CVVHD treatment with CARPEDIEM: small solute clearance at different blood and dialysate flows with three different surface area filter configurations

The Brophy Kit: A Manual Hemodialysis Device for Neonates

Introduction

Acute kidney injury (AKI) is common in critically ill neonates, including very and extremely low birth weight (VLBW, ELBW) neonates. In severe cases, kidney replacement therapy (KRT) may be warranted. Currently, available KRT devices are only indicated for those weighing ≥ 2.5 kg and require a double lumen or 2 separate single lumen catheters. We miniaturized the Kirpa Kit manual dialysis device, naming it the Brophy Kit, and we assessed its in vitro clearance and ultrafiltration (UF) performance.

Methods

We diluted packed red blood cells to a normal hematocrit (Hct: 31.1%-36.8%) and conducted 12 clearance and 3 UF experiments. A cycle consisted of aspirating 10 ml of blood from the blood bag, passing it through a hemofilter, and returning it in a circular path. For clearance experiments, we tested 4 configurations, with varied timing and volume of saline flushes to refresh the dialysis compartment, then measured blood urea nitrogen (BUN) and potassium concentrations every 5 cycles. For each UF cycle, 1 ml of ultrafiltrate was removed, and Hct was measured every 10 cycles.

Results

Median BUN and potassium reduction were 31.0% (interquartile range [IQR]: 17.6-37.9) and 35.0% (IQR: 26.9-41.7), respectively, after 30 clearance cycles. Median Hct increased to 52.6% (IQR: 52.5-53.8) after 60 UF cycles, more than the expected Hct (47.7%).

Conclusion

The Brophy Kit performs in vitro clearance efficiently and UF consistently. The Brophy Kit may address a technological KRT gap for small neonates because of its minimal extracorporeal volume and ability to function with single lumen access.

Kidney REPLACEment therapies in patients with acute kidney injury and RHABDOmyolysis (ReplaceRhabdo): a pilot trial

BACKGROUND

Rhabdomyolysis is frequently associated with acute kidney injury (AKI). Due to the nephrotoxic properties of myoglobin, its rapid removal is relevant. If kidney replacement therapy (KRT) is necessary for AKI, a procedure with effective myoglobin elimination should be preferred. This pilot trial was designed to compare different KRT modes that enable myoglobin elimination.

METHODS

In this prospective randomized single-center study, 15 patients with rhabdomyolysis and severe AKI requiring KRT were randomized 1:1:1 into three groups: continuous veno-venous hemofiltration (CVVH), continuous veno-venous hemodialysis (CVVHD) using a high cut-off dialyzer (CVVHD-HCO), or CVVHD using a high-flux dialyzer in combination with the adsorber CytoSorb (CVVHD-CS). Concentrations of serum myoglobin, urea, creatinine, β2-microglobulin, interleukin-6, and albumin were measured before and after the dialyzer 1, 6, 12, and 24 h after initiating KRT.

RESULTS

There was no significant difference in the median myoglobin clearance between the KRT modes during the 24-h study period. Nevertheless, the CVVHD-CS group showed a significantly higher myoglobin elimination compared to the other modes in the first hours of treatment. However, as a greater decline in clearance performance was observed over time, no better performance was detected over the whole study period. Simulation of different device combinations showed the highest myoglobin clearance for CVVHD-HCO combined with CS with a 12-hourly adsorber exchange interval.

CONCLUSIONS

All tested modes showed an effective myoglobin elimination capacity. The time-dependent elimination performance could be further increased by combining KRT with more frequent adsorber exchange.

TRIAL REGISTRATION

German Clinical Trials Registry ( DRKS00023998 ); date of registration 03/03/2021.

Recent Advances in Kidney Replacement Therapy in Infants: A Review

Kidney replacement therapy (KRT) is used to treat children and adults with acute kidney injury (AKI), fluid overload, kidney failure, inborn errors of metabolism, and severe electrolyte abnormalities. Peritoneal dialysis and extracorporeal hemodialysis/filtration can be performed for different durations (intermittent, prolonged intermittent, and continuous) through either adaptation of adult devices or use of infant-specific devices. Each of these modalities have advantages and disadvantages, and often multiple modalities are used depending on the scenario and patient-specific needs. Traditionally, these therapies have been challenging to deliver in infants due the lack of infant-specific devices, small patient size, required extracorporeal volumes, and the risk of hemodynamic stability during the initiation of KRT. In this review, we discuss challenges, recent advancements, and optimal approaches to provide KRT in hospitalized infants, including a discussion of peritoneal dialysis and extracorporeal therapies. We discuss each specific KRT modality, review newer infant-specific devices, and highlight the benefits and limitations of each modality. We also discuss the ethical implications for the care of infants who need KRT and areas for future research.

