Pediatric convective hemofiltration: Normocarb replacement fluid and citrate anticoagulation

Citrate anticoagulation and systemic heparin anticoagulation during continuous renal replacement therapy among critically-ill children

BAKCGROUND

The aim of this study was to evaluate the efficacy and safety of citrate versus heparin anticoagulation for CRRT in critically-ill children.

METHODS

This retrospective comparative cohort reviewed the clinical records of critically-ill children undergoing CRRT with either RCA or systemic heparin anticoagulation. The primary outcome measure was hemofilter survival time. Secondary outcomes included the comparison of complications and metabolic disorders.

RESULTS

A total of 131 patients (55 RCA and 76 systemic heparin) were included, in which a cumulative number of 280 hemofilters were used (115 in RCA with 5762 h total CRRT time, and 165 in systemic heparin with 6230 h total CRRT time). Hemofilter survival was significantly longer for RCA (51.0 h; IQR: 24-67 h) compared to systemic heparin (29.5 h; IQR, 17-48 h) (p = 0.002). Clotting-related hemofilter failure occurred in 9.6% of the RCA group compared to 19.6% in the systemic heparin group (p = 0.038). Citrate accumulation occurred in 4 (3.5%) of 115 RCA sessions. Hypocalcemia and metabolic alkalosis episodes were significantly more frequent in RCA recipients (35.7% vs 15.2%, p < 0.0001; 33.0% vs 19.4%, p = 0.009).

CONCLUSION

RCA is a safe and effective anticoagulation method for CRRT in critically-ill children and it prolongs hemofilter survival.

IMPACT

RCA is superior to systemic heparin for the prolongation of circuit survival (overall and for clotting-related loss) during CRRT. These data indicate that RCA can be used to maximize the effective delivery of CRRT in critically-ill patients admitted to the PICU. There are potential cost-saving implications from our results owing to benefits such as less circuit downtime and fewer circuit changes.

Selective Cytopheretic Device Use in Continuous Kidney Replacement Therapy in Children: A Cohort Study With a Historical Comparator

Rationale and Objective

Critically ill children with acute kidney injury (AKI) requiring continuous renal replacement therapy (CRRT) are at increased risk of death. The selective cytopheretic device (SCD) promotes an immunomodulatory effect at circuit-ionized calcium of <0.40 mmol/L. In an adult CRRT patient study, SCD-treated patients reported improved survival or dialysis independence. We reported safety data from children who received CRRT-SCD therapy and compared outcomes with a historic pediatric CRRT cohort.

Study Design

We performed 2 prospective multicenter studies to evaluate the safety and feasibility of SCD in critically ill children.

Setting and Participants

Four pediatric institutions enrolled children weighing 10 kg or more with AKI and multi-organ dysfunction receiving CRRT as the standard of care with the SCD-integrated post-CRRT membrane.

Exposure

Patients received CRRT-SCD with regional citrate anticoagulation for up to 7-10 days, or CRRT discontinuation, whichever came first.

Analytical Approach

We reported serious adverse events among patients and CRRT-SCD-related process and outcome variables. We compared survival to intensive care unit (ICU) discharge rates between the CRRT-SCD cohort and a matched cohort from the prospective pediatric CRRT registry, using odds ratios in multivariable analysis for factors associated with prospective pediatric CRRT patient ICU mortality. To validate these crude analyses, Bayesian logistic regression was performed to assess for attributable benefit-risk assessment of the SCD.

Results

Twenty-two patients received CRRT-SCD treatments. Fifteen serious adverse events were recorded; none were SCD-related. Seventeen patients survived till ICU discharge or day 60. Both multivariable and Bayesian analyses revealed a probable benefit of the addition of SCD. Fourteen of the 16 patients surviving ICU discharge reported a normal estimated glomerular filtration rate and no patient was dialysis dependent at 60 days.

Limitations

The study had a few limitations, such as (1) a small sample size in the SCD-PED cohort group; (2) unchanging historic control group; and (3) adverse events were not recorded in the control group.

Conclusions

The SCD therapy is feasible, safe, and demonstrates probable benefit for critically ill children who require CRRT for AKI.

A simplified protocol of regional citrate anticoagulation with phosphate-containing solutions in infants and children treated with continuous kidney replacement therapy

BACKGROUND

Regional citrate anticoagulation (RCA) is the preferred modality of anticoagulation used in continuous kidney replacement therapy (CKRT) in adults and less extensively in children. Potential metabolic complications limit widespread use in infants, neonates, and in children with liver failure.

METHODS

We report our experience with a simplified protocol in 50 critically ill children, infants, and neonates, some of them with liver failure, with commercially available solutions containing phosphorous and higher concentration of potassium and magnesium.

