High-dose continuous renal replacement therapy for neonatal hyperammonemia

Continuous renal replacement therapy in neonates and children: what does the pediatrician need to know? An overview from the Critical Care Nephrology Section of the European Society of Paediatric and Neonatal Intensive Care (ESPNIC)

Continuous renal replacement therapy (CRRT) is the preferred method for renal support in critically ill and hemodynamically unstable children in the pediatric intensive care unit (PICU) as it allows for gentle removal of fluids and solutes. The most frequent indications for CRRT include acute kidney injury (AKI) and fluid overload (FO) as well as non-renal indications such as removal of toxic metabolites in acute liver failure, inborn errors of metabolism, and intoxications and removal of inflammatory mediators in sepsis. AKI and/or FO are common in critically ill children and their presence is associated with worse outcomes. Therefore, early recognition of AKI and FO is important and timely transfer of patients who might require CRRT to a center with institutional expertise should be considered. Although CRRT has been increasingly used in the critical care setting, due to the lack of standardized recommendations, wide practice variations exist regarding the main aspects of CRRT application in critically ill children.     Conclusion: In this review, from the Critical Care Nephrology section of the European Society of Paediatric and Neonatal Intensive Care (ESPNIC), we summarize the key aspects of CRRT delivery and highlight the importance of adequate follow up among AKI survivors which might be of relevance for the general pediatric community. What is Known: • CRRT is the preferred method of renal support in critically ill and hemodynamically unstable children in the PICU as it allows for gentle removal of fluids and solutes. • Although CRRT has become an important and integral part of modern pediatric critical care, wide practice variations exist in all aspects of CRRT. What is New: • Given the lack of literature on guidance for a general pediatrician on when to refer a child for CRRT, we recommend timely transfer to a center with institutional expertise in CRRT, as both worsening AKI and FO have been associated with increased mortality. • Adequate follow-up of PICU patients with AKI and CRRT is highlighted as recent findings demonstrate that these children are at increased risk for adverse long-term outcomes.

Use of extracorporeal therapies to treat life-threatening intoxications

Toxic ingestions are a significant cause of pediatric morbidity and mortality, with some requiring extracorporeal removal for therapy. Given the emergent and life-threatening nature of such scenarios, it is paramount that clinicians caring for intoxicated children be familiar with the subject. This review summarizes the following: (a) the properties of a substance which lend it amenable to removal; (b) the current extracorporeal treatment modalities available for such removal (of which hemodialysis is typically the ideal choice); (c) an introduction and framework to use a quick reference guide from the Extrip organization, which has a website available to guide clinicians' rapid decisions; and (d) new membranes/approaches that may optimize clearance of certain intoxications.

Evaluation of the efficacy and associated complications of regional citrate anticoagulation in neonates: experience from a fourth level neonatal intensive care unit

Continuous kidney replacement therapy (CKRT) use has increased in recent years, but anticoagulation is a challenge for neonates. Regional citrate anticoagulation (RCA) is rarely preferred in neonates because of citrate accumulation (CA) and metabolic complications. We aimed to demonstrate the efficacy and safety of RCA in neonates. We retrospectively analyzed the medical records of 11 neonates treated with RCA-CKRT between 2018 and 2023. The initial dose of RCA was 2.1-3 mmol/l, and then, its dose was increased according to the level of ionized calcium (iCa+2) in the circuit and patients. The total/iCa+2 ratio after-treatment > 2.5 was indicated as CA. We evaluated to citrate dose, CA, circuit lifespan, and dialysis effectivity. The median gestational age was 39 (36.4-41.5) weeks, the median body weight (BW) was 3200 (2400-4000) grams, and the mean postnatal age was 4 (2-24) days. The most common indication for CKRT was hyperammonemia (73%). All neonates had metabolic acidosis and hypocalcemia during CKRT. Other common metabolic complications were hypophosphatemia (90%), hypokalemia (81%), and hypomagnesemia (63%). High dialysate rates with a median of 5765 ml/h/1.73 m2 allowed for a rapid decrease in ammonia levels to normal. Four patients (36.3%) had CA, and seven (63.7%) did not (non-citrate accumulation, NCA). Mean BW, median postnatal age, biochemical parameters, coagulation tests, and ammonia levels were similar between the CA and NCA groups. Low pH, low HCO3, high lactate, and SNAPPE-II scores could be associated with a higher T/iCa ratio.

CONCLUSION

 RCA was an efficient and safe anticoagulation for neonates requiring CKRT. Metabolic complications may occur, but they could be managed with adequate supplementation.

WHAT IS KNOWN

• Continuous kidney replacement therapy (CKRT) has become popular in recent years due to its successful treatment of fluid overload, electrolyte imbalance, metabolic acidosis, multi-organ failure, and hyperleucinemia/hyperammonemia associated with inborn errors of metabolism. • The need for anticoagulation is the major difficulty in neonatal CKRT. In adult and pediatric patients, regional citrate anticoagulation has been shown to be effective.

WHAT IS NEW

• RCA is an effective and safe anticoagulation method for neonates who require CKRT. • Electrolyte imbalances and metabolic acidosis could be managed with adequate supplementation and appropriate treatment parameters such as citrate dose, blood flow rate, and dialysate flow rate.

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.

[Expert consensus on the diagnosis and treatment of neonatal hyperammonemia]

Neonatal hyperammonemia is a disorder of ammonia metabolism that occurs in the neonatal period. It is a clinical syndrome characterized by abnormal accumulation of ammonia in the blood and dysfunction of the central nervous system. Due to its low incidence and lack of specificity in clinical manifestations, it is easy to cause misdiagnosis and missed diagnosis. In order to further standardize the diagnosis and treatment of neonatal hyperammonemia, the Youth Commission, Subspecialty Group of Neonatology, Society of Pediatrics, Chinese Medical Association formulated the expert consensus based on clinical evidence in China and overseas and combined with clinical practice experience,and put forward 18 recommendations for the diagnosis and treatment of neonatal hyperaminemia.