New perspectives in pediatric dialysis technologies: the case for neonates and infants with acute kidney injury

Advancements in pediatric dialysis generally rely on adaptation of technology originally developed for adults. However, in the last decade, particular attention has been paid to neonatal extracorporeal therapies for acute kidney care, an area in which technology has made giant strides in recent years. Peritoneal dialysis (PD) is the kidney replacement therapy (KRT) of choice in the youngest age group because of its simplicity and effectiveness. However, extracorporeal blood purification provides more rapid clearance of solutes and faster fluid removal. Hemodialysis (HD) and continuous KRT (CKRT) are thus the most used dialysis modalities for pediatric acute kidney injury (AKI) in developed countries. The utilization of extracorporeal dialysis for small children is associated with a series of clinical and technical challenges which have discouraged the use of CKRT in this population. The revolution in the management of AKI in newborns has started recently with the development of new CKRT machines for small infants. These new devices have a small extracorporeal volume that potentially prevents the use of blood to prime lines and dialyzer, allow a better volume control and the use of small-sized catheter without compromising the blood flow amount. Thanks to the development of new dedicated devices, we are currently dealing with a true "scientific revolution" in the management of neonates and infants who require an acute kidney support.

Meropenem extraction by ex vivo extracorporeal life support circuits

BACKGROUND

Meropenem is a broad-spectrum carbapenem-type antibiotic commonly used to treat critically ill patients infected with extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae. As many of these patients require extracorporeal membrane oxygenation (ECMO) and/or continuous renal replacement therapy (CRRT), it is important to understand how these extracorporeal life support circuits impact meropenem pharmacokinetics. Based on the physicochemical properties of meropenem, it is expected that ECMO circuits will minimally extract meropenem, while CRRT circuits will rapidly clear meropenem. The present study seeks to determine the extraction of meropenem from ex vivo ECMO and CRRT circuits and elucidate the contribution of different ECMO circuit components to extraction.

METHODS

Standard doses of meropenem were administered to three different configurations (n = 3 per configuration) of blood-primed ex vivo ECMO circuits and serial sampling was conducted over 24 h. Similarly, standard doses of meropenem were administered to CRRT circuits (n = 4) and serial sampling was conducted over 4 h. Meropenem was administered to separate tubes primed with circuit blood to serve as controls to account for drug degradation. Meropenem concentrations were quantified, and percent recovery was calculated for each sample.

RESULTS

Meropenem was cleared at a similar rate in ECMO circuits of different configurations (n = 3) and controls (n = 6), with mean (standard deviation) recovery at 24 h of 15.6% (12.9) in Complete circuits, 37.9% (8.3) in Oxygenator circuits, 47.1% (8.2) in Pump circuits, and 20.6% (20.6) in controls. In CRRT circuits (n = 4) meropenem was cleared rapidly compared with controls (n = 6) with a mean recovery at 2 h of 2.36% (1.44) in circuits and 93.0% (7.1) in controls.

CONCLUSION

Meropenem is rapidly cleared by hemodiafiltration during CRRT. There is minimal adsorption of meropenem to ECMO circuit components; however, meropenem undergoes significant degradation and/or plasma metabolism at physiological conditions. These ex vivo findings will advise pharmacists and physicians on the appropriate dosing of meropenem.

CARPEDIEM® for continuous kidney replacement therapy in neonates and small infants: a French multicenter retrospective study

BACKGROUND

The Cardio-Renal Pediatric Dialysis Emergency Machine (CA.R.P.E.D.I.E.M.®) device is a continuous kidney replacement therapy (CKRT) equipment dedicated to neonates and small infants. This study aimed to assess the effectiveness, feasibility, outcomes, and technical considerations relating to CARPEDIEM® use.