RESULTS

RCA allowed attainment of a mean filter lifetime of 54.5 ± 18.2 h, 42.5% of circuits lasted more than 70 h, and scheduled change was the most frequent cause of CKRT interruption. Patient Ca++ and circuit Ca++ were maintained in the target range with mean values of 1.15 ± 0.13 mmol/l and 0.38 ± 0.07 mmol/l, respectively. No session had to be stopped because of metabolic complications. The most frequent complications were hyponatremia, hypomagnesemia, and metabolic acidosis mostly related to primary disease and critical illness. No session had to be stopped because of citrate accumulation (CA). Transitory CA occurred in 6 patients and was managed without requiring RCA interruption. No patients with liver failure presented CA episodes.

CONCLUSIONS

In our experience, RCA with commercially available solutions was easily applied and managed in critically ill children, even in patients with low weight or with liver failure. Solutions containing phosphate and higher concentrations of magnesium and potassium allowed reduction of metabolic derangement during CKRT. Prolonged filter life was ensured with no detrimental effects on patients and reduced staff workload. A higher resolution version of the Graphical abstract is available as Supplementary information.

Hemolytic Uremic Syndrome-Induced Acute Kidney Injury Treated via Immunomodulation with the Selective Cytopheretic Device

INTRODUCTION

Shiga-toxin associated-hemolytic uremic syndrome (STEC-HUS) is a severe cause of acute kidney injury (AKI) in children. Although most children recover, about 5% die and 30% develop chronic renal morbidity. HUS pathophysiology includes activated neutrophils damaging vascular endothelial cells. Therapeutic immunomodulation of activated neutrophils may alter the progression of disease. We present 3 pediatric patients treated with the selective cytopheretic device (SCD).

METHODS

We describe a 12 y.o. (patient 1) and two 2 y.o. twins (patients 2 and 3) with STEC-HUS requiring continuous renal replacement therapy (CRRT) who were enrolled in two separate studies of the SCD.

RESULTS

Patient 1 presented with STEC-HUS causing AKI and multisystem organ failure and received 7 days of SCD and CRRT treatment. After SCD initiation, the patient had gradual recovery of multi-organ dysfunction, with normal kidney and hematologic parameters at 60-day follow-up. Patients 2 and 3 presented with STEC-HUS with AKI requiring dialysis. Each received 24 h of SCD therapy. Thereafter, both gradually improved, with normalization (patient 2) and near-normalization (patient 3) of kidney function at 60-day follow-up.

CONCLUSION

Immunomodulatory treatment with the SCD was associated with improvements in multisystem stigmata of STEC-HUS-induced AKI and was well-tolerated without any device-related adverse events.

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.

Semiautomated Regional Citrate Anticoagulation for Continuous Kidney Replacement Therapy: An Observational Study in Young Children

OBJECTIVES

To review use of semiautomated regional citrate anticoagulation (saRCA) for continuous kidney replacement therapy (CKRT) in young children.

DESIGN

Retrospective cohort study.

SETTING

Three independent PICUs.

PATIENTS

All consecutive children weighing less than 11 kg who received CKRT with saRCA from January 2015 to June 2020.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Twenty-one children weighing less than 11 kg underwent CKRT with saRCA. The total duration of the CKRT was 2,014 hours, with a total of 64 CKRT sessions. Citrate intoxication occurred in four of 64 CKRT sessions (6%). Citrate intoxication was consistently observed in the few CKRT sessions where the initial lactate concentration was greater than 4 mmol/L or the ratio of replacement fluid flow to citrate flow less than 50%. The rate of unscheduled interruptions of CKRT sessions was 25% (16/64).

CONCLUSIONS

We have used saRCA for CKRT in children weighing less than 11 kg. A strict protocol and intensive training are required to minimize complications.

Regional Citrate Anticoagulation and Systemic Anticoagulation during Pediatric Continuous Renal Replacement Therapy: A Systematic Literature Review

Background: Clotting is a major drawback of continuous renal replacement therapy (CRRT) performed on critically ill pediatric patients. Although anticoagulation is recommended to prevent clotting, limited results are available on the effect of each pharmacological strategy in reducing filter clotting in pediatric CRRT. This study defines which anticoagulation strategy, between regional citrate anticoagulation (RCA) and systemic anticoagulation with heparin, is safer and more efficient in reducing clotting, patient mortality, and treatment complications during pediatric CRRT. Methods: A systematic literature review was run considering papers published in English until December 2021 and describing patients’ and treatments’ complications in CRRT performed with heparin and RCA on patients aged less than 18 years. Results: Eleven studies were considered, cumulatively comprising 1.706 CRRT sessions (62% with systemic anticoagulation and 38% with RCA). Studies have consistently identified RCA’s superiority over systemic anticoagulation with heparin in prolonging circuit life. The pooled estimate (95% CI) of filter clotting risk showed that RCA is a protective factor for clotting risk (RR = 0.204). Conclusions: RCA has a potential role in prolonging circuit life and seems superior to systemic anticoagulation with heparin in decreasing the risk of circuit clotting during CRRT performed in critically ill pediatric patients.

