Clinical review: Optimal dose of continuous renal replacement therapy in acute kidney injury

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.

Knowledge, attitude, practice, needs, and implementation status of intensive care unit staff toward continuous renal replacement therapy: a survey of 66 hospitals in central and South China

BACKGROUND

Continuous renal replacement therapy (CRRT) is a commonly utilized form of renal replacement therapy (RRT) in the intensive care unit (ICU). A specialized CRRT team (SCT, composed of physicians and nurses) engage playing pivotal roles in administering CRRT, but there is paucity of evidence-based research on joint training and management strategies. This study armed to evaluate the knowledge, attitude, and practice (KAP) of ICU staff toward CRRT, and to identify education pathways, needs, and the current status of CRRT implementation.

METHODS

This study was performed from February 6 to March 20, 2023. A self-made structured questionnaire was used for data collection. Descriptive statistics, T-tests, Analysis of variance (ANOVA), multiple linear regression, and Pearson correlation coefficient tests (α = 0.05) were employed.

RESULTS

A total of 405 ICU staff from 66 hospitals in Central and South China participated in this study, yielding 395 valid questionnaires. The mean knowledge score was 51.46 ± 5.96 (61.8% scored highly). The mean attitude score was 58.71 ± 2.19 (73.9% scored highly). The mean practice score was 18.15 ± 0.98 (85.1% scored highly). Multiple linear regression analysis indicated that gender, age, years of CRRT practice, ICU category, and CRRT specialist panel membership independently affected the knowledge score; Educational level, years of CRRT practice, and CRRT specialist panel membership independently affected the attitude score; Education level and teaching hospital employment independently affected the practice score. The most effective method for ICU staff to undergo training and daily work experience is within the department.

CONCLUSION

ICU staff exhibit good knowledge, a positive attitude and appropriately practiced CRRT. Extended CRRT practice time in CRRT, further training in a general ICU or teaching hospital, joining a CRRT specialist panel, and upgraded education can improve CRRT professional level. Considering the convenience of training programs will enhance ICU staff participation. Training should focus on basic CRRT principles, liquid management, and alarm handling.

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.

CVVHD results in longer filter life than pre-filter CVVH: Results of a quasi-randomized clinical trial

BACKGROUND

Filter clotting is a major issue in continuous kidney replacement therapy (CKRT) that interrupts treatment, reduces delivered effluent dose, and increases cost of care. While a number of variables are involved in filter life, treatment modality is an understudied factor. We hypothesized that filters in pre-filter continuous venovenous hemofiltration (CVVH) would have shorter lifespans than in continuous venovenous hemodialysis (CVVHD).

METHODS

This was a single center, pragmatic, unblinded, quasi-randomized cluster trial conducted in critically ill adult patients with severe acute kidney injury (AKI) at the University of Iowa Hospitals and Clinics (UIHC) between March 2020 and December 2020. Patients were quasi-randomized by time block to receive pre-filter CVVH (convection) or CVVHD (diffusion). The primary outcome was filter life, and secondary outcomes were number of filters used, number of filters reaching 72 hours, and in-hospital mortality.

RESULTS

In the intention-to-treat analysis, filter life in pre-filter CVVH was 79% of that observed in CVVHD (mean ratio 0.79, 95% CI 0.65-0.97, p = 0.02). Median filter life (with interquartile range) in pre-filter CVVH was 21.8 (11.4-45.3) and was 26.6 (13.0-63.5) for CVVHD. In addition, 11.8% of filters in pre-filter CVVH were active for >72 hours, versus 21.2% in the CVVHD group. Finally, filter clotting accounted for the loss of 26.7% of filters in the CVVH group compared to 17.5% in the CVVHD group. There were no differences in overall numbers of filters used or mortality between groups.

CONCLUSIONS

Among critically patients with severe AKI requiring CKRT, use of pre-filter CVVH resulted in significantly shorter filter life compared to CVVHD.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT04762524. Registered 02/21/21-Retroactively registered, https://clinicaltrials.gov/ct2/show/NCT04762524?cond=The+Impact+of+CRRT+Modality+on+Filter+Life&draw=2&rank=1.

The effect of a loading dose of meropenem on outcomes of patients with sepsis treated by continuous renal replacement: study protocol for a randomized controlled trial

Background

Sepsis and continuous renal replacement therapy (CRRT) are both responsible for the alterations of the pharmacokinetics of antibiotics. For patients with sepsis receiving CRRT, the serum concentrations of meropenem in the early phase (< 48 h) was significantly lower than that in the late phase (> 48 h). This current trial aimed to investigate whether administration of a loading dose of meropenem results in a more likely achievement of the pharmacokinetic (PK)/pharmacodynamics (PD) target (100% fT > 4 × MIC) and better therapeutic results in the patients with sepsis receiving CRRT.

Methods

This is a single-blinded, single-center, randomized, controlled, two-arm, and parallel-group trial. This trial will be carried out in Guangzhou First People’s Hospital, School of Medicine, South China University of Technology Guangdong, China. Adult patients (age ≥ 18 years) with critical sepsis or sepsis-related shock receiving CRRT will be included in the study. The subjects will be assigned to the control group and the intervention group (LD group) randomly at a 1:1 ratio, the estimated sample size should be 120 subjects in each group. In the LD group, the patient will receive a loading dose of 1.5-g meropenem resolved in 30-ml saline which is given via central line for 30 min. Afterward, 0.75-g meropenem will be given immediately for 30 min every 8 h. In the control group, the patient will receive 0.75-g meropenem for 30 min every 8 h. The primary objective is the probabilities of PK/PD target (100% fT > 4 × MIC) achieved in the septic patients who receive CRRT in the first 48 h. Secondary objectives include clinical cure rate, bacterial clearance rate, sepsis-related mortality and all-cause mortality, the total dose of meropenem, duration of meropenem treatment, duration of CRRT, Sequential Organ Failure Assessment (SOFA), C-reactive protein levels, procalcitonin levels, white blood cell count, and safety.