METHODS

This retrospective multicenter study included 19 newborns and six infants receiving CARPEDIEM® in five French pediatric and neonatal intensive care units. Laboratory parameters were collected at the initiation and end of the first CARPEDIEM® session. Results are presented as median [IQR] (range).

RESULTS

At initiation, age was 4 days [2-13] (1-1134) with a body weight of 3.3 kg [2.5-4] (1.3-11.1). Overall, 131 sessions and 2125 h of treatment were performed. Treatment duration per patient was 42 h [24-91] (8-557). Continuous veno-venous hemofiltration (CVVH) was performed in 20 children. Blood flow rate was 8 mL/kg/min [6-9] (3-16). The effluent flow rate for CVVH was 74 mL/kg/h [43-99] (28-125) and net ultrafiltration (UF) 6 mL/kg/h [2-8] (1-12). In the five children treated by hemodialysis, the blood and dialysate flow rates were 6 mL/kg/min [5-7] (4-7) and 600 mL/h [300-600] (120-600), respectively, while session duration was 8 h [6-12] (2-24). Most infants required a catheter between 4.5 and 6.5 French. Hemodynamic instability with a need for volume replacement occurred in 31 sessions (23%). Thrombocytopenia was observed in 29 sessions (22%). No hemorrhage occurred; all the patients survived the sessions, but only eight patients (32%) were alive at hospital discharge.

CONCLUSIONS

These data confirm that the use of CARPEDIEM® is safe and effective in critically ill neonates and infants. A higher resolution version of the Graphical abstract is available as Supplementary information.

Neonatal fluid overload-ignorance is no longer bliss

Excessive accumulation of fluid may result in interstitial edema and multiorgan dysfunction. Over the past few decades, the detrimental impact of fluid overload has been further defined in adult and pediatric populations. Growing evidence highlights the importance of monitoring, preventing, managing, and treating fluid overload appropriately. Translating this knowledge to neonates is difficult as they have different disease pathophysiologies, and because neonatal physiology changes rapidly postnatally in many of the organ systems (i.e., skin, kidneys, and cardiovascular, pulmonary, and gastrointestinal). Thus, evaluations of the optimal targets for fluid balance need to consider the disease state as well as the gestational and postmenstrual age of the infant. Integration of what is known about neonatal fluid overload with individual alterations in physiology is imperative in clinical management. This comprehensive review will address what is known about the epidemiology and pathophysiology of neonatal fluid overload and highlight the known knowledge gaps. Finally, we provide clinical recommendations for monitoring, prevention, and treatment of fluid overload.

Remdesivir and GS-441524 Extraction by Ex Vivo Extracorporeal Life Support Circuits

Patients with severe, COVID-related multi-organ failure often require extracorporeal life support (ECLS) such as extracorporeal membrane oxygenation (ECMO) or continuous renal replacement therapy (CRRT). An ECLS can alter drug exposure via multiple mechanisms. Remdesivir (RDV) and its active metabolite GS-441524 are likely to interact with ECLS circuits, resulting in lower than expected exposures. We evaluated circuit-drug interactions in closed loop, ex vivo ECMO and CRRT circuits. We found that mean (standard deviation) recovery of RDV at 6 hours after dosing was low in both the ECMO (33.3% [2.0]) and CRRT (3.5% [0.4]) circuits. This drug loss appears to be due primarily to drug adsorption by the circuit materials and potentially due to metabolism in the blood. GS-441524 recovery at 6 hours was high in the ECMO circuit 75.8% (16.5); however, was not detectable at 6 hours in the CRRT circuit. Loss in the CRRT circuit appears to be due primarily to efficient hemodiafiltration. The extent of loss for both molecules, especially in CRRT, suggests that in patients supported with ECMO and CRRT, RDV dosing adjustments are needed.

Survival of infants treated with CKRT: comparing adapted adult platforms with the Carpediem™

BACKGROUND

The most severely ill neonates and infants with AKI who need kidney replacement therapy have had to rely upon peritoneal dialysis, or adaptations of veno-venous continuous kidney replacement therapy (CKRT) devices for adults. Data from the Prospective Pediatric CRRT (ppCRRT) registry observed children < 10 kg had a lower survival rate than children > 10 kg (44% vs. 64%, p < 0.001). A CKRT device designed specifically for small children could improve outcomes. The Cardio-Renal Pediatric Dialysis Emergency Machine (CARPEDIEM™) is specifically dedicated to providing CKRT for newborns and small infants.