Controversies in paediatric acute kidney injury and continuous renal replacement therapy: can paediatric care lead the way to precision acute kidney injury medicine?

PURPOSE OF REVIEW

Paediatric patients represent a unique challenge for providers managing acute kidney injury (AKI). Critical care for these children requires a precise approach to assessment, diagnostics and management.

RECENT FINDINGS

Primarily based on observational data, large epidemiologic datasets have demonstrated a strong association between AKI prevalence (one in four critically ill children) and poor patient outcome. Drivers of AKI itself are multifactorial and the causal links between AKI and host injury remain incompletely defined, creating a management paradigm primarily supportive in nature. The previous decades of research have focused primarily on elucidating the population-level epidemiologic signal of AKI and use of renal replacement therapy (RRT), but in order to reverse the course of the AKI 'epidemic', future decades will require more attention to the individual patient. A patient-level approach to AKI in children will require sophisticated approaches to risk stratification, diagnostics and targeted utilization of therapies (both supportive and targeted towards drivers of injury).

SUMMARY

In this review, we will summarize the past, present and future of AKI care in children, discussing the ongoing work and future goals of a personalized approach to AKI medicine.

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.

Use of the Selective Cytopheretic Device in Critically Ill Children

Introduction

Critically ill children with acute kidney injury (AKI) requiring continuous kidney replacement therapy (CKRT) are at increased risk of death. The selective cytopheretic device (SCD) promotes an immunomodulatory effect when circuit ionized calcium (iCa²⁺) is maintained at <0.40 mmol/l with regional citrate anticoagulation (RCA). In a randomized trial of adult patients on CRRT, those treated with the SCD maintaining an iCa²⁺ <0.40 mmol/l had improved survival/dialysis independence. We conducted a US Food and Drug Administration (FDA)–sponsored study to evaluate safety and feasibility of the SCD in 16 critically ill children.

Methods

Four pediatric intensive care units (ICUs) enrolled children with AKI and multiorgan dysfunction receiving CKRT to receive the SCD integrated post-CKRT membrane. RCA was used to achieve a circuit iCa²⁺ level <0.40 mmol/l. Subjects received SCD treatment for 7 days or CKRT discontinuation, whichever came first.

Results

The FDA target enrollment of 16 subjects completed the study from December 2016 to February 2020. Mean age was 12.3 ± 5.1 years, weight was 53.8 ± 28.9 kg, and median Pediatric Risk of Mortality II was 7 (range 2–19). Circuit iCa²⁺ levels were maintained at <0.40 mmol/l for 90.2% of the SCD therapy time. Median SCD duration was 6 days. Fifteen subjects survived SCD therapy; 12 survived to ICU discharge. All ICU survivors were dialysis independent at 60 days. No SCD-related adverse events (AEs) were reported.

Conclusion

Our data demonstrate that SCD therapy is feasible and safe in children who require CKRT. Although we cannot make efficacy claims, the 75% survival rate and 100% renal recovery rate observed suggest a possible favorable benefit-to-risk ratio.

Kidney Replacement Therapy in COVID-19 Induced Kidney Failure and Septic Shock: A Pediatric Continuous Renal Replacement Therapy [PCRRT] Position on Emergency Preparedness With Resource Allocation

The recent worldwide pandemic of COVID-19 has had a detrimental worldwide impact on people of all ages. Although data from China and the United States indicate that pediatric cases often have a mild course and are less severe in comparison to adults, there have been several cases of kidney failure and multisystem inflammatory syndrome reported. As such, we believe that the world should be prepared if the severity of cases begins to further increase within the pediatric population. Therefore, we provide here a position paper centered on emergency preparation with resource allocation for critical COVID-19 cases within the pediatric population, specifically where renal conditions worsen due to the onset of AKI.

Basics of continuous renal replacement therapy in pediatrics

In the last three decades, significant advances have been made in the care of children requiring renal replacement therapy (RRT). The move from the use of only hemodialysis and peritoneal dialysis to continuous venovenous hemofiltration with or without dialysis (continuous renal replacement therapy, CRRT) has become a mainstay in many intensive care units. The move to CRRT is the result of greater clinical experience as well as advances in equipment, solutions, vascular access, and anticoagulation. CRRT is the mainstay of dialysis in pediatric intensive care unit (PICU) for critically ill children who often have hemodynamic compromise. The advantages of this modality include the ability to promote both solute and fluid clearance in a slow continuous manner. Though data exist suggesting that approximately 25% of children in any PICU may have some degree of renal insufficiency, the true need for RRT is approximately 4% of PICU admissions. This article will review the history as well as the progress being made in the provision of this care in children.