Discussion

This trial will assess for the first time whether administration of a loading dose of meropenem results in a more likely achievement of the PK/PD target and better therapeutic results in the patients with sepsis receiving CRRT. Since CRRT is an important therapeutic strategy for sepsis patients with hemodynamic instability, the results from this trial may help to provide evidence-based therapy for septic patients receiving CRRT.

Trial registration

Chinese Clinical Trials Registry, ChiCTR2000032865. Registered on 13 May 2020, http://www.chictr.org.cn/showproj.aspx?proj=53616.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06264-2.

The association between continuous renal replacement therapy as treatment for sepsis-associated acute kidney injury and trend of lactate trajectory as risk factor of 28-day mortality in intensive care units

Background

Sepsis has high incidence and fatality rates in intensive care units, often leading to renal failure. The effectiveness of continuous renal replacement therapy (CRRT) in sepsis-associated acute kidney injury (S-AKI) patients is currently uncertain.

Aim

Joint model was used to determine the association between CRRT and the lactate trajectory trend and how it correlated to 28-day mortality for S-AKI patient in ICU.

Methods

A retrospective study was applied to patients with sepsis and AKI, which were extracted from the MIMIC-III public database, with the endpoint being 28-day mortality. Every lactate level measurement within 28 days was observed and calculated using logarithms. Joint model combined the longitudinal analysis of the natural logarithm of the lactate level [log(lactate)] in longitudinal submodel and Cox regression by trajectory function, demonstrating the effects of CRRT on 28-day survival and log(lactate) changes, and its final relationship with the event status.

Results

Among the 717 S-AKI patients, 157 received CRRT. CRRT was not associated with 28-day mortality. After adjustments, the relationship between CRRT use and log(lactate) elevation was statistically significant. The parameter estimation of CRRT and log(lactate) indicated that using CRRT will increase log(lactate) by 0.041 in S-AKI patients. The joint model also instigated a fixed association between changes in the lactate level and the event result, revealing an exp value of (0.755) = 2.12, indicating that an increase of one unit in log(lactate) will increase the risk of 28-day mortality 2.12-times.

Conclusion

There was no significant association between CRRT use and 28-day survival in S-AKI patients, and JM showed that CRRT use might be associated with elevation of longitudinal lactate levels. Therefore, additional attention should be paid to other treatments to control lactate levels when providing renal support for patients with S-AKI.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12873-022-00589-6.

The effect of continuous venovenous hemodiafiltration on amino acid delivery, clearance, and removal in children

BACKGROUND

In critically ill children with acute kidney injury (AKI), continuous kidney replacement therapy (CKRT) enables nutrition provision. The magnitude of amino acid loss during continuous venovenous hemodiafiltration (CVVHDF) is unknown and needs accurate quantification. We investigated the mass removal and clearance of amino acids in pediatric CVVHDF.

METHODS

This is a prospective observational cohort study of patients receiving CVVHDF from August 2014 to January 2016 in the pediatric intensive care unit (PICU) of a tertiary children's hospital.

RESULTS

Fifteen patients (40% male, median age 2.0 (IQR 0.7, 8.0) years) were enrolled. Median PICU and hospital lengths of stay were 20 (9, 59) and 36 (22, 132) days, respectively. Overall survival to discharge was 66.7%. Median daily protein prescription was 2.00 (1.25, 2.80) g/kg/day. Median daily amino acid mass removal was 299.0 (174.9, 452.0) mg/kg body weight, and median daily amino acid mass clearance was 18.2 (13.5, 27.9) ml/min/m², resulting in a median 14.6 (8.3, 26.7) % protein loss. The rate of amino acid loss increased with increasing dialysis dose and blood flow rate.

CONCLUSION

CVVHDF prescription and related amino acid loss impact nutrition provision, with 14.6% of the prescribed protein removed. Current recommendations for protein provision for children requiring CVVHDF should be adjusted to compensate for circuit-related loss. A higher resolution version of the Graphical abstract is available as Supplementary information.

Dose of Continuous Renal Replacement Therapy in Critically Ill Patients: A Bona Fide Quality Indicator

Acute kidney injury (AKI) is common in critically ill patients, and renal replacement therapy (RRT) constitutes an important aspect of acute management during critical illness. Continuous RRT (CRRT) is frequently utilized in intensive care unit settings, particularly in patients with severe AKI, fluid overload, and hemodynamic instability. The main goal of CRRT is to timely optimize solute control, acid-base, and volume status. Total effluent dose of CRRT is a deliverable that depends on multiple factors and therefore should be systematically monitored (prescribed vs. delivered) and iteratively adjusted in a sustainable mode. In this manuscript, we review current evidence of CRRT dosing and provide recommendations for its implementation as a quality indicator of CRRT delivery.