METHODS

We performed a retrospective cohort analysis comparing patient severity of illness and outcomes between the ppCRRT and CARPEDIEM registries, involving 6 Italian pediatric intensive care units. Thirty-eight subjects from the CARPEDIEM registry and 84 subjects from the ppCRRT registry < 10 kg were screened for comparison. We compared patient outcomes with a weight-matched cohort (< 5 kg) of 34 patients from the CARPEDIEM registry and 48 patients from the ppCRRT registry.

RESULTS

The ppCRRT subjects had higher rates of vasoactive medication at CKRT initiation. Survival to CKRT termination was higher for CARPEDIEM subjects (33/34 vs. 21/48, p < 0.0001). Multivariable logistic regression showed that CARPEDIEM registry cohort was the only variable to retain an association with survival to CKRT discontinuation.

CONCLUSIONS

We suggest children receiving CKRT using CARPEDIEM have excellent survival. Our data should be interpreted with caution given the retrospective comparison across two eras more than a decade apart.

Advances in pediatric acute kidney injury

The objective of this study was to inform the pediatric nephrologists of recent advances in acute kidney injury (AKI) epidemiology, pathophysiology, novel biomarkers, diagnostic tools, and management modalities. Studies were identified from PubMed, EMBASE, and Google Scholar for topics relevant to AKI. The bibliographies of relevant studies were also reviewed for potential articles. Pediatric (0-18 years) articles from 2000 to May 2020 in the English language were included. For epidemiological outcomes analysis, a meta-analysis on data regarding AKI incidence, mortality, and proportion of kidney replacement therapy was performed and an overall pooled estimate was calculated using the random-effects model. Other sections were created highlighting pathophysiology, novel biomarkers, changing definitions of AKI, evolving tools for AKI diagnosis, and various management modalities. AKI is a common condition seen in hospitalized children and the diagnosis and management have shown to be quite a challenge. However, new standardized definitions, advancements in diagnostic tools, and the development of novel management modalities have led to increased survival benefits in children with AKI. IMPACT: This review highlights the recent innovations in the field of AKI, especially in regard to epidemiology, pathophysiology, novel biomarkers, diagnostic tools, and management modalities.

Neonatal Acute Kidney Injury: Understanding of the Impact on the Smallest Patients

The study of neonatal acute kidney injury (AKI) has transitioned from small, single-center studies to the development of a large, multicenter cohort. The scope of research has expanded from assessment of incidence and mortality to analysis of more specific risk factors, novel urinary biomarkers, interplay between AKI and other organ systems, impact of fluid overload, and quality improvement efforts. The intensification has occurred through collaboration between the neonatology and nephrology communities. This review discusses 2 case scenarios to illustrate the clinical presentation of neonatal AKI, important risk factors, and approaches to minimize AKI events and adverse long-term outcomes.

Vascular access, membranes and circuit for CRRT

The advances in the technology for providing continuous renal replacement therapy (CRRT) have led to an increase in its utilization throughout the world. However, circuit life continues to be a major problem. It leads not only to decreased delivery of dialysis but also causes blood loss, waste of disposables, alters dose delivery of medications and nutrition, and increases nurse workload, all of which increases healthcare cost. Premature circuit failure can be caused by numerous factors that can be difficult to dissect out. The first component is the vascular access; without a well-placed, functioning access, delivery of CRRT becomes very difficult. This is usually accomplished by placing a short-term dialysis catheter into either the right internal jugular or femoral vein. The tips should be located at the caval atrial junction or inferior vena cava. In addition to establishing suitable vascular access, a comprehensive understanding of the circuit facilitates the development of a methodical approach in providing efficient CRRT characterized by optimal circuit life. Moreover, it aids in determining the cause of circuit failure in patients experiencing recurrent episodes. This review therefore summarizes the essential points that guide providers in establishing optimal vascular access. We then provide an overview of the main components of the CRRT circuit including the blood and fluid pumps, the hemofilter, and pressure sensors, which will assist in identifying the key mechanisms contributing to premature failure of the CRRT circuit.

