Renal replacement therapy for AKI: When? How much? When to stop?

C-176 inhibits macrophage polarization towards M1-subtype and ameliorates LPS induced acute kidney injury

Sepsis-induced acute kidney injury (SI-AKI) has become a focal point in nephrology research field due to its high mortality and potential progression to chronic kidney disease (CKD). The increase of M1 macrophages within renal tissue and their associated inflammatory responses are key contributors to renal inflammation and subsequent damage. Additionally, the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) signaling pathway is abnormally activated during the onset of acute kidney injury (AKI). However, the relationship between the activation of this pathway and the increase in M1 macrophages has not been fully elucidated. This study investigated the protective effects and underlying mechanisms of the STING pathway-specific inhibitor C-176 on LPS-induced AKI, using an LPS and IFN-γ induced M1 macrophage model and an LPS-induced sepsis AKI mouse model. The in vivo results demonstrate that C-176 intervention can alleviate acute kidney injury and improve renal function by reducing macrophage infiltration in renal tissue, decreasing the proportion of M1 macrophages, and mitigating the inflammatory response. Additionally, in vitro results indicate that C-176 intervention inhibits the polarization of M0 macrophages to M1 macrophages, promotes their polarization to M2 macrophages, and reduces the amounts of pro-inflammatory cytokines such as IL-6 and TNF-α at both the protein and gene expression levels. The biological effects of C-176 are associated with the inhibition of STING-IRF3 signaling pathway activation. In summary, the findings of this study have certain scientific significance and application value for exploring the pathogenesis and treatment methods of SI-AKI.

Kidney replacement therapy in COVID-19-Related acute kidney injury: The impact of timing on mortality

The objective of this study was to determine the impact of the timing of KRT, dichotomized by a temporal criterion or by creatinine level, in patients with COVID-19-related AKI. This was a retrospective study involving 512 adult patients admitted to the ICU. All participants had laboratory-confirmed COVID-19 and a confirmed diagnosis of AKI. The potential predictors were the determination of the timing of KRT based on a temporal criterion (days since hospital admission) and that based on a serum creatinine cutoff criterion. Covariates included age, sex, and the SOFA score, as well as the need for mechanical ventilation and vasopressors. The main outcome measure was in-hospital mortality. We evaluated 512 patients, of whom 69.1% were men. The median age was 64 years. Of the 512 patients, 76.6% required dialysis after admission. The overall in-hospital mortality rate was 72.5%. When the timing of KRT was determined by the temporal criterion, the risk of in-hospital mortality was significantly higher for later KRT than for earlier KRT-84% higher in the univariate analysis (OR = 1.84, 95%, [CI]: 1.10-3.09) and 140% higher after adjustment for age, sex, and SOFA score (OR = 2.40, 95% CI: 1.36-4.24). When it was determined by the creatinine cutoff criterion, there was no such difference between high and low creatinine at KRT initiation. In patients with COVID-19-related AKI, earlier KRT might be associated with lower in-hospital mortality.

Current practices in pediatric continuous kidney replacement therapy: a systematic review-guided multinational modified Delphi consensus study

BACKGROUND

Continuous kidney replacement therapy (CKRT) has become an integral part of the care of critically ill children. However, uncertainty exists regarding the current state of how CKRT is prescribed and delivered in children. The main objective of this study was to identify the current practices for pediatric CKRT.

METHODS

We conducted a systematic review of the literature from 2012 to 2022 to identify data regarding CKRT timing of initiation, dosing, anticoagulation, fluid removal, and quality monitoring. Using this data, we then performed a two-round modified Delphi process using a multinational internet-assisted survey of prescribers of CKRT.