Regional citrate anticoagulation for continuous renal replacement therapy in newborns

Background

Regional citrate anticoagulant (RCA) is recommended as the preferred anticoagulant regimen for continuous renal replacement therapy (CRRT) in adults; however, it is rarely reported in neonates due to concerns associated with their immature liver. Few studies have reported on the use of RCA to evaluate the safety and efficacy of RCA-CRRT in neonates.

Method

In this retrospective observational study, we reviewed the clinical records of neonates who underwent RCA-CRRT at our pediatric intensive care unit between September 2015 to January 2021.

Results

A total of 23 neonates underwent 57 sessions of RCA-CRRT. Their mean age was 10.1 ± 6.9 days and mean weight was 3.0 ± 0.7 kg (range, 0.95-4 kg). The mean filter life was 31.54 ± 19.58 h (range, 3.3-72.5 h). Compared to pretreatment values, the total-to-ionized calcium ratio (T/iCa) on RCA-CRRT increased (2.00 ± 34 0.36 vs. 2.19 ± 0.40, P = 0.056) as did the incidence of T/iCa levels >2.5 (11.4 vs. 14.3, P = 0.477), albeit not significantly. Using a post-treatment T/iCa threshold of 2.5, we divided all the cases into citrate accumulation (CA) and non-CA (NCA) groups. Compared with the NCA group, the CA group had significantly higher body weight (3.64 ± 0.32 kg vs. 2.95 ± 0.41 kg, P = 0.033) and significantly lower blood flow rate per body weight ml/kg/min (3.08 ± 0.08 vs. 4.07 ± 0.71, P = 0.027); however, there was no significant difference between the two groups in terms of age, corrected gestational age, the PRISM-III score, and biochemical tests.

Conclusion

RCA-CRRT is safe and effective for neonates. After appropriate adjustments of the RCA-CRRT parameters, the incidence of CA was not higher in neonates than in children or adults, and CA was not found to be significantly correlated with age or corrected gestational age.

Literature Review of the Efficacy of High-Volume Hemofiltration in Critically Ill Pediatric Patients

BACKGROUND

Pediatric sepsis is a significant public health issue. This condition is exacerbated by rising serum creatinine and inflammatory cytokines that lead to deleterious effects upon the body. The current standard of care involves the use of continuous kidney replacement therapy to remove harmful cytokines until the body returns to homeostasis. In order to promote faster clearance and reduced stay in the ICU, high-volume hemofiltration (HVHF) has shown promise. However, there is a paucity of studies to fully elucidate its benefits.

METHODS

A literature search was done using PubMed/ MEDLINE and Embase. The literature was reviewed by two independent reviewers, who independently assessed the quality of randomized controlled trials by using the Cochrane risk of bias tool for RCTs and Newcastle-Ottawa Scale (NOS) for assessing the quality of nonrandomized controlled trials. Data were combined from studies with a similar design.

RESULTS

The primary endpoint of all-cause mortality was found to be reduced by 40% across all of the pooled studies. For secondary endpoints, significant reductions of serum creatinine were found. Additionally, duration of ICU stays and treatment course was found to be significantly shorter in HVHF patients than the current standard of care. The rate of adverse effects was analyzed, and there was no difference in the proportion of patients developing hypokalemia, hyperkalemia, hypernatremia, or hyponatremia. The proportion of patients developing hyperglycemia was higher in patients undergoing HVHF, whereas the proportions of patients developing bleeding were significantly less in patients undergoing HVHF. One study reported a total number of adverse events between the two groups which were significantly lesser in patients undergoing HVHF.

CONCLUSION

HVHF shows promise as a modality to treat pediatric patients with sepsis. In order to confirm the benefits of this modality, future studies need significantly more patients for analysis.

Continuous Veno-Venous Hemodiafiltration in Neonates with Maple Syrup Urine Disease

INTRODUCTION

Herein, we aimed to discuss our experience in 16 newborn patients with Maple syrup urine disease (MSUD) who were treated with urgent renal replacement therapy (RRT).

METHODS

The patients underwent continuous veno-venous hemodiafiltration (CVVHDF) or peritoneal dialysis (PD) as renal replacement therapy.

RESULTS

Eleven (68.75%) patients underwent CVVHDF and five (31.25%) underwent peritoneal dialysis. The median leucine reduction rate per hour was 2.56%(1.75-7.6) in the CVVHDF group, 0.78%(0.54-1.83) in the PD group, and was significantly higher in the CVVHDF group (p = 0.001). Post-treatment plasma leucine levels were found to be 198 (20-721) μmol/L in the CVVHDF group and 600 (250-967) μmol/L in the PD group, and CVVHDF was found to be significantly lower (p = 0.08). Complications such as hypotension, electrolyte imbalance, and filter obstruction occurred in the CVVHDF group.

CONCLUSION

This study showed that CVVHDF is more effective than PD for rapidly eliminating elevated leucine levels caused by MSUD in the newborn and it is not associated with increased complication rates. This article is protected by copyright. All rights reserved.

Newborn treated with continuous renal replacement therapy for citrulinemia-type 1

Introduction: Hyperammonemia occurs as a result of the inability to convert ammonia, a metabolic toxin, into urea due to a block in the urea cycle, and there resulting neurotoxicity is responsible for the pathogenesis. Case Presentation: Our patient was 7 days old when followed up in an external center for 3 days with a preliminary diagnosis of neonatal sepsis. Lethargy, vomiting, tachypnea, and convulsions, which are frequently seen in the first neonatal forms of urea cycle disorders, were also present in our patient. He was referred to us as a result of high ammonia levels when he was examined in terms of congenital metabolic diseases. He was intubated due to the rapid development of respiratory failure. When he was admitted to our intensive care unit with hyperammonemia, light reflex could not be obtained, and widespread cutis marmaratus was developed. Continuous renal replacement therapy was started in our patient and administered intermittently for 120 hours. The glucose infusion rate was followed by high fluid. When it orally tolerated, it is supported with sodium benzoate and sodium stearyl fumarate to reduce ammonia. Nutrition was limited to protein with Basic P. Conclusion: After staying in the intensive care unit for 30 days, our patient was discharged with the recommendation of outpatient follow-up by the pediatric metabolism physician. When our patient came for his check up after two months, there was no nystagmus and no seizures.