Pediatric acute kidney injury: new advances in the last decade

Pediatric acute kidney injury (AKI) is a frequently missed complication. AKI has a significant impact on both short- and long-term outcomes in children. Within the last decade, there have been major landmark developments in this field of critical care pediatric nephrology. The topic was searched by two independent researchers using Google Scholar and PubMed and related studies published in the last 10 years. The terms used for the search were 'pediatric acute kidney injury,' 'pediatric acute renal failure,' 'pediatric dialysis,' 'biomarkers,' 'nephrotoxins,' 'nephrotoxicity in children,' and 'pediatric critical care nephrology.' We found that AKI is common in critically ill neonates and children. Among the various definitions, the Kidney Disease: Improving Global Outcomes (KDIGO) definition is most commonly used. In addition, it is imperative to risk stratify sick children at admission in the hospital to predict AKI and worse outcomes as this aids in early management. There are now major landmark trials that describe the epidemiology, prevention, and management guidelines in this field and health care professionals need to be aware they should diagnose AKI early. Overall, this review highlights the landmark studies in the last decade and shows that early diagnosis and management of AKI in 'at risk' children can improve outcomes.

Improving the quality of neonatal acute kidney injury care: neonatal-specific response to the 22nd Acute Disease Quality Initiative (ADQI) conference

With the adoption of standardized neonatal acute kidney injury (AKI) definitions over the past decade and the concomitant surge in research studies, the epidemiology of and risk factors for neonatal AKI have become much better understood. Thus, there is now a need to focus on strategies designed to improve AKI care processes with the goal of reducing the morbidity and mortality associated with neonatal AKI. The 22nd Acute Dialysis/Disease Quality Improvement (ADQI) report provides a framework for such quality improvement in adults at risk for AKI and its sequelae. While many of the concepts can be translated to neonates, there are a number of specific nuances which differ in neonatal AKI care. A group of experts in pediatric nephrology and neonatology came together to provide neonatal-specific responses to each of the 22nd ADQI consensus statements.

I-KID study protocol: evaluation of efficacy, outcomes and safety of a new infant haemodialysis and ultrafiltration machine in clinical use: a randomised clinical investigation using a cluster stepped-wedge design

INTRODUCTION

The I-KID study aims to determine the clinical efficacy, outcomes and safety of a novel non-CE-marked infant haemodialysis machine, the Newcastle Infant Dialysis Ultrafiltration System (NIDUS), compared with currently available therapy in the UK. NIDUS is specifically designed for renal replacement therapy in small babies between 0.8 and 8 kg.

METHODS AND ANALYSIS

The clinical investigation is taking place in six UK centres. This is a randomised clinical investigation using a cluster stepped-wedge design. The study aims to recruit 95 babies requiring renal replacement therapy in paediatric intensive care units over 20 months.

ETHICS AND DISSEMINATION

The study has high parent and public involvement at all stages in its design and parents will be involved in dissemination of results to parents and professionals via publications, conference proceedings and newsletters. The study has has ethics permissions from Tyne and Wear South Research Ethics Committee.

TRIAL REGISTRATION NUMBERS

IRAS ID number: 170 481MHRA Reference: CI/2017/0066ISRCT Number: 13 787 486CPMS ID number: 36 558NHS REC reference: 16/NE/0008Eudamed number: CIV-GB-18-02-023105Link to full protocol v6.0: https://fundingawards.nihr.ac.uk/award/14/23/26.

Advances in Kidney Replacement Therapy in Infants

Acute kidney injury continues to be a highly occurring disease in the intensive care unit, specifically affecting up to a third of critically ill neonates as per various studies. Although first-line treatments of acute kidney injury are noninvasive, kidney replacement therapy (KRT) is indicated when conservative management modes fail. There are various modalities of KRT which can be used for neonatal populations, including peritoneal dialysis, hemodialysis, and continuous KRT. However, these KRT modalities present their own challenges in this specific patient population Thus, it is the aim of this review to introduce each of these KRT modalities in terms of their challenges, advances, and future directions, with specific emphasis on new technology including the Cardio-Renal Pediatric Emergency Dialysis Machine, Newcastle infant dialysis and ultrafiltration system, and the Aquadex system for ultrafiltration.

