–1.072), p < 0.001) was a significant factor in predicting in-hospital mortality, along with an increased SOFA score, lower serum albumin and prolonged prothrombin time.

Conclusions

Our study shows that specialized CRRT team intervention reduced CRRT initiation time, down-time and in-hospital mortality. This study could serve as a logical basis for implementing specialized CRRT teams hospital-wide.

Electronic supplementary material

The online version of this article (10.1186/s12882-017-0746-8) contains supplementary material, which is available to authorized users.

The prognostic value of the furosemide stress test in predicting delayed graft function following deceased donor kidney transplantation

OBJECTIVES AND METHODS

The Furosemide Stress Test (FST) is a novel dynamic assessment of tubular function that has been shown in preliminary studies to predict patients who will progress to advanced stage acute kidney injury, including those who receive renal replacement therapy (RRT). The aim of this study is to investigate if the urinary response to a single intraoperative dose of intravenous furosemide predicts delayed graft function (DGF) in patients undergoing deceased donor kidney transplant.

RESULTS

On an adjusted multiple logistic regression, a single 100 mg dose of intraoperative furosemide after the anastomosis of the renal vessels (FST) predicted the need for RRT at 2 and 6 h post kidney transplantation (KT). Recipient urinary output was measured at 2 and 6 h post furosemide administration. In receiver-operating characteristic (ROC) analysis, the FST predicted DGF with an area-under-the curve of 0.85 at an optimal urinary output cut-off of <600 mls at 6 h with a sensitivity of and a specificity of 83% and 74%, respectively.

CONCLUSIONS

The FST is a predictor of DGF post kidney transplant and has the potential to identify patients requiring RRT early after KT.

Acute kidney injury in high-risk cardiac surgery patients: roles of inflammation and coagulation

AIMS

Acute kidney injury (AKI) is a common complication following cardiac surgery. Cardiopulmonary bypass elicits coagulation and inflammation activation and oxidative stress, all involved in AKI but never simultaneously assessed. We aimed to evaluate relations between oxidative stress, inflammatory and coagulation systems activation and postoperative renal function in patients with normal preoperative renal function.

METHODS

Forty-one high-risk patients (EuroSCORE >6 and preoperative haemoglobin <12 g/dl in women and <13 g/dl in men) were prospectively enrolled. Prothrombin fragment 1.2 (coagulation marker), interleukin-6 and interleukin-10 (pro/anti-inflammatory markers) and 8-oxo-2'-deoxyguanosine (oxidative stress marker) were evaluated until postoperative day 5.

RESULTS

Patients were divided into two groups according to estimated glomerular filtration rate reduction observed postoperatively (reduction <25% in 26 patients: NO-AKI group; reduction >25% in 15 patients: AKI group). No differences were found for inflammatory markers. Oxidative stress slightly increased in the AKI group. Twenty-four hours after the operation prothrombin fragment 1.2 levels were significantly higher in the AKI group (506.6 ± 548 vs. 999 ± 704.1 pmol/l; P = 0.018), and they were independently associated with estimated glomerular filtration rate reduction, with an area under the receiving operating characteristic of 0.744.

CONCLUSION

Thrombin generation is higher in patients with renal function worsening, and it is an independent risk factor for AKI in patients with anaemia, possibly leading to microcirculation impairment and tubular cells damage.

Initiation and Cessation Timing of Renal Replacement Therapy in Patients with Type 1 Cardiorenal Syndrome: An Observational Study

BACKGROUND/AIMS

Renal replacement therapy (RRT) is a rescue therapy for patients with type 1 cardiorenal syndrome (CRS) with poor prognoses. However, the optimal timing for initiation and cessation of RRT remains controversial. The purpose of this study was to determine the optimal timing of initiation and cessation of RRT for patients with type 1 CRS.

METHODS

In this retrospective analysis, patients with refractory type 1 CRS receiving RRT were divided into 3 groups according to weaning from RRT and death within 90 days. Baseline characteristics, underlying heart disease, comorbidities, drug use before RRT, indicators of RRT initiation, and prognosis were compared between the 3 groups.

RESULTS

Fifty-two patients were enrolled, which included 27 males and 25 females with a mean age of 70.7 ± 16.1 years and a 90-day mortality rate of 65.4%. The mean urine output before RRT initiation was 800 mL/ 24 h in the RRT-independent group, 650 mL/24 h in the RRT-dependent group, and 345 mL/ 24 h in the death group (p = 0.021). Additionally, there were obvious differences in fluid balance between the 3 groups (167, 250, and 1,270 mL, respectively, p = 0.016). Patients could be successfully weaned from RRT when urine output was >880 mL and fluid balance volume was <150 mL.