Characteristics of continuous venovenous hemodiafiltration in the acute treatment of inherited metabolic disorders

BACKGROUND

Continuous kidney replacement therapies (CKRT) have been reported to be an effective approach to removing toxic metabolites in inborn errors of metabolism (IEM). The present study evaluates efficiency and complications of CKRT in children with IEM.

METHODS

Patients diagnosed with IEM who underwent CKRT in pediatric and neonatal intensive care units were analyzed. CKRT were initiated in patients with persistently high blood ammonia levels (≥ 500 μmol/L), blood ammonia levels > 250 μmol/L in the presence of moderate encephalopathy, high blood leucine levels (≥ 1500 μmol/L), and blood leucine levels < 1500 μmol/L in the presence of deteriorating neurological status or persistent metabolic acidosis.

RESULTS

Of 22 patients enrolled, nine (40.9%) Maple syrup urine disease (MSUD), eight (36.4%) urea cycle disorders (UCD), and five (22.7%) organic acidemias (OA). Median age was 72.3 [9.9-1040.8] days. In total, 28 dialysis sessions were analyzed [16 (57.1%) continuous venovenous hemodialysis, and 12 (42.9%) continuous venovenous hemodiafiltration]. A significant decrease was noted in leucine levels (from 1608.4 ± 885.3 to 314.6 ± 109.9 µmol/L) of patients with MSUD, while ammonia levels were significantly decreased in patients with UCD and OA (from 1279.9 ± 612.1 to 85.1 ± 21.6 µmol/L). The most frequent complications of CKRT were thrombocytopenia (60.7%), hypotension (53.6%), and hypocalcemia (42.9%). Median age of patients with hypotension treated with vasoactive medications was significantly lower than median age of those with normal blood pressure.

CONCLUSION

CKRT is a reliable approach for effective and rapid removal of toxic metabolites in children with IEM, and CKRT modalities can be safely used and are well-tolerated in infants.

Towards an Algorithm-Based Tailored Treatment of Acute Neonatal Hyperammonemia

Acute neonatal hyperammonemia is associated with poor neurological outcomes and high mortality. We developed, based on kinetic modeling, a user-friendly and widely applicable algorithm to tailor the treatment of acute neonatal hyperammonemia. A single compartmental model was calibrated assuming a distribution volume equal to the patient's total body water (V), as calculated using Wells' formula, and dialyzer clearance as derived from the measured ammonia time-concentration curves during 11 dialysis sessions in four patients (3.2 ± 0.4 kg). Based on these kinetic simulations, dialysis protocols could be derived for clinical use with different body weights, start concentrations, dialysis machines/dialyzers and dialysis settings (e.g., blood flow QB). By a single measurement of ammonia concentration at the dialyzer inlet and outlet, dialyzer clearance (K) can be calculated as K = QB∙[(Cinlet - Coutlet)/Cinlet]. The time (T) needed to decrease the ammonia concentration from a predialysis start concentration Cstart to a desired target concentration Ctarget is then equal to T = (-V/K)∙LN(Ctarget/Cstart). By implementing these formulae in a simple spreadsheet, medical staff can draw an institution-specific flowchart for patient-tailored treatment of hyperammonemia.

[Application of continuous renal replacement therapy in the treatment of neonates with inherited metabolic diseases]

OBJECTIVE

To study the efficacy and safety of continuous renal replacement therapy (CRRT) in the treatment of neonates with inherited metabolic diseases and hyperammonemia.

METHODS

A retrospective analysis was performed on the medical records of neonates with inherited metabolic diseases and hyperammonemia who were hospitalized and underwent CRRT in the Department of Neonatology, Hunan Children's Hospital, from September 2016 to March 2020, including general conditions, clinical indices, laboratory markers, and adverse reactions.

RESULTS

A total of 11 neonates were enrolled, with 7 boys (64%) and 4 girls (36%). The neonates had a mean gestational age of (38.9±0.8) weeks, a mean body weight of (3 091±266) g on admission, and an age of (5.7±2.0) days at the time of CRRT. The main clinical manifestations were vomiting (100%), convulsions (100%), and coma (55%), and the main primary disease was urea cycle disorder (55%). The mean duration of CRRT was (44±14) hours, the medium duration of coma before CRRT was 2 hours, and the total duration of coma was 10 hours. The patients had a mean hospital stay of (18±10) days and a survival rate of 73%, and 2 survivors had epilepsy. After treatment, all patients had significant reductions in blood ammonia, lactic acid, and K⁺ concentration (P < 0.001) and a significant increase in pH (P < 0.001). The incidence rate of adverse reactions was 27%.

CONCLUSIONS

CRRT is safe and effective in the treatment of neonates with inherited metabolic diseases and hyperammonemia.

Extracorporeal renal and liver support in pediatric acute liver failure

The liver is the only organ which can regenerate and, thus, potentially negate the need for transplantation in acute liver failure (ALF). Cerebral edema and sepsis are leading causes of mortality in ALF. Both water-soluble and protein-bound toxins have been implicated in pathogenesis of various ALF complications. Ammonia is a surrogate marker of water-soluble toxin accumulation in ALF and high levels are associated with higher grades of hepatic encephalopathy, raised intracranial pressure, and mortality. Therefore, extracorporeal therapies aim to lower ammonia and maintain fluid balance and cytokine homeostasis. The most common and easily available modality is continuous kidney replacement therapy (CKRT). Early initiation of high-volume CKRT utilizing an anticoagulation regimen minimizing treatment downtime and delivering the prescribed dose is highly desirable. Ideally, extracorporeal liver-assist devices (ECLAD) should perform both synthetic and detoxification functions of the liver. ECLAD may temporarily replace lost liver function and serve as a bridge, either to spontaneous recovery or liver transplantation. Various bioartificial and biologic liver-assist devices are described in specialty literature, including molecular adsorbent recirculating system (MARS), single pass albumin dialysis (SPAD), and total plasma exchange (TPE); however, clinicians commonly use modalities easily available in intensive care units. There is a lack of standardization of indications for ECLAD, availability of different extracorporeal devices with varied technical approaches, and, of note, the differences in doses of ECLAD provided in clinical practice. We review the practicalities and evidence regarding these four artificial liver support devices in pediatric ALF.