Continuous kidney replacement therapy in critically ill neonates and infants: a retrospective analysis of clinical results with a dedicated device

BACKGROUND

Providing extracorporeal renal support to neonates and infants involves a number of technical and clinical issues, possibly discouraging early utilization. This report aims to describe a multicenter experience of continuous kidney replacement therapy (CKRT) delivery to small infants using a device specifically designed for this age group.

METHODS

A retrospective cohort analysis of all patients treated with the Carpediem™ machine (Bellco-Medtronic, Mirandola, Italy) in 6 centers between June 2013 and December 2016.

RESULTS

Twenty-six neonates and small infants received 165 CKRT sessions in convective modality. Median age at neonatal intensive care unit admission 1 day (IQR 1-11), median body weight 2.9 kg (IQR 2.2-3.6). Median circuit duration 14 h (IQR 10-22), with delivered/prescribed time ratio of 84%. CKRT was conducted using 4 Fr (27%), 5 Fr (35%), 6.5 Fr (11%), and 7 Fr (3%) vascular access, and with umbilical and peripheral accesses (11% each) allowing overall median blood flow of 4.5 ml/kg/min (IQR 3.4-6) and median effluent flow rate 35 ml/kg/h (IQR 28-42). Circuits were primed with normal saline in 58% of treatments, colloids in 31%, and packed red blood cells in 11%. No serious adverse events directly related to machine application were reported by any center. Twenty-five (96%) patients survived their CKRT course and 13 patients (50%) survived to ICU discharge.

CONCLUSIONS

CKRT in neonates was easy to initiate and conduct when performed with small central vascular accesses coupled with this device. A dedicated technology for infant CKRT delivery enables patients to be safely treated avoiding technical complications. Graphical abstract.

Acute Kidney Injury and Special Considerations during Renal Replacement Therapy in Children with Coronavirus Disease-19: Perspective from the Critical Care Nephrology Section of the European Society of Paediatric and Neonatal Intensive Care

Children seem to be less severely affected by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) as compared to adults. Little is known about the prevalence and pathogenesis of acute kidney injury (AKI) in children affected by SARS-CoV-2. Dehydration seems to be the most common trigger factor, and meticulous attention to fluid status is imperative. The principles of initiation, prescription, and complications related to renal replacement therapy are the same for coronavirus disease (COVID) patients as for non-COVID patients. Continuous renal replacement therapy (CRRT) remains the most common modality of treatment. When to initiate and what modality to use are dependent on the available resources. Though children are less often and less severely affected, diversion of all hospital resources to manage the adult surge might lead to limited CRRT resources. We describe how these shortages might be mitigated. Where machines are limited, one CRRT machine can be used for multiple patients, providing a limited number of hours of CRRT per day. In this case, increased exchange rates can be used to compensate for the decreased duration of CRRT. If consumables are limited, lower doses of CRRT (15-20 mL/kg/h) for 24 h may be feasible. Hypercoagulability leading to frequent filter clotting is an important issue in these children. Increased doses of unfractionated heparin, combination of heparin and regional citrate anticoagulation, or combination of prostacyclin and heparin might be used. If infusion pumps to deliver anticoagulants are limited, the administration of low-molecular-weight heparin might be considered. Alternatively in children, acute peritoneal dialysis can successfully control both fluid and metabolic disturbances. Intermittent hemodialysis can also be used in patients who are hemodynamically stable. The keys to successfully managing pediatric AKI in a pandemic are flexible use of resources, good understanding of dialysis techniques, and teamwork.

Pediatric Acute Kidney Injury-The Time for Nihilism Is Over

Nihilism has been pervasive in the acute kidney injury field for decades, given that no studies, had been able to reduce AKI rates in hospitalized patients. Furthermore, children with AKI comprise an orphan population, where there is little incentive to develop diagnostics, therapeutics or devices specifically for them. The 3rd International Symposium on Acute Kidney Injury in Children, held in Cincinnati in October 2018, provided a platform to demonstrate the advancements in the diagnosis and treatment of children with, or at-risk for AKI, and also highlighted barriers to advancing care for this population. The progress made in the pediatric AKI since the 2nd International Symposium in 2016, highlighted the positive outcomes emanating from federal agency, private foundation and corporate sponsor investment in pediatric AKI. As a result, the time should be over for nihilism in the pediatric field.

