Renal failure and renal replacement therapy

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.

A retrospective analysis: the outcome of renal replacement therapies in critically ill children

OBJECTIVE

A few pediatric studies were present which focused on renal replacement therapy used for critically ill children. This research aimed to determine the ratio of utilization of intermittent hemodialysis, continuous renal replacement therapy, and peritoneal dialysis, and to study the properties and outcomes of critically ill pediatric patients who underwent renal replacement therapy.

METHODS

Critically ill children admitted to the intensive care unit and received renal replacement therapy from February 2020 to May 2022 were included. The children were divided into three groups: hemodialysis, continuous renal replacement therapy, and peritoneal dialysis.

RESULTS

A total of 37 patients (22 boys and 15 girls) who received renal replacement therapy met the criteria for this study. Continuous renal replacement therapy was used in 43%, hemodialysis in 38%, and peritoneal dialysis in 19%. In all, 28 (73%) children survived and 9 (27%) died in intensive care unit. The mean systolic blood pressure was significantly lower among children who received continuous renal replacement therapy (p<0.001). The need for inotropic medications and a higher PRISM III score were found to be the greatest indicators of mortality.

CONCLUSION

The outcome of children receiving renal replacement therapy seems to be related to their needs for vasoactive drugs and the severity of the underlying disease in the continuous renal replacement therapy group relative to the other groups.

Outcomes associated with the use of renal replacement therapy in children receiving extracorporeal membrane oxygenation after heart surgery: a multi-institutional analysis

BACKGROUND

The primary objective of this investigation was to study the association between renal replacement therapy (RRT) and outcomes in children receiving extracorporeal membrane oxygenation (ECMO).

METHODS

Patients aged ≤18 years receiving ECMO before or after a pediatric heart operation at a Pediatric Health Information System (PHIS)-participating hospital (2004-2013) were included. The associations between RRT and study outcomes were computed using multivariate logistic regression analysis.

RESULTS

A total of 3,502 patients from 43 hospitals qualified for inclusion. Of these, 484 (14 %) patients received RRT at some point during their hospital stay. After adjusting for patient and center characteristics, the odds of mortality were significantly higher in the RRT group (OR: 1.86, 95 % CI: 1.46- 2.37, p < 0.0001). However, there were considerable reductions in adjusted odds of mortality, compared to unadjusted odds of mortality. In adjusted models, length of ECMO was longer by 0.81 days (95 % CI: 0.13- 1.49, p = 0.02) in patients receiving RRT.

CONCLUSIONS

We demonstrated worsening outcomes in children receiving ECMO with RRT compared to children receiving ECMO without RRT. Although the results could reflect confounding by severity of illness, they provide a rationale for prospective testing of use of RRT in critically ill children receiving ECMO with heart surgery.

Temporary peritoneal dialysis in newborns and children: a single-center experience over five years

AIM

To evaluate the indications, complications, and outcomes of temporary peritoneal dialysis (TPD) in children with acute renal failure (ARF).

PATIENTS AND METHODS

All patients undergoing TPD between February 2006 and January 2011 in a children's hospital were included in the study. Patient characteristics, indications, complications, and duration of TPD (DPD), requirement of re-operation, length of stay, presence of sepsis, and outcome were recorded.

RESULTS

There were 21 newborns (14 prematures), 9 infants, and 9 children. The main nephrotoxic agents were gentamicin (n = 7), netilmisin (n = 5), vancomycin (n = 3), and ibuprophen (n = 3). Patients with multiorgan failure (n = 9) had significantly higher blood urea nitrogen (BUN) and creatinine levels than those without multiorgan failure (n = 30) [BUN: 94 ± 27.3 vs. 34.3 ± 4.9) and creatinine: 4.1 ± 0.8 vs. 1.9 ± 0.2)]. The mean DPD was longer in mature patients than in prematures (newborn: 3.7; children: 7.1). Nine complications were observed (23%) (leakage in three and poor drainage in six patients). Twenty-five patients (64.1%) responded to TPD treatment and were discharged, and 14 patients (10 newborns and 7 of them were premature) died (35.9%). Mortality rate was higher in prematures (n = 7) and patients with a history of nephrotoxic agent (n = 10).

CONCLUSION

TPD is effective especially in neonates with ARF and it is a reliable alternative to the hemodialysis or other continuous renal replacement therapies but it is not free of complications. It has limited effects, particularly in patients with multiorgan failure.

