The Japanese Clinical Practice Guideline for acute kidney injury 2016

Intensive care unit continuous kidney replacement therapy: time to change dosage recommendations?

Continuous kidney replacement therapy (CKRT) is the predominant form of acute kidney support used for hemodynamically unstable adult ICU patients with severe AKI (KDIGO stage 3). The success of CKRT depends on the achieved doses. Practice patterns worldwide are highly variable. A contemporary understanding of treatment adequacy is essential. The KDIGO AKI clinical guidelines recommend delivering effluent volumes of 20-25 ml/kg/hour for CKRT in the ICU setting, with the caveat that higher prescribed doses (25-30 ml(kg/h) may be necessary to achieve adequate delivered CKRT doses. The reference landmark trials provide definitive evidence that increases of delivered CKRT doses beyond the recommended dose are not beneficial for unselected ICU patients with severe AKI. However, the minimum delivered CKRT intensity at which underdosing becomes harmful remains unknown. The answer to this question has clinical relevance (dosing of critically ill patients with obesity or Covid-19 disease, minimizing adverse effects of CKRT) and a relevant impact on the costs of CKRT. The delivered dose of CKRT for Japanese ICU patients with severe AKI has been generally smaller (median 15 ml/h/kg) than the recommended delivered KDIGO dose. The most recently published retrospective cohort study by Okamoto et al. demonstrated that low delivered CKRT doses were associated with a higher mortality among critically ill patients with severe AKI. These data challenge the nation-wide accepted hypothesis that a lower limit of delivered CKRT (< 20 ml/ kg/h) may adequately control uremia/volume overload. Thus, there is an unmet clinical need for prospective randomized trials defining the minimal effective dose of CKRT. Given the dynamic nature of the precipitating critical illness and the natural course of most episodes of AKI, CKRT dose targets are likely to vary. Doses should be tailored to the needs of the individual patient within the limits of the KDIGO guideline recommendations. The Japanese experience with low-dose CKRT is not practice changing.

Hepatic function markers as prognostic factors in patients with acute kidney injury undergoing continuous renal replacement therapy

Acute kidney injury (AKI) requiring continuous renal replacement therapy (CRRT), secondary to cardiovascular disease and sepsis, is associated with high in-hospital mortality. Although studies have examined cardiovascular disease and sepsis in AKI, the association between AKI and hepatic functional impairment remains unclear. We hypothesized that hepatic function markers would predict mortality in patients undergoing CRRT. We included 1,899 CRRT patients from a multi-centre database. In Phase 1, participants were classified according to the total bilirubin (T-Bil) levels on the day of, and 3 days after, CRRT initiation: T-Bil < 1.2, 1.2 ≤ T-Bil < 2, and T-Bil ≥ 2 mg/dL. In Phase 2, propensity score matching (PSM) was performed to examine the effect of a T-Bil cutoff of 1.2 mg/dL (supported by the Sequential Organ Failure Assessment score); creating two groups based on a T-Bil cutoff of 1.2 mg/dL 3 days after CRRT initiation. The primary endpoint was total mortality 90 days after CRRT initiation, which was 34.7% (n = 571). In Phase 1, the T-Bil, aspartate transaminase (AST), alanine transaminase (ALT), and AST/ALT (De Ritis ratio) levels at CRRT initiation were not associated with the prognosis, while T-Bil, AST, and the De Ritis ratio 3 days after CRRT initiation were independent factors. In Phase 2, T-Bil ≥1.2 mg/dL on day 3 was a significant independent prognostic factor, even after PSM [hazard ratio: 2.41 (95% CI; 1.84-3.17), p < 0.001]. T-Bil ≥1.2 mg/dL 3 days after CRRT initiation predicted 90-day mortality. Changes in hepatic function markers in acute renal failure may enable stratification of high-risk patients.

Reduction Rate of Uric Acid in Blood during Continuous Renal Replacement Therapy for Acute Kidney Injury: A Multicenter Retrospective Observational Study

INTRODUCTION

Continuous renal replacement therapy (CRRT) eliminates these small solutes with equal efficacy under the same conditions. However, variations in the reduction rates of these solutes observed in patients with CRRT are likely influenced by factors other than removal through CRRT. This study evaluated the reduction rates of these small solutes during CRRT and their possible association with mortality.

METHODS

This study used the data of limited patients registered in the CHANGE study, which is a large retrospective observational study on CRRT management across 18 Japanese ICUs. Reduction rates of three solutes in blood, calculated on the 1st and 2nd days, were compared in patients with acute kidney injury (AKI) treated by CRRT. The potential association between solute reduction rates and mortality during CRRT or within 7 days after the termination of CRRT was evaluated.

RESULTS

In total, 163 patients with AKI were included in the analysis. The reduction rates of uric acid (UA) were significantly higher than those of urea and creatinine for the 1st and 2nd tests in the entire cohort. Receiver operating characteristic (ROC) curve analysis revealed that lower UA reduction rates were significantly associated with mortality during CRRT or within 7 days after CRRT termination {area under the ROC curve: 0.62 [95% confidence interval (CI): 0.52-0.71] for the 1st test and 0.63 [95% CI: 0.54-0.72] for the 2nd test}. After adjusting for age and SOFA score, a significant association was observed between lower UA reduction rates and hospital mortality for both tests.