RESULTS

The survey was constructed using 172 articles that met inclusion criteria (12% of studies were pediatric focused). A total of 147 and 126 practitioners completed the survey in rounds 1 and 2, respectively. Participants represented Europe (9.5-11.6%) and North America including pediatric intensivists, nephrologists, and advance practice providers. Consensus (defined as a ≥ 75% participant response of "sometimes" or "always") was achieved for 26 statements. There was consensus in the practices of CKRT initiation, dosing, method of anticoagulation, and fluid removal. In contrast, there appears to be greater variability in the methods used for monitoring anticoagulation and the quality of the delivered treatment.

CONCLUSIONS

Our study results suggest that the current state of pediatric CKRT practice is reflective of the literature over the last 10 years, which is largely based on the care of adult patients. This data provides a framework to study best practices to further improve outcomes for children receiving CKRT. A higher resolution version of the Graphical abstract is available as Supplementary information.

Association and prediction of red blood cell distribution width to albumin ratio in all-cause mortality of acute kidney injury in critically ill patients

Aim

The progression of acute kidney injury (AKI) might be associated with systemic inflammation. Our study aims to explore the association and predictive value of the red blood cell distribution width (RDW) to human serum albumin (ALB) ratio (RDW/ALB ratio), an inflammation-related indicator, in the risk of all-cause mortality and renal replacement therapy (RRT) in AKI patients admitted in intensive care units (ICU).

Methods

A retrospective cohort study was designed, and data were extracted from the Medical Information Mart for Intensive Care III (MIMIC-III). The primary outcome was the risk of all-cause mortality (1-month, 3-month, and 12-month), and the secondary outcome was the risk of RRT. The association between the RDW/ALB ratio and the risk of all-cause mortality and RRT was assessed using the Cox regression analysis, with results shown as hazard ratio (HR) and 95% confidence intervals (CIs). The relationship between the RDW/ALB ratio and crude probability of all-cause mortality or RRT was assessed using restricted cubic splines (RCS). The concordance index (C-index) was used to assess the discrimination of the prediction model.

Results

A total of 13,856 patients were included in our study. In the fully adjusted Cox regression model, we found that a high RDW/ALB ratio was associated with an increased risk of 1-month, 3-month, and 12-month all-cause mortality and RRT (all p < 0.05). Moreover, RCS curves showed the linear relationship between the RDW/ALB ratio and the probability of all-cause mortality and RRT, and the probability was elevated with the increase of the ratio. In addition, the RDW/ALB ratio showed a good predictive performance in the risk of 1-month all-cause mortality, 3-month all-cause mortality, 12-month all-cause mortality, and RRT, with a C-index of 0.728 (95%CI: 0.719–0.737), 0.728 (95%CI: 0.721–0.735), 0.719 (95%CI: 0.713–0.725), and 0.883 (95%CI: 0.876–0.890), respectively.

Conclusion

The RDW/ALB ratio performed well to predict the risk of all-cause mortality and RRT in critically ill patients with AKI, indicating that this combined inflammatory indicator might be effective in clinical practice.

Serum Cystatin C Level Monitoring for Intervention Opportunity of CBP in Children with Severe Sepsis

Objective

The aim of this study is to investigate the instruction value of the serum cystatin C (Cys C) level monitoring for intervention opportunity of continuous blood purification technology (CBP) in children with severe sepsis.

Methods

67 children with severe sepsis in the pediatric intensive care unit (PICU) with CBP treatment were retrospectively selected from May 2016 to April 2020. According to the time intervals between the time point of serum Cys C level began to increase (>15 mg/L) and the time point of CBP began, all children were divided into group A (<24 h, 29 cases), group B (24–48 h, 22 cases), and group C (>48 h, 16 cases). The children's general characteristics, vital signs, biochemical parameters, acute physiology and chronic health evaluation (APACHE II), and sequential organ failure assessment (SOFA) scores were evaluated. The influence factors of prognosis of children with severe sepsis were analyzed by multivariate regression analysis.

