Continuous Renal Replacement Therapy With Prismaflex HF20 Disposable Set in Children From 4 to 15 kg

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.

Expanding the Spectrum of Extracorporeal Strategies in Small Infants with Hyperammonemia

Hyperammonemia is a life-threatening condition mainly due to the neurotoxicity of ammonia. Ammonia scavengers may be insufficient, and extracorporeal treatment may be required. Continuous treatments are preferred, and a high-dose continuous renal replacement therapy (CRRT) must be prescribed to ensure a fast ammonia depletion. Many of the children with hyperammonemia are newborns, with lower blood volume than older children. The majority of the CRRT systems are adult-based, with large extracorporeal priming volumes and inadequate UF control. Recent strides have been made in the development of CRRT systems more suitable for young children with smaller sets to use in adult machines and dedicated monitors for neonates and infants. The main advantage of the machines for adults is the higher dialysis fluid flows, however with greater hemodynamic risks. Pediatric monitors have been designed to reduce the extracorporeal volume and to increase the precision of the treatment. However, they have substantial limitation in clearance performances. In this review, we discuss on current strategies to provide CRRT in newborns and small infants with hyperammonemia. We also presented our experience with the use of CARPEDIEM™ implemented in a CVVHDF modality, boosting the diffusive clearance with a post-replacement convective mechanism.

Continuous Kidney Replacement Therapy Practices in Pediatric Intensive Care Units Across Europe

IMPORTANCE

Continuous kidney replacement therapy (CKRT) is the preferred method of kidney support for children with critical illness in pediatric intensive care units (PICUs). However, there are no data on the current CKRT management practices in European PICUs.

OBJECTIVE

To describe current CKRT practices across European PICUs.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional survey of PICUs in 20 European countries was conducted by the Critical Care Nephrology Section of the European Society of Pediatric and Neonatal Intensive Care from April 1, 2020, to May 31, 2022. Participants included intensivists and nurses working in European PICUs. The survey was developed in English and distributed using SurveyMonkey. One response from each PICU that provided CKRT was included in the analysis. Data were analyzed from June 1 to June 30, 2022.

MAIN OUTCOME AND MEASURES

Demographic characteristics of European PICUs along with organizational and delivery aspects of CKRT (including prescription, liberation from CKRT, and training and education) were assessed.

RESULTS

Of 283 survey responses received, 161 were included in the analysis (response rate, 76%). The attending PICU consultant (70%) and the PICU team (77%) were mainly responsible for CKRT prescription, whereas the PICU nurses were responsible for circuit setup (49%) and bedside machine running (67%). Sixty-one percent of permanent nurses received training to use CKRT, with no need for certification or recertification in 36% of PICUs. Continuous venovenous hemodiafiltration was the preferred dialytic modality (51%). Circuit priming was performed with normal saline (67%) and blood priming in children weighing less than 10 kg (56%). Median (IQR) CKRT dose was 35 (30-50) mL/kg/h in neonates and 30 (30-40) mL/kg/h in children aged 1 month to 18 years. Forty-one percent of PICUs used regional unfractionated heparin infusion, whereas 35% used citrate-based regional anticoagulation. Filters were changed for filter clotting (53%) and increased transmembrane pressure (47%). For routine circuit changes, 72 hours was the cutoff in 62% of PICUs. Some PICUs (34%) monitored fluid removal goals every 4 hours, with variation from 12 hours (17%) to 24 hours (13%). Fluid removal goals ranged from 1 to 3 mL/kg/h. Liberation from CKRT was performed with a diuretic bolus followed by an infusion (32%) or a diuretic bolus alone (19%).

CONCLUSIONS AND RELEVANCE

This survey study found a wide variation in current CKRT practice, including organizational aspects, education and training, prescription, and liberation from CKRT, in European PICUs. This finding calls for concerted efforts on the part of the pediatric critical care and nephrology communities to streamline CKRT education and training, research, and guidelines to reduce variation in practice.

Anticoagulation in patients with acute kidney injury undergoing kidney replacement therapy

Kidney replacement therapy (KRT) is used to provide supportive therapy for critically ill patients with severe acute kidney injury and various other non-renal indications. Modalities of KRT include continuous KRT (CKRT), intermittent hemodialysis (HD), and sustained low efficiency daily dialysis (SLED). However, circuit clotting is a major complication that has been investigated extensively. Extracorporeal circuit clotting can cause reduction in solute clearances and can cause blood loss, leading to an upsurge in treatment costs and a rise in workload intensity. In this educational review, we discuss the pathophysiology of the clotting cascade within an extracorporeal circuit and the use of various types of anticoagulant methods in various pediatric KRT modalities.

Extracorporeal membrane oxygenation in children: An update of a single tertiary center 11-Year experience from Croatia

INTRODUCTION

Extracorporeal membrane oxygenation (ECMO) is an important treatment option for organ support in respiratory insufficiency, cardiac failure, or as an advanced tool for cardiopulmonary resuscitation. Reports on pediatric ECMO use in our region are lacking.