CONCLUSION

Among the small solutes, UA reduction rates in patients with AKI treated with CRRT were notably higher than those of creatinine and urea. Furthermore, the significant association between lower UA reduction rates and mortality suggests that UA reduction rate may serve as a valuable indicator of insufficient removal of uremic solutes by CRRT, although the decline in UA production must be taken into account.

INTRODUCTION

Continuous renal replacement therapy (CRRT) eliminates these small solutes with equal efficacy under the same conditions. However, variations in the reduction rates of these solutes observed in patients with CRRT are likely influenced by factors other than removal through CRRT. This study evaluated the reduction rates of these small solutes during CRRT and their possible association with mortality.

METHODS

This study used the data of limited patients registered in the CHANGE study, which is a large retrospective observational study on CRRT management across 18 Japanese ICUs. Reduction rates of three solutes in blood, calculated on the 1st and 2nd days, were compared in patients with acute kidney injury (AKI) treated by CRRT. The potential association between solute reduction rates and mortality during CRRT or within 7 days after the termination of CRRT was evaluated.

RESULTS

In total, 163 patients with AKI were included in the analysis. The reduction rates of uric acid (UA) were significantly higher than those of urea and creatinine for the 1st and 2nd tests in the entire cohort. Receiver operating characteristic (ROC) curve analysis revealed that lower UA reduction rates were significantly associated with mortality during CRRT or within 7 days after CRRT termination {area under the ROC curve: 0.62 [95% confidence interval (CI): 0.52-0.71] for the 1st test and 0.63 [95% CI: 0.54-0.72] for the 2nd test}. After adjusting for age and SOFA score, a significant association was observed between lower UA reduction rates and hospital mortality for both tests.

CONCLUSION

Among the small solutes, UA reduction rates in patients with AKI treated with CRRT were notably higher than those of creatinine and urea. Furthermore, the significant association between lower UA reduction rates and mortality suggests that UA reduction rate may serve as a valuable indicator of insufficient removal of uremic solutes by CRRT, although the decline in UA production must be taken into account.

Low-Dose Continuous Kidney Replacement Therapy and Mortality in Critically Ill Patients With Acute Kidney Injury: A Retrospective Cohort Study

RATIONALE & OBJECTIVE

Continuous kidney replacement therapy (CKRT) is preferred when available for hemodynamically unstable acute kidney injury (AKI) patients in the intensive care unit (ICU). The Kidney Disease: Improving Global Outcomes (KDIGO) guidelines recommend a delivered CKRT dose of 20-25mL/kg/h; however, in Japan the doses are typically below this recommendation due to government health insurance system restrictions. This study investigated the association between mortality and dose of CKRT.

STUDY DESIGN

Single-center retrospective cohort study.

SETTING & PARTICIPANTS

Critically ill patients with AKI treated with CKRT at a tertiary Japanese university hospital between January 1, 2012, and December 31, 2021.

EXPOSURE

Delivered CKRT doses below or above the median.

OUTCOME

90-day mortality after CKRT initiation.

ANALYTICAL APPROACH

Multivariable Cox regression analysis and Kaplan-Meier analysis.

RESULTS

The study population consisted of 494 patients. The median age was 72 years, and 309 patients (62.6%) were men. Acute tubular injury was the leading cause of AKI, accounting for 81.8%. The median delivered CKRT dose was 13.2mL/kg/h. Among the study participants, 456 (92.3%) received delivered CKRT doses below 20mL/kg/h, and 204 (41.3%) died within 90 days after CKRT initiation. Multivariable Cox regression analysis revealed increased mortality in the below-median group (HR, 1.73 [95% CI, 1.19-2.51], P=0.004). Additionally, a significant, inverse, nonlinear association between 90-day mortality and delivered CKRT dose was observed using delivered CKRT dose as a continuous variable.

LIMITATIONS

Single-center, retrospective, observational study.

CONCLUSIONS

A lower delivered CKRT dose was independently associated with higher 90-day mortality among critically ill patients who mostly received dosing below the current KDIGO recommendations.

PLAIN-LANGUAGE SUMMARY

The Kidney Disease: Improving Global Outcomes (KDIGO) guidelines recommend delivering a continuous kidney replacement therapy (CKRT) dose of 20-25mL/kg/h. However, it is not clear if it is safe to use delivered CKRT doses below this recommendation. In this study, over 90% of the patients received CKRT with a delivered dose below the KDIGO recommendation. We divided these patients into 2 groups based on the median delivered CKRT dose. Our findings show that a delivered CKRT dose below the median was associated with increased risk of death within 90 days. These findings show that a lower delivered CKRT dose was independently associated with higher 90-day mortality among critically ill patients who mostly received dosing below current KDIGO recommendations.

Solute Clearance Evaluation and Filter Clotting Prediction in Continuous Renal Replacement Therapy

Unexpected filter clotting is a major problem in continuous renal replacement therapy (CRRT). Reduced solute clearance is observed prior to filter clotting. This single-center, retrospective, observational study aimed to determine whether reduced solute clearance of low- and medium-molecular-weight molecules in CRRT can predict filter clotting. Solute clearances of urea and myoglobin (Mb) were measured at 24 h after initiation of continuous hemodiafiltration (CHDF). Clearance per flow (CL/F) was calculated. The primary outcome was clotting of the filter in the subsequent 24 h, and 775 CHDF treatments conducted on 230 patients for at least 24 consecutive hours in our ICU were analyzed. Filter clotting was observed in 127 treatments involving 39 patients. Urea and Mb CL/F at 24 h were significantly lower in the patients who experienced clotting. Further analysis was limited to the first CHDF treatment of each patient to adjust for confounding factors. Multivariate logistic regression analysis revealed that both urea CL/F < 94% and Mb CL/F < 64% were significant predictors of clotting within the next 24 h. Lower urea and Mb CL/F measured at 24 h after CRRT initiation were associated with filter clotting in the next 24 h. Further study is necessary to ascertain whether measurement of urea and MB CL/F will help with avoiding unexpected filter clotting.

