Validity of low-intensity continuous renal replacement therapy*

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.

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.

The Effects of Early-Phase, Low- or Standard-Intensity Continuous Renal Replacement Therapy on Acid-Base Control and Clinical Outcomes: An Observational Study

INTRODUCTION

The Kidney Disease Improving Global Outcomes (KDIGO) clinical practice guideline recommends administering an effluent volume of 20-25 mL/kg/h during continuous renal replacement therapy (CRRT) for acute kidney injury. Recent evidence on CRRT initiation showed that less intervention might be beneficial for renal recovery. This study aimed to explore the association between early-phase low CRRT intensity and acid-base balance corrections and clinical outcomes.

METHODS

This was a single-centre, retrospective, observational study at a tertiary intensive care unit (ICU) in Japan. All adult patients requiring CRRT in the ICU were included. Eligible patients were classified into the Low group (dialysate flow rate [QD] 10.0-19.9 mL/kg/h) and the Standard group (QD ≥20 mL/kg/h) by the intensity of CRRT at the beginning. The primary outcomes were acid-base parameters 6 h after CRRT initiation. We used an inverse probability of treatment weighting analysis to estimate the association between the intensity group and the outcomes.

RESULTS

Overall, 194 patients were classified into the Low group (n = 144) and the Standard group (n = 50). The Standard group presented with more severe acid-base disturbances, including lower pH and base excess (BE) at baseline. At 6 h after CRRT initiation, pH, BE, and strong ion difference values were comparable, even after adjusting for baseline severity. Despite the efficient correction, no evident differences were observed in clinical outcomes between the two groups.

CONCLUSIONS

The initial standard intensity appeared to be efficient in correcting acid-base imbalance at the early phase of CRRT; however, further studies are needed to assess the impact on clinical outcomes.

Pharmacokinetics of GS-441524, the active metabolite of remdesivir, in patients receiving continuous renal replacement therapy: A case series

Remdesivir plays a key role in the treatment of coronavirus disease in 2019 (COVID-19). Haemodialysis is sometimes required for hospitalised patients with COVID-19, and patients undergoing haemodialysis are at an increased risk of severe COVID-19. In the present study, we report the serum concentrations of GS-441524, the active metabolite of remdesivir, in four patients undergoing continuous renal replacement therapy (CRRT). Patient 1, a male aged 70s, received a loading dose of 200 mg remdesivir on day 1, followed by 100 mg remdesivir from day 2, according to the package insert as in non-haemodialysis patients. The mean trough serum concentration of GS-441524 was 783.5 ng/mL, which was approximately 7-fold higher than the mean for patients with an estimated glomerular filtration rate (eGFR) ≥ 60 mL/min. Patients 2-4 received a loading dose of 200 mg remdesivir on day 1, followed by 100 mg once every 2 days from day 2. The mean trough serum concentrations of GS-441524 were 302.2 ng/mL, 585.8 ng/mL and 677.3 ng/mL, respectively. These were 3 to 6-fold higher than the mean for patients with eGFR ≥60 mL/min. The target doses for patients 1, 2, 3, and 4 receiving CRRT were 13.6 mL/kg/h, 6.0-12.5 mL/kg/h, 20.1 mL/kg/h, and 15.1 mL/kg/h, respectively, using a polysulphone membrane. The package insert dose of remdesivir is an overdose for CRRT patients with a target dose of 10-20 mL/kg/h. In low-intensity CRRT, as in Japan, it may be necessary to extend the interval between the doses of remdesivir.

Rapid implementation of an emergency on-site CKRT dialysate production system during the COVID-19 pandemic

BACKGROUND

On December 29, 2021, during the delta wave of the Coronavirus Disease 2019 (COVID-19) pandemic, the stock of premanufactured solutions used for continuous kidney replacement therapy (CKRT) at the University of New Mexico Hospital (UNMH) was nearly exhausted with no resupply anticipated due to supply chain disruptions. Within hours, a backup plan, devised and tested 18 months prior, to locally produce CKRT dialysate was implemented. This report describes the emergency implementation and outcomes of this on-site CKRT dialysate production system.