Regional citrate versus systemic heparin anticoagulation for continuous renal replacement therapy in critically ill children

OBJECTIVES

Anticoagulation is used to prevent filter clotting in patients undergoing continuous renal replacement therapy. Regional citrate anticoagulation is associated with lower rates of bleeding complications and prolongs the filter life span; however, a number of metabolic side effects had been associated with this therapy. The aim of this study was to evaluate the effect and safety of citrate versus heparin anticoagulation for continuous renal replacement therapy in critically ill children.

METHODS

A retrospective comparative cohort study. Department of Pediatric Intensive Care, Acibadem Mehmet Ali Aydınlar University School of Medicine.

RESULTS

From August 2016 to August 2018, 45 patients (19 in the citrate group and 26 in the heparin group) were included. A total of 101 hemofilters were used in all therapies: 44 in the citrate group (total continuous renal replacement therapy time: 2699 h) and 57 in the heparin group (total continuous renal replacement therapy time: 2383 h). The median circuit lifetime was significantly longer for regional citrate anticoagulation (53.0; interquartile range, 40-70 h) than for heparin anticoagulation (40.25; interquartile range, 22.75-53.5 h; p = 0.025). Mortality rates were similar in both groups (31.58% vs 30.77%). The most common indication for dialysis was hypervolemia in both groups. Transfusion rates were 1.65 units (interquartile range, 0.5-2.38) with heparin and 0.8 units (interquartile range, 0.3-2.0) with citrate (p = 0.32). Clotting-related hemofilter failure occurred in 11.36% of filters in the citrate group compared with 26.31% of filters in the heparin group.

CONCLUSION

Our study showed that citrate is superior in terms of safety and efficacy, with longer filter life span. Regional citrate should be considered as a better anticoagulation method than heparin for continuous renal replacement therapy in critically ill children.

Prevention of Dialysis Disequilibrium by use of CVVH

Objective.

Dialysis disequilibrium occurs due to a rapid shift of osmols when hemodialysis is used in cases of extreme uremia. Continuous veno-venous hemofiltration (CVVH) with citrate anticoagulation may offer a safe method of urea reduction.

Design.

Retrospective, clinical observation.

Setting.

Tertiary pediatric intensive care unit and nephrology program.

Patients

Two males, ages 10 and 12 years of age.

Intervention.

CVVH with citrate anticoagulation.

Results.

Three to four day reduction of BUN from 180 mg/dL to 22 mg/dL and from 279 mg/dL to 23 mg/dL.

Conclusion.

Slow and safe improvement of severe urea, hyperphosphatemia, hypocalcemia, and anemia without untoward side effects.

Membrane pressures predict clotting of pediatric continuous renal replacement therapy circuits

BACKGROUND

Clotting of continuous renal replacement therapy (CRRT) circuits leads to inadequate clearance, decreased ultrafiltration, and increased resource use. We identified factors associated with premature clotting of circuits during CRRT in children.

METHODS

In a retrospective cohort of 26 children (median age 11.8 years) receiving 79 CRRT circuits (51 heparin, 22 citrate, 6 using no anticoagulation), we captured hourly pressure, flow, and fluid removal rates along with all activated clotting time (ACT) and circuit ionized calcium measurements. Cox and logistic regression models were used to examine factors associated with premature circuit clotting before the scheduled 3-day circuit change.

RESULTS

Of the 79 circuits, 51 (64.6%) underwent unplanned filter change due to filter clotting (median duration 18.25 h, interquartile range [IQR] 9.25, 33.5 h), and 28 (35.4%) underwent scheduled change (median duration 66 h, IQR 61.00, 69.00 h). Patient age, catheter size and location, blood flow rate, and the percentage of pre-filter replacement fluid were not associated with premature clotting. Heparin circuits were less likely than citrate circuits to clot prematurely. Each 1-mmHg increase in the transmembrane or filter pressure was independently associated with a 1.5% (95% confidence interval [CI] 1.0-2.0%) and 1.5% (95% CI 1.0-2.0%) higher risk of clotting, respectively. Higher ACTs were associated with lower transmembrane (p = 0.03) and filter (p < 0.001) pressures.

CONCLUSIONS

The majority of circuits in our cohort were subject to unplanned filter changes. Elevated transmembrane and filter pressures were associated with clotting. Our results suggest that maintaining higher ACT may decrease the risk of circuit clotting. Larger studies are needed to examine other factors that may prolong the lifespan of the CRRT circuit in this high-risk population.

Regional citrate anticoagulation for continuous renal replacement therapy in children

BACKGROUND

Anticoagulation of the continuous renal replacement therapy (CRRT) circuit is an important technical aspect of this medical procedure. Most studies evaluating the efficacy and safety of citrate use have been carried out in adults, and little evidence is available for the pediatric patient population. The aim of this study was to compare regional citrate anticoagulation versus systemic heparin anticoagulation in terms of the lifetime of hemofilters in a pediatric population receiving CRRT at a pediatric center in Bogota, Colombia.