Preceding risks and mortality outcomes of different neonatal acute kidney injury in preterm infants

BACKGROUND

The aim of the study was to examine preceding risks and mortality outcomes of oliguric and non-oliguric acute kidney injury (AKI) in very preterm infants.

METHODS

Infants born ≤30 weeks' gestation were included. AKI was diagnosed based on neonatal Kidney Disease: Improving Global Outcomes criteria and was classified as oliguric and non-oliguric according to the urine-output criteria. We used modified Poisson and Cox proportional-hazards models for statistical comparisons.

RESULTS

Of 865 enrolled infants (gestational age 27.2 ± 2.2 weeks and birth weight 983 ± 288 gm), 204 (23.6%) developed AKI. Before AKI, the oliguric AKI group had significantly higher prevalence of small-for-gestational age (p = 0.008), lower 5-min Apgar score (p = 0.009) and acidosis (p = 0.009) on admission, and hypotension (p = 0.008) and sepsis (p = 0.001) during admission than the non-oliguric AKI group. Oliguric (adjusted risk ratio 3.58, 95% CI 2.33-5.51; adjusted hazard ratio 4.93, 95% CI 3.14-7.72) instead of non-oliguric AKI had significantly higher mortality risks than no AKI. Oliguric AKI showed significantly higher mortality risks than non-oliguric AKI, irrespective of serum creatinine and severity of AKI.

CONCLUSIONS

Categorizing AKI as oliguric and non-oliguric was crucial because of the distinct preceding risks and mortality outcomes of these two types of AKI in very preterm neonates.

IMPACT

The differences of the underlying risks and prognosis between oliguric and non-oliguric AKI in very preterm infants remain unclear. We found that oliguric AKI, but not non-oliguric AKI, carries higher mortality risks than infants without AKI. Oliguric AKI possessed higher mortality risks than non-oliguric AKI, irrespective of concomitant serum creatinine elevation and severe AKI. Oliguric AKI is more associated with prenatal small-for-the-gestational age and perinatal and postnatal adverse events, while non-oliguric AKI is associated with nephrotoxins exposures. Our finding highlighted the importance of oliguric AKI and is helpful in developing future protocol in neonatal critical care.

Association between intrarenal venous flow from Doppler ultrasonography and acute kidney injury in patients with sepsis in critical care: a prospective, exploratory observational study

BACKGROUND

Intrarenal venous flow (IRVF) patterns assessed using Doppler renal ultrasonography are real-time bedside visualizations of renal vein hemodynamics. Although this technique has the potential to detect renal congestion during sepsis resuscitation, there have been few studies on this method. We aimed to examine the relationship between IRVF patterns, clinical parameters, and outcomes in critically ill adult patients with sepsis. We hypothesized that discontinuous IRVF was associated with elevated central venous pressure (CVP) and subsequent acute kidney injury (AKI) or death.

METHODS

We conducted a prospective observational study in two tertiary-care hospitals, enrolling adult patients with sepsis who stayed in the intensive care unit for at least 24 h, had central venous catheters placed, and received invasive mechanical ventilation. Renal ultrasonography was performed at a single time point at the bedside after sepsis resuscitation, and IRVF patterns (discontinuous vs. continuous) were confirmed by a blinded assessor. The primary outcome was CVP obtained at the time of renal ultrasonography. We also repeatedly assessed a composite of Kidney Disease Improving Global Outcomes of Stage 3 AKI or death over the course of a week as a secondary outcome. The association of IRVF patterns with CVP was examined using Student's t-test (primary analysis) and that with composite outcomes was assessed using a generalized estimating equation analysis, to account for intra-individual correlations. A sample size of 32 was set in order to detect a 5-mmHg difference in CVP between IRVF patterns.

RESULTS

Of the 38 patients who met the eligibility criteria, 22 (57.9%) showed discontinuous IRVF patterns that suggested blunted renal venous flow. IRVF patterns were not associated with CVP (discontinuous flow group: mean 9.24 cm H2O [standard deviation: 3.19], continuous flow group: 10.65 cm H2O [standard deviation: 2.53], p = 0.154). By contrast, the composite outcome incidence was significantly higher in the discontinuous IRVF pattern group (odds ratio: 9.67; 95% confidence interval: 2.13-44.03, p = 0.003).

CONCLUSIONS

IRVF patterns were not associated with CVP but were associated with subsequent AKI in critically ill adult patients with sepsis. IRVF may be useful for capturing renal congestion at the bedside that is related to clinical patient outcomes.