Kidney Support in Children using an Ultrafiltration Device: A Multicenter, Retrospective Study

BACKGROUND AND OBJECTIVES

Provision of kidney replacement therapy (KRT) to manage kidney injury and volume overload in critically ill neonates and small children is technically challenging. The use of machines designed for adult-sized patients, necessitates large catheters, a high extracorporeal volume relative to patient size, and need for blood priming. The Aquadex FlexFlow System (CHF Solutions Inc., Eden Prairie, MN) is an ultrafiltration device designed for fluid removal in adults with diuretic resistant heart failure. It has an extracorporeal volume of 33 ml, which can potentially mitigate some complications seen at onset of KRT in smaller infants.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In this multicenter, retrospective case series of children who received KRT with an ultrafiltration device (n=119 admissions, 884 circuits), we report demographics, circuit characteristics, complications, and short- and long-term outcomes. Patients were grouped according to weight (<10, 10-20, and >20 kg), and received one of three modalities: slow continuous ultrafiltration, continuous venovenous hemofiltration (CVVH), or prolonged intermittent KRT. Our primary outcome was survival to end of KRT.

RESULTS

Treatment patterns and outcomes varied between the groups. In patients who weighed <10 kg, the primary indication was AKI in 40%, volume overload in 46%, and ESKD in 14%. These patients primarily received CVVH (66%, n=48) and prolonged intermittent KRT (21%, n=15). In the group weighing >20 kg, volume overload was the primary indication in 91% and slow continuous ultrafiltration was the most common modality. Patients <10 kg had lower KRT survival than those >20 kg (60% versus 97%), more volume overload at onset, and received KRT for a longer duration. Cardiovascular complications at initiation were seen in 3% of treatments and none were severe. Complications during therapy were seen in 15% treatments and most were vascular access-related.

CONCLUSIONS

We report the first pediatric experience using an ultrafiltration device to provide a range of therapies, including CVVH, prolonged intermittent KRT, and slow continuous ultrafiltration. We were able to initiate KRT with minimal complications, particularly in critically ill neonates. There is an unmet need for devices specifically designed for younger patients. Having size-appropriate machines will improve the care of smaller children who require kidney support.

Choice of Catheter Size for Infants in Continuous Renal Replacement Therapy: Bigger Is Not Always Better

OBJECTIVES

Renal replacement therapy in infants and small children is the treatment of choice for severe oligoanuric renal dysfunction, with an increasing consensus that early initiation might contribute to preventing acute kidney injury complications. Safer renal replacement therapy devices specifically designed for neonates may contribute to ameliorating outcomes and increasing chances of survival. One of the crucial factors to achieve an effective renal replacement therapy in small infants is adequate vascular access. The interaction of small size central vascular catheters with renal replacement therapy devices has never been investigated. The aim of this study was to characterize both the operating conditions and performance of three different central vascular catheters sizes (4F, 5F, and 7F) connected to two different extracorporeal blood circulation models (adult and pediatric). The rheologic performance of each vascular access size in combination with the adult and pediatric renal replacement therapy models was described.

DESIGN

Series of experimental extracorporeal circulation circuit tests were conducted with different setups. A two-roller pump was used to simulate a standard adult dialysis machine, whereas a small three-roller pump served as pediatric renal replacement therapy device.

SETTING

A pressure-flow setup aimed to collect pressure and flow values under different test conditions. A second experiment focused on hemolysis estimation induced by the extracorporeal system. Hemolysis exclusively induced by the 4F catheter was also evaluated. Finally, our data were applied to estimate the optimal catheter size theoretically capable of delivering adequate doses basing on anthropometric data (patient weight and cannulation site) in absence of direct ultrasound vessel measurement.

SUBJECTS

In vitro tests conducted on simulated extracorporeal circuit models of continuous pediatric and neonatal renal replacement therapy.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

When 4F and 5F catheters are used, maximal blood flows within safe circuit pressures can be set at the values of 13 and 29 mL/min, respectively, when a small pump is used. Differently, when using adult roller pumps, only maximal flows of 10 and 20 mL/min are reached. However, hemolysis is higher when using a three-roller pump compared with the two-roller. The clinical impact of this increased hemolytic burden is likely not relevant.