PCRRT Expert Committee ICONIC Position Paper on Prescribing Kidney Replacement Therapy in Critically Sick Children With Acute Liver Failure

Management of acute liver failure (ALF) and acute on chronic liver failure (ACLF) in the pediatric population can be challenging. Kidney manifestations of liver failure, such as hepatorenal syndrome (HRS) and acute kidney injury (AKI), are increasingly prevalent and may portend a poor prognosis. The overall incidence of AKI in children with ALF has not been well-established, partially due to the difficulty of precisely estimating kidney function in these patients. The true incidence of AKI in pediatric patients may still be underestimated due to decreased creatinine production in patients with advanced liver dysfunction and those with critical conditions including shock and cardiovascular compromise with poor kidney perfusion. Current treatment for kidney dysfunction secondary to liver failure include conservative management, intravenous fluids, and kidney replacement therapy (KRT). Despite the paucity of evidence-based recommendations concerning the application of KRT in children with kidney dysfunction in the setting of ALF, expert clinical opinions have been evaluated regarding the optimal modalities and timing of KRT, dialysis/replacement solutions, blood and dialysate flow rates and dialysis dose, and anticoagulation methods.

Continuous Renal Replacement Therapy for Two Neonates With Hyperammonemia

Objectives: This study aims to assess the feasibility of using hemofiltration for ammonia clearance in low body weight infants with an inborn error of metabolism. Design: A study of two cases. Setting: Quaternary pediatric hospital (Saint Louis Children's Hospital) NICU and PICU. Patients: Infants <6 months of age with an ICD-9 diagnosis of 270.6 (hyperammonemia). Interventions: Continuous renal replacement therapy (CRRT). Measurements and Main Results: We measure serum ammonia levels over time and the rate of ammonia clearance over time. Continuous renal replacement therapy was more effective than scavenger therapy alone (Ammonul™) for rapid removal of ammonia in low weight infants (as low as 2.5 kg). Conclusions: Continuous renal replacement therapy is technically feasible in low weight infants with severe hyperammonemia secondary to an inborn error of metabolism.

Changing the terminology from kidney replacement therapy to kidney support therapy

Kidney replacement therapy (KRT) is a common supportive treatment for renal dysfunction, especially acute kidney injury. However, critically ill or immunosuppressed patients with renal dysfunction often have dysfunction in other organs as well. To improve patient outcomes, clinicians began to initiate kidney replacement therapy in situations where nonrenal conditions may lead to acute kidney injury, such as septic shock, hematopoietic stem cell transplantation, veno-occlusive renal disease, cardiopulmonary bypass, chemotherapy, tumor lysis syndrome, hyperammonemia, and various others. In this review, we discuss the use of various modes of kidney replacement therapy in treating renal and nonrenal complications to illustrate why kidney support therapy is a more appropriate terminology than kidney replacement therapy.

Renal Replacement Therapy in Neonates

Acute kidney injury (AKI) is a highly prevalent disease entity in the NICU, affecting nearly one-quarter of critically ill neonates by some reports. Though medical management remains the mainstay in the treatment of AKI, renal replacement therapy (RRT) is indicated when conservative measures are unable to maintain electrolytes, fluid balance, toxins, or waste products within a safe margin. Several modalities of RRT exist for use in neonatal populations, including peritoneal dialysis, hemodialysis, and continuous RRT. It is the aim of this review to introduce each of these RRT modalities, as well as to discuss their technical considerations, benefits, indications, contraindications, and complications.

Renal replacement therapies for infants and children in the ICU

PURPOSE OF REVIEW

Pediatric acute kidney injury (AKI) in critically ill patients is associated with increased morbidity and mortality. Emerging data support that the incidence of pediatric AKI in the ICU is rising. For children with severe AKI, renal replacement therapy (RRT) can provide a lifesaving supportive therapy. The optimal timing to deliver and modality by which to deliver RRT remain a point of discussion within pediatric (and adult) literature. This review discusses the use of RRT for pediatric patients in the ICU. We discuss the most recent evidence-based methods for RRT with a focus on continuous RRT.

RECENT FINDINGS

The feasibility of dialyzing the smallest infants and more medically complex children in the ICU is dependent on the advancements in dialysis access and circuit technology. At present, data indicate that upward of 27% of children in the ICU develop AKI and 6% require RRT. Newer dialysis modalities including prolonged intermittent hemodialysis and continuous flow peritoneal dialysis as well as newer dialysis technologies such as the smaller volume circuits (e.g., Cardio-Renal Pediatric Dialysis Emergency Machine, Newcastle Infant Dialysis and Ultrafiltration System) have made the provision of dialysis safer and more effective for pediatric patients of a variety of sizes.

SUMMARY

Renal replacement in the ICU requires a multidisciplinary team approach that is facilitated by a pediatric nephrologist in conjunction with intensivists and skilled nursing staff. Although mortality rates for children on dialysis remain high, outcomes are improving with the support of the multidisciplinary team and dialysis technology advancements.