Continuous Renal Replacement Therapy Dosing in the Severely Underweight: A Case Report

Guidelines recommend that patients treated with continuous renal replacement therapy be delivered an effluent dose of 20 to 25 mL/kg/h. There is debate, especially at the extremes of body mass index, as to whether actual or ideal body weight (IBW) should be used in these dose calculations. A middle-aged woman with severe anorexia presented with 48 hours of altered mental status. Laboratory tests showed severe metabolic acidosis necessitating intubation, which was ultimately found to be due to nonprescribed use of metformin for weight loss. The patient became anuric and was initiated on continuous venovenous hemodialysis. Due to refractory acidosis, the modality was converted to continuous venovenous hemodiafiltration by adding postfilter hypertonic bicarbonate solution. Based on changes in sodium and bicarbonate levels over 4 hours with hypertonic bicarbonate solution, we were able to calculate an “effective” volume of distribution for this severely underweight patient. Our calculations suggest that IBW gives a better approximation of effective volume of distribution than actual body weight in a severely underweight woman. Inadequate effluent flow rate calculated based on actual rather than IBW may lead to insufficient correction of metabolic derangements in extremely underweight patients.

Renal replacement therapy: a practical update

Acute kidney injury (AKI) is defined as an abrupt decrease in kidney function, with the most severe form requiring some method of renal replacement therapy (RRT). The use of RRT is required in 5-10% of critically ill patients who develop severe AKI. Renal replacement therapy can be provided as either intermittent hemodialysis or one of the various modes of continuous renal replacement therapy (CRRT), with CRRT potentially conferring an advantage with respect to renal recovery and dialysis independence. There is no difference in mortality when comparing low (< 25 mL·kg^-1·hr^-1) vs high (> 40 mL·kg^-1·hr^-1) RRT dosing. Continuous renal replacement therapy may be run in different modes of increasing complexity depending on a given patient's clinical needs. Regional citrate anticoagulation is recommended as the therapy of choice for the majority of critically ill patients requiring CRRT.

Process based quality improvement using a continuous renal replacement therapy dashboard

BACKGROUND

The prevalence of continuous renal replacement therapy (CRRT) utilization in critically ill patients with acute kidney is increasing. In comparison to published and on-going trials attempting to answer questions surrounding the optimal timing of CRRT initiation, anticoagulation, and modality, a paucity of literature describes the quality of the therapy delivered.

METHODS

We conducted a single-center process improvement project to determine if a methodology to assess the quality of CRRT delivery could lead to improvement in CRRT delivery outcomes. We developed three broad categories of objective CRRT metrics to assess longitudinally, enabling creation of a CRRT Dashboard. Following the objective categories of "filter", "prescription", and "fluid balance" over time allowed us to perform quarterly analyses, target provider based CRRT education, and address variation from our standard of care. From 2012 to 2017, 184 critically ill patients received CRRT.

RESULTS

We report a mean filter life of 56 + 28.4 h, a 60-h filter life of 62%, and unplanned filter changes of 15%. Compared to a minimum target prescription of 2000 ml/1.73 m2/hour, we report the mean prescribed dose (2300 ml/1.73 m2/hour) and the rate of patients receiving at least the minimum prescription (98%). Finally, using a 10% deviation in the acceptable range of desired daily patient fluid balance, we report 83% CRRT patient days achieving an acceptable stipulated fluid goal.

CONCLUSION

We report the implementation of a quality dashboard and adopting quality improvement strategies provided a platform for measuring adherence to our institutional standards and the delivery of CRRT, specifically on the process of the care.

Antibiotic Dosing in Sustained Low-Efficiency Dialysis in Critically Ill Patients

Purpose of review

Sustained low-efficiency dialysis (SLED) is increasingly used as a renal replacement modality in critically ill patients with acute kidney injury (AKI) and hemodynamic instability. There is, therefore, a greater need for the understanding of the antibiotic dosage and pharmacokinetics in these patients, to provide them with optimal therapy.

Sources of information

PubMed/Medline, Embase, and Google Scholar.

Methods

PubMed/Medline, Embase, and Google Scholar databases were searched using a combination of key words: dialysis, end stage renal disease, renal failure, sustained low efficiency dialysis, extended daily dialysis, prolonged intermittent renal replacement therapy (PIRRT), and antibiotic dosing. Studies that investigated antibiotic dosing and pharmacokinetics during SLED/extended daily dialysis/PIRRT were selected for this review.

Key findings

Eleven studies met inclusion criteria and selected for data extraction. The data with regard to dialysis specifications, type of antibiotic including dosages, drug clearances, and dosage recommendations are summarized in Table 1. It is a challenge to find therapeutic doses for antibiotics during SLED therapy because, in general, only aminoglycosides and vancomycin can be assayed in clinical laboratories.

Limitations

Although current studies on antibiotic dosing in SLED are limited due to diverse and undersized patient populations, antibiotic dosage adjustments for patients receiving SLED discussed here will serve as a valuable guide. Future large-scale research should focus on establishing guidelines for antibiotic dosage in SLED.

Implications

Pharmacokinetic principles should be taken into consideration for the appropriate dosing of drugs during SLED, yet it is vital to monitor response to drug to make sure therapeutic goals are achieved. Antibiotic dosing and timing relative to the initiation of SLED may be important to maximize either the time above the minimum inhibitory concentration (MIC) (time-dependent) or the peak to MIC ratio (concentration-dependent), balancing efficacy and toxicity concerns. Critical care physicians should liaise with nephrologists to make decisions regarding appropriate antibiotic dosing in patients undergoing SLED.