Results

The intervals between the time point of PICU hospitalization and the time point of CBP began and the times of CBP in group A were significantly more than those in group B and C (P < 0.05). There was no statistically significant duration of CBP among three groups (P > 0.05). After follow-up of 28 d, there was no significant difference on the occurrence of coagulation disorders and hypovolemic shock induced by CBP among three groups (P > 0.05). However, the mortality of children in group A was lower than that in group C (P < 0.05). Children in group A had lower APACHE II scores, SOFA scores, serum K+, blood urea nitrogen (BUN), serum creatine (SCr), partial pressure of carbon dioxide (PCO₂), and higher partial pressure of oxygen (PO₂) than those of children in group C after CBP. (P < 0.05). SOFA scores ≥5 after CBP treatment and the time intervals between the time point of serum Cys C level began to increase (>15 mg/L) and the time point of CBP began ≥24 h were the independent influence factors on the prognosis by multivariate regression analysis.

Conclusion

There are significant evidences that continuous blood purification technology within 24 h of serum Cys C level may better control the condition of children with severe sepsis.

Continuous Renal Replacement Therapy Liberation and Outcomes of Critically Ill Patients With Acute Kidney Injury

OBJECTIVE

To examine the association between continuous renal replacement therapy (CRRT) liberation and clinical outcomes among patients with acute kidney injury (AKI) requiring CRRT.

METHODS

This single-center, retrospective cohort study included adult patients admitted to intensive care units with AKI and treated with CRRT from January 1, 2007, to May 4, 2018. Based on the survival and renal replacement therapy (RRT) status at 72 hours after the first CRRT liberation, we classified patients into liberated, reinstituted, and those who died. We observed patients for 90 days after CRRT initiation to compare the major adverse kidney events (MAKE₉₀).

RESULTS

Of 1135 patients with AKI, 228 (20%), 437 (39%), and 470 (41%) were assigned to liberated, reinstituted, and nonsurvival groups, respectively. The MAKE₉₀, mortality, and RRT independence rates of the cohort were 62% (707 cases), 59% (674 cases), and 40% (453 cases), respectively. Compared with reinstituted patients, the liberated group had a lower MAKE₉₀ (29% vs 39%; P=.009) and higher RRT independence rate (73% vs 65%; P=.04) on day 90, but without significant difference in 90-day mortality (26% vs 33%; P=.05). After adjustments for confounders, successful CRRT liberation was not associated with lower MAKE₉₀ (odds ratio, 0.71; 95% CI, 0.48 to 1.04; P=.08) but was independently associated with improved kidney recovery at 90-day follow-up (hazard ratio, 1.81; 95% CI, 1.41 to 2.32; P<.001).

CONCLUSION

Our study demonstrated a high occurrence of CRRT liberation failure and poor 90-day outcomes in a cohort of AKI patients treated with CRRT.

Predicting successful continuous renal replacement therapy liberation in critically ill patients with acute kidney injury

PURPOSE

No standardized criteria for continuous renal replacement therapy (CRRT) liberation have been established. We sought to develop and internally validate prediction models for successful CRRT liberation in critically ill patients with acute kidney injury (AKI).

MATERIALS AND METHODS

This single-center, retrospective cohort study included adult patients admitted to intensive care units (ICUs) with AKI and treated with CRRT from January 1, 2007, to May 4, 2018, at a tertiary referral hospital. The cohort was randomly divided into derivation and validation sets. The outcomes were successful CRRT liberation, defined as renal replacement therapy (RRT)-free survival within 72 h after the liberation and hospital discharge. Multivariate logistic regression models were developed and internally validated.

RESULTS

Of 1135 AKI patients requiring CRRT, successful CRRT liberation and RRT-free survival at hospital discharge were observed in 228 (20%) and 395 (35%) individuals, respectively. The independent predictors included mean hourly urine output within 12 h before liberation, mean serum creatinine value within 24 h before liberation, cumulative fluid balance from ICU admission to liberation, CRRT duration before liberation, and the requirement of vasoactive agents within 24 h before liberation. The models demonstrated good discrimination (AUROC, 0.76 and 0.78; positive predictive value, 36% and 48%; negative predictive value, 92% and 94%; respectively) and calibration in the validation set.