METHODS

This study is a retrospective review of all pediatric cases that underwent a veno-arterial (VA) or veno-venous (VV) ECMO protocol between November 2009 and August 2020 at the Department of Pediatrics, University Hospital Center Zagreb, Croatia.

RESULTS

Fifty-two ECMO runs identified over the period; data were complete for 45 cases, of which 23 (51%) were female, and median age was 8 months. Thirty-eight (84%) patients were treated using the VA-and 7 (16%) using VV-ECMO. The overall survival rate was 51%. Circulatory failure was the most common indication for ECMO (N = 38, 84%), and in 17 patients ECMO was started after cardiopulmonary resuscitation (E-CPR). Among survivors, 74% had no or minor neurological sequelae. Variables associated with poor outcome were renal failure with renal replacement therapy (p < .001) and intracranial injury (p < .001).

CONCLUSION

Overall survival rate in our cohort is comparable to the data published in the literature. The use of hemodialysis was shown to be associated with higher mortality. High rates of full neurological recovery among survivors are a strong case for further ECMO program development in our institution.

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.

Kidney support therapy in the pediatric patient: Unique considerations for a unique population

The use of kidney support therapy (KST) for use in managing patients with acute kidney injury (AKI) has expanded greatly in the last several decades. The growing use of KST modalities in children, and now in neonates, has been associated with opportunities for education, clinical research, clinical practice improvements, and outcomes research. A multitude of controversies exist in the field of pediatric KST-many of which are shared by adult critical care nephrology practice. Simultaneously, pediatric KST has led the way to a burgeoning exploration of the importance of fluid overload as it relates to KST initiation and management and also with quality improvement. In this review, we will explore and describe the paradigms contained with pediatric KST used to support children with AKI. In addition to the governing principles related to the mechanics of KST, we will describe the novel aspects of newer support machines and ethical considerations of KST provision. Anticoagulation, dose, and modality will be discussed as well as priming procedures for special considerations. The utilization of KST across pediatric populations represents the next frontier of critical care nephrology.

A Meta-Analysis of Extracorporeal Anticoagulants in Pediatric Continuous Kidney Replacement Therapy

OBJECTIVE

Continuous kidney replacement therapy (CKRT) is the primary therapeutic modality utilized in hemodynamically unstable patients with severe acute kidney injury. As the circuit is extracorporeal, it poses an increased risk of blood clotting and circuit loss; frequent circuit losses affect the provider's ability to provide optimal treatment. The objective of this meta-analysis is to evaluate the safety and efficacy of the extracorporeal anticoagulants in the pediatric CKRT population.

DATA SOURCES

We conducted a literature search on PubMed/Medline and Embase for relevant citations.

STUDY SELECTION

Studies were included if they involved patients under the age of 18 years undergoing CKRT, with the use of anticoagulation (heparin, citrate, or prostacyclin) as a part of therapy. Only English articles were included in the study.

DATA EXTRACTION

Initial search yielded 58 articles and a total of 24 articles were included and reviewed. A meta-analysis was performed focusing on the safety and effectiveness of regional citrate anticoagulation (RCA) vs unfractionated heparin (UFH) anticoagulants in children.

DATA SYNTHESIS

RCA had statistically significantly longer circuit life of 50.65 hours vs. UFH of 42.10 hours. Two major adverse effects metabolic alkalosis and electrolyte imbalance seen more commonly in RCA compared to UFH. There was not a significant difference in the risk of systemic bleeding when comparing RCA vs. UFH.

CONCLUSION

RCA is the preferred anticoagulant over UFH due to its significantly longer circuit life, although vigilant circuit monitoring is required due to the increased risk of electrolyte disturbances. Prostacyclin was not included in the meta-analysis due to the lack of data in pediatric patients. Additional studies are needed to strengthen the study results further.

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.

Clinical evaluation of the Prismaflex™ HF 20 set and Prismaflex™ system 7.10 for acute continuous kidney replacement therapy (CKRT) in children

BACKGROUND

Continuous kidney replacement therapy (CKRT) is a common modality for treatment of severe acute kidney injury (AKI) in children. Adult technologies routinely utilized to provide this therapy have a large extracorporeal volume. The Prismaflex™ HF20 filter set has a relatively low extracorporeal blood volume of 60 mL, which provides technological benefit for smaller children compared with current filter sets available in the USA.

METHODS

We conducted a multicenter, open-label single group study to evaluate whether the Prismaflex™ HF20 filter set delivers efficacious and safe CKRT to support patients with AKI, fluid overload, or both in pediatric patients weighing ≥ 8 to 20 kg.