CONCLUSION

The mean fluid balance of survivors was remarkably less than that of the death group at RRT initiation. RRT termination can be considered when urine output is >880 mL/24 h and volume balance is <150 mL/24 h.

Acute kidney injury in the ICU: from injury to recovery: reports from the 5th Paris International Conference

The French Intensive Care Society organized its yearly Paris International Conference in intensive care on June 18-19, 2015. The main purpose of this meeting is to gather the best experts in the field in order to provide the highest quality update on a chosen topic. In 2015, the selected theme was: "Acute Renal Failure in the ICU: from injury to recovery." The conference program covered multiple aspects of renal failure, including epidemiology, diagnosis, treatment and kidney support system, prognosis and recovery together with acute renal failure in specific settings. The present report provides a summary of every presentation including the key message and references and is structured in eight sections: (a) diagnosis and evaluation, (b) old and new diagnosis tools,

Acute kidney injury in the ICU: from injury to recovery: reports from the 5th Paris International Conference

The French Intensive Care Society organized its yearly Paris International Conference in intensive care on June 18-19, 2015. The main purpose of this meeting is to gather the best experts in the field in order to provide the highest quality update on a chosen topic. In 2015, the selected theme was: "Acute Renal Failure in the ICU: from injury to recovery." The conference program covered multiple aspects of renal failure, including epidemiology, diagnosis, treatment and kidney support system, prognosis and recovery together with acute renal failure in specific settings. The present report provides a summary of every presentation including the key message and references and is structured in eight sections: (a) diagnosis and evaluation, (b) old and new diagnosis tools,

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.

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.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-017-0486-9) contains supplementary material, which is available to authorized users.

Early continuous renal replacement therapy in septic acute kidney injury could be defined by its initiation within 24 hours of vasopressor infusion

PURPOSE

The optimal timing for the initiation of early continuous renal replacement therapy (CRRT) is uncertain and requires a practically feasible definition with acceptable evidence.

MATERIALS AND METHODS

We investigated the clinical impacts of 3-time interval parameters on the morbidity and mortality of 177 patients with septic shock-induced acute kidney injury: (1) time from vasopressor initiation to CRRT initiation (T_vaso-CRRT), (2) time from intensive care unit (ICU) admission to CRRT initation (T_ICU-CRRT), and (3) time from endotracheal intubation to CRRT initiation (T_endo-CRRT).

RESULTS

The proportion of the patients with T_vaso-CRRT less than 24 h (median, 14 h, interquartile range [IQR], 5-30 h) was significantly higher in the survival group than in the non-survival group (84.3% vs. 58.5%, p < 0.001). T_vaso-CRRT less than 24 h and Sequential Organ Failure Assessment score were independent factors associated with 28-day mortality and 90-day mortality. T_ICU-CRRT (median, 17 h, IQR, 5-72 h) and T_endo-CRRT (median, 13 h, IQR, 4-48 h) were significantly correlated with both the length of ICU stay (p < 0.001) and mechanical ventilation duration (p < 0.001), but not mortality.

CONCLUSIONS

Considering the possible therapeutic measurement by physician on the basis of the results in this study, early CRRT could be defined by a T_vaso-CRRT less than 24 h.

Continuous Renal Replacement Therapy for Acute Renal Failure in Patients with Traumatic Brain Injury

Objective

The purpose of this study was to investigate the impact of continuous renal replacement therapy (CRRT) on survival and relevant factors in patients who underwent CRRT after traumatic brain injury (TBI).

Methods

We retrospectively reviewed the laboratory, clinical, and radiological data of 29 patients who underwent CRRT among 1,190 TBI patients treated at our institution between April 2011 and June 2015. There were 20 men and 9 women, and the mean age was 60.2 years. The mean initial Glasgow Coma Scale score was 9.2, and the mean injury severity score was 24. Kaplan-Meier method and Cox regression were used for analysis of survival and relevant factors.

Results

The actuarial median survival time of the 29 patients was 163 days (range, 3-317). Among the above 29 patients, 22 died with a median survival time of 8 days (range, 3-55). The causes of death were TBI-related in 8, sepsis due to pneumonia or acute respiratory distress syndrome (ARDS) in 4, and multi-organ failure in 10. Among the various factors, urine quantity of more than 500 mL for 24-hours before receiving CRRT was a significant and favorable factor for survival in the multivariate analysis (p=0.026).