CONCLUSIONS

These validated models could assist the decision-making related to the CRRT liberation in critically ill patients with AKI.

Optimal timing of initiating CRRT in patients with acute kidney injury after liver transplantation

BACKGROUND

Acute kidney injury (AKI) is a frequent complication after liver transplantation (LT), and is associated with high mortality. Continuous renal replacement therapy (CRRT) is an important treatment for AKI, but the optimal time for initiation is still controversial. The purpose of this study was to investigate the prognostic effect of initial CRRT treatment time.

METHODS

We retrospectively reviewed the clinical data of 173 recipients undergoing LT from January 2018 to March 2019. AKI was defined according to Kidney Disease: Improving Global Outcomes (KDIGO) criteria. All patients receiving CRRT were divided into early and late group according to urine output. Prognosis was compared between the two groups.

RESULTS

A total of 48 (27.8%) patients were identified with AKI, 23 (13.3%) of whom received CRRT. According to urine output, 13 (56.5%) patients were in early group and 10 (43.5%) patients in late group. AKI was associated with longer intensive care unit (ICU) and hospital stay, increased post-operative 90-day mortality and the incidence of early allograft dysfunction (EAD). Patients in late CRRT group had a longer ICU stay {median, IQR, 183.5 [92.25-336.75] vs. 139 [94-240] hours, P=0.043} and hospital stay {median, IQR, 38.5 [17.5-62.75] vs. 35 [17-38] days, P=0.019} than patients in early CRRT group, respectively. The rate of severe infection was significantly higher in the late CRRT group than in the early CRRT group (80.0% vs. 30.8%, P=0.026).

CONCLUSIONS

AKI was associated with longer length of ICU and hospital stay, poor short-term mortality and functional recovery of transplanted organ. Early initiation of CRRT could reduce the severe infection and length of ICU and hospital stay.

Association between regional economic status and renal recovery of dialysis-requiring acute kidney injury among critically ill patients

The association between regional economic status and the probability of renal recovery among patients with dialysis-requiring AKI (AKI-D) is unknown. The nationwide prospective multicenter study enrolled critically ill adult patients with AKI-D in four sampled months (October 2014, along with January, April, and July 2015) in Taiwan. The regional economic status was defined by annual disposable income per capita (ADIPC) of the cities the hospitals located. Among the 1,322 enrolled patients (67.1 ± 15.5 years, 36.2% female), 833 patients (63.1%) died, and 306 (23.1%) experienced renal recovery within 90 days following discharge. We categorized all patients into high (n = 992) and low economic status groups (n = 330) by the best cut-point of ADIPC determined by the generalized additive model plot. By using the Fine and Gray competing risk regression model with mortality as a competing risk factor, we found that the independent association between regional economic status and renal recovery persisted from model 1 (no adjustment), model 2 (adjustment to basic variables), to model 3 (adjustment to basic and clinical variables; subdistribution hazard ratio, 1.422; 95% confidence interval, 1.022–1.977; p = 0.037). In conclusion, high regional economic status was an independent factor for renal recovery among critically ill patients with AKI-D.

Dialysis modalities for the management of pediatric acute kidney injury

Acute kidney injury (AKI) is an increasingly frequent complication among hospitalized children. It is associated with high morbidity and mortality, especially in neonates and children requiring dialysis. The different renal replacement therapy (RRT) options for AKI have expanded from peritoneal dialysis (PD) and intermittent hemodialysis (HD) to continuous RRT (CRRT) and hybrid modalities. Recent advances in the provision of RRT in children allow a higher standard of care for increasingly ill and young patients. In the absence of evidence indicating better survival with any dialysis method, the most appropriate dialysis choice for children with AKI is based on the patient's characteristics, on dialytic modality performance, and on the institutional resources and local practice. In this review, the available dialysis modalities for pediatric AKI will be discussed, focusing on indications, advantages, and limitations of each of them.