Hemofiltration circuit use beyond 72 hours in pediatric continuous renal replacement therapy

INTRODUCTION

During continuous renal replacement therapy (CRRT), hemofiltration circuits ideally are changed after 72 h since tubing integrity and flow rates are not guaranteed after this time interval. This potential risk must be weighed against the risk of hypotension during elective circuit changes in the unstable patient. The aim of this study was to examine the safety of circuits used beyond 72 h in pediatric CRRT.

METHODS

A retrospective chart review of all patients who underwent CRRT at our institution from January 2003 to October 2005 was performed. Procedures were divided into standard (≤72 h) and extended (>72 h) circuit duration groups. Patients who had more than one CRRT procedure (n=13) were excluded from study.

RESULTS

71 CRRT procedures were performed for 71 patients. A total of 254 circuits were used, of which 64 (25%) were used for >72 h. For circuits >72 h, the mean duration of use was 5.5 days ± 1.8 (range 4-11). There were no differences between the groups in age (p=0.12), weight (p=0.48), diagnosis (p=0.21), CRRT indication (p=0.07), CRRT mode (p=0.37), anticoagulation (p=0.53), blood flow rate (p=0.06), replacement rate (p=0.50) or dialysate rate (p=0.89). There were no incidents of membrane or tubing rupture in either group.

CONCLUSIONS

Use of hemofiltration circuits beyond 72 h may be safe in pediatric patients undergoing CRRT without increased risk of tubing rupture. Our data suggest a need to redefine the limits of prolonged circuit use in pediatric CRRT.

Renal replacement therapy in critically ill patients receiving extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) is a lifesaving procedure used in neonates, children, and adults with severe, reversible, cardiopulmonary failure. On the basis of single-center studies, the incidence of AKI occurs in 70%-85% of ECMO patients. Those with AKI and those who require renal replacement therapy (RRT) are at high risk for mortality, independent of potentially confounding variables. Fluid overload is common in ECMO patients, and is one of the main indications for RRT. RRT to maintain fluid balance and metabolic control is common in some but not all centers. RRT on ECMO can be performed via an in-line hemofilter or by incorporating a standard continuous renal replacement machine into the ECMO circuit. Both of these methods require specific technical considerations to provide safe and effective RRT. This review summarizes available epidemiologic data and how they apply to our understanding of AKI pathophysiology during ECMO, identifies indications for RRT while on ECMO, reviews technical elements for RRT application in the setting of ECMO, and finally identifies specific research-focused questions that need to be addressed to improve outcomes in this at-risk population.

Recovery of renal function and survival after continuous renal replacement therapy during extracorporeal membrane oxygenation

OBJECTIVE

To assess the outcome of pediatric patients supported by concomitant extracorporeal membrane oxygenation (ECMO) and continuous renal replacement therapy (CRRT).

DESIGN, SETTING, AND PATIENTS

Acute kidney injury is associated with mortality in ECMO patients. CRRT in patients on ECMO provides an efficient and potentially beneficial method of acute kidney injury management. Concern that concomitant CRRT use increases the risk of developing anuria and chronic renal failure limits its use in some centers. We hypothesized that development of chronic renal failure is rare with concurrent ECMO and CRRT. We evaluated the outcomes of 154 ECMO/CRRT patients cared for over 10 yrs at a referral pediatric medical center.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Among 68 (44%) ECMO/CRRT survivors, 45 were assigned a pediatric risk, injury, failure, loss and end-stage (referred to as "pRIFLE") score at CRRT initiation. Seventeen (38%) patients met the criteria for Risk, 15 (33%) for Injury, and 10 (22%) for Failure. Two Failure patients later met End stage criteria. Of all survivors, 18 (26%) required ongoing renal replacement therapy (15 required continuous veno-venous hemofiltration, two required peritoneal dialysis, and one patient required intermittent hemodialysis) post ECMO discontinuation. Renal recovery occurred in 65 (96%) of 68 patients before discharge. One neonatal patient had sepsis-induced renal injury on transfer, but had normal creatinine 1 month later. Two pediatric patients with vasculitis and primary renal disease at presentation (both meeting Failure criteria) developed end-stage renal disease. One received peritoneal dialysis and subsequent renal transplant. The other has diminished function without need for renal replacement therapy.