METHODS

This was an analytical, observational, retrospective cohort study in which we assessed the survival of 150 hemofilters (citrate group 80 hemofilters, heparin group 70 hemofilters) used in a total of 3442 hours of CCRT (citrate group 2248 h, heparin group 1194 h). Hemofilter survival was estimated beginning at placement and continuing until filter replacement due to clotting or high trans-membrane pressures.

RESULTS

Hemofilter survival was higher in the citrate group than in the heparin group (72 vs. 18 h; p <0.0001). Bivariate analysis showed that the hemofilter coagulation risk was significantly increased when heparin was used, regardless of hemofilter size and pump flow (hazard ratio 3.70, standard error 0.82, 95% confidence interval 2.39-5.72; p <0.00001).

CONCLUSIONS

Regional citrate anticoagulation could be more effective than heparin systemic anticoagulation in terms of prolonging the hemofilter lifetime in patients with acute renal injury who require CRRT.

Renal replacement therapy in adult and pediatric intensive care : Recommendations by an expert panel from the French Intensive Care Society (SRLF) with the French Society of Anesthesia Intensive Care (SFAR) French Group for Pediatric Intensive Care Emergencies (GFRUP) the French Dialysis Society (SFD)

Acute renal failure (ARF) in critically ill patients is currently very frequent and requires renal replacement therapy (RRT) in many patients. During the last 15 years, several studies have considered important issues regarding the use of RRT in ARF, like the time to initiate the therapy, the dialysis dose, the types of catheter, the choice of technique, and anticoagulation. However, despite an abundant literature, conflicting results do not provide evidence on RRT implementation. We present herein recommendations for the use of RRT in adult and pediatric intensive care developed with the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system by an expert group of French Intensive Care Society (SRLF), with the participation of the French Society of Anesthesia and Intensive Care (SFAR), the French Group for Pediatric Intensive Care and Emergencies (GFRUP), and the French Dialysis Society (SFD). The recommendations cover 4 fields: criteria for RRT initiation, technical aspects (access routes, membranes, anticoagulation, reverse osmosis water), practical aspects (choice of the method, peritoneal dialysis, dialysis dose, adjustments), and safety (procedures and training, dialysis catheter management, extracorporeal circuit set-up). These recommendations have been designed on a practical point of view to provide guidance for intensivists in their daily practice.

Regional citrate anticoagulation for pediatric CRRT using integrated citrate software and physiological sodium concentration solutions

BACKGROUND

In continuous renal replacement therapy (CRRT), regional citrate anticoagulation offers an attractive alternative to heparinization, especially for children with a high bleeding risk.

METHODS

We report on a new management approach to CRRT using integrated citrate software and physiological sodium concentration solutions. Convective filtration was performed with pre-filter citrate anticoagulation using an 18 mmol/L citrate solution and a post-filter replacement fluid. The citrate flow rate was automatically adjusted to the blood flow rate by means of integrated citrate software. Similarly, calcium was automatically infused into children to maintain their blood calcium levels within normal range.

RESULTS

Eleven CRRT sessions were performed (330 h) in seven critically ill children aged 3-15 years (extreme values 15-66 kg). Disease categories included sepsis with multiorgan dysfunction (n = 2) and hemolytic uremic syndrome (n = 5). Median effluent dose was 2.1 (extreme values 1.7-3.3) L/h/1.73 m2. No session had to be stopped because of metabolic complications. Calcium levels, both in the circuits and in the circulating blood of the children, remained stable and secure.

CONCLUSIONS

Regional citrate anticoagulation can be used in children with a body weight of >15 kg using integrated citrate software and commercially available solutions with physiological sodium concentrations in a safe, effective and convenient procedure.

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.

Renal complications and therapy in the PICU: hypertension, CKD, AKI, and RRT

This article provides the bedside clinician an overview of the unique renal complications that are seen commonly in the pediatric intensive care unit. These sections are purposely succinct to give a quick guide to the clinician for the care of these children. We have identified four major areas that should result in discussion and cooperative care between intensive care physicians and nephrologists for the care of these children: (1) hypertension, (2) chronic kidney failure, (3) acute kidney injury, and (4) renal replacement therapy.

Standardization of continuous renal-replacement therapy fluids using a commercial product

PURPOSE

Patient safety and cost-control benefits achieved through a medical center's conversion to commercial fluids for continuous renal-replacement therapy (CRRT) are described.