Consensus guidelines for management of hyperammonaemia in paediatric patients receiving continuous kidney replacement therapy

Hyperammonaemia in children can lead to grave consequences in the form of cerebral oedema, severe neurological impairment and even death. In infants and children, common causes of hyperammonaemia include urea cycle disorders or organic acidaemias. Few studies have assessed the role of extracorporeal therapies in the management of hyperammonaemia in neonates and children. Moreover, consensus guidelines are lacking for the use of non-kidney replacement therapy (NKRT) and kidney replacement therapies (KRTs, including peritoneal dialysis, continuous KRT, haemodialysis and hybrid therapy) to manage hyperammonaemia in neonates and children. Prompt treatment with KRT and/or NKRT, the choice of which depends on the ammonia concentrations and presenting symptoms of the patient, is crucial. This expert Consensus Statement presents recommendations for the management of hyperammonaemia requiring KRT in paediatric populations. Additional studies are required to strengthen these recommendations.

This expert Consensus Statement from the Pediatric Continuous Renal Replacement Therapy (PCRRT) workgroup presents recommendations for the management of hyperammonaemia requiring kidney replacement therapy in paediatric populations. Additional studies are needed to strengthen these recommendations, which will be reviewed every 2 years.

Continuous venovenous hemodiafiltration in the treatment of newborns with an inborn metabolic disease: a single center experience

Background/aim

Most inborn metabolic diseases are diagnosed during the neonatal period. The accumulation of toxic metabolites may cause acute metabolic crisis with long-term neurological dysfunction and death. Renal replacement therapy (RRT) modalities allow the efficient removal of toxic metabolites. In this study, we reviewed our experience with continuous venovenous hemodiafiltration (CVVHDF) as RRT for newborns with an inborn metabolic disease.

Materials and methods

Patients diagnosed with an inborn metabolic disease and who received CVVHDF treatment at our neonatal intensive care unit between January 2014 and December 2017 were included in this study. Their demographic and clinical data were collected, and the efficacy and safety of CVVHDF was evaluated.

Results

A total of nine continuous RRT (CRRT) sessions as CVVHDF were performed in eight newborns with a diagnosis of urea cycle defect (n = 5), maple syrup urine disease (n = 2), or methylmalonic acidemia (n = 1). The mean age at admission was 10 ± 8.6 days (range: 3–28 days). The mean plasma levels of ammonium were 1120 ± 512.6 mg/dL and 227.5 ± 141.6 mg/dL before and at the end of the treatment, respectively. Plasma levels of leucine were 2053.5 ± 1282 µmol/L and 473.5 ± 7.8 µmol/L before and at the end of the treatment, respectively. The CVVHDF duration was 32.3 ± 11.1 h (median: 37 h; range: 16–44 h), and the mean length of hospitalization was 14.6 ± 12.9 days. The mean duration of CVVHDF was 32.3 ± 11.1 h (range: 16–44 h). Circuit clotting was the most common observed complication (37.5%) and the survival rate was 50%. Among surviving patients, two developed severe and two developed mild mental and motor retardation.

Conclusion

CVVHDF is a CRRT modality that can be used to treat newborns with an inborn metabolic disease. Early diagnosis, commencement of specific medical therapy, diet, and extracorporeal support, if needed, are likely to result in improved short and long-term outcomes.

Clinical effectiveness of MARS treatment - multidirectional analysis of positive clinical response to treatment

Aim of the study

Liver failure is a life-threatening condition which often requires intensive care treatment. It is essential to quickly determine whether there are indications for extracorporeal liver support systems for the patient. The aims of the study were: to assess effectiveness of molecular adsorbent recirculating system (MARS) therapy based on selected clinical criteria, to analyze the moment of clinical response and to create a patient’s profile, who will benefit clinically from the treatment.

Material and methods

The analysis encompassed medical histories of 65 patients treated with MARS. Effectiveness of treatment was evaluated based on selected clinical parameters. Statistical analysis was performed based on medical data gathered.

Results

There were 158 cycles of MARS performed, with effectiveness documented in 57 cycles (36.6%). The first MARS session was effective in 43.1% of patients. They also more often responded to the second cycle (63.6% vs. 15.4%). A significant part of the analysis was devoted to create a profile of the patient in whom positive response can be expected. A low MELD score and low baseline white blood cells (WBC) level are statistically significant factors in multivariate analysis of selected features of positive clinical response to treatment.

Conclusions

MARS therapy is an effective form of treatment in a properly selected group of patients with liver failure. The first MARS session is the most effective one. It is also a good prognostic factor for further clinical response to treatment. Multifactorial analysis of positive clinical response to treatment enables to create a patient’s profile based on the lower baseline MELD score and WBC.

Suggested guidelines for the diagnosis and management of urea cycle disorders: First revision

In 2012, we published guidelines summarizing and evaluating late 2011 evidence for diagnosis and therapy of urea cycle disorders (UCDs). With 1:35 000 estimated incidence, UCDs cause hyperammonemia of neonatal (~50%) or late onset that can lead to intellectual disability or death, even while effective therapies do exist. In the 7 years that have elapsed since the first guideline was published, abundant novel information has accumulated, experience on newborn screening for some UCDs has widened, a novel hyperammonemia-causing genetic disorder has been reported, glycerol phenylbutyrate has been introduced as a treatment, and novel promising therapeutic avenues (including gene therapy) have been opened. Several factors including the impact of the first edition of these guidelines (frequently read and quoted) may have increased awareness among health professionals and patient families. However, under-recognition and delayed diagnosis of UCDs still appear widespread. It was therefore necessary to revise the original guidelines to ensure an up-to-date frame of reference for professionals and patients as well as for awareness campaigns. This was accomplished by keeping the original spirit of providing a trans-European consensus based on robust evidence (scored with GRADE methodology), involving professionals on UCDs from nine countries in preparing this consensus. We believe this revised guideline, which has been reviewed by several societies that are involved in the management of UCDs, will have a positive impact on the outcomes of patients by establishing common standards, and spreading and harmonizing good practices. It may also promote the identification of knowledge voids to be filled by future research.