CONCLUSION

In the absence of primary renal disease, chronic renal failure did not occur after concurrent use of CRRT with ECMO. Concern for precipitating chronic renal failure by using CRRT during ECMO is not substantiated by this large single-center experience. Consistent with previous reports, mortality is higher in patients receiving concomitant CRRT and ECMO compared with those receiving ECMO alone. Mortality is similar to patients requiring CRRT who are not on ECMO. Additional studies are warranted to determine the optimal role of CRRT use in ECMO patients.

Interventions for haemolytic uraemic syndrome and thrombotic thrombocytopenic purpura

BACKGROUND

Haemolytic uraemic syndrome (HUS) and thrombotic thrombocytopenic purpura (TTP) are related conditions with similar clinical features of variable severity. Survival of patients with HUS and TTP has improved greatly over the past two decades with improved supportive care for patients with HUS and by the use of plasma exchange (PE) with fresh frozen plasma (FFP) for patients with TTP. Separate pathogenesis of these two disorders has become more evident, but management overlaps.

OBJECTIVES

To evaluate the benefits and harms of different interventions for HUS and TTP separately, in patients of all ages.

SEARCH STRATEGY

We searched MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), conference proceedings, reference lists of articles and text books and contact with investigators were used to identify relevant studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) evaluating any interventions for HUS or TTP in patients of all ages.

DATA COLLECTION AND ANALYSIS

Three authors independently extracted data and evaluated study reporting quality using standard Cochrane criteria. Analysis was undertaken using a random effects model and results expressed as risk ratio (RR) and 95% confidence intervals (CI).

MAIN RESULTS

For TTP, we found six RCTs (331 participants) evaluating PE with FFP as the control. Interventions tested included antiplatelet therapy (APT) plus PE with FFP, FFP transfusion and PE with cryosupernatant plasma (CSP). Two studies compared plasma infusion (PI) to PE with FFP and showed a significant increase in failure of remission at two weeks (RR 1.48, 95% 1.12 to 1.96) and all-cause mortality (RR 1.91, 95% 1.09 to 3.33) in the PI group. Seven RCTs were undertaken in children with HUS. None of the assessed interventions used (FFP transfusion, heparin with or without urokinase or dipyridamole, shiga toxin binding protein and steroids) were superior to supportive therapy alone, for all-cause mortality, neurological/extrarenal events, renal biopsy changes, proteinuria or hypertension at the last follow-up visit. Bleeding was significantly higher in those receiving anticoagulation therapy compared to supportive therapy alone (RR 25.89, 95% CI 3.67 to 182.83).

AUTHORS' CONCLUSIONS

PE with FFP is still the most effective treatment available for TTP. For patients with HUS, supportive therapy including dialysis is still the most effective treatment. All studies in HUS have been conducted in the diarrhoeal form of the disease. There were no RCTs evaluating the effectiveness of any interventions on patients with atypical HUS who have a more chronic and relapsing course.

Dialysis and pediatric acute kidney injury: choice of renal support modality

Dialytic intervention for infants and children with acute kidney injury (AKI) can take many forms. Whether patients are treated by intermittent hemodialysis, peritoneal dialysis or continuous renal replacement therapy depends on specific patient characteristics. Modality choice is also determined by a variety of factors, including provider preference, available institutional resources, dialytic goals and the specific advantages or disadvantages of each modality. Our approach to AKI has benefited from the derivation and generally accepted defining criteria put forth by the Acute Dialysis Quality Initiative (ADQI) group. These are known as the risk, injury, failure, loss, and end-stage renal disease (RIFLE) criteria. A modified pediatrics RIFLE (pRIFLE) criteria has recently been validated. Common defining criteria will allow comparative investigation into therapeutic benefits of different dialytic interventions. While this is an extremely important development in our approach to AKI, several fundamental questions remain. Of these, arguably, the most important are "When and what type of dialytic modality should be used in the treatment of pediatric AKI?" This review will provide an overview of the limited data with the aim of providing objective guidelines regarding modality choice for pediatric AKI. Comparisons in terms of cost, availability, safety and target group will be reviewed.