Treatment dose and the elimination rates of electrolytes, vitamins, and trace elements during continuous veno-venous hemodialysis (CVVHD)

INTRODUCTION

During continuous renal replacement therapy, achievement of recommended treatment dose is important. However, relevant substrate loss may occur and recommended nutrition during critical illness could not be sufficient for higher dialysis doses. We investigated the correlation of dialysis dose and substrate loss for a broad range of dialysis doses.

METHODS

Forty critically ill patients with acute kidney injury undergoing citrate CVVHD were included in this prospective study. Three different corresponding blood flow (BF) and dialysate flow (DF) rates were applied (BF/DF: 100 ml/min, 2000 ml/h; 80 ml/min, 1500 ml/h; 120 ml/min, 2500 ml/h). Delivered effluent flow rate (DEFR) was calculated and correlated with losses of vitamins, electrolytes, and trace elements during recommended nutritional supplementation.

RESULTS

For folic acid, vitamin B12, zinc, inorganic phosphate, and magnesium, no correlation of losses and DEFR was detected. For ionized calcium, a correlation was observed and additional substitution was required.

CONCLUSION

Clinically relevant loss of folic acid, vitamin B12, zinc, inorganic phosphate, and magnesium was not observed for differently used dialysis doses of CVVHD, and the loss was covered sufficiently by daily recommended nutritional supplementation. Increased loss of ionized calcium for higher dialysis doses occurred during citrate CVVHD. Therefore, a strict protocol must maintain calcium homeostasis to avoid calcium depletion.

What the non-nephrologist needs to know about dialysis

The End-Stage Renal Disease (ESRD) program now serves approximately 675,000 individuals in the United States at a cost of $26.1 billion to the Medicare system. Given the size of this population, healthcare providers from all disciplines will deliver care to patients on dialysis. Mortality remains high among patients on chronic dialysis, with 42.3% surviving 5 years. As this is a vulnerable population, it is important in the care of ESRD patients that non-nephrologists have a working knowledge of issues germane to dialysis. This review examines the physiology, mechanics, complications, and care delivery concerns of kidney dialysis modalities relevant to the non-nephrologist. The majority of patients receive in-center hemodialysis thrice weekly, with a small proportion on home-based therapies such as peritoneal dialysis or home hemodialysis. Inpatients may undergo hemodialysis or peritoneal dialysis, and in critically ill patients, continuous renal replacement therapies are utilized. Practical aspects of each of these modalities are discussed.

Acute Kidney Injury in Elderly Population: A Prospective Observational Study

BACKGROUND/AIMS

Acute kidney injury (AKI) has been reported as a recognized condition among the elderly population; however, its clinical epidemiology is still poorly evaluated. We propose to evaluate the epidemiological profile of AKI in hospitalized elderly patients and the variables associated with renal replacement therapy (RRT) dependency at discharge after an episode of AKI.

METHODS

This prospective observational study enrolled 286 elderly patients (aged ≥60 years), who had a diagnosis of AKI and were admitted to a tertiary care hospital. Clinical data were analyzed, which included RRT indication, referral time to nephrologist support, standby period in the emergency care units (ECU) before a transfer to an intensive care unit, staff criteria used to indicate palliative care, and the incidence of patients who stayed on chronic dialysis for at least 6 months after discharge.

RESULTS

The overall hospital mortality was 56.3%. Acute Kidney Injury Network (AKIN) 3 at the time of admission was significantly higher in patients who underwent RRT. Intrinsic AKI (p < 0.001), AKIN 3 (p < 0.001), RRT (p < 0.001), and increased length of stay in ECUs (p = 0.01) all had a significantly higher prevalence among non-survivors. On multivariate analysis, however, only renal aetiology (intrinsic AKI) was independently associated with mortality (OR 2.88; 95% CI [1.29-6.13]). Approximately 85% of the discharged patients (n = 125) were dialysis free and 36.4% of them who had a previous diagnosis of chronic kidney disease (CKD) upon admission had a worse renal function. Age, AKIN 3, RRT, prior history of CKD, diabetes mellitus, and the number of hemodialysis sessions showed to have an impact on dialysis dependence. Furthermore, 24 of 161 patients who had a dialysis indication were placed on palliative care.

CONCLUSIONS

The severity of AKI and the need for RRT were risk factors for mortality and dependence on dialysis. Antecedents of CKD seem to be associated with a poor renal outcome following an AKI episode. Starting RRT had an impact on the clinical decision to enroll these patients into palliative care.

Challenges and pitfalls when implementing renal replacement therapy in the ICU

Several new methods of renal replacement therapy (RRT) are now available for treating patients in the ICU setting. However, utilization of RRT in the ICU is subject to considerable variation and the need for RRT is associated with worse outcomes. Several factors influence the application of dialysis and reflect the interplay of patient and process of care elements that are dynamic in nature. Despite multiple studies evaluating RRT and its application, there are gaps in our knowledge that must be overcome to improve outcomes. This article discusses some of the important issues that require attention in delivering RRT in critically ill patients and provides a framework for the optimal use of RRT in the ICU.

Prognostic robustness of serum creatinine based AKI definitions in patients with sepsis: a prospective cohort study

Background

It is unclear how modifications in the way to calculate serum creatinine (sCr) increase and in the cut-off value applied, influences the prognostic value of Acute Kidney Injury (AKI). We wanted to evaluate whether these modifications alter the prognostic value of AKI for prediction of mortality at 3 months, 1 and 2 years.