Continuous Renal Replacement Therapy with High Flow Rate Can Effectively, Safely, and Quickly Reduce Plasma Ammonia and Leucine Levels in Children

Introduction: Peritoneal dialysis and continuous renal replacement therapy (CRRT) are the most frequently used treatment modalities for acute kidney injury. CRRT is currently being used for the treatment of several non-renal indications, such as congenital metabolic diseases. CRRT can efficiently remove toxic metabolites and reverse the neurological symptoms quickly. However, there is not enough data for CRRT in children with metabolic diseases. Therefore, we aimed a retrospective study to describe the use of CRRT in metabolic diseases and its associated efficacy, complications, and outcomes. Materials and Methods: We performed a retrospective analysis of the records of all patients admitted in the pediatric intensive care unit (PICU) for CRRT treatment. Results: Between December 2014 and November 2018, 97 patients were eligible for the present study. The age distribution was between 2 days and 17 years, with a mean of 3.77 ± 4.71 years. There were 13 (36.1%) newborn with metabolic diseases. The patients were divided into two groups: CRRT for metabolic diseases and others. There was a significant relationship between the groups, including age (p ≤ 0.001), weight (p = 0.028), blood flow rate (p ≤ 0.001); dialysate rate (p ≤ 0.001), and replacement rate (p ≤ 0.001). The leucine reduction rate was 3.88 ± 3.65 (% per hour). The ammonia reduction rate was 4.94 ± 5.05 in the urea cycle disorder group and 5.02 ± 4.54 in the organic acidemia group. The overall survival rate was 88.9% in metabolic diseases with CRRT. Conclusion: In particularly hemodynamically unstable patients, CRRT can effectively and quickly reduce plasma ammonia and leucine.

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

Renal replacement therapy in the neonatal intensive care unit

BACKGROUND

Renal replacement therapy (RRT) is becoming increasingly necessary for supporting critically ill neonates. Few studies have reported the use of RRT in the neonatal intensive care unit (NICU). Therefore, we performed a retrospective study to describe the use of RRT in our NICU and its associated efficacy, complications, and outcomes.

METHODS

We identified patients requiring RRT between January 2009 and January 2017. Demographic data, mode of RRT, and associated factors were recorded. Efficacy was calculated as the percentage reduction in the blood urea nitrogen (BUN) or toxic metabolite level after 24 h of RRT. Complications including hypotension, electrolyte disturbance, and technical and catheter-related complications were documented. Measures of clinical outcome included in-hospital survival, presence of neurological sequelae, and chronic kidney disease. The chi-square test and Mann-Whitney U test were used for categorical and continuous variables, respectively.

RESULTS

We included 17 neonates in our study. The median gestational age at birth was 37 weeks (32-39 weeks), and the median birth weight was 2.7 kg (1.5-3.6 kg). Twelve neonates, including three with inborn errors of metabolism (IEM), received continuous RRT (CRRT), and five neonates underwent peritoneal dialysis (PD). The percentage reduction in ammonia in neonates with IEM who received CRRT was 87.2% at 24 h. The percentage reductions in BUN in the non-IEM neonates in the CRRT and PD groups were 33.7% and 23.7% at 24 h, respectively. The main complication was electrolyte disturbance including hypokalemia, hypocalcemia, and hypophosphatemia. All neonates with IEM survived, whereas the mortality rates for the non-IEM neonates in the CRRT and PD groups were 78% and 80%, respectively.

CONCLUSION

Our study findings reveal RRT to be feasible, even in preterm neonates with low birth weight. CRRT had a higher efficacy level, particularly in neonates with IEM, and the complications encountered were transient and correctable.

Continuous Renal Replacement Therapy: Who, When, Why, and How

Continuous renal replacement therapy (CRRT) is commonly used to provide renal support for critically ill patients with acute kidney injury, particularly patients who are hemodynamically unstable. A variety of techniques that differ in their mode of solute clearance may be used, including continuous venovenous hemofiltration with predominantly convective solute clearance, continuous venovenous hemodialysis with predominantly diffusive solute clearance, and continuous venovenous hemodiafiltration, which combines both dialysis and hemofiltration. The present article compares CRRT with other modalities of renal support and reviews indications for initiation of renal replacement therapy, as well as dosing and technical aspects in the management of CRRT.

The impact of continuous renal replacement therapy for metabolic disorders in infants

BACKGROUND

While Continuous Renal Replacement Therapy (CRRT) is a well established treatment modality for patients with acute kidney insufficiency (AKI), it is now also being used for the management of various illnesses such as acute metabolic disorders presenting with hyperammonemia and elevated leucine levels. Herein, we aimed to describe our experience with CRRT in treatment of acute decompensation of 14 patients with a diagnosis of metabolic disorder who has been admitted to our pediatric intensive care unit (PICU) in the last year.

METHODS

Patients who have had life threatening acute metabolic crisis due to various metabolic disorders and were treated with continuous renal replacement therapy (CRRT) were evaluated retrospectively.

RESULTS

Between November 2014 and December 2015, 14 patients were found to have received CRRT for various metabolic disorders in the PICU. Ten patients had hyperammonemia and four patients had elevated leucine levels. Nine patients were male and five were female. The age interval was between 2 days and 18 months, with a mean of 5.5 ± 7.4 months. The weight distribution was between 2.5 and 18 kg, with a mean of 7.3 ± 5.6 kg. Eleven patients received continuous veno-venous hemodiafiltration (CVVHDF), and 3 patients with MSUD received continuous veno-venous hemodialysis (CVVHD). All patients have received high throughput hemodialysis and hemofiltration. The dialyzate rate was set to be minimum 4042 ml/h/1.73 m², and maximum 12,900 ml/h/1.73 m². Hemofiltration was performed with a replacement rate of 40-76 ml/kg/h. The average CRRT duration was 16.6 ± 15.6 h.

CONCLUSIONS

We suggest that CRRT is an efficient method that can be used in hyperammonemia and elevated leucine levels which are metabolic emergencies.