Metabolic disturbances following the use of inadequate solutions for hemofiltration in acute renal failure

Continuous renal replacement therapy (CRRT) has become an important supportive therapy for critically ill children with acute renal failure. In Turkey, commercially available diafiltration and replacement fluids cannot be found on the market. Instead, peritoneal dialysis fluids for dialysis and normal saline as replacement fluid are used. The first objective of this study was to examine metabolic complications due to CRRT treatments. The second objective was to determine demographic characteristics and outcomes of patients who receive CRRT. We did a retrospective chart review of all pediatric patients treated with CRRT between February and December 2004. Thirteen patients received CRRT; seven survived (53.8%). All patients were treated with continuous venovenous hemodiafiltration. Median patient age was 71.8 +/- 78.8 (1.5-180) months. Hyperglycemia occurred in 76.9% (n=10), and metabolic acidosis occurred in 53.8% (n=7) of patients. Median age was younger (48.8 vs.106.2 months), median urea level (106.2 vs. 71 mg/dl) and percent fluid overload (FO) (17.2% vs. 7.6%, respectively) were higher, and CRRT initiation time was longer (8.6 vs 5.6 days) in nonsurvivors vs. survivors for all patients, although these were not statistically significant. CRRT was stopped in all survivors, and four nonsurvivors (67%) were on renal replacement therapy at the time of death. Hyperglycemia and metabolic acidosis were frequently seen in CRRT patients when commercially available diafiltration fluids were not available. Using peritoneal dialysis fluid as dialysate is not a preferable solution. Early initiation of CRRT offered survival benefits to critically ill pediatric patients. Mortality was associated with the primary disease diagnosis.

Continuous renal replacement therapy in patients following traumatic injury

In critically injured patients, the incidence of acute renal failure has been reported to occur in as many as 31% of patients. The use of CRRT modalities for patients following traumatic injuries is becoming more common, albeit slowly, and this therapy may impact upon long-term recovery of renal function and mortality. Historical studies investigating the early use of intermittent dialysis reported significant improvement in survival in patients who were dialyzed earlier and more vigorously than in control subjects. Early trauma patients also showed improved survival following war injuries when dialyzed prophylactically. Although there is a growing acceptance in favor of earlier renal replacement therapy, the published consensus and the practice in many centers has been to dialyze/filter relatively ill rather than relatively healthy patients. The R Adams Cowley Shock Trauma Center (STC) in Baltimore, Maryland, USA, admits over 8,000 trauma patients each year. Within the STC, a program of continuous renal replacement therapy was established in the early 1980's. We review both historical and current literature on the use of renal replacement therapies after traumatic injury, and suggest some future areas of investigation and indications for these modalities.

Extracorporeal Therapies in the Treatment of Sepsis: Experience and Promise

Desire to restore the balance of body elements has enamored physicians since the ancient practice of bloodletting. More recently, extracorporeal techniques have been employed in both adults and children in treating sepsis. Extracorporeal therapies include continuous renal replacement (CRRT), plasma-based removal techniques, and extracorporeal membrane oxygenation (ECMO). These treatments could theoretically 1) provide immunohomeostasis of pro- and anti-inflammatory cytokines and other sepsis mediators, 2) decrease organ microthrombosis through removal of pro-coagulant factors and modulating the impaired septic coagulation response in sepsis, and 3) provide mechanical support of organ perfusion during the acute septic episode to allow time for response to traditional sepsis therapies and antimicrobials. CRRT is beneficial in managing fluid overload and acute renal failure in sepsis. Removal of sepsis mediators through the technique is variable, and the outcome impact of CRRT on sepsis has not been definitively determined. High-flow CRRT has demonstrated benefit in septic adults. Intriguing early results suggest that plasma exchange could improve outcomes in both adults and children. Based on experience, ECMO is recommended for refractory septic shock in neonates and should be considered for use in children. Ongoing trials may help determine whether the promise of extracorporeal therapies translates into outcome improvement in septic children.

Removal of inflammatory cytokines and endotoxin by veno-venous continuous renal replacement therapy for burned patients with sepsis

OBJECTIVE

To evaluate the effect of veno-venous continuous renal replacement therapy (CRRT) on the plasma levels of endotoxin and cytokines in severely burned patients with sepsis.

METHODS

Twenty adult severely burned patients with sepsis were studied. For the diagnosis of sepsis, patients were randomly divided into CRRT (n=10) and Control (n=10). Both groups received conventional therapy after admission. Veno-venous CRRT was administered to 10 patients in the CRRT group whenever patients were determined to be septic. The plasma level of endotoxin, TNF-alpha, IL-1 beta, IL-6 and IL-8 were measured at 0, 1, 2, 6, 12, 36 and 60 h after CRRT initiation, and at 0, 12, 36 and 60 h after the patients were diagnosed as having sepsis in the Control group.

