Hemofiltration is not associated with increased mortality in children receiving extracorporeal membrane oxygenation

Concurrent use of continuous kidney replacement therapy during extracorporeal membrane oxygenation: what pediatric nephrologists need to know-PCRRT-ICONIC practice points

Extracorporeal membrane oxygenation (ECMO) provides temporary cardiorespiratory support for neonatal, pediatric, and adult patients when traditional management has failed. This lifesaving therapy has intrinsic risks, including the development of a robust inflammatory response, acute kidney injury (AKI), fluid overload (FO), and blood loss via consumption and coagulopathy. Continuous kidney replacement therapy (CKRT) has been proposed to reduce these side effects by mitigating the host inflammatory response and controlling FO, improving outcomes in patients requiring ECMO. The Pediatric Continuous Renal Replacement Therapy (PCRRT) Workgroup and the International Collaboration of Nephrologists and Intensivists for Critical Care Children (ICONIC) met to highlight current practice standards for ECMO use within the pediatric population. This review discusses ECMO modalities, the pathophysiology of inflammation during an ECMO run, its adverse effects, various anticoagulation strategies, and the technical aspects and outcomes of implementing CKRT during ECMO in neonatal and pediatric populations. Consensus practice points and guidelines are summarized. ECMO should be utilized in patients with severe acute respiratory failure despite the use of conventional treatment modalities. The Extracorporeal Life Support Organization (ELSO) offers guidelines for ECMO initiation and management while maintaining a clinical registry of over 195,000 patients to assess outcomes and complications. Monitoring and preventing fluid overload during ECMO and CKRT are imperative to reduce mortality risk. Clinical evidence, resources, and experience of the nephrologist and healthcare team should guide the selection of ECMO circuit.

Timing of Kidney Replacement Therapy Initiation and Survival During Pediatric Extracorporeal Membrane Oxygenation: An Extracorporeal Life Support Organization Registry Study

To characterize kidney replacement therapy (KRT) and pediatric extracorporeal membrane oxygenation (ECMO) outcomes and to identify the optimal timing of KRT initiation during ECMO associated with increased survival. Observational retrospective cohort study using the Extracorporeal Life Support Organization Registry database in children (0-18 yo) on ECMO from January 1, 2016, to December 31, 2020. Of the 14,318 ECMO runs analyzed, 26% of patients received KRT during ECMO. Patients requiring KRT before ECMO had increased mortality to ECMO decannulation (29% vs. 17%, OR 1.97, P < 0.001) and to hospital discharge (58% vs. 39%, OR 2.16, P < 0.001). Patients requiring KRT during ECMO had an increased mortality to ECMO decannulation (25% vs. 15%, OR 1.85, P < 0.001) and to hospital discharge (56% vs. 34%, OR 2.47, P < 0.001). Multivariable logistic regression demonstrated that the need for KRT during ECMO was an independent predictor for mortality to ECMO decannulation (OR 1.49, P < 0.001) and to hospital discharge (OR 2.02, P < 0.001). Patients initiated on KRT between 24 and 72 hours after cannulation were more likely to survive to ECMO decannulation and showed a trend towards survival to hospital discharge as compared to those initiated before 24 hours and after 72 hours.

Application of Near-Infrared Spectroscopy to Monitor Perfusion During Extracorporeal Membrane Oxygenation After Pediatric Heart Surgery

Objective: Venoarterial extracorporeal membrane oxygenation is an effective mechanical circulatory support that is used to rescue critically ill patients after congenital heart surgery. As there was still no recommended guideline for monitoring parameters during extracorporeal membrane oxygenation (ECMO), this study aimed to investigate the role of near-infrared spectroscopy (NIRS) in the early period of venoarterial (VA)-ECMO. Method: This study enrolled patients with NIRS monitoring during ECMO after pediatric cardiac surgery at Shanghai Children's Medical Center (2018-2020). The information obtained from the retrospective, the observational dataset included the demographic information, diagnoses, baseline characteristics, procedural details, ECMO data, monitoring data, in-hospital mortality, and complications of the patients. Results: The overall mortality rate was 43.6%. Lactate was significantly higher in non-survivors compared to survivors at 12 h (11.25 ± 7.26 vs. 6.96 ± 5.95 mmol/l, p = 0.022) and 48 h [2.2 (0.7, 20) vs. 1.4 (0.7, 5.8) mmol/l, p = 0.008] after initiation of ECMO. The cranial regional oxygen saturation (CrSO₂) was significantly higher in survivors compared to non-survivors at 24 h (62.5 ± 14.61 vs. 52.05 ± 13.98%, p = 0.028), 36 h (64.04 ± 14.12 vs. 51.27 ± 15.65%, p = 0.005), and 48 h (65.32 ± 11.51 vs. 55.00 ± 14.18%, p = 0.008). Multivariate logistics regression analysis of the hemodynamic and laboratory parameters revealed that the CrSO₂ at 36 h (OR = 0.945, p = 0.049) and 48 h (OR = 0.919, p = 0.032) was related to mortality. The use of continuous renal replacement therapy (OR = 14.940, p = 0.039) was also related to mortality. The optimal cutoff values for CrSO₂ for predicting mortality after weaning off ECMO at 36 and 48 h were 57% (sensitivity: 61.5%, specificity: 80%) and 56% (sensitivity: 76.9%, specificity: 70%), respectively. The risk of mortality was higher among patients with a CrSO₂(36h) < 57% (p = 0.028) by Kaplan-Meier analysis. Conclusion: Near-infrared spectroscopy may be a useful tool for monitoring the hemodynamic stability during the early period of ECMO, while CrSO₂ can predict the in-hospital mortality after ECMO.