Methods

We prospectively included 195 septic patients and evaluated the prognostic value of AKI by using three different algorithms to calculate sCr increase: either as the difference between the highest value in the first 24 h after ICU admission and a pre-admission historical (ΔHIS) or an estimated (ΔEST) baseline value, or by subtracting the ICU admission value from the sCr value 24 h after ICU admission (ΔADM). Different cut-off levels of sCr increase (0.1, 0.2, 0.3, 0.4 and 0.5 mg/dl) were evaluated.

Results

Mortality at 3 months, 1 and 2 years in AKI defined as ΔADM > 0.3 mg/dl was 48.1 %, 63.0 % and 63.0 % vs 27.7 %, 39.8 % and 47.6 % in no AKI respectively (OR(95%CI): 2.42(1.06-5.54), 2.58(1.11-5.97) and 1.87(0.81-4.33); 0.3 mg/dl was the lowest cut-off value that was discriminatory. When AKI was defined as ΔHIS > 0.3 mg/dl or ΔEST > 0.3 mg/dl, there was no significant difference in mortality between AKI and no AKI.

Conclusions

The prognostic value of a 0.3 mg/dl increase in sCr, on mortality in sepsis, depends on how this sCr increase is calculated. Only if the evolution of serum creatinine over the first 24 h after ICU admission is taken into account, an association with mortality is found.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-015-0107-4) contains supplementary material, which is available to authorized users.

Application of continuous renal replacement therapy for acute kidney injury in elderly patients

This study aims to analyze the factors that affect the prognosis of continuous renal replacement therapy (CRRT) in elderly patients with acute kidney injury (AKI). Data obtained from 41 elderly patients with AKI who underwent CRRT in our department between January 2001 and December 2010 was retrospectively evaluated in this study. The enrolled patients were 80 to 100 years old, with a mortality of 60.98%. The mean Acute Physiology and Chronic Health Evaluation II (APACHE II) score was 27.8±5.6 points, and the mean risk coefficient was 0.80±0.10. The APACHE II score of the survival group was significantly higher than that of the death group. The comparisons of therapeutic dosages between <25 mL/(kg⋅h) and 25-50 mL/(kg⋅h), and between 25-50 mL/(kg⋅h) and >50 mL/(kg⋅h) all had no statistical significance. The prognosis of CRRT and the number of involved organs were related to the APACHE II score. Logistic regression analysis revealed that the number of involved organ, APACHE II score, mechanical ventilation, and hypoalbuminemia were the major risk coefficients that affected the prognosis of patients with bedside hemofiltration. The turnover of elderly CRRT patients was related to the number of involved organs, APACHE II score, mechanical ventilation, hypoalbuminemia, and other factors. The APACHE II score was the important reference index of CRRT starting time and could predict mortality risk.

Application of continuous renal replacement therapy for acute kidney injury in elderly patients

This study aims to analyze the factors that affect the prognosis of continuous renal replacement therapy (CRRT) in elderly patients with acute kidney injury (AKI). Data obtained from 41 elderly patients with AKI who underwent CRRT in our department between January 2001 and December 2010 was retrospectively evaluated in this study. The enrolled patients were 80 to 100 years old, with a mortality of 60.98%. The mean Acute Physiology and Chronic Health Evaluation II (APACHE II) score was 27.8±5.6 points, and the mean risk coefficient was 0.80±0.10. The APACHE II score of the survival group was significantly higher than that of the death group. The comparisons of therapeutic dosages between <25 mL/(kg⋅h) and 25-50 mL/(kg⋅h), and between 25-50 mL/(kg⋅h) and >50 mL/(kg⋅h) all had no statistical significance. The prognosis of CRRT and the number of involved organs were related to the APACHE II score. Logistic regression analysis revealed that the number of involved organ, APACHE II score, mechanical ventilation, and hypoalbuminemia were the major risk coefficients that affected the prognosis of patients with bedside hemofiltration. The turnover of elderly CRRT patients was related to the number of involved organs, APACHE II score, mechanical ventilation, hypoalbuminemia, and other factors. The APACHE II score was the important reference index of CRRT starting time and could predict mortality risk.

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.

Beta-lactam dosing in critically ill patients with septic shock and continuous renal replacement therapy

Although early and appropriate antibiotic therapy remains the most important intervention for successful treatment of septic shock, data guiding optimization of beta-lactam prescription in critically ill patients prescribed with continuous renal replacement therapy (CRRT) are still limited. Being small hydrophilic molecules, beta-lactams are likely to be cleared by CRRT to a significant extent. As a result, additional variability may be introduced to the per se variable antibiotic concentrations in critically ill patients. This article aims to describe the current clinical scenario for beta-lactam dosing in critically ill patients with septic shock and CRRT, to highlight the sources of variability among the different studies that reduce extrapolation to clinical practice, and to identify the opportunities for future research and improvement in this field. Three frequently prescribed beta-lactams (meropenem, piperacillin and ceftriaxone) were chosen for review. Our findings showed that present dosing recommendations are based on studies with drawbacks limiting their applicability in the clinical setting. In general, current antibiotic dosing regimens for CRRT follow a one-size-fits-all fashion despite emerging clinical data suggesting that drug clearance is partially dependent on CRRT modality and intensity. Moreover, some studies pool data from heterogeneous populations with CRRT that may exhibit different pharmacokinetics (for example, admission diagnoses different to septic shock, such as trauma), which also limit their extrapolation to critically ill patients with septic shock. Finally, there is still no consensus regarding the %T_>MIC (percentage of dosing interval when concentration of the antibiotic is above the minimum inhibitory concentration of the pathogen) value that should be chosen as the pharmacodynamic target for antibiotic therapy in patients with septic shock and CRRT. For empirically optimized dosing, during the first day a loading dose is required to compensate the increased volume of distribution, regardless of impaired organ function. An additional loading dose may be required when CRRT is initiated due to steady-state equilibrium breakage driven by clearance variation. From day 2, dosing must be adjusted to CRRT settings and residual renal function. Therapeutic drug monitoring of beta-lactams may be regarded as a useful tool to daily individualize dosing and to ensure optimal antibiotic exposure.