Conclusion

According to our results, we suggest that early intervention with CRRT may be beneficial in the treatment of TBI patients with impending acute renal failure (ARF). To define the therapeutic advantages of early CRRT in the TBI patients with ARF, a well-designed and controlled study with more cases is required.

Initiation Strategies for Renal-Replacement Therapy in the Intensive Care Unit

BACKGROUND

The timing of renal-replacement therapy in critically ill patients who have acute kidney injury but no potentially life-threatening complication directly related to renal failure is a subject of debate.

METHODS

In this multicenter randomized trial, we assigned patients with severe acute kidney injury (Kidney Disease: Improving Global Outcomes [KDIGO] classification, stage 3 [stages range from 1 to 3, with higher stages indicating more severe kidney injury]) who required mechanical ventilation, catecholamine infusion, or both and did not have a potentially life-threatening complication directly related to renal failure to either an early or a delayed strategy of renal-replacement therapy. With the early strategy, renal-replacement therapy was started immediately after randomization. With the delayed strategy, renal-replacement therapy was initiated if at least one of the following criteria was met: severe hyperkalemia, metabolic acidosis, pulmonary edema, blood urea nitrogen level higher than 112 mg per deciliter, or oliguria for more than 72 hours after randomization. The primary outcome was overall survival at day 60.

RESULTS

A total of 620 patients underwent randomization. The Kaplan-Meier estimates of mortality at day 60 did not differ significantly between the early and delayed strategies; 150 deaths occurred among 311 patients in the early-strategy group (48.5%; 95% confidence interval [CI], 42.6 to 53.8), and 153 deaths occurred among 308 patients in the delayed-strategy group (49.7%, 95% CI, 43.8 to 55.0; P=0.79). A total of 151 patients (49%) in the delayed-strategy group did not receive renal-replacement therapy. The rate of catheter-related bloodstream infections was higher in the early-strategy group than in the delayed-strategy group (10% vs. 5%, P=0.03). Diuresis, a marker of improved kidney function, occurred earlier in the delayed-strategy group (P<0.001).

CONCLUSIONS

In a trial involving critically ill patients with severe acute kidney injury, we found no significant difference with regard to mortality between an early and a delayed strategy for the initiation of renal-replacement therapy. A delayed strategy averted the need for renal-replacement therapy in an appreciable number of patients. (Funded by the French Ministry of Health; ClinicalTrials.gov number, NCT01932190.).

Evaluation of the quality of care of a haemodialysis public-private partnership programme for patients with end-stage renal disease

BACKGROUND

Haemodialysis (HD) is one of the life-saving options for patients with end stage renal disease but demand for this treatment exceeds capacity in publicly funded hospitals. One novel approach to addressing this problem is through a shared-care model whereby government hospitals partner with qualified private HD service providers to increase the accessibility of HD for needy patients. The aim of this study is to evaluate and enhance the quality of care (QOC) provided in such a shared-care programme in Hong Kong, the Haemodialysis Public-Private Partnership Programme (HD-PPP).

METHODS/DESIGN

This is a longitudinal study based on Action Learning and Audit Spiral methodologies to measure the achievement of pre-set target standards for the HD-PPP programme over three evaluation cycles. The QOC evaluation framework is comprised of structure, process and outcome criteria with target standards in each domain developed from review of the evidence and in close collaboration with the HD-PPP working group. During each evaluation cycle, coordinators of each study site complete a questionnaire to determine adherence with structural criteria of care. Process and clinical outcomes, such as adverse events and dialysis adequacy, are extracted from the patient records of consenting study participants while face-to-face interviews are conducted to ascertain patient-reported outcomes such as self-efficacy and health-related quality of life.

DISCUSSION

The study relies on the successful implementation of partnership-based action research to develop an evidence-based and pragmatic framework for evaluation of quality of care in an iterative fashion, and to use it to identify possible areas of quality enhancements in a shared-care programme for HD patients. The approach we take in this study emphasizes partnership and engagement with the clinical and administrative programme team, a robust but flexible evaluation framework, direct observation and the potential to realize positive change. The experience will be useful to inform the process of coordinating research studies involving multiple stakeholders and results will help to guide service planning and policy decision making.

TRIAL REGISTRATION

US Clinical Trial Registry NCT02307903.

Risk Stratification for Acute Kidney Injury: Are Biomarkers Enough?