CONCLUSIONS

Small size central vascular catheters display optimal rheologic performances in terms of pressures and flows particularly when the renal replacement therapy device is equipped with pumps proportional to central vascular catheters sizes, and even when relatively high blood flows are set. This is achieved at the risk of a higher hemolysis rate.

Renal replacement therapy in neonates with an inborn error of metabolism

Hyperammonemia can be caused by several genetic inborn errors of metabolism including urea cycle defects, organic acidemias, fatty acid oxidation defects, and certain disorders of amino acid metabolism. High levels of ammonia are extremely neurotoxic, leading to astrocyte swelling, brain edema, coma, severe disability, and even death. Thus, emergency treatment for hyperammonemia must be initiated before a precise diagnosis is established. In neonates with hyperammonemia caused by an inborn error of metabolism, a few studies have suggested that peritoneal dialysis, intermittent hemodialysis, and continuous renal replacement therapy (RRT) are effective modalities for decreasing the plasma level of ammonia. In this review, we discuss the current literature related to the use of RRT for treating neonates with hyperammonemia caused by an inborn error of metabolism, including optimal prescriptions, prognosis, and outcomes. We also review the literature on new technologies and instrumentation for RRT in neonates

Clinical study of blood purification therapy in critical care in Japan: results from the survey research of the Japan Society for Blood Purification in Critical Care in 2013

To clarify the clinical status of blood purification therapy (BPT) in critical care in Japan, we conducted a cohort study using data from a nationwide registry of the Japan Society for Blood Purification in Critical Care in 2013. We enrolled 2227 patients treated with BPT (female, 39.1%; mean age, 65.5 ± 12.1 years) in the intensive care units of 43 facilities. Patient characteristics, modes of BPT, and survival rate for each disease were investigated. In total, BPT was performed 3053 times. Continuous renal replacement therapy (CRRT) (57.9%) was the most common mode of BPT, followed by intermittent renal replacement therapy (20.2%) and direct hemoperfusion with the polymyxin B-immobilized fiber column (PMX-DHP) (11.5%). Nafamostat mesilate (84.9%) was most frequently used as the anticoagulant. The 28-day survival rate was 56.8% in all patients. The most common mode for acute kidney injury (AKI) and multiple organ failure was CRRT, while PMX-DHP and CRRT were most common for sepsis. There was no significant difference in survival rates among AKI stages 1-3. Survival rate (38.3%) was significantly lower in patients with acute lung injury (ALI) than in those with multiple organ failure (41.8%) and those with sepsis (46.6%). Multivariate regression analysis revealed that the APACHE II score and the presence of acute ALI and acute hepatic failure were significantly associated with death. This large-scale cohort study showed the clinical status of BPT in Japan. Further investigations are required to clarify the efficacy of BPT for critically ill patients.

Continuous Renal Replacement Therapy: Forty-year Anniversary

In 1977 Peter Kramer performed the first CAVH (continuous arteriovenous hemofiltration) treatment in Gottingen, Germany. CAVH soon became a reliable alternative to hemo- or peritoneal dialysis in critically ill patients. The limitations of CAVH spurred new research and the discovery of new treatments such as CVVH and CVVHD (continuous veno-venous hemofiltration and continuous veno-venous hemodialysis). The alliance with industry led to development of new specialized equipment with improved accuracy and performance in delivering continuous renal replacement therapies (CRRTs). Machines and filters have progressively undergone a series of technological steps, reaching a high level of sophistication. The evolution of technology has continued, leading to the development and clinical application of new membranes, new techniques and new treatment modalities. With the progress of technology, the entire field of critical care nephrology moved forward, expanding the areas of application of extracorporeal therapies to cardiac, liver and pulmonary support. A great deal of research made extracorporeal therapies an interesting option for the treatment of sepsis and intoxication and the additional use of sorbents was explored. With the progress in understanding the pathophysiology of acute kidney injury (AKI), new guidelines were developed, driving indications, modalities of prescription, monitoring techniques and quality assurance programs. Information technology and precision medicine have recently contributed to further evolution of CRRT, with the possibility of collecting data in large databases and evaluating policies and practice patterns. This is likely to ultimately result in improved patient care. CRRTs are 40 years old today, but they are still young and full of potential for further evolution.