Veno-Venous Extracorporeal Membrane Oxygenation for Continuous Renal Replacement in a Neonate with Propionic Acidemia

The usual indications for extra corporeal membrane oxygenation (ECMO) are for respiratory or cardiac failure. Although continuous renal replacement therapy (CRRT) is frequently used when patients are on ECMO, the need for CRRT as the primary indication for ECMO is rare. A case of a neonate placed onto veno-venous ECMO for the use of CRRT to treat hyperammonemia from propionic acidemia is presented.

Fluid overload and outcomes in neonates receiving continuous renal replacement therapy

BACKGROUND

Continuous renal replacement therapy (CRRT) has emerged as the modality of choice for the management of high-risk neonates with acute kidney injury (AKI), inborn errors of metabolism and multi-organ dysfunction. The aim of this study was to evaluate fluid overload (FO) and investigate the factors associated with outcomes in neonates undergoing CRRT.

METHODS

We retrospectively reviewed the medical records of 34 neonates with AKI who were admitted to the neonatal intensive care unit (NICU) of Samsung Medical Center, Seoul, Republic of Korea between January 2007 and December 2014 where they underwent at least 24 h of CRRT.

RESULTS

The survival rates of patients with an FO of ≥30 % at the time of CRRT initiation were lower than those of patients with an FO of <30 % at the same time-point. Univariate Cox regression analysis revealed that a higher percentage FO at CRRT initiation and decreased urine output at the end of CRRT were associated with mortality, and multivariate Cox regression analysis indicated that mortality was associated with decreased urine output at the end of CRRT. Univariate linear regression analysis revealed that the length of hospital stay was associated with higher levels of serum creatinine at CRRT initiation, longer stay in the NICU prior to initiation of CRRT, longer duration of CRRT and lower body weight at the time of NICU admission.

CONCLUSIONS

Neonates with a higher percentage FO and higher levels of serum creatinine at CRRT initiation showed poor outcomes. Early initiation of CRRT before the development of severe FO or azotemia might improve the outcomes of neonates requiring CRRT.

The Role of RRT in Hyperammonemic Patients

Hyperammonemia is an important cause of cerebral edema in both adults with liver failure and children with inborn errors of metabolism. There are few studies that have analyzed the role of extracorporeal dialysis in reducing blood ammonia levels in the adult population. Furthermore, there are no firm guidelines about when to implement RRT, because many of the conditions that are characterized by hyperammonemia are extremely rare. In this review of existing literature on RRT, we present the body's own mechanisms for clearing ammonia as well as the dialytic properties of ammonia. We review the available literature on the use of continuous venovenous hemofiltration, peritoneal dialysis, and hemodialysis in neonates and adults with conditions characterized by hyperammonemia and discuss some of the controversies that exist over selecting one modality over another.

Smaller circuits for smaller patients: improving renal support therapy with Aquadex™

BACKGROUND

Providing renal support for small children is very challenging using the machinery currently available in the United States. As the extracorporeal volume (ECV) relative to blood volume increases and the state of critical illness worsens, the chance for instability during continuous renal replacement therapy (CRRT) initiation also increases. CRRT machines with smaller ECV could reduce the risks and improve outcomes.

METHODS

We present a case series of small children (n = 12) who received continuous venovenous hemofiltration (CVVH) via an Aquadex™ machine (ECV = 33 ml) with 30 ml/kg/h of prereplacement fluids at Children's of Alabama between December 2013 and April 2015. We assessed in vitro fluid precision using the adapted continuous veno-venous hemofiltration (CVVH) system.

RESULTS

We used 101 circuits over 261 days to provide CVVH for 12 children (median age 30 days; median weight 3.4 kg). Median CVVH duration was 14.5 days [interquartile range (IQR) = 10; 22.8 days]. Most circuits were routinely changed after 72 h. Five of 101 (5 %) initiations were associated with mild transient change in vital signs. Complications were infrequent (three transient cases of hypothermia, three puncture-site bleedings, one systemic bleed, and one right atrial thrombus). Most patients (7/12, 58 %) were discharged from the intensive care unit; six of them (50 %) were discharged home.

CONCLUSIONS

CRRT machines with low ECV can enable clinicians to provide adequate, timely, safe, and efficient renal support to small, critically ill infants.

Experience of Circuit Survival in Extracorporeal Continuous Renal Replacement Therapy Using Small-Calibre Venous Cannulae

OBJECTIVES

To describe an experience of circuit survival in extracorporeal continuous renal replacement therapy using small-calibre (< 7 French gauge [F]) venous cannulae.

DESIGN

An observational study.

SETTING

A multidisciplinary, university-affiliated PICU.

SUBJECTS

Case note review of all continuous renal replacement therapy episodes (1998-2010), which used vascular access cannulae of an external diameter less than 7F, was performed.

MEASUREMENTS AND MAIN RESULTS

Forty-nine patients underwent continuous renal replacement therapy treatment during which circuit blood flow was delivered using either 5F or 6.5F double-lumen cannulae. One hundred thirty-nine circuits were employed (median per patient, 2; interquartile range, 1-3) in providing 4,903 hours of therapy (median duration of therapy, 43 hr; interquartile range, 22-86 hr); allowing for censoring, the median circuit survival time was 40 hours (95% CI, 28-66). Eighty-one circuits (58%) failed because of clotting/technical problems, equating to a circuit failure rate of 16.5 (95% CI, 13.3-20.5) per 1,000 hours of continuous renal replacement therapy. The probability of a circuit surviving 40 hours or greater was 50% with 43% (95% CI, 34-53%) expected to survive 60 hours or more. No significant relationship between circuit survival and the calibre of the cannula deployed was identified; however, placement of venous access in an internal jugular vein was associated with improved circuit survival.

CONCLUSIONS

Contrary to previous reports, vascular access cannulae of a caliber less than 7F can support sufficiently prolonged continuous renal replacement therapy to make them a useful means of delivering renal support in neonates and small infants.