Effectiveness of pharmacist dosing adjustment for critically ill patients receiving continuous renal replacement therapy: a comparative study

Background

The impact of continuous renal replacement therapy (CRRT) on drug removal is complicated; pharmacist dosing adjustment for these patients may be advantageous. This study aims to describe the development and implementation of pharmacist dosing adjustment for critically ill patients receiving CRRT and to examine the effectiveness of pharmacist interventions.

Methods

A comparative study was conducted in an intensive care unit (ICU) of a university-affiliated hospital. Patients receiving CRRT in the intervention group received specialized pharmacy dosing service from pharmacists, whereas patients in the no-intervention group received routine medical care without pharmacist involvement. The two phases were compared to evaluate the outcome of pharmacist dosing adjustment.

Results

The pharmacist carried out 233 dosing adjustment recommendations for patients receiving CRRT, and 212 (90.98%) of the recommendations were well accepted by the physicians. Changes in CRRT-related variables (n=144, 61.81%) were the most common risk factors for dosing errors, whereas antibiotics (n=168, 72.10%) were the medications most commonly associated with dosing errors. Pharmacist dosing adjustment resulted in a US$2,345.98 ICU cost savings per critically ill patient receiving CRRT. Suspected adverse drug events in the intervention group were significantly lower than those in the preintervention group (35 in 27 patients versus [vs] 18 in eleven patients, P<0.001). However, there was no significant difference between length of ICU stay and mortality after pharmacist dosing adjustment, which was 8.93 days vs 7.68 days (P=0.26) and 30.10% vs 27.36% (P=0.39), respectively.

Conclusion

Pharmacist dosing adjustment for patients receiving CRRT was well accepted by physicians, and was related with lower adverse drug event rates and ICU cost savings. These results may support the development of strategies to include a pharmacist in the multidisciplinary ICU team.

Clinical and economic impact of a switch from high- to low-volume renal replacement therapy in patients with acute kidney injury

High-intensity renal replacement therapy protocols in intensive care patients with acute kidney injury have failed to translate to improved patient outcomes when compared with lower-intensity protocols. This retrospective study explored the clinical and economic impacts of switching from a 30-35 ml.kg(-1) .h(-1) (high-volume) to a 20 ml.kg(-1) .h(-1) (low-volume) protocol. Patients (n = 366) admitted 12 months before (n = 187) and after (n = 179) the switch were included in the study. There was no difference in in-hospital mortality (77/187 (41%) vs 75/179 (42%), respectively, p = 0.92), intensive care unit mortality (55/187 (29%) vs 61/179 (34%), respectively, p = 0.40), duration of organ support or extent of renal recovery between the high- and low-volume cohorts. A 25% reduction in daily replacement fluid usage was observed, equating to a cost saving of over £27 000 per annum. In conclusion, a switch from high- to low-volume continuous haemodiafiltration had minimal effects on clinical outcomes and resulted in marked cost savings.

Effects of the volume of processed plasma on the outcome, arterial pressure and blood procalcitonin levels in patients with severe sepsis and septic shock treated with coupled plasma filtration and adsorption

AIMS

To understand how coupled plasma filtration and adsorption (CPFA) could influence the time course of the advanced stages of sepsis, mean arterial pressure (MAP) and norepinephrine dosage.

METHODS

Patients with severe sepsis and septic shock with ≥2 organ failures not responding to volume resuscitation and vasopressor infusion were treated with CPFA within 8 h of admission to the intensive care unit.

RESULTS

Thirty-nine patients were treated (median age: 63 years, median SAPS II score: 45) and 28 survived advanced sepsis. In the latter, the median MAP increased and the norepinephrine dosage decreased significantly after CPFA, whereas in the nonsurvivors these values did not change significantly. The volume of treated plasma was significantly higher in survivors than nonsurvivors.

CONCLUSION

These results suggest a possible existence of a dose-response effect for CPFA. Future studies are therefore recommended to evaluate the efficacy of this treatment and to determine its best timing and intensity.

Continuous renal replacement therapy with regional citrate anticoagulation: do we really know the details?

PURPOSE OF REVIEW

A significant proportion of critically ill patients with acute kidney injury require continuous renal replacement therapy (CRRT). This article summarizes current evidence on the diagnosis and treatment of acute kidney injury. Regional citrate anticoagulation (RCA) is an emerging but complex technique. A variety of solutions and systems are currently used for RCA. Descriptions of the dosage and methods differ significantly and may cause confusion in everyday practice. This article reviews important scientific findings and highlights pharmacological and pathophysiological aspects of RCA, with a special emphasis on practical clinical issues regarding dosage and available citrate solutions.