SUMMARY

In keeping with national patient safety recommendations, a medical center undertook a quality-improvement initiative to increase the standardization of CRRT fluids and associated patient care practices. After a feasibility study to ascertain CRRT fluid usage patterns and baseline costs, an appropriate commercial product was selected. The transition was implemented over several months in a three-phase process entailing (1) conversion to a commercial product for regional citrate anticoagulation, (2) changing the standard formula on preprinted orders to one that modeled a commercial product, and (3) conversion to the actual commercial product as the standard. Thorough education of all parties involved, as well as modifications to preprinted orders, occurred during each phase of the project. The use of the commercial product reduced the need for pharmacy compounding of CRRT fluids by more than 80%. A postconversion cost analysis indicated sharp reductions of product and labor (i.e., compounding) expenses relative to estimated baseline costs, with estimated total savings of at least $399,290 during the first six months after the conversion initiative. Implementation challenges included the need to manually adjust the potassium content of the commercial CRRT fluid and the need to provide i.v. supplementation of phosphorus and magnesium to some patients receiving the fluid. The initiative emphasized the need for institution-specific research and planning before conversion initiatives targeting CRRT fluids and other critical therapies, as well as proper education and training of all parties involved.

CONCLUSION

The standardization of CRRT fluids using commercially available products improved a medical center's compliance with patient safety standards and yielded substantial cost savings.

Advances in pediatric renal replacement therapy for acute kidney injury

The disease spectrum leading to pediatric renal replacement therapy (RRT) provision has broadened over the last decade. In the 1980s, intrinsic renal disease and burns comprised the most common pediatric acute renal failure etiologies; more recent data demonstrate that pediatric acute kidney injury (AKI) most often results from complications of other systemic diseases resulting from the advancements in congenital heart surgery, neonatal care, and bone marrow and solid organ transplantation. In addition, RRT modality preferences to treat critically ill children have shifted from peritoneal dialysis to continuous renal replacement therapy (CRRT) as a result of improvements in CRRT technologies. In this article, we aim to review the pediatric specific causes for RRT provision, emphasizing the emerging practice patterns with respect to modality and timing of treatment. We will focus on the application of different RRT modalities and related outcome of children with AKI who receive RRT.

Management of regional citrate anticoagulation in pediatric high-flux dialysis: activated coagulation time versus post-filter ionized calcium

Recent years has seen an increasing use of regional citrate anticoagulation in pediatric dialysis. Several approaches have been described for monitoring anticoagulation in the extracorporeal circuit, such as serum citrate levels, post-filter ionized calcium (iCa), and activated coagulation time (ACT). However, no standard recommendations have yet been established for applying any of these parameters, especially for iCa. The objective of this retrospective analysis was to establish adequate coagulation management using post-filter iCa values. Normal values for ACTester-based ACT were established using a group of 64 children who were divided into two subgroups, with one subgroup comprising children without chronic kidney disease or coagulation disorder (age 1.2-17.5 years, median 9.7 years) and one consisting of 32 uremic patients (age 0.6-17.5 years, median 13.7 years). In a second group of 13 patients (aged 7-17 years), all of whom were undergoing high-flux dialysis (HD) with regional citrate anticoagulation (RCA), we assessed 73 post-filter blood samples for ionized calcium and ACT. A receiver operating characteristic graph was used to identify the iCa threshold needed to achieve adequate anticoagulation. Normal values for ACT were 90 s [2 standard deviations (SD) 72-109] in healthy children and 94 s (2 SD 75-113) in the uremic children. There was no statistically significant difference between the groups. In the children undergoing HD with RCA, the post-filter iCa level correlated with ACT (r = -0.94, p < 0.001). A post-filter iCa level of < or = 0.30 mmol/l reliably predicted an ACT >120 s. Our citrate protocol [citrate 3% rate (ml/h) approximately blood flow rate (ml/min) x 2] meets the established criteria with a high sensitivity. Based on these results, we conclude that the post-filter iCa level can be reliably used for the management of extracorporeal anticoagulation with citrate in pediatric HD. We recommend the application of our citrate prescription protocol in the setting of pediatric intermittent hemodialysis.

Physical compatibility of magnesium sulfate and sodium bicarbonate in a pharmacy-compounded hemofiltration solution

PURPOSE

The physical compatibility of magnesium sulfate and sodium bicarbonate in a pharmacy-compounded hemofiltration solution was assessed.

METHODS

Two bicarbonate-buffered hemofiltration solutions (low- and high-magnesium formulations) were compounded in triplicate. The concentrations of magnesium (15 meq/L) and sodium bicarbonate (50 meq/L) in the high-magnesium formulation were chosen to be somewhat below the concentrations reported as being incompatible in a popular reference. The six hemofiltration bags were stored at 22-25 degrees C without protection from light for 48 hours. Physical compatibility was assessed by visual inspection and microscopy. The pH of the solutions was assayed 3-4 and 52-53 hours after compounding. Electrolyte and glucose concentrations of the solutions were assayed at 3-4 and 50-51 hours after preparation.