Acute kidney injury (AKI) is a common and serious complication that is associated with several adverse outcomes in hospitalized patients. AKI significantly increases the risk of mortality, need for renal replacement therapy, and intensive care admission, and it also has serious economic ramifications. Effective risk stratification to identify patients at risk for severe AKI is essential for targeting our health care and research resources to tackle this important public health issue. The overwhelming majority of research in earlier diagnosis and risk stratification of AKI over the past 10 years has focused on novel biomarker development. The purpose of this review is to provide an update on other novel risk stratification tools than can be used in the prognostication of AKI. We discuss the utility of the furosemide stress test in predicting the severity of AKI and the renal angina index in predicting the occurrence of AKI. We also discuss NephroCheck, a prognostic test that measures tissue inhibitor of metalloproteinase-2 and insulin-like growth factor binding protein 7 for the early detection of severe AKI.

Fluid Overload Is Associated With Higher Mortality and Morbidity in Pediatric Patients Undergoing Cardiac Surgery

OBJECTIVES

Fluid overload after pediatric cardiac surgery is common and has been shown to increase both mortality and morbidity. This study explores the risk factors of early postoperative fluid overload and its relationship with adverse outcomes.

DESIGN

Secondary analysis of the prospectively collected data of children undergoing open-heart surgery between 2004 and 2008.

SETTING

Tertiary national cardiac center.

PATIENTS

One thousand five hundred twenty consecutive pediatric patients (<18 years old) were included in the analyses.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

In the first 72 hours of the postoperative period, the daily fluid balance was calculated as milliliter per kilogram and the daily fluid overload was calculated as fluid balance (L)/weight (kg) × 100. The primary endpoint was in-hospital mortality; the secondary outcomes were low cardiac output syndrome and prolonged mechanical ventilation. One thousand three hundred and sixty-seven patients (89.9%) had a cumulative fluid overload below 5%; 120 patients (7.8%), between 5% and 10%; and 33 patients (2.1%), above 10%. After multivariable analysis, higher fluid overload on the day of the surgery was independently associated with mortality (adjusted odds ratio, 1.14; 95% CI, 1.008-1.303; p = 0.041) and low cardiac output syndrome (adjusted odds ratio, 1.21; 95% CI, 1.12-1.30; p = 0.001). Higher maximum serum creatinine levels (adjusted odds ratio, 1.01; 95% CI, 1.003-1.021; p = 0.009), maximum vasoactive-inotropic scores (adjusted odds ratio, 1.01; 95% CI, 1.005-1.029; p = 0.042), and higher blood loss on the day of the surgery (adjusted odds ratio, 1.01; 95% CI, 1.004-1.025; p = 0.015) were associated with a higher risk of fluid overload that was greater than 5%.

CONCLUSIONS

Fluid overload in the early postoperative period was associated with higher mortality and morbidity. Risk factors for fluid overload include underlying kidney dysfunction, hemodynamic instability, and higher blood loss on the day of the surgery.

Predictive value of the RIFLE urine output criteria on contrast-induced nephropathy in critically ill patients

Background

To investigate the predictive value of decreased urine output based on the Risk of renal dysfunction, Injury to the kidney, Failure of kidney function, Loss of kidney function and End-stage renal disease (RIFLE) classification on contrast- induced acute kidney injury (CA-AKI) in intensive care (ICU) patients.

Methods

All patients who received contrast media (CM) injection for CT scan or coronary angiography during a 3-year period in a 24 bed medico-surgical ICU were reviewed.

Results

Daily serum creatinine concentrations and diuresis were measured for 3 days after CM injection. We identified 23 cases of CA-AKI in the 149 patients included (15.4 %). Patients who developed CA-AKI were more likely to require renal replacement therapy and had higher ICU mortality rates. At least one RIFLE urine output criteria was observed in 45 patients (30.2 %) and 14 of these 45 patients (31.1 %) developed CA-AKI based on creatinine concentrations. In 30 % of these cases, urine output decreased or didn’t change after the increase in creatinine concentrations. The RIFLE urine output criteria had low sensitivity (39.1 %) and specificity (67.9 %) for prediction of CA-AKI, a low positive predictive value of 50 % and a negative predictive value of 87.2 %. The maximal dose of vasopressors before CM was the only independent predictive factor for CA-AKI.

Conclusions

CA-AKI is a frequent pathology observed in ICU patients and is associated with increased need for renal replacement therapy and increased mortality. The predictive value of RIFLE urine output criteria for the development of CA-AKI based on creatinine concentrations was low, which limits its use for assessing the effects of therapeutic interventions on the development and progression of AKI.