Effectiveness of remdesivir with corticosteroids for COVID-19 patients in intensive care unit: A hospital-based observational study

The effectiveness of remdesivir on survival in coronavirus disease 2019 (COVID-19), especially in cases treated in the intensive care unit (ICU), is controversial. We investigated the effectiveness of remdesivir with corticosteroids on the survival of COVID-19 patients in a real ICU clinical practice. For laboratory-confirmed COVID-19 patients admitted to the ICU of a tertiary hospital in Tokyo (April 2020-November 2021) and who received corticosteroids, the effectiveness of remdesivir for survival, stratified by interval length (within 9 or 10+ days), was retrospectively analyzed using Cox regression model. A total of 168 patients were included: 35 with no remdesivir use (control), 96 with remdesivir use within 9 days, and 37 with remdesivir use with an interval of 10+ days. In-hospital mortality was 45.7%, 10.4%, and 16.2%, respectively. After adjusting for possible covariates including comorbidities, laboratory data, oxygen demand, or level of pneumonia, remdesivir use within 9 days from symptom onset reduced mortality risk (hazard ratio [HR]: 0.10; 95% confidence interval (CI): 0.025-0.428) compared to the control group. However, remdesivir use with an interval of 10+ days showed no significant association with mortality (HR: 0.42; 95% CI: 0.117-1.524). Among COVID-19 patients who received corticosteroids in ICU, remdesivir use within 9 days from symptom onset was associated with reduced in-hospital mortality risk.

Association Between the Presence of Pulmonary Hypertension Before Cardiovascular Surgery and the Nephroprotective Effect of Carperitide: A Retrospective Cohort Study

Introduction

We hypothesized that the nephroprotective and diuretic effects of carperitide are effective in patients with pulmonary hypertension. We examined the presence of preoperative pulmonary hypertension and the effects of carperitide.

Methods

In this retrospective cohort study, we included patients aged 20 years or older who received carperitide during cardiovascular surgery and were admitted to the postoperative intensive care unit. We used hospital data from March 2019 to September 2021. The outcomes were the incidence of acute kidney injury, the number of patients using renal replacement therapy in the intensive care unit, urine volume in the first 24 hours after surgery, and the difference in serum creatinine concentrations between before and after surgery. After adjusting for confounding factors by multivariate analysis, we compared the difference in outcomes with and without preoperative pulmonary hypertension (systolic pulmonary artery pressure ≥36 mmHg).

Results

The study included 244 patients, with 72 (29.5%) in the pulmonary hypertension group and 172 (70.5%) in the control group. Acute kidney injury occurred in eight (11.1%) patients in the pulmonary hypertension group and in 18 (10.5%) patients in the control group, with no significant difference by logistic regression analysis (odds ratio 1.40, 95% confidence interval 0.54-3.62, p=0.49). Additionally, the use of renal replacement therapy, urine volume at 24 hours postoperatively, and the difference in serum creatinine concentrations were not different between the two groups.

Conclusions

Our results suggest that the effect of carperitide during cardiovascular surgery is not affected by the presence or absence of pulmonary hypertension.

Association between Nafamostat Mesylate and In-Hospital Mortality in Patients with Coronavirus Disease 2019: A Multicenter Observational Study

Nafamostat mesylate may be effective against coronavirus disease 2019 (COVID-19). However, it is not known whether its use is associated with reduced in-hospital mortality in clinical practice. We conducted a retrospective observational study to evaluate the effect of nafamostat mesylate in patients with COVID-19 using the Medical Data Vision Co. Ltd. hospital-based database in Japan. We compared patients with COVID-19 who were (n = 121) and were not (n = 15,738) administered nafamostat mesylate within 2 days of admission between January and December 2020. We conducted a 1:4 propensity score matching with multiple imputations for smoking status and body mass index and combined the 20 imputed propensity score-matched datasets to obtain the adjusted odds ratio for in-hospital mortality. Crude in-hospital mortality was 13.2% (16/121) and 5.0% (790/15,738), respectively. In the propensity score-matched analysis with multiple imputations, the adjusted odds ratio (use vs. no use of nafamostat mesylate) for in-hospital mortality was 1.27 (95% confidence interval: 0.61–2.64; p = 0.52). Sensitivity analyses showed similar results. The results of this retrospective observational study did not support an association between nafamostat mesylate and improved in-hospital outcomes in patients with COVID-19, although further studies with larger sample sizes are warranted to assess the generalizability of our findings.

Filter lifetimes of different hemodiafiltration membrane materials in dogs: reevaluation of the optimal anticoagulant dosage

Background

In continuous renal replacement therapy (CRRT), administration of anticoagulants is necessary for achieving a certain level of filter lifetime. Generally, anticoagulant doses are controlled to keep activated partial thromboplastin time and other indicators within a certain target range, regardless of the membrane materials used for the filter. However, in actual clinical practice, the filter lifetime varies significantly depending on the membrane material used. The objective of this study was to demonstrate that the minimum anticoagulant dose necessary for prolonging the filter lifetime while reducing the risk of hemorrhagic complications varies depending on the type of membrane.

Methods

In three beagles, hemodiafiltration was performed with hemofilters using polysulfone (PS), polymethylmethacrylate (PMMA), and AN69ST membranes separately. The minimum dose of nafamostat mesylate (NM) that would allow for 6 h of hemodiafiltration (required dose) was investigated for each membrane material.

Results

The NM doses required for 6 h of hemodiafiltration were 2 mg/kg/h for the PS membrane, 6 mg/kg/h for the PMMA membrane, and 6 mg/kg/h for the AN69ST membrane.

Conclusion

For hemodiafiltration performed in beagles, the required NM dose varied for each filter membrane material. Using the optimal anticoagulant dose for each membrane material would allow for safer CRRT performance.