RECENT FINDINGS

RCA provides a similar or even longer circuit run, with manageable metabolic complications. Although large-scale multicentre trials are needed, there is increasing evidence for the benefits of citrate solutions in CRRT. International guidelines recommend using citrate anticoagulation rather than heparin in patients without contraindications against citrate.

SUMMARY

RCA-CRRT is a technique that can be safely used in the majority of intensive care patients with severe multiple-organ failure. The range of citrate solutions available, the different methods in use--continuous venovenous haemofiltration, continuous venovenous haemodialysis and continuous venovenous haemodiafiltration--and the lack of a generally accepted complete CRRT 'set' have impeded implementation of the technique in clinical practice. Unresolved questions regarding dosage and assessment preclude evidence-based comparison in prospective, multicentre studies. For the moment, each institution has to develop a local working protocol. In clinical practice, detailed staff training and monitoring of possible metabolic disturbances for this complex intervention is essential.

Efficacy of coupled plasma filtration adsorption (CPFA) in patients with septic shock: a multicenter randomised controlled clinical trial

OBJECTIVES

Coupled plasma filtration adsorption (CPFA, Bellco, Italy), to remove inflammatory mediators from blood, has been proposed as a novel treatment for septic shock. This multicenter, randomised, non-blinded trial compared CPFA with standard care in the treatment of critically ill patients with septic shock.

DESIGN

Prospective, multicenter, randomised, open-label, two parallel group and superiority clinical trial.

SETTING

18 Italian adult, general, intensive care units (ICUs).

PARTICIPANTS

Of the planned 330 adult patients with septic shock, 192 were randomised to either have CPFA added to the standard care, or not. The external monitoring committee excluded eight ineligible patients who were erroneously included.

INTERVENTIONS

CPFA was to be performed daily for 5 days, lasting at least 10 h/day.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary endpoint was mortality at discharge from the hospital at which the patient last stayed. Secondary endpoints were: 90-day mortality, new organ failures and ICU-free days within 30 days.

RESULTS

There was no statistical difference in hospital mortality (47.3% controls, 45.1% CPFA; p=0.76), nor in secondary endpoints, namely the occurrence of new organ failures (55.9% vs 56.0%; p=0.99) or free-ICU days during the first 30 days (6.8 vs 7.5; p=0.35). The study was terminated on the grounds of futility. Several patients randomised to CPFA were subsequently found to be undertreated. An a priori planned subgroup analysis showed those receiving a CPFA dose >0.18 L/kg/day had a lower mortality compared with controls (OR 0.36, 95% CI 0.13 to 0.99).

CONCLUSIONS

CPFA did not reduce mortality in patients with septic shock, nor did it positively affect other important clinical outcomes. A subgroup analysis suggested that CPFA could reduce mortality, when a high volume of plasma is treated. Owing to the inherent potential biases of such a subgroup analysis, this result can only be viewed as a hypothesis generator and should be confirmed in future studies.

CLINICALTRIALSGOV

NCT00332371; ISRCTN24534559.

Validity of low-intensity continuous renal replacement therapy*

OBJECTIVE

To study the hospital mortality of patients with severe acute kidney injury treated with low-intensity continuous renal replacement therapy.

DESIGN

Multicenter retrospective observational study (Japanese Society for Physicians and Trainees in Intensive Care), combined with previously conducted multinational prospective observational study (Beginning and Ending Supportive Therapy).

SETTING

Fourteen Japanese ICUs in 12 tertiary hospitals (Japanese Society for Physicians and Trainees in Intensive Care) and 54 ICUs in 23 countries (Beginning and Ending Supportive Therapy).

PATIENTS

Consecutive adult patients with severe acute kidney injury requiring continuous renal replacement therapy admitted to the participating ICUs in 2010 (Japanese Society for Physicians and Trainees in Intensive Care, n = 343) and 2001 (Beginning and Ending Supportive Therapy Beginning and Ending Supportive Therapy, n = 1,006).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Patient characteristics, variables at continuous renal replacement therapy initiation, continuous renal replacement therapy settings, and outcomes (ICU and hospital mortality and renal replacement therapy requirement at hospital discharge) were collected. Continuous renal replacement therapy intensity was arbitrarily classified into seven subclasses: less than 10, 10-15, 15-20, 20-25, 25-30, 30-35, and more than 35 mL/kg/hr. Multivariable logistic regression analysis was conducted to investigate risk factors for hospital mortality. The continuous renal replacement therapy dose in the Japanese Society for Physicians and Trainees in Intensive Care database was less than half of the Beginning and Ending Supportive Therapy database (800 mL/hr vs 2,000 mL/hr, p < 0.001). Even after adjusting for the body weight and dilution factor, continuous renal replacement therapy intensity was statistically different (14.3 mL/kg/hr vs 20.4 mL/kg/hr, p < 0.001). Patients in the Japanese Society for Physicians and Trainees in Intensive Care database had a lower ICU mortality (46.1% vs 55.3%, p = 0.003) and hospital mortality (58.6% vs 64.2%, p = 0.070) compared with patients in the Beginning and Ending Supportive Therapy database. In multivariable regression analysis after combining the two databases, no continuous renal replacement therapy intensity subclasses were found to be statistically different from the reference intensity (20-25 mL/kg/hr). Several sensitivity analyses (patients with sepsis, patients from Western countries in the Beginning and Ending Supportive Therapy database) confirmed no intensity-outcome relationship.