METHODS

This is a single-center retrospective case series and narrative report describing and reporting the outcomes of the implementation of an on-site CKRT dialysate production system. All adults treated with locally produced CKRT dialysate in December 2021 and January 2022 at UNMH were included. CKRT dialysate was produced locally using intermittent hemodialysis machines, hemodialysis concentrate, sterile parenteral nutrition bags, and connectors made of 3-D printed biocompatible rigid material. Outcomes analyzed included dialysate testing for composition and microbiologic contamination, CKRT prescription components, patient mortality, sequential organ failure assessment (SOFA) scores, and catheter-associated bloodstream infections (CLABSIs).

RESULTS

Over 13 days, 22 patients were treated with 3,645 L of locally produced dialysate with a mean dose of 20.0 mL/kg/h. Fluid sample testing at 48 h revealed appropriate electrolyte composition and endotoxin levels and bacterial colony counts at or below the lower limit of detection. No CLABSIs occurred within 7 days of exposure to locally produced dialysate. In-hospital mortality was 81.8% and 28-day mortality was 68.2%, though illness severity was high, with a mean SOFA score of 14.5.

CONCLUSIONS

Though producing CKRT fluid with IHD machines is not novel, this report represents the first description of the rapid and successful implementation of a backup plan for local CKRT dialysate production at a large academic medical center in the U.S. during the COVID-19 pandemic. Though conclusions are limited by the retrospective design and limited sample size of our analysis, our experience could serve as a guide for other centers navigating similar severe supply constraints in the future.

Continuous KRT: A Contemporary Review

AKI is a common complication of critical illness and is associated with substantial morbidity and risk of death. Continuous KRT comprises a spectrum of dialysis modalities preferably used to provide kidney support to patients with AKI who are hemodynamically unstable and critically ill. The various continuous KRT modalities are distinguished by different mechanisms of solute transport and use of dialysate and/or replacement solutions. Considerable variation exists in the application of continuous KRT due to a lack of standardization in how the treatments are prescribed, delivered, and optimized to improve patient outcomes. In this manuscript, we present an overview of the therapy, recent clinical trials, and outcome studies. We review the indications for continuous KRT and the technical aspects of the treatment, including continuous KRT modality, vascular access, dosing of continuous KRT, anticoagulation, volume management, nutrition, and continuous KRT complications. Finally, we highlight the need for close collaboration of a multidisciplinary team and development of quality assurance programs for the provision of high-quality and effective continuous KRT.

Results of the 2018 Japan Society for Blood Purification in Critical Care survey: current status and outcomes

Background

The Japan Society for Blood Purification in Critical Care (JSBPCC) has reported survey results on blood purification therapy (BPT) for critically ill patients in 2005, 2009, and 2013. To clarify the current clinical status, including details of the modes used, treated diseases, and survival rate, we conducted this cohort study using data from the nationwide JSBPCC registry in 2018.

Methods

We analyzed data of 2371 patients who underwent BPT in the intensive care units of 43 facilities to investigate patient characteristics, disease severity, modes of BPTs, including the dose of continuous renal replacement therapy (CRRT) and hemofilters, treated diseases, and the survival rate for each disease. Disease severity was assessed using Acute Physiology and Chronic Health Evaluation (APACHE) II and Sequential Organ Failure Assessment (SOFA) scores.

Results

BPT was performed 2867 times in the 2371 patients. Mean APACHE II and SOFA scores were 23.5 ± 9.4 and 10.0 ± 4.4, respectively. The most frequently used mode of BPT was CRRT (67.4%), followed by intermittent renal replacement therapy (19.1%) and direct hemoperfusion with the polymyxin B-immobilized fiber column (7.3%). The most commonly used anticoagulant was nafamostat mesilate (78.6%). Among all patients, the 28-day survival rate was 61.7%. CRRT was the most commonly used mode for many diseases, including acute kidney injury (AKI), multiple organ failure (MOF), and sepsis. The survival rate decreased according to the severity of AKI (P = 0.001). The survival rate was significantly lower in patients with multiple organ failure (MOF) (34.6%) compared with acute lung injury (ALI) (48.0%) and sepsis (58.0%). Multivariate logistic regression analysis revealed that sepsis, ALI, acute liver failure, cardiovascular hypotension, central nervous system disorders, and higher APACHE II scores were significant predictors of higher 28-day mortality.