Inhibiting microRNA-449 Attenuates Cisplatin-Induced Injury in NRK-52E Cells Possibly via Regulating the SIRT1/P53/BAX Pathway

Background

Acute kidney injury (AKI) is quite common in the patients who frequently use the anticancer drug cisplatin. microRNAs (miRNAs) are powerful tools in modulating the expression of key factors in disease progression, but little is known about roles of miRNAs in AKI. This study explored the expression and function of miR-449 in cisplatin-induced AKI.

Material/Methods

Rat renal proximal tubular cell line NRK-52E was used for cisplatin treatment and miR-449 sponge transfection. MTT assay and flow cytometry were performed to detect cell viability and apoptosis in different cell groups. Protein expression of sirtuin 1 (SIRT1), acetylated p53, and BCL-associated X protein (BAX) was detected to deduce the possible regulatory mechanism of miR-449.

Results

Results showed that cisplatin treatment in NRK-52E cells significantly up-regulated miR-449 levels (P<0.05), inhibited cell viability (P<0.05), accelerated cell apoptosis (P<0.05), and changed SIRT1, acetylated p53, and BAX protein levels (P<0.01). However, inhibiting miR-449 by its sponge transfection in cisplatin-treated cells significantly promoted cell viability (P<0.05), suppressed cell apoptosis (P<0.05), elevated SIRT1 expression (P<0.01), and inhibited acetylated p53 and BAX protein levels (P<0.001).

Conclusions

These results indicate that inhibiting miR-449 allows the attenuation of cisplatin-induced injury in NRK-52E cells, suggesting that miR-449 is a potential target for treating AKI. miR-449 regulates the SIRT1/p53/BAX pathway, which may be its possible mechanism in modulating cell apoptosis of cisplatin-induced AKI. Further verification and a thorough understanding are necessary for targeting miR-449 in AKI treatment.

Initiating acute dialysis at earlier Acute Kidney Injury Network stage in critically ill patients without traditional indications does not improve outcome: a prospective cohort study

AIM

Optimal timing for acute renal replacement therapy (ARRT) initiation in critically ill patients with acute kidney injury (AKI) is unclear. We aimed to evaluate outcomes in patients who initiated ARRT for traditional indications versus those who met Acute Kidney Injury Network (AKIN) criteria without traditional indications.

METHODS

This was a single-centre prospective cohort study of medical and surgical intensive care patients with AKI. Traditional indications for ARRT initiation included: serum potassium ≥6.0 mmol/L, serum urea ≥30 mmol/L, arterial pH < 7.25, serum bicarbonate <10 mmol/L, acute pulmonary oedema, acute uraemic encephalopathy or pericarditis. In absence of these indications, ARRT was commenced if patients had (i) AKIN Stage 3 or (ii) AKIN Stage 1 or 2 with 'compelling' conditions. Primary outcomes were intensive care unit (ICU) and in-hospital mortality.

RESULTS

ARRT was initiated in 140 patients: traditional indications in 56 (40%); AKIN Stage 3 without traditional indications in 38 (27%); and AKIN Stage 1 or 2 with 'compelling' conditions in 46 (33%) patients. Traditional indications at ARRT initiation was associated with increased in-hospital mortality (adjusted odds ratio (95% confidence interval), 6.48 (1.54, 27.29)). In absence of traditional indications, earlier ARRT initiation, as defined by those with AKIN Stage 1 or 2, did not decrease ICU deaths (30.0% vs 18.8%, P = 0.30) or in-hospital mortality (50.0% vs 34.2%, P = 0.15) compared with those who were started on ARRT for AKIN Stage 3.

CONCLUSIONS

Presence of traditional indications at ARRT initiation was associated with greater mortality. Initiating dialysis at earlier AKIN stage did not improve survival in patients without traditional indications.

Application of Continuous Renal Replacement Therapy: What Should We Consider Based on Existing Evidence?

BACKGROUND

Continuous renal replacement therapy (CRRT) is performed mainly in patients with acute kidney injury, severe sepsis, or septic shock. Evidence has emerged about the indications for and therapeutic conditions of CRRT. In this review, we focus on the evidence for CRRT to date.