CONCLUSIONS

Continuous renal replacement therapy at a mean intensity of 14.3 mL/kg/hr did not have worse outcome compared with 20-25 mL/kg/hr of continuous renal replacement therapy, currently considered the standard intensity. However, our study is insufficient to support the use of low-intensity continuous renal replacement therapy, and more studies are needed to confirm our findings.

Actually delivered dose of continuous renal replacement therapy is underestimated in hemofiltration

Dose determination in continuous renal replacement therapy (CRRT) is controversial. Most clinical trials use effluent flow rate as a surrogate of the dose. However, such definition may overestimate actually delivered dose due to declining filter function. The current study aimed to determine the difference between prescribed and delivered clearance and its association with transmembrane pressure. Hemofiltration was done in a mixed pre- and postdilution mode. Creatinine concentrations in serum and effluent fluid were measured simultaneously at 4, 10, 16, 28, 40, 52, and 64 hours for an individual hemofilter. Prescribed clearance (K) was estimated as the effluent flow rate corrected for predilution, and delivered clearance (Kx) was estimated using the ratio of serum and effluent creatinine. A total of 60 patients involving 248 filters were included in our analysis. The mean filter life span was 37.7 hours (standard deviation: 17.6). K overestimated Kx by 9.3% (95% confidence interval: -4.4% to 32.3%). The differences between K and Kx increased progressively over time. Transmembrane pressure was significantly correlated to the reduction with a Spearman's rho of 0.44 (p < 0.001). K significantly overestimates Kx during CRRT, and the difference increases progressively over time. Filters are recommended to be changed at 48-72 hours on a routine basis.

Extracorporeal renal replacement therapy and blood purification in critical care

OBJECTIVE

To review indications methods of renal replacement therapies (RRT) and practical considerations for the creation of a RRT program.

DATA SOURCES

Current human and veterinary literature review with a focus on advanced renal physiology and clinical experience in RRT and acute/chronic kidney diseases.

DATA SYNTHESIS

Renal replacement therapies encompass intermittent hemodialysis, continuous renal replacement therapy as well as some "hybrid" techniques. Each method of RRT has practical and theoretical advantages but currently there is no evidence that one technique is superior to the other.

CONCLUSIONS

RRT is a valuable therapeutic tool for treatment of acute kidney injury and chronic kidney disease. The implementation of an RRT program needs to take into consideration multiple parameters beyond the choice of an RRT platform.

Renal replacement therapy in healthy adult horses

BACKGROUND

Renal replacement therapy (RRT) has been implemented extensively in people to facilitate recovery from acute renal failure (ARF). RRT has not been explored in horses, but might provide a further treatment option in horses with ARF.

OBJECTIVE

To investigate efficacy and safety of RRT in horses.

ANIMALS

Five healthy adult horses.

METHODS

A prospective study was performed on horses restrained in stocks and intravenously connected to a commercial RRT machine to allow continuous venovenous hemodiafiltration to be performed for 6 hours. The RRT machine was set at the following flow rates: blood flow rate 250 mL/min; dialysate rate 3,000 mL/h; prefilter replacement pump 3,000 mL/h; and postfilter replacement pump rate 2,000 mL/h. Balanced electrolyte solution was used as dialysate and replacement fluid. Heart rate, respiratory rate, body temperature, direct arterial blood pressure, urine output, and various clinicopathologic parameters were measured over the study period.

RESULTS

Renal replacement therapy was successfully performed in horses, resulting in a mean creatinine clearance of 0.127 mL/kg/min (68.9 mL/min) and urea reduction ratio of 24%. No adverse effects were detected although a significant decrease in rectal temperature was observed (P ≤ .007). A significant increase in serum phosphorus (P ≤ .001) and decrease in BUN (P < .001) were also noted. A significant prolongation of prothrombin (P < .01) and partial thromboplastin time (P < .0001) were observed along with a decrease in platelet count (P ≤ .04).

CONCLUSIONS AND CLINICAL IMPORTANCE

Renal replacement therapy can safely and effectively be used in adult horses.

Low-dose continuous renal replacement therapy for acute kidney injury

BACKGROUND

Continuous renal replacement therapy (CRRT) is used increasingly to treat acute kidney injury (AKI), which is a common condition in the intensive care unit (ICU). However, the optimal CRRT dose for the treatment of AKI is still a matter of controversy. This study was conducted to ascertain the minimal dose of CRRT that can be effective on AKI patient outcomes.

METHODS

This was a retrospective observational study in two ICUs of academic medical centers in Japan. Patients aged 15 years or older admitted to the ICUs from January 2007 to July 2010 and treated with CRRT for AKI during their ICU stay were included. Data were retrospectively collected from patient records. Patients were categorized by doses that were above (higher-dose group) or below (lower-dose group) the median. Major outcome measures were hospital mortality, ICU mortality, and renal recovery at hospital discharge.

RESULTS

131 AKI patients were treated with continuous veno-venous hemodiafiltration (CVVHDF) during the study period. The median dose of CVVHDF was 16 ml/kg per hr (IQR = 14 to 20). Hospital mortality was 44%, which was significantly lower than the predicted mortality (56%, p<0.01). Patients who received lower-dose CRRT tend to have lower mortality rates (36% vs. higher-dose 53%; p = 0.055).

CONCLUSIONS

We found that low-dose CRRT did not increase mortality in critically ill patients with AKI. We also found that AKI patients treated with lower-dose CRRT non-significantly but numerically lower hospital mortality compared to higher-dose CRRT.