Conclusion

This large-scale cohort study revealed the current status of BPT in Japan. It was found that CRRT was the most frequently used mode for critically ill patients in Japan and that 28-day survival was lower in those with MOF or sepsis. Further investigations are required to clarify the efficacy of BPT for critically ill patients.

Trial Registration: UMIN000027678.

Enhanced loading dose of teicoplanin for three days is required to achieve a target trough concentration of 20 μg/mL in patients receiving continuous venovenous haemodiafiltration with a low flow rate

INTRODUCTION

Because of its lower risk of renal toxicity than vancomycin, teicoplanin is the preferred treatment for methicillin-resistant Staphylococcus aureus infection in patients undergoing continuous venovenous haemodiafiltration (CVVHDF) in whom renal function is expected to recover. The dosing regimen for achieving a trough concentration (C_min) of ≥20 μg/mL remains unclear in patients on CVVHDF using the low flow rate adopted in Japan.

METHODS

The study was conducted in patients undergoing CVVHDF with a flow rate of <20 mg/kg/h who were treated with teicoplanin. We adopted three loading dose regimens for the initial 3 days: the conventional regimen, a high-dose regimen (four doses of 10 mg/kg), and an enhanced regimen (four doses of 12 mg/kg). The initial C_min was obtained at 72 h after the first dose.

RESULTS

Overall, 60 patients were eligible for study inclusion. The proportion of patients achieving the C_min target was significantly higher for the enhanced regimen than for the high-dose regimen (52.9% versus 8.3%, p = 0.003). In multivariate analysis, the enhanced regimen (odds ratio [OR] = 39.93, 95% confidence interval [CI] = 5.03-317.17) and hypoalbuminaemia (OR = 0.04, 95% CI = 0.01-0.44) were independent predictors of the achievement of C_min ≥ 20 μg/mL.

CONCLUSIONS

An enhanced teicoplanin regimen was proposed to treat complicated or invasive infections by methicillin-resistant Staphylococcus aureus in patients receiving CVVHDF even with a low flow rate.

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.

Intermittent Hemodialysis for Managing Metabolic Acidosis During Resuscitation of Septic Shock: A Descriptive Study

Septic shock is often complicated by severe metabolic acidosis, for which renal replacement therapy may be considered. However, little is known about the use of intermittent hemodialysis to manage this condition. The aim of this study was to compare physiologic and biochemical variables and vasopressor requirements before and after intermittent hemodialysis among patients who received intermittent hemodialysis to manage metabolic acidosis during resuscitation of septic shock.

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.

The Japanese clinical practice guideline for acute kidney injury 2016

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

The Japanese Clinical Practice Guideline for acute kidney injury 2016

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

Faster Blood Flow Rate Does Not Improve Circuit Life in Continuous Renal Replacement Therapy: A Randomized Controlled Trial

OBJECTIVES

To determine whether blood flow rate influences circuit life in continuous renal replacement therapy.

DESIGN

Prospective randomized controlled trial.

SETTING

Single center tertiary level ICU.

PATIENTS

Critically ill adults requiring continuous renal replacement therapy.