SUMMARY

CRRT employs diffusion, convection and adsorption to remove solutes from plasma. Indications can be divided into renal and non-renal indications. Concrete renal indications have not yet been determined, except for life-threatening absolute indications. Modality selection is a point of debate. Intermittent renal replacement therapy is reportedly equivalent to CRRT in terms of overall survival. However, the selection of modality must consider individual circumstances. The optimal dosage of CRRT has proven to be lower than that previously recommended, and the dosage is almost the same as the one employed in the 'real-world' setting. Patients treated by CRRT often have bleeding complications. In this situation, regional citrate anticoagulation can be used, but nafamostat is widely used in Japan. The right jugular vein is the most preferred vascular access site because it has the lowest likelihood of catheter malfunction. As for the complications of CRRT, hypophosphatemia and nutrient loss should be managed properly. When CRRT is no longer necessary, we should consider the appropriate timing of discontinuation.

KEY MESSAGES

Even though CRRT is an established technique, several points remain under debate. Individualization of therapy should be considered in light of the changes in patient characteristics.

Microcirculatory alterations during continuous renal replacement therapy in ICU: A novel view on the 'dialysis trauma' concept

OBJECTIVE

The purpose of this study was to evaluate microcirculation over 24 h renal replacement therapy (CRRT) in critically ill patients.

METHODS

We conducted a single-center, prospective, observational study, measuring microcirculation parameters, monitored by near infrared spectroscopy (NIRS) before hemodiafiltration onset (H0), and at six (H6) and 24 h (H24) during CRRT in critically ill patients. Serum Cystatin C (sCysC) and soluble (s)E-selectin levels were measured at the same time points. Twenty-eight patients [19 men (68%)] were included in the study.

RESULTS

Tissue oxygen saturation (StO2, %) [76.5 ± 12.5 (H0) vs 75 ± 11 (H6) vs 70 ± 16 (H24), p = 0.04], reperfusion rate, indicating endothelial function (EF, %/sec) [2.25 ± 1.44 (H0) vs 2.1 ± 1.8 (H6) vs 1.6 ± 1.4 (H24), p = 0.02] and sCysC (mg/L) [2.7 ± 0.8 (H0) vs 2.2 ± 0.6 (H6) vs 1.8 ± 0.8 (H24), p < 0.0001] significantly decreased within the 24 h CRRT. Change of EF positively correlated with changes of sCysC within 24 h CRRT (r = 0.464, p = 0.013) while in patients with diabetes the change of StO2 correlated with dose (r = − 0.8, p = 0.01). No correlation existed between hemoglobin and temperature changes with the deteriorated microcirculation indices. sE-Selectin levels in serum were elevated; no difference was established over the 24 h CRRT period. A strong correlation existed between the sE-Selectin concentration change at H6 and H24 and the mean arterial pressure change in the same period (r = 0.77, p < 0.001).

CONCLUSIONS

During the first 24 h of CRRT implementation in critically ill patients, deterioration of microcirculation parameters was noted. Microcirculatory alterations correlated with sCysC changes and with dose in patients with diabetes.

Impact of weaning from acute dialytic therapy on outcomes of chronic kidney disease following urgent-start dialysis

Discontinuation of acute, unplanned dialysis is always an important therapeutic goal in dialysis-requiring patients with existing chronic kidney disease. Only a limited proportion of patients could be weaned off dialysis and remained dialysis-free. Here we performed a multicenter, observational study to investigate factors associated with successful weaning from acute dialysis, and to explore the potential impact of weaning itself on outcomes of patients with chronic kidney disease following urgent-start dialysis. We recruited 440 chronic kidney disease patients with a baseline estimated glomerular filtration rate <45 ml/min per 1/73 m2, and used propensity score-adjusted Cox regression analysis to measure the effect of weaning from acute dialysis on death during the index hospitalization and death or readmission after discharge. Over 2 years, 64 of 421 (15.2%) patients who survived >1 month died, and 36 (8.6%) were removed from dialysis, with 26 (6.2%) remaining alive and dialysis-free. Logistic regression analysis found that age ≧ 65 years, ischemic acute tubular necrosis, nephrotoxic exposure, urinary obstruction, and higher predialysis estimated glomerular filtration rate and serum hemoglobin were predictors of weaning off dialysis. After adjustment for propensity scores for dialysis weaning, Cox proportional hazards models showed successful weaning from dialysis (adjusted hazard ratio 0.06; 95% confidence interval 0.01 to 0.35), along with a history of hypertension and serum albumin, were independent protectors for early death. Conversely, a history of stroke, peripheral arterial disease and cancer predicted the occurrence of early mortality. In conclusion, this prospective cohort study shows that compared to patients with chronic kidney disease who became end-stage renal disease after acute dialysis, patients who could be weaned off acute dialytic therapy were associated with reduced risk of premature death over a 2-year observation period.