When and why to start continuous renal replacement therapy in critically ill patients with acute kidney injury

Acute kidney injury (AKI) is a common condition in critically ill patients, and may contribute to significant medical, social, and economic consequences, including death. Although there have been advances in medical technology, including continuous renal replacement therapy (CRRT), the mortality rate of AKI is high, and there is no fundamental treatment that can reverse disease progression. The decision to implement CRRT is often subjective and based primarily on the clinician’s judgment without consistent and concrete guidelines or protocols regarding when to initiate and discontinue CRRT and how to manage complications. Recently, several randomized controlled trials addressing the initiation of renal replacement therapy in critically ill patients with AKI have been completed, but clinical application of the findings is limited by the heterogeneity of the objectives and research designs. In this review, the advantages and disadvantages of CRRT initiation, clinical guideline recommendations, and the results of currently published clinical trials and meta-analyses are summarized to guide patient care and identify future research priorities.

Quantitative and qualitative analyses of urinary L-FABP for predicting acute kidney injury after emergency laparotomy

PURPOSE

The aim of this study was to explore the clinical utility of urinary L-FABP for earlier prediction of acute kidney injury (AKI) after emergency laparotomy, and to assess the clinical utility of a point-of-care (POC) kit for urinary L-FABP.

METHODS

Forty-eight patients undergoing emergency laparotomy were divided into AKI and non-AKI groups by the kidney diseases: improving global outcome (KDIGO) criteria. Ten patients were included in the AKI group. Urinary L-FABP, albumin, N-acetyl-β-D-glucosaminidase (NAG), TIMP-2, IGFBP7, serum creatinine (SCr), and blood presepsin were measured perioperatively and compared between groups. Perioperative urinary L-FABP was also evaluated qualitatively using a POC kit.

RESULTS

L-FABP and albumin levels were significantly higher in the AKI group at all measurement points. NAG was significantly higher only postoperatively in the AKI group. There were no inter-group differences in [TIMP-2] × [IGFBP7] at any measuring point. The area under the receiver operating characteristic curve of urinary L-FABP was greater than 0.8 perioperatively, which was larger than that of other biomarkers throughout the study period. The correlation coefficient at 2 h after entering the operating room between quantitative and qualitative tests for urinary L-FABP was 0.714, which was the maximum. The sensitivity, specificity, and negative predictive value of the urinary L-FABP POC kit at 2 h after entry were 55.6%, 91.9%, and 89.5%, respectively.

CONCLUSION

Quantitative L-FABP analyses is suitable for predicting postoperative AKI earlier in the perioperative period of emergency laparotomy. Conversely, the higher specificity of qualitative L-FABP analysis suggests that it may be useful for excluding the risk of AKI but its overall clinical validity should be further investigated.

Clinical Implementation and Initial Experience of Neutrophil Gelatinase-Associated Lipocalin Testing for the Diagnostic and Prognostic Assessment of Acute Kidney Injury Events in Hospitalized Patients

INTRODUCTION

The use of novel kidney injury biomarkers has been shown to improve diagnostic assessment and prognostic prediction in various populations with acute kidney injury (AKI), but their use in a standard clinical practice have been rarely reported.

METHODS

We reported the clinical implementation of neutrophil gelatinase-associated lipocalin (NGAL) measurement for routine AKI diagnostic workup of patients receiving nephrology consultation in a tertiary academic centre. Specific focus was made on the diagnostic performance to discriminate functional ("pre-renal") from intra-renal AKI and to predict AKI progression.

RESULTS

Forty-five urine NGAL (uNGAL) and 25 plasma NGAL (pNGAL) samples in the first 50 consecutive patients were analysed. KDIGO Stage 1, 2, 3 AKI, and renal replacement therapy occurred in 10%, 40%, 50%, and 24% of cases, respectively. The uNGAL was lower in patients with transient AKI (<48 h) and no sign of urinary tract infections (37 [25-167] ng/mL) than sustained or progressive AKI (298 [74-1,308] ng/mL) (p = 0.016), while pNGAL did not discriminate transient (264 [100-373] ng/mL) from persistent AKI (415 [220-816] ng/mL) (p = 0.137). The median uNGAL level was 63 (35-1,123) ng/mL for functional/pre-renal AKI and 451 (177-1,315) ng/mL for intra-renal AKI (p = 0.043), while the pNGAL was 264 (114-468) and 415 (230-816) ng/mL (p = 0.235), respectively.

CONCLUSION

NGAL, as part of the routine workup, is useful for diagnostic and prognostic assessment of new-onset AKI in clinical practice. Interpretation of an increased NGAL level should be clinically evaluated in its clinical context, particularly considering concomitant infection (urinary or systemic). Clinical adoption of emerging AKI biomarkers as diagnostic tests in clinical practice should be further encouraged.

Biomarker-Based Management of AKI: Fact or Fantasy?

New biomarkers for acute kidney injury (AKI) have improved our understanding of the etiology and pathogenesis of AKI. Depending on their origin, function, and kinetic profile, biomarkers have a role in screening, diagnosis, prognostication, and monitoring of AKI. This offers opportunities to improve the management of AKI, but concerns and limitations remain. In this review, we summarize the current role of new AKI biomarkers in the management of AKI and outline some of the ongoing limitations and challenges.

Antineutrophil Cytoplasmic Antibody-Associated Vasculitis With Acute Kidney Injury: Short-Term Recovery Predicts Long-Term Outcome

Background

Kidney involvement is common in antineutrophil cytoplasmic antibody (ANCA) associated vasculitis (AAV). It tends to be aggressive, and in some patients, the kidney involvement may reach the criteria of acute kidney injury (AKI). Here, we aim to describe the clinical characteristics of these patients and find risk factors for poor outcomes.