INTERVENTIONS

Patients were randomized to receive one of two blood flow rates: 150 or 250 mL/min.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was circuit life measured in hours. Circuit and patient data were collected until each circuit clotted or was ceased electively for nonclotting reasons. Data for clotted circuits are presented as median (interquartile range) and compared using the Mann-Whitney U test. Survival probability for clotted circuits was compared using log-rank test. Circuit clotting data were analyzed for repeated events using hazards ratio. One hundred patients were randomized with 96 completing the study (150 mL/min, n = 49; 250 mL/min, n = 47) using 462 circuits (245 run at 150 mL/min and 217 run at 250 mL/min). Median circuit life for first circuit (clotted) was similar for both groups (150 mL/min: 9.1 hr [5.5-26 hr] vs 10 hr [4.2-17 hr]; p = 0.37). Continuous renal replacement therapy using blood flow rate set at 250 mL/min was not more likely to cause clotting compared with 150 mL/min (hazards ratio, 1.00 [0.60-1.69]; p = 0.68). Gender, body mass index, weight, vascular access type, length, site, and mode of continuous renal replacement therapy or international normalized ratio had no effect on clotting risk. Continuous renal replacement therapy without anticoagulation was more likely to cause clotting compared with use of heparin strategies (hazards ratio, 1.62; p = 0.003). Longer activated partial thromboplastin time (hazards ratio, 0.98; p = 0.002) and decreased platelet count (hazards ratio, 1.19; p = 0.03) were associated with a reduced likelihood of circuit clotting.

CONCLUSIONS

There was no difference in circuit life whether using blood flow rates of 250 or 150 mL/min during continuous renal replacement therapy.

Intensive Versus Minimal Standard Dosage for Peritoneal Dialysis in Acute Kidney Injury: A Randomized Pilot Study

BACKGROUND

Dosage for peritoneal dialysis (PD) in acute kidney injury (AKI) is controversial. This study aims to find benefits and risks of intensive versus minimal standard dosage of PD in AKI.

METHODS

In a tertiary-hospital, 93 AKI patients who required PD between May 2015 and January 2016 were enrolled in a randomized, open-label controlled study. Patients were randomized to intensive group (> 30 L) and minimal standard group (< 20 L) of PD volume per day for the first 2 consecutive days. The primary outcome was in-hospital mortality. The secondary outcomes were peritonitis rate, dialysis dependence, and PD leakage.

RESULTS

Seventy-five patients were analyzed (intensive PD n = 39; minimal standard PD n = 36). Mean age was 60 years. Most patients were in critical care (72% unstable hemodynamic, mean APACHE II score 26.2). Kt/V delivery per session was 0.61 and 0.38 in intensive and minimal standard PD dosage for the first 2 consecutive sessions. According to intention-to-treat analysis, the in-hospital mortality rate of intensive PD dosage was not significantly different from the minimal standard PD dosage (79% vs 63%, relative risk [RR] 1.11, 95% confidence interval [CI] 0.80 to 1.51, p = 0.13). The dialysis dependence rate and PD leakage were not significantly different between the 2 groups. The rate of PD peritonitis was slightly higher in the intensive PD dosage group (15.3% vs 8.3%, p = 0.34).

CONCLUSION

Among AKI patients who required PD, there was no significant difference in in-hospital mortality between intensive and minimal standard PD dosage.

IMPACT OF CONTINUOUS RENAL REPLACEMENT THERAPY INTENSITY ON SEPTIC ACUTE KIDNEY INJURY

The intensity of continuous renal replacement therapy (CRRT) for acute kidney injury (AKI) has been evaluated, but recent randomized clinical trials have failed to demonstrate a beneficial impact of high intensity on the outcomes. High intensity might cause some detrimental results recognized recently as CRRT trauma. This study was undertaken to evaluate the association of CRRT intensity with mortality in a population of AKI patients treated with lower-intensity CRRT in Japan. A retrospective single-center cohort study enrolled 125 AKI patients treated with CRRT in mixed intensive care units of a university hospital in Japan. Subanalysis was conducted for septic and postsurgical AKI. The median value of the prescribed total effluent rate was 20.1 (interquartile range 15.3-27.1) mL/kg/h. Overall, univariate Cox regression analysis indicated no association of the CRRT intensity with the 60-day in-hospital mortality rate (hazard ratio 1.006, 95% confidence interval [CI] 0.991-1.018, P = 0.343). In subanalysis with the septic AKI patients, multivariate analysis revealed two factors associated independently with the 60-day mortality rate: the Sequential Organ Failure Assessment score at initiation of CRRT (hazard ratio 1.152, 95% CI 1.025-1.301, P = 0.0171) and the CRRT intensity (hazard ratio 1.024, 95% CI 1.004-1.042, P = 0.0195). The CRRT intensity was associated significantly with higher 60-day in-hospital mortality in septic AKI, suggesting that unknown detrimental effects of CRRT with high-intensity CRRT might worsen the outcomes in septic AKI patients.