Higher body mass index is not a protective risk factor for 28-days mortality in critically ill patients with acute kidney injury undergoing continuous renal replacement therapy

Background: Acute kidney injury (AKI) requiring continuous renal replacement therapy (CRRT) is a fatal and common clinical disorder in critically ill patients. Recent studies have shown that the relationship between BMI and the outcome of patients with AKI undergoing CRRT is conflicting.

Methods: A retrospective cohort study based on data reuse. Univariate analysis, multi-factor regression analysis and subgroup analyses were used to explore the association of the BMI with the 28-days mortality risk in patients with AKI undergoing CRRT.

Results: From January 2009 to September 2016, a total of 1120 cases met the inclusion criteria and were enrolled in this study. The univariate analysis showed that BMI was associated with 28-days mortality of patients with AKI undergoing CRRT, its HR value was 0.98 (0.96, 0.99). The multi-factor regression analysis showed that BMI was not associated with 28-days mortality of patients with AKI undergoing CRRT in the four models, the adjusted HR value of four models were 1.00 (0.96, 1.04), 1.01 (0.97, 1.04), 1.00 (0.96, 1.04) and 1.00 (0.96, 1.04), respectively. The subgroups analyses showed that the BMI was a risk factor of the 28-days mortality in patients with AKI undergoing CRRT when GFR ≥30 mL/min, its HR value was 1.04 (1.01, 1.09).

Conclusion: Higher BMI was not a protective risk of 28-day mortality in patients with AKI undergoing CRRT. Especially, when GFR ≥30 mL/min, higher BMI increased the risk of the 28-day mortality rate in patients with AKI undergoing CRRT.

Prognostic Impact of Early Versus Late Initiation of Renal Replacement Therapy Based on Early Warning Algorithm in Critical Care Patients With Acute Kidney Injury

The aim of our study is to evaluate the impact of early vs. late initiation of continuous renal replacement therapy (CRRT), defined by clinical information system (CIS) software using an early warning algorithm based on acute kidney injury network (AKIN) stages, on survival outcome of critically ill intensive care unit (ICU) patients with acute kidney injury (AKI). Of 1144 patients (mean [SD] age: 61.3 [17.9] years, 57.7% were males) hospitalized in ICU over a 2-year-period from January 2016 to December 2017, a total of 272 patients who had developed AKI requiring CRRT were included in this retrospective cross-sectional study. Data on patient demographics (age, gender), reason for ICU hospitalization, AKIN stage, Sequential Organ Failure Assessment (SOFA) score, Acute Physiology and Chronic Health Evaluation II (APACHE II) score, indications for CRRT, and time of CRRT initiation with respect to AKIN early warning algorithm were retrieved from hospital records and the CIS software database. Survivorship status was assessed based on total, in-hospital and 90-day post-discharge mortality rates and analyzed with respect to CRRT onset before vs. after AKIN alarm. CRRT was initiated before the AKIN alarm in 41(15.0%) patients, and after the AKIN alarm in 231(85.0%) patients involving treatment within 0-24 h of alarm in 146 (63.2%) patients and within 24-120 h of alarm in 85 (36.8%) patients. Mortality occurred in 175 (64.3%) patients involving 25 (61.0%) out of 41 patients who received CRRT before AKIN alarm and 150 (64.9%) out of 231 patients who received CRRT after AKIN alarm. Mortality rate was significantly higher in those who received CRRT 24-120 h vs. 0-24 h after the AKIN alarm (82.4% vs. 54.8%, P < 0.001). Pre- and post-CRRT SOFA scores were significantly lower in patients who received CRRT 0-24 h vs. 24-120 h after the AKIN alarm (P = 0.009 and P = 0.004, respectively), while pre-CRRT APACHE II scores were significantly lower in patients who received CRRT before vs. after the AKIN alarm (P = 0.008). In conclusion, our findings indicate the potential role of using AKIN stage-based early warning system in guiding time to start CRRT and improved survival in critically ill patients with AKI, provided that the CRRT was initiated within the early (first 24 h) of the alarming AKIN Stage II-III events. Future well-designed clinical trials addressing early vs. late initiation of CRRT in critical care patients with AKI are needed to find and answer to the ongoing controversy and help clinicians in refining their indications for starting CRRT.