Methods

Patients diagnosed with AAV in our hospital from February 2003 to February 2017 were included. Those who reached the KDIGO AKI criteria were reclassified according to the KDIGO AKI stage. The clinical features of these patients were analyzed. Also, according to the variation of serum creatinine 3 months after AKI episode, patients were further divided into two groups: patients whose serum creatinine (Scr) level at the third month decreased by 30% or more from the peak Scr level was classified into G1 and others were classified into G2. Long-term renal and survival outcomes of these patients were analyzed with a Cox model. The renal endpoint was reaching end-stage renal disease (ESRD), and the survival endpoint was death. Nomograms were built based on cox models.

Results

Of 141 AAV patients included, during the median follow-up period of 64.0 (IQR 34.8, 85.4) months, 36 (25.5%) patients reached renal endpoints, and 22 (15.6%) patients died. The median renal survival time was 35.9 (IQR 21.3, 72.6) months and the median survival time was 48.4 (IQR 26.8, 82.8) months. Multivariate analysis showed that poor recovery of Scr level at 90 days (P < 0.001, RR = 9.150, 95%CI 4.163-20.113), BVAS score (P = 0.014, RR = 1.110, 95% CI1.021-1.207), and AKI stage 3 (P = 0.012 RR = 3.116, 95%CI 1.278-7.598) were independent risk factors for renal endpoints; poor recovery of Scr level at 90 days (P = 0.010, RR = 3.264, 95%CI 1.326-8.035), BVAS score (P = 0.010, RR = 1.171, 95%CI 1.038-1.320) and age (P = 0.017, RR = 1.046, 95%CI 1.008-1.086) were independent risk factors for all-cause death. The c-index of nomograms is 0.830 for the renal outcome and 0.763 for the survival outcome.

Conclusion

KDIGO AKI stage 3 is the risk factor for ESRD in AAV patients with AKI. The BVAS score and level of kidney function recovery at 90 days are the independent risk factors for both ESRD and all-cause death and are of predictive value for the outcome.

The Potential Use of Vitamin C to Prevent Kidney Injury in Patients with COVID-19

The newly found SARS-CoV-2 has led to the pandemic of COVID-19, which has caused respiratory distress syndrome and even death worldwide. This has become a global public health crisis. Unfortunately, elders and subjects with comorbidities have high mortality rates. One main feature of COVID-19 is the cytokine storm, which can cause damage in cells and tissues including the kidneys. Here, we reviewed the current literature on renal impairments in patients with COVID-19 and analyzed the possible etiology and mechanisms. In addition, we investigated the potential use of vitamin C for the prevention of renal injury in those patients. It appears that vitamin C could be helpful to improve the outcomes of patients with COVID-19. Lastly, we discussed the possible protective effects of vitamin C on renal functions in COVID-19 patients with existing kidney conditions.

The effect of N-acetyl cysteine injection on renal function after coronary artery bypass graft surgery: a randomized double blind clinical trial

BACKGROUND

This study aimed to compare the effects of N-acetyl cysteine on renal function after coronary artery bypass graft surgery.

METHODS

In this randomized clinical trial conducted in Golestan Hospital, Ahvaz, Iran, 60 candidates for coronary artery bypass graft surgery were selected and divided into two N-acetyl cysteine and control groups (30 people each). Patients received 3 (2 intraoperative and 1 postoperative) doses of IV N-acetyl cysteine (100 mg/kg) (n = 30) or placebo (n = 30) over 24 h. Prescription times were as follows: after induction of anesthesia, in the Next 4 h, and in the 16 h after on. Primary outcomes were serum levels of BUN and Cr, at baseline,4 and 48 h after surgery. And also need renal replacement therapy (RRT). Secondary outcomes included the hemodynamic variables, Blood products transfusion.

RESULTS

There were significant differences in BUN between groups at 4 h (P = 0.02) and 48 h after surgery (P = 0.001) There were significant differences in Cr level between groups at 4 h (P < 0.001) and 48 h after surgery (P = 0.001). MAP at different times (at 4 h p = 0.002 and 48 h after surgery P < 0.001) were significantly different between the two groups. There was a significant difference between the two groups in terms of the unit of Packed cell transfusion (P = 0.002) and FFP transfusion (P < 0.001).

CONCLUSION

In the present study, we found that administration of N-acetyl cysteine can reduce the incidence of acute kidney injury in patients undergoing coronary artery bypass graft surgery and improved kidney functions.

TRIAL REGISTRY

IRCT20190506043492N3 Registered at 2020.06.07.

Comparing Renal Replacement Therapy Modalities in Critically Ill Patients With Acute Kidney Injury: A Systematic Review and Network Meta-Analysis

OBJECTIVES

To compare different modalities of renal replacement therapy in critically ill adults with acute kidney injury.

DATA SOURCES

We searched Medline, PubMed, Embase, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov from inception to 25 May, 2020. We included randomized controlled trials comparing the efficacy and safety of different renal replacement therapy modalities in critically ill patients with acute kidney injury.

STUDY SELECTION

Ten reviewers (working in pairs) independently screened studies for eligibility, extracted data, and assessed risk of bias.