RESULTS

No particulate matter was observed by visual or microscopic inspection in the compounded hemofiltration solutions at 48 hours. The mean +/- S.D. pH values of the low-magnesium solutions were 8.01 +/- 0.02 and 8.04 +/- 0.02 at 3-4 and 52-53 hours after compounding, respectively. The mean +/- S.D. pH values of the high-magnesium solutions were 7.96 +/- 0.02 and 7.98 +/- 0.01 at 3-4 and 52-53 hours after compounding, respectively. The electrolyte and glucose concentrations in the low- and high-magnesium solutions were similar 3-4 and 50-51 hours after preparation.

CONCLUSION

Magnesium sulfate 1.5 meq/L and sodium bicarbonate 50 meq/L were physically compatible in a pharmacy-compounded hemofiltration solution for 48 hours when stored at 22-25 degrees C without protection from light.

Regional citrate anticoagulation is safe in intermittent high-flux haemodialysis treatment of children and adolescents with an increased risk of bleeding

BACKGROUND

Regional citrate anticoagulation (RCA) is strongly recommended for adults with an increased risk of bleeding complications. The objective of this retrospective analysis was to evaluate an RCA protocol concerning feasibility and safety in intermittent high-flux haemodialysis (iHD) treatment in children and adolescents.

METHODS

Eighteen children and adolescents aged 5-17 years (median 15 years) underwent 74 iHD treatment sessions with RCA. Twelve of 18 patients presented with overt local or diffuse haemorrhage before beginning the HD sessions, and six had an increased risk of haemorrhagic complications. Forty children on acute haemodialysis with general heparin anticoagulation, matched for bleeding risk, age and body surface area, served as a control group. Citrate 3% solution was begun with 3.3% blood flow rate, and calcium gluconate 10% substitution was started with 0.4% of blood flow rate. Citrate flow was adapted to achieve a post-filter ionized calcium of ≤0.30 mmol/L; calcium substitution was adapted to maintain the patients' serum calcium levels within the physiological range. Calcium-free dialysis fluid was used. The blood flow rate ranged from 3 to 5 mL per minute and kilogram body weight.

RESULTS

Regional anticoagulation was successfully achieved within the extracorporeal blood circuit, while the coagulation of all 18 patients remained within physiological parameters. No adverse effects of RCA were observed. In all 18 children, neither new haemorrhage nor worsening of the bleeding situation occurred, and in 10/12 patients, bleeding stopped during dialysis with RCA. In contrast, one-third of the control group developed new haemorrhagic complications or presented with worsening of pre-existing bleeding during haemodialysis (P = 0.006).

CONCLUSION

RCA is feasible, safe and effective in paediatric intermittent haemodialysis treatment.

Overview of pediatric renal replacement therapy in acute kidney injury

The disease spectrum leading to pediatric renal replacement therapy (RRT) provision has broadened over the last decade. In the 1980's, intrinsic renal disease and burns comprised the most common pediatric acute kidney injury (AKI) etiologies. More recent data demonstrate that pediatric AKI most often results from complications of other systemic diseases resulting from the advancements in congenital heart surgery, neonatal care, and bone marrow and solid organ transplantation. In addition, RRT modality preferences to treat critically ill children have shifted from peritoneal dialysis to continuous renal replacement therapy (CRRT) as a result of improvements in CRRT technologies. Currently, multicenter prospective outcome studies for critically ill children with AKI are sorely lacking. The aims of this paper are to review the pediatric specific causes necessitating RRT provision with an emphasis on emerging practice patterns with respect to modality and the timing of treatment, and focus upon the application of the different RRT modalities and assessment of the outcome of children with AKI who receive RRT.

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.

Multiple organ system extracorporeal support in critically ill children

Multiple organ system extracorporeal support effectively supports brain, heart, lung, liver, kidney, coagulation, red blood cell, and immune cell function in the sickest infants and children who have multiple organ system failure. These therapies have optimum benefit if: (1) the underlying disease is reversible; (2) the therapies are performed expertly and are monitored to prevent and minimize systemic hemolysis; and (3) the therapies are provided in a goal-directed manner. These therapies represent a significant advance in pediatric critical care medicine. This article provides a framework for this multidisciplinary team approach for implementing these therapies.

Phenylacetate and benzoate clearance in a hyperammonemic infant on sequential hemodialysis and hemofiltration

An infant with a suspected inborn metabolism error was treated with a metabolic cocktail of intravenous sodium phenylacetate (NaPh) and sodium benzoate (NaBz) for hyperammonemia. Sequential hemodialysis (HD) then hemofiltration (HF) was performed due to hyperammonemia. Dialytic and convective clearance (K; ml/min) of ammonia, NaPh, and NaBz was measured. The K of ammonia was 57 and 37 for HD and HF, respectively. The K of NaBz was 37 and 12 for HD and HF, respectively. The K of NaPh was 38 and 14 ml/min for HD and HF, respectively. Despite high clearance of both NaPh and NaBz by HD and HF, the hyperammonemia was corrected.