MAIN RESULTS

Plasma level of endotoxin and all the cytokines after CRRT initiation were significantly lower than those before the treatment (P<0.01). The serial change of endotoxin, IL-1 beta, IL-6 and IL-8 was significantly lower at 12, 36 and 60 h after treatment compared with Control groups (P<0.01). A significant decrease in plasma TNF-alpha levels was seen at 36 and 60 h after treatment compared with Control groups (P<0.01).

CONCLUSION

Plasma endotoxin and cytokines (TNF-alpha, IL-1 beta, IL-6 and IL-8) can be removed effectively with CRRT in severely burned patients with sepsis.

Acute renal failure in children and infants

PURPOSE OF REVIEW

This review provides an overview of various topics related to acute renal failure and summarizes the results of recent advancements of particular significance in the care of children with acute renal failure.

RECENT FINDINGS

Over the past two decades, the treatment and prognosis of children with acute renal failure has notably shifted owing to advances in continuous treatment modalities, improvements in vascular access, and increased acknowledgment and understanding of the importance of optimizing nutritional support.

SUMMARY

After discussing the various causes of acute renal failure in children and infants, this review focuses on recent advancements in the management of acute renal failure, including acute dialysis modalities and continuous renal replacement therapy.

Anticoagulation Monitoring Part 2: Unfractionated Heparin and Low-Molecular-Weight Heparin

OBJECTIVE

To review the availability, mechanisms, limitations, and clinical application of point-of-care (POC) devices used in monitoring anticoagulation with unfractionated heparin (UFH) and low-molecular-weight heparins (LMWHs).

DATA SOURCES

Articles were identified through a MEDLINE search (1966–August 2004), device manufacturer Web sites, additional references listed in articles and Web sites, and abstracts from scientific meetings.

STUDY SELECTION AND DATA EXTRACTION

English-language literature from clinical trials was reviewed to evaluate the accuracy, reliability, and clinical application of POC monitoring devices.

DATA SYNTHESIS

The activated partial thromboplastin time (aPTT) and activated clotting time (ACT) are common tests for monitoring anticoagulation with UFH. Multiple devices are available for POC aPTT, ACT, and heparin concentration testing. The aPTT therapeutic range for UFH will vary depending upon the reagent and instrument employed. Although recommended by the American College of Chest Physicians Seventh Conference on Antithrombotic and Thrombolytic Therapy, establishing a heparin concentration–derived therapeutic range for UFH is rarely performed. Additional research evaluating anti-factor Xa monitoring of LMWHs using POC testing is necessary.

CONCLUSIONS

Multiple POC devices are available to monitor anticoagulation with UFH. For each test, there is some variability in results between devices and between reagents used in the same device. Despite these limitations, POC anticoagulation monitoring of UFH using aPTT and, more often, ACT is common in clinical practice, particularly when evaluating anticoagulation associated with interventional cardiology procedures and cardiopulmonary bypass surgery.

Pediatric convective hemofiltration: Normocarb replacement fluid and citrate anticoagulation

BACKGROUND

Continuous venovenous hemofiltration (CVVH) may be preferable over continuous venovenous hemodialysis (CVVHD) in sepsis; however, CVVH use is limited by the lack of commercially produced bicarbonate replacement solutions in the United States. Anticoagulation used for hemofiltration traditionally has been either heparin or citrate based, but to date, citrate protocols have been used predominately in CVVHD. When CVVH has been used with citrate anticoagulation, replacement solutions have had to be custom made in the pharmacy.

METHODS

We describe a protocol used in a series of 9 children with sepsis who underwent CVVH with the use of a commercially available bicarbonate solution (Normocarb; Dialysis Solutions Inc, Richmond Hill, Ontario, Canada) and a commercially available citrate solution (Anticoagulant Citrate Dextrose Solution Formula A [ACD-A]; Baxter Health Care, Deerfield, IL). This simplified approach to citrate anticoagulation with CVVH used Normocarb as a prefilter replacement solution under provisions of the 1997 Food and Drug Administration Modernization Act.

RESULTS

All patients had acceptable levels of solute and ultrafiltration clearance with this approach. CVVH circuit life averaged 71 hours (range, 37 to 131 hours), influenced in part by the industry recommendation to change the circuit at 72 hours, whereas no complications from this protocol were identified.

CONCLUSION

Similar to CVVHD, this protocol is effective and simple in its components, using industry-produced solutions, avoiding the need for pharmacy-made solutions, and limiting cost and potential risk for compounding errors. Although not the purpose of this report, the patient survival rate was 55%.