RESULTS

Twenty-three patients were enrolled between April 24, 2016 and April 8, 2018. The mean reduction in blood urea nitrogen from baseline to 24 h was 58.12 ± 20.08% (95% CI, - 68.45 and - 47.79 (p = 0.0008)). Median cumulative normalized effluent rate at 24 h was 60.8 mL/kg/h (25.9, 83.7). None of the patients participating in the study suffered a serious adverse event; thus, no obvious safety concerns were noted.

CONCLUSIONS

We suggest that the Prismaflex HF20™ filter set used in conjunction with the Prismaflex™ System Software Version 7.10 or 7.20 is a suitable alternative to larger filter sets for use in pediatric patients weighing less than 20 kg. Graphical abstract.

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.

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.

Development of an accurate fluid management system for a pediatric continuous renal replacement therapy device

Acute kidney injury is common in critically ill children, and renal replacement therapies provide a life-saving therapy to a subset of these children. However, there is no Food and Drug Administration-approved device to provide pediatric continuous renal replacement therapy (CRRT). Consequently, clinicians adapt approved adult CRRT devices for use in children because of lack of safer alternatives. Complications occur using adult CRRT devices in children because of inaccurate fluid balance (FB) between the volumes of ultrafiltrate (UF) removed and replacement fluid (RF) delivered. We demonstrate the design and validation of a pediatric fluid management system for obtaining accurate instantaneous and cumulative FB. Fluid transport was achieved via multiple novel pulsatile diaphragm pumps. The conservation of volume principle leveraging the physical property of fluid incompressibility along with mechanical coupling via a crankshaft was used for FB. Accuracy testing was conducted in vitro for 8 hour long continuous operation of the coupled UF and RF pumps. The mean cumulative FB error was <1% across filtration flows from 300 to 3000 ml/hour. This approach of FB control in a pediatric-specific CRRT device would represent a significant accuracy improvement over currently used clinical implementations.

Use of HF20 membrane in critically ill unstable low-body-weight infants on inotropic support

BACKGROUND

Initiating continuous renal replacement therapy (CRRT) in infants exposes them to the dual hemodynamic challenges of high circuit extracorporeal volumes and potential membrane reactions, in the case of acrylonitrile AN69 membranes. The use of the new Prismaflex HF20 membrane in hemodynamically unstable low-body-weight infants on inotropic support has not been reported.

TREATMENT

We describe the use of the HF20 (Gambro Lundia AB, Lund, Sweden) membrane in four low-body-weight infants (2.3 to 5.4 kg) with multi-organ dysfunction syndrome who were critically ill in the Pediatric Intensive Care Unit (PICU), hemodynamically unstable, and on inotropes. We were able to achieve target volume loss in all infants without compromising their hemodynamic status. Mean arterial pressures were maintained between 39 and 57 mmHg. The relatively low circuit volume of the HF20 set (60 ml) obviated the need for blood prime in the majority; however, when blood prime was required, there was no adverse reaction with the polyarylethersulfone (PAES) membrane. Solute clearance in these small infants was efficient with correction of metabolic acidosis and electrolyte abnormalities. Excellent circuit lifespan (56.3 ± 32.3 h) was observed.

CONCLUSIONS

CRRT using the HF20 membrane is safe and hemodynamically well tolerated in high-risk, unstable low-body-weight infants with cardiac dysfunction on multiple inotropes.

Continuous renal replacement therapy for children ≤10 kg: a report from the prospective pediatric continuous renal replacement therapy registry

OBJECTIVE

To report circuit characteristics and survival analysis in children weighing ≤10 kg enrolled in the Prospective Pediatric Continuous Renal Replacement Therapy (ppCRRT) Registry.

STUDY DESIGN

We conducted prospective cohort analysis of the ppCRRT Registry to: (1) evaluate survival differences in children ≤10 kg compared with other children; (2) determine demographic and clinical differences between surviving and non-surviving children ≤10 kg; and (3) describe continuous renal replacement therapy (CRRT) circuit characteristics differences in children ≤5 kg versus 5-10 kg.

RESULTS

The ppCRRT enrolled 84 children ≤10 kg between January 2001 and August 2005 from 13 US tertiary centers. Children ≤10 kg had lower survival rates than children >10 kg (36/84 [43%] versus 166/260 [64%]; P < .001). In children ≤10 kg, survivors were more likely to have fewer days in intensive care unit prior to CRRT, lower Pediatric Risk of Mortality 2 scores at intensive care unit admission and lower mean airway pressure (P(aw)), higher urine output, and lower percent fluid overload (FO) at CRRT initiation. Adjusted regression analysis revealed that Pediatric Risk of Mortality 2 scores, FO, and decreased urine output were associated with mortality. Compared with circuits from children 5-10 kg at CRRT initiation, circuits from children ≤5 kg more commonly used blood priming for initiation, heparin anticoagulation, and higher blood flows/effluent flows for body weight.

CONCLUSION

Mortality is more common in children who are ≤10 kg at the time of CRRT initiation. Like other CRRT populations, urine output and FO at CRRT initiation are independently associated with mortality. CRRT prescription differs in small children.