Acute kidney injury

Acute kidney injury (AKI) is defined by a rapid increase in serum creatinine, decrease in urine output, or both. AKI occurs in approximately 10-15% of patients admitted to hospital, while its incidence in intensive care has been reported in more than 50% of patients. Kidney dysfunction or damage can occur over a longer period or follow AKI in a continuum with acute and chronic kidney disease. Biomarkers of kidney injury or stress are new tools for risk assessment and could possibly guide therapy. AKI is not a single disease but rather a loose collection of syndromes as diverse as sepsis, cardiorenal syndrome, and urinary tract obstruction. The approach to a patient with AKI depends on the clinical context and can also vary by resource availability. Although the effectiveness of several widely applied treatments is still controversial, evidence for several interventions, especially when used together, has increased over the past decade.

Preemptive renal replacement therapy in post-cardiotomy cardiogenic shock patients: a historically controlled cohort study

BACKGROUND

The aim of the study was to evaluate whether the preemptive renal replacement therapy (RRT) might improve outcomes in post-cardiotomy cardiogenic shock (PCCS) patients.

METHODS

In Period A (September 2014-April 2016), patients with PCCS received RRT, depending on conventional indications or bedside attendings. In Period B (May 2016-November 2017), the preemptive RRT strategy was implemented in all PCCS patients in our intensive care unit. The goal-directed RRT was applied for the RRT patients. The hospital mortality and renal recovery were compared between the two periods.

RESULTS

A total of 155 patients (76 patients in Period A and 79 patients in Period B) were ultimately enrolled in this study. There were no significant differences in demographic characteristics and intraoperative and postoperative parameters between the two groups. The duration between surgery and RRT initiation was significantly shorter in Period B than in Period A [23 (17, 66) vs. 47 (20, 127) h, P<0.01]. The hospital mortality in Period B was significantly lower than that in Period A (38.0% vs. 59.2%, P<0.01). There were fewer patients with no renal recovery in Period B (4.1% vs. 19.4%, P=0.026). Patients in Period B displayed a significantly shorter time to completely renal recovery (12±15 vs. 25±15 d, P<0.05).

CONCLUSIONS

Among PCCS patients, preemptive RRT compared with conventional initiation of RRT reduced mortality in hospital and also led to faster and more frequent recovery of renal function. Our preliminary study supposed that preemptive initiation of RRT might be an effective approach to PCCS with acute kidney injury (AKI).

Developments to monitor the exhalome in organ failure in critically ill patients-a look into the future

Critically ill patients typically need some kind of functional organ support or replacement. Cardiopulmonary and renal replacement therapies are well established measures in intensive care units. However, there are also inherent risks associated with these treatments. The appropriate and timely commencement, maintenance and termination of organ replacement procedures currently use weak surrogates as decision support in clinical practice. A more reasonable application of extracorporeal organ support can be expected to potentially lower adverse events and save costs in healthcare systems, if a precise online monitoring was available. The analysis of the exhalome offers great opportunities to detect circulatory, pulmonary, and renal failure in critically ill patients. Volatile organic compounds and exhalation patterns are associated with a series of metabolic disorders and may be key to indicate the appropriate time point for initiation, maintenance and termination of organ support technologies. It may thus be expected that mortality, infection risk, replacement therapy days, and medical costs of intensive care treatment may possibly be reduced using exhalome analysis for control of organ replacement therapies in the distant future.