Performance and Validation of the U.S. NCDR Acute Kidney Injury Prediction Model in Japan

BACKGROUND

Stratifying patient risk for acute kidney injury (AKI) prior to percutaneous coronary intervention (PCI) can enable clinicians to tailor their approach to minimize AKI. The National Cardiovascular Data Registry (NCDR) CathPCI Registry recently developed 2 prediction models: for AKI and AKI requiring dialysis (AKI-D).

OBJECTIVES

This study sought to externally validate the NCDR AKI and AKI-D models in a Japanese population. Determining the generalizability of the U.S. model could support quality improvement efforts in Japan.

METHODS

The NCDR prediction models were applied to 11,041 consecutive patients in the Japanese multicenter PCI registry. AKI was defined as an absolute increase ≥ 0.3 mg/dl or a relative increase of 50% in serum creatinine, in accordance with the definition of AKI Network criteria; AKI-D was defined as initiation of dialysis after PCI. Discrimination and calibration of the NCDR models were tested in the Japanese cohort. If the model was perfectly calibrated, the slope and intercept would equal 1.0 and 0.0, respectively.

RESULTS

In the Japanese PCI cohort, AKI and AKI-D occurred in 10.5% and 1.5% of patients, respectively. The NCDR AKI prediction model showed good discrimination (c-statistic = 0.76) and calibration (slope = 0.93 and intercept = -0.10) in both acute and nonacute PCI. The AKI-D prediction model had good discrimination (c-statistic = 0.92), but while the calibration slope was good (1.04), the intercept was significantly underestimated (0.96). However, this was corrected with recalibration (slope = 1.04 and intercept = -0.087).

CONCLUSIONS

In a Japanese population, the NCDR AKI models validly predict post-procedural AKI and, with recalibration, AKI-D. Prospective use of these models to inform clinical decision making should be tested as a means of reducing AKI after PCI in Japan. (Japan Cardiovascular Database, Percutaneous Coronary Intervention Registry; UMIN R000004736).

Renal Replacement Therapy

Renal replacement therapy (RRT) is a cornerstone in the clinical management of patients with acute kidney injury. Results from different studies agree that early renal support therapy (aimed to support the residual kidney function during early phases of organ dysfunction) may reduce mortality with respect to late RRT (aimed to substitute the complete loss of function during the advanced kidney insufficiency). Although it seems plausible that a timely initiation of RRT may be associated with improved renal and nonrenal outcomes in these patients, there is scarce evidence in literature to exactly identify the most adequate onset timing for RRT.

Current state of continuous renal replacement therapy for acute kidney injury in Japanese intensive care units in 2011: analysis of a national administrative database

BACKGROUND

Nationwide data for the prevalence and outcomes of patients receiving continuous renal replacement therapy (CRRT) in intensive care units (ICUs) are scarce. This study assessed the status of CRRT in Japanese ICUs using a nationwide administrative claim database.

METHODS

Data were extracted from the Japanese Diagnosis Procedure Combination database for 2011. From a cohort of critically ill patients aged 12 years or older who were admitted to ICUs for 3 days or longer, acute kidney injury (AKI) patients treated with CRRT were identified. The period prevalence of CRRT and in-hospital mortality were calculated. Logistic regression analysis identified factors associated with in-hospital mortality.

RESULTS

Of 165 815 ICU patients, 6478 (3.9%) received CRRT for AKI. The most frequent admission diagnosis category was diseases of the circulatory system (n = 3074). The overall in-hospital mortality rate of the CRRT-treated AKI patients was 50.6%. Clustering patients into four groups by background revealed the lowest in-hospital mortality rate of 41.5% for the cardiovascular surgery group (n = 1043) compared with 53.5% for the nonsurgical cardiovascular group (n = 2031), 51.7% for the sepsis group (n = 1863) and 51.6% for other cases (n = 1541). Multiple logistic regression analysis showed a significant association of these four group classifications with in-hospital mortality in addition to age, hospital characteristics (type and volume), time from hospital admission to CRRT initiation and interventions performed on the day of CRRT initiation.