DATA EXTRACTION

We performed random-effects frequentist network meta-analyses and used the Grading of Recommendations, Assessment, Development, and Evaluation approach to assess certainty of evidence. The primary analysis was a four-node analysis: continuous renal replacement therapy, intermittent hemodialysis, slow efficiency extended dialysis, and peritoneal dialysis. The secondary analysis subdivided these four nodes into nine nodes including continuous veno-venous hemofiltration, continuous veno-venous hemodialysis, continuous veno-venous hemodiafiltration, continuous arterio-venous hemodiafiltration, intermittent hemodialysis, intermittent hemodialysis with hemofiltration, slow efficiency extended dialysis, slow efficiency extended dialysis with hemofiltration, and peritoneal dialysis. We set the minimal important difference threshold for mortality as 2.5% (relative difference, 0.04).

DATA SYNTHESIS

Thirty randomized controlled trials (n = 3,774 patients) proved eligible. There may be no difference in mortality between continuous renal replacement therapy and intermittent hemodialysis (relative risk, 1.04; 95% CI, 0.93-1.18; low certainty), whereas continuous renal replacement therapy demonstrated a possible increase in mortality compared with slow efficiency extended dialysis (relative risk, 1.06; 95% CI, 0.85-1.33; low certainty) and peritoneal dialysis (relative risk, 1.16; 95% CI, 0.92-1.49; low certainty). Continuous renal replacement therapy may increase renal recovery compared with intermittent hemodialysis (relative risk, 1.15; 95% CI, 0.91-1.45; low certainty), whereas both continuous renal replacement therapy and intermittent hemodialysis may be worse for renal recovery compared with slow efficiency extended dialysis and peritoneal dialysis (low certainty). Peritoneal dialysis was probably associated with the shortest duration of renal support and length of ICU stay compared with other interventions (low certainty for most comparisons). Slow efficiency extended dialysis may be associated with shortest length of hospital stay (low or moderate certainty for all comparisons) and days of mechanical ventilation (low certainty for all comparisons) compared with other interventions. There was no difference between continuous renal replacement therapy and intermittent hemodialysis in terms of hypotension (relative risk, 0.92; 95% CI, 0.72-1.16; moderate certainty) or other complications of therapy, but an increased risk of hypotension and bleeding was seen with both modalities compared with peritoneal dialysis (low or moderate certainty). Complications of slow efficiency extended dialysis were not sufficiently reported to inform comparisons.

CONCLUSIONS

The results of this network meta-analysis suggest there is no difference in mortality between continuous renal replacement therapy and intermittent hemodialysis although continuous renal replacement therapy may increases renal recovery compared with intermittent hemodialysis. Slow efficiency extended dialysis with hemofiltration may be the most effective intervention at reducing mortality. Peritoneal dialysis is associated with good efficacy, and the least number of complications however may not be practical in all settings. Importantly, all conclusions are based on very low to moderate certainty evidence, limited by imprecision. At the very least, ICU clinicians should feel comfortable that the differences between continuous renal replacement therapy, intermittent hemodialysis, slow efficiency extended dialysis, and, where clinically appropriate, peritoneal dialysis are likely small, and any of these modalities is a reasonable option to employ in critically ill patients.

Clinical and histopathological features of acute kidney injury in adult-onset minimal change nephrotic syndrome

BACKGROUND

Acute kidney injury (AKI) is a common complication of minimal change nephrotic syndrome (MCNS), particularly in adults. To predict development of AKI, as defined by the Kidney Disease Improving Global Outcomes classification, we investigated clinical and histopathological features of adult-onset MCNS patients.

METHODS

A retrospective study was conducted with biopsy-proven adult-onset MCNS patients treated with corticosteroids.

RESULTS

A total of 58 MCNS patients [49 (24-71) years old, 38 males] were diagnosed using kidney biopsy findings from 2005 to 2018 at Osaka City University Hospital, of whom 24 (41.4%) were found to be complicated with AKI. Age, urinary protein, increased body weight (difference from admission to discharge), and histopathological scores were significantly greater in patients with as compared to without AKI, while urinary protein, increased body weight, and interstitial edema score were significantly associated with AKI development [OR 1.55 (95% CI 1.04-2.31), 1.37 (95% CI 1.03-1.81), 20.7 (95% CI 1.76-243), respectively]. Of the 24 MCNS patients with AKI, 10 underwent transient hemodialysis treatment. Although histopathological features were not different, the time interval between disease onset and kidney biopsy was significantly longer for MCNS patients complicated with AKI requiring hemodialysis as compared to those for whom that was not required [32 (24-46) vs. 13 (10-23) days, p = 0.034].

CONCLUSION

These results indicate that urinary protein, increased body weight, and interstitial edema score are important information for predicting development of AKI in adult-onset MCNS patients.

RRT Selection for AKI Patients With Critical Illness

Acute kidney injury (AKI) is a critical burden on intensive care units in Asia. Renal replacement therapy (RRT) acts as strong supportive care for severe AKI. However, various RRT modalities are used in Asia because of the diversity in ethics, climate, geographic features, and socioeconomic status. Extracorporeal blood purification is used commonly in Asian intensive care units; however, intermittent RRT is preferred in developing countries because of cost and infrastructure issues. Conversely, continuous RRT is preferred in developed countries, indicating the predominance of hospital-acquired AKI patients with complications of hemodynamic instability. Peritoneal dialysis is delivered less frequently, although several studies have suggested promising results for peritoneal dialysis in AKI treatment. Of note, not all RRT modalities are available as a standard procedure in some Asian regions, and it is absolutely necessary to develop a sustainable infrastructure that can deliver optimal care for all AKI patients.