Renal Replacement Therapy in the Pediatric Critical Care Unit

Renal replacement therapy is becoming more prevalent in the pediatric intensive care units for a large variety of disease states, including multiorgan dysfunction syndrome, fluid overload, and electrolyte imbalance. Three modalities-continuous renal replacement therapy, hemodialysis, and peritoneal dialysis-are commonly used. When deciding among the three therapies, there are several advantages and disadvantages of each modality that must be considered. This manuscript provides an overview of each modality as well as its pros and cons.

Peritoneal dialysis in an extremely low-birth-weight infant with acute kidney injury

Critically ill neonates are at high risk for acute kidney injury (AKI). Renal supportive therapy (RST) can be an important tool for supporting critically ill neonates with AKI, particularly in cases of oliguria and fluid overload. There are few reports of RST for management of oligo-anuric AKI in the extremely low-birth-weight infant weighing <1000 g. We report successful provision of peritoneal dialysis (PD) to an 830-g neonate with oligo-anuric AKI through adaptation of a standard pediatric acute PD catheter.

Pharmacokinetic assessment in patients receiving continuous RRT: perspectives from the Kidney Health Initiative

The effect of AKI and modern continuous RRT (CRRT) methods on drug disposition (pharmacokinetics) and response has been poorly studied. Pharmaceutical manufacturers have little incentive to perform pharmacokinetic studies in patients undergoing CRRT because such studies are neither recommended in existing US Food and Drug Administration (FDA) guidance documents nor required for new drug approval. Action is urgently needed to address the knowledge deficit. The Kidney Health Initiative has assembled a work group composed of clinicians and scientists representing academia, the FDA, and the pharmaceutical and dialysis industries with expertise related to pharmacokinetics, AKI, and/or CRRT. The work group critically evaluated key considerations in the assessment of pharmacokinetics and drug dosing in CRRT, practical constraints related to conducting pharmacokinetic studies in critically ill patients, and the generalizability of observations made in the context of specific CRRT prescriptions and specific patient populations in order to identify efficient study designs capable of addressing the knowledge deficit without impeding drug development. Considerations for the standardized assessment of pharmacokinetics and development of corresponding drug dosing recommendations in critically ill patients with AKI receiving CRRT are proposed.

Renal replacement therapy in neonates

The incidence of acute kidney injury (AKI) has steadily increased in the last decade in neonates and infants. Despite the extensive proposed pharmacologic approaches to treat or prevent AKI, renal replacement therapy is the only available therapeutic approach to manage the consequences of significant AKI and maintain electrolyte homeostasis and fluid balance in infants with AKI. The objective of this article is to summarize the different approaches and modalities of renal replacement therapy in neonatal intensive care units.

Citrate anticoagulation during continuous renal replacement therapy in pediatric critical care

OBJECTIVE

To provide the pediatric intensivist an in-depth understanding of citrate as regional anticoagulant during continuous renal replacement therapy.

DATA SOURCES AND DATA SELECTION

We searched the PubMed.gov database using the initial key words: citrate anticoagulation [title] AND continuous; citrate [title] AND pediatric AND continuous; prospective pediatric renal replacement AND citrate; and regional citrate anticoagulation. Additional searchers were performed using EMBASE, CINAHL, and SCOPUS with similar keywords and limits. Further articles were gathered from bibliographic references of relevant studies and reviews. Only articles published in English were reviewed.

DATA EXTRACTION AND DATA SYNTHESIS

In the pediatric population, there are no prospective interventional or randomized studies comparing regional versus systemic anticoagulation. However, there are 11 (retrospective and prospective observational studies) in the pediatric population using citrate anticoagulation. These studies have shown that regional citrate anticoagulation in the pediatric population can be effective, provide equivalent circuit survival, and decrease bleeding compared with heparin anticoagulation. In the adult population, there are six prospective randomized controlled trials comparing the efficacy of regional citrate anticoagulation versus heparin. Two systematic reviews with meta-analysis of these six trials have been performed. The adult data on the use of regional citrate anticoagulation during continuous renal replacement therapy show a decreased risk of bleeding and at the least equivalent circuit survival as compared to heparin. Current pediatric and adult studies support regional citrate anticoagulation as an effective alternative to systemic heparin anticoagulation in most patient populations.

CONCLUSIONS

Continuous renal replacement therapy is the most common modality of renal replacement in the critical care setting. Regional anticoagulation is an ideal option in a critically ill child after recent surgery or with coagulopathy. Therefore, regional citrate anticoagulation in the pediatric critical care population requiring renal replacement therapy is commonly employed. Complications of citrate anticoagulation can be avoided with a greater understanding of the properties and clearance of citrate. Continued reporting of observational data and the development of prospective multicenter trials using citrate anticoagulation are needed to ensure safe and standardized care in the pediatric population.

A biphasic dialytic strategy for the treatment of neonatal hyperammonemia

BACKGROUND

Neonates with inborn errors of metabolism (IEM) often develop hyperammonemia which, if not corrected quickly, may result in poor neurologic outcomes. As pharmacologic therapy cannot rapidly lower ammonia levels, dialysis is frequently required. Both hemodialysis (HD) and standard-dose continuous renal replacement therapy (CRRT) are effective; however, HD may be followed by post-dialytic ammonia rebound, and standard-dose CRRT may not effect a rapid enough decrease in ammonia levels.

CASE-DIAGNOSIS/TREATMENT

We present two cases of IEM-associated neonatal hyperammonemia in which we employed a biphasic, high-dose CRRT treatment strategy, initially using dialysate flow rates of 5,000 mL/h (approximately 40,000 mL/h/1.73 m(2)) in order to rapidly decrease ammonia levels, then decreasing the dialysate flow rates to 500 mL/h (approximately 4,000 mL/h/1.73 m(2)) in order to prevent ammonia rebound.

CONCLUSIONS

This biphasic dialytic treatment strategy for neonatal hyperammonemia effected rapid ammonia reduction without rebound and accomplished during a single dialysis run without equipment changes.