CONCLUSIONS

Using a large Japanese nationwide database, this study revealed remarkably high in-hospital mortality of CRRT-treated AKI patients, although the period prevalence of CRRT for AKI in ICUs was low.

The lower limit of intensity to control uremia during continuous renal replacement therapy

Introduction

The recommended lower limit of intensity during continuous renal replacement therapy (CRRT) is 20 or 25 mL/kg/h. However, limited information is available to support this threshold. We aimed to evaluate the impact of different intensities of CRRT on the clearance of creatinine and urea in critically ill patients with severe acute kidney injury (AKI).

Methods

This is a multicenter retrospective study conducted in 14 Japanese ICUs in 12 centers. All patients older than 18 years and treated with CRRT due to AKI were eligible. We evaluated the effect of CRRT intensity by two different definitions: daily intensity (the mean intensity over each 24-h period) and average intensity (the mean of daily intensity during the period while CRRT was performed). To study the effect of different CRRT intensity on clearance of urea and creatinine, all patients/daily observations were arbitrarily allocated to one of 4 groups based on the average intensity and daily intensity: <10, 10–15, 15–20, and >20 mL/kg/h.

Results

Total 316 patients were included and divided into the four groups according to average CRRT intensity. The groups comprised 64 (20.3%), 138 (43.7%), 68 (21.5%), and 46 patients (14.6%), respectively. Decreases in creatinine and urea increased as the average intensity increased over the first 7 days of CRRT. The relative changes of serum creatinine and urea levels remained close to 1 over the 7 days in the “<10” group. Total 1,101 daily observations were included and divided into the four groups according to daily CRRT intensity. The groups comprised 254 (23.1%), 470 (42.7%), 239 (21.7%), and 138 observations (12.5%), respectively. Creatinine and urea increased (negative daily change) only in the “<10” group and decreased with the increasing daily intensity in the other groups.

Conclusions

The lower limit of delivered intensity to control uremia during CRRT was approximately between 10 and 15 mL/kg/h in our cohort. A prescribed intensity of approximately 15 mL/kg/h might be adequate to control uremia for patients with severe AKI in the ICU. However, considering the limitations due to the retrospective nature of this study, prospective studies are required to confirm our findings.

[Renal replacement therapy in Intensive Care Units in Catalonia (Spain)]

OBJECTIVE

To assess the indications, settings and techniques used in renal replacement therapy (RRT) in Intensive Care Units (ICUs).

STUDY DESIGN

A prospective, multicenter observational study was carried out.

SETTING

Intensive Care Units.

PATIENTS

All patients admitted to ICUs during the two-month study period in 2011 who required RRT.

INTERVENTIONS

None.

VARIABLES OF INTEREST

Patient demographic characteristics, baseline clinical data, RRT technique and materials used.

RESULTS

Thirty-three patients were analyzed. RRT was started within the first 24hours after ICU admission in 17 of the 33 patients (52%). At the start of RRT, 18% of the patients (n=6) presented grade R on the RIFLE acute kidney injury (AKI) scale. The most common disorder associated with AKI was multiple organ dysfunction syndrome (64%; n=21). At the start of RRT, most patients (76%; n=25) presented hemodynamic instability, while the remaining 24% (n=8) were considered hemodynamically stable. The most common RRT technique in hemodynamically stable patients was continuous renal replacement therapy (CRRT) (63%; n=5). CRRT was the technique of choice in all 25 of the hemodynamically unstable patients (100%). Anticoagulation was used in 55% (n=18) of the patients. In most cases (61%, n=20), RRT was administered through the right femoral vein. In 84% (n=28) of the patients, the ultrafiltration effluent flow rate was ≤ 35ml/kg/h.

CONCLUSIONS

The ICU physicians in this study followed current RRT guidelines. CRRT was preferred over intermittent renal replacement therapy, regardless of patient hemodynamic status.