Pembrolizumab-associated nephrotic syndrome recovered from transient hemodialysis in a patient with lung cancer

A 70-year-old man diagnosed with lung adenocarcinoma was referred to our department for an evaluation of acute onset of nephrotic syndrome with acute kidney injury (AKI) after the 7th course of pembrolizumab treatment. Renal biopsy could not be performed, because he needed anticoagulation therapy for venous thrombosis. Pembrolizumab was discontinued, and prednisolone was started. Hemodialysis was also started, because oliguria was not resolved, and dyspnea due to pulmonary congestion appeared even with the high dose of diuretics. Hemodialysis was successfully withdrawn within 5-week duration because of renal function recovery and increase of urine volume. Complete remission was achieved 4 months after initiating prednisolone. He has never experienced hemodialysis again and remains remission of nephrotic syndrome even the dose of prednisolone was tapered for 8 months. Renal pathology in the current case was uncertain. However, minimal change disease seemed to be a plausible cause of nephrotic syndrome with AKI because of a good response to steroid therapy and acute onset of nephrotic syndrome. In addition, renal pathology in all of the reported cases of pembrolizumab-associated nephrotic syndrome with AKI was minimal change disease. Our case shows for the first time that renal function could be reversible with prednisolone in pembrolizumab-associated nephrotic syndrome with severe AKI even after progression of renal failure which needs dialysis.

Intensity of renal replacement therapy and outcomes in critically ill patients with acute kidney injury: Critical appraisal of the dosing recommendations

The current care of critically ill patients with severe acute kidney injury requiring dialysis (AKI-D) is limited to supportive management in which renal replacement therapy (RRT) plays a central role. Renal replacement techniques are invasive bioincompatible procedures and are therefore associated with complications that may prove harmful to fragile patients. Inexperience with the standards and lacking or misinterpreted recommendations for the delivery of the RRT dose increases the risk of serious complications. Neither the optimal doses of intermittent or continuous RRTs nor the minimal or maximal effective doses are known. The Kidney Disease Improving Global outcomes (KDIGO) AKI guidelines for RRT dosing recommendations are inflexible, based on limited research, and may be at least partially outdated. High-intensity therapy may be associated with clinically relevant alterations in systemic and renal hemodynamics, profound electrolyte imbalances, the loss of nutrients or thermal energy, and underdosing of antimicrobial agents. However, higher doses of continuous renal replacement therapy (CRRT) may confer a survival benefit for certain subgroups of intensive care patients with severe AKI. Lower CRRT doses than the recommended adequate dosage may not lead to negative health outcomes, at least in Asian patients. Future research should evaluate the demand-capacity concept, recognizing that the delivery of the RRT dose is dynamic and should be modified in response to patient-related factors. There is a need for large-scale studies evaluating whether precision RRT dose modifications may improve patient-centered outcomes in subgroups of critically ill patients.

Association between intravenous contrast media exposure and non-recovery from dialysis-requiring septic acute kidney injury: a nationwide observational study

PURPOSE

This study aimed to examine the association between the use of intravenous contrast and non-recovery from dialysis-requiring acute kidney injury (AKI-D) and in-hospital mortality among patients with sepsis.

METHODS

This was a retrospective observational study using the Japanese Diagnosis Procedure Combination inpatient database between January 2011 and December 2016. We identified patients with septic AKI who began continuous renal replacement therapy (RRT) within 2-days of admission and underwent computed tomography. We compared patients with AKI-D with and without the use of intravenous contrast for computed tomography and performed propensity score matching to adjust for confounders for the association between exposure to intravenous contrast and outcomes, including a composite outcome of in-hospital mortality and RRT dependence at discharge and RRT duration.

RESULTS

From 3782 and 6619 patients with septic AKI-D with and without intravenous contrast exposure, respectively, 3485 propensity score-matched pairs were generated. No significant differences were found in the outcomes between the propensity score-matched groups: a composite outcome of in-hospital mortality and RRT dependence, 49.6% vs. 50.2% (odds ratio (OR) 0.98; 95% CI (confidence interval) 0.88, 1.07); in-hospital mortality, 45.3% vs. 46.1% (OR 0.97; 95% CI 0.87, 1.06); RRT dependence, 4.4% vs 4.1% (OR 1.08; 95% CI 0.85, 1.31); and median (interquartile range) of RRT duration, 4 [2-11] days vs. 4 [2-11] days (P = 0.58).

CONCLUSIONS

This large observational study did not support an association between intravenous contrast media and adverse in-hospital outcomes in patients with septic AKI-D. Further studies are warranted to assess the generalizability.

Changes in acute blood purification therapy in critical care: republication of the article published in the Japanese Journal of Artificial Organs

Acute blood purification therapy is an essential artificial organ in critical care. In the review article, looking back on the history, we describe our present knowledge and techniques of acute blood purification therapy in critical care. The topics include continuous hemodiafiltration (CHDF), online HDF as an artificial liver support, blood purification therapy aiming to remove pathogenic substances of sepsis, a procedure for connecting a CRRT device into an extra-corporeal membrane oxygenation circuit, and replacement fluid for CHDF. We also raise remaining issues and clarify the future direction of acute blood purification therapy in critical care. This review was created based on a translation of the Japanese review written in the Japanese Journal of Artificial Organs in 2017 (Vol. 46, No. 1, pp. 67-70), with adding some references.