Regional citrate anticoagulation in continuous venovenous haemofiltration using commercial preparations

AIM

The aim of the present study was to test the feasibility of using commercial preparations of replacement and citrate anticoagulation solution in continuous venovenous haemofiltration (CVVH) in a safe, efficient and simple manner.

METHODS

Retrospective review of the database of a large continuous renal replacement therapy programme that uses a standardized prescription of high ultrafiltrate CVVH with commercial solutions for replacement fluid and regional citrate anticoagulation was performed.

RESULTS

Records of 28 patients who underwent 91 CVVH sessions were analysed. Median circuit survival time was 37 (59.5-15.5) h and the 48 h survival probability was 40%. Bleeding or metabolic complications were not noted, and the procedure was simple to administer.

CONCLUSION

Continuous venovenous haemofiltration using commercial preparations of replacement fluid and citrate anticoagulation can be safe, efficient and simple.

Hemolysis due to inadvertent hemodialysis against distilled water: Perils of bedside dialysate preparation

OBJECTIVE

To describe the physiologic consequences of dialysis against distilled water and to provide recommendations by which other institutions may avoid similar errors in dialysate preparation.

DATA SOURCE

Four cases of dialysis against distilled water are described, occurring at three teaching hospitals within a 2-yr period. In addition, an in vitro experiment of banked whole blood exposure to distilled water dialysate was performed.

DATA EXTRACTION

Because all four cases occurred within a critical care setting, intensive monitoring of clinical, biochemical, and hematologic abnormalities was possible.

DATA SYNTHESIS

Serum sodium decreased by an average of 22 mmol/L, followed by a decrease in hemoglobin averaging 32 g/L. Additional investigations and the in vitro experiment provided evidence that hemolysis occurred primarily via clearance of damaged erythrocytes within the patient's reticuloendothelial system. Physiologic derangements secondary to dialysis against distilled water likely contributed to a stroke suffered by one patient and the death of at least one other patient.

CONCLUSIONS

Accidental dialysis against distilled water is a potentially serious but preventable complication of bedside dialysate preparation.

Medication errors and patient complications with continuous renal replacement therapy

Continuous renal replacement therapy (CRRT) is commonly used for renal support in the intensive care unit. While the risk of medication errors in the intensive care unit has been described, errors related specifically to CRRT are unknown. The purpose of this study is to characterize medication errors related to CRRT and compare medication errors that occur with manually compounded solutions versus commercially available solutions. We surveyed three separate internet-based, pediatric list serves that are commonly used for communications for programs utilizing CRRT. Data regarding CRRT practices and medication errors were recorded. Medication errors were graded for degree of severity and compared between programs using manually compounded dialysis solutions versus commercially available dialysis solutions. In a survey with 31 program responses, 18 reported medication errors. Two of the 18 were related to heparin compounding, while 16/18 were due to solution compounding errors. Half of the medication errors were classified as causing harm, two of which were fatal. All medication errors were reported by programs that manually compounded their dialysis solutions. Medication errors related to CRRT are associated with a high degree of severity, including death. Industry-based, commercially available solutions can decrease the occurrence of medication errors due to CRRT.

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.

Multi-centre evaluation of anticoagulation in patients receiving continuous renal replacement therapy (CRRT)

BACKGROUND

Heparin (hepACG) and regional citrate anticoagulation (citACG) remain the most commonly reported continuous renal replacement therapy (CRRT) ACG methods employed. No prospective multi-centre published data exist that compare different ACG methods with respect to CRRT filter life span or patient complications.

METHODS

A total of 138 patients from seven US centres receiving 18 208 h of CRRT comprising a total of 442 CRRT circuits were utilized to assess filter life span and ACG-related complications in patients receiving CRRT with hepACG, citACG or no ACG (noACG).

RESULTS

Mean circuit life was 41.2+/-30.8 h. Mean circuit survival was no different for circuits receiving hepACG (42.1+/-27.1 h) and citACG (44.7+/-35.9 h), but was significantly lower for circuits with noACG (27.2+/-21.5 h, P<0.005). Kaplan-Meier analyses revealed no survival difference between hepACG and citACG circuits, but significantly lower survival for noACG circuits (P<0.001). Log-rank analysis showed that 69% of hepACG and citACG circuits whereas only 28% of noACG were functional at 60 h. Clotting rates were similar for hepACG circuits (58 out of 230, 25%) and citACG circuits (43 out of 158, 27%), but were significantly higher for noACG circuits (27 out of 54, 50%, P < 0.001). Life-threatening bleeding complications attributable to ACG were noted in the hepACG group but were absent in the citACG group.

CONCLUSIONS

The current analysis represents the largest evaluation of CRRT ACG methods to date. While the standard hepACG and citACG methods studied in the prospective paediatric CRRT registry led to similar filter life spans and were superior to noACG, our data suggest that citACG may result in less life-threatening complications.