Impact of CRRT in Patients with PARDS Treated with VV-ECMO

The high mortality of pediatric acute respiratory distress syndrome (PARDS) is partly related to fluid overload. Extracorporeal membrane oxygenation (ECMO) is used to treat pediatric patients with severe PARDS, but can result in acute kidney injury (AKI) and worsening fluid overload. The objective of this study was to determine whether the addition of CRRT to ECMO in patients with PARDS is associated with increased mortality. Methods: We conducted a retrospective 7-year study of patients with PARDS requiring ECMO and divided them into those requiring CRRT and those not requiring CRRT. We calculated severity of illness scores, the amount of blood products administered to both groups, and determined the impact of CRRT on mortality and morbidity. Results: We found no significant difference in severity of illness scores except the vasoactive inotropic score (VIS, 45 ± 71 vs. 139 ± 251, p = 0.042), which was significantly elevated during the initiation and the first three days of ECMO. CRRT was associated with an increase in the use of blood products and noradrenaline (p < 0.01) without changing ECMO duration, length of PICU stay or mortality. Conclusion: The addition of CRRT to ECMO is associated with a greater consumption of blood products but no increase in mortality.

Early Fluid Accumulation and Intensive Care Unit Mortality in Children Receiving Extracorporeal Membrane Oxygenation

Purpose of this study was to evaluate the impact of early fluid accumulation and renal dysfunction on mortality in children receiving extracorporeal membrane oxygenation (ECMO). Retrospective cohort study of neonatal and pediatric patients who received ECMO between January 2010 and December 2012 in a tertiary level multidisciplinary pediatric intensive care unit (ICU). Ninety-six patients were included, and forty-six (48%) of them received continuous renal replacement therapy (CRRT) during ECMO. Overall mortality was 38.5%. Proportion of patients with acute kidney injury (AKI) at ICU admission was 33% and increased to 47% at ECMO initiation. High-risk diagnoses, extracorporeal cardiopulmonary resuscitation (ECPR), and venoarterial (VA)-ECMO were more common among nonsurvivors. Nonsurvivors had significantly higher proportion of AKI at ICU admission (OR: 2.59, p = 0.04) and fluid accumulation on ECMO day 1 (9% vs. 1%, p = 0.05) compared with survivors. Multivariable logistic regression analysis (adjusted for a propensity score based on nonrenal factors associated with increased mortality) demonstrated that fluid accumulation on ECMO day 1 is significantly associated with increased ICU mortality (OR: 1.07, p = 0.04). Fluid accumulation within the first 24 hours after ECMO cannulation is significantly associated with increased ICU mortality in neonatal and pediatric patients. Prospective studies evaluating the impact of conservative fluid management and CRRT during the initial phase of ECMO may help further define this relationship.

Extracorporeal Membrane Oxygenation for Hemodynamic Support

Extracorporeal membrane oxygenation was first successfully achieved in 1975 in a neonate with meconium aspiration. Neonatal extracorporeal membrane oxygenation has expanded to include hemodynamic support in cardiovascular collapse before and after cardiac surgery, medical heart disease, and rescue therapy for cardiac arrest. Advances in pump technology, circuit biocompatibility, and oxygenators efficiency have allowed extracorporeal membrane oxygenation to support neonates with increasingly complex pathophysiology. Contraindications include extreme prematurity, extremely low birth weight, lethal chromosomal abnormalities, uncontrollable hemorrhage, uncontrollable disseminated intravascular coagulopathy, and severe irreversible brain injury. The future will involve collaboration to guide and evolve evidence-based practices for this life-sustaining therapy.

Hematologic concerns in extracorporeal membrane oxygenation

This ISTH "State of the Art" review aims to critically evaluate the hematologic considerations and complications in extracorporeal membrane oxygenation (ECMO). ECMO is experiencing a rapid increase in clinical use, but many questions remain unanswered. The existing literature does not address or explicitly state many pertinent details that may influence hematologic complications and, ultimately, patient outcomes. This review aims to broadly introduce modern ECMO practices, circuit designs, circuit materials, hematologic complications, transfusion-related considerations, age- and size-related differences, and considerations for choosing outcome measures. Relevant studies from the 2019 ISTH Congress in Melbourne, which further advanced our understanding of these processes, will also be highlighted.

ECMO for Neonatal Sepsis in 2019

Sepsis and septic shock in newborns causes mortality and morbidity depending on the organism and primary site. ECMO provides cardiorespiratory support to allow adequate organ perfusion during the time for antibiotics and source control surgery (if needed) to occur. ECMO mode and cannulation site vary depending on support required and local preference. Earlier and more aggressive use of ECMO can improve survival.

Renal function in children assisted with extracorporeal membrane oxygenation

Acute kidney injury is a frequent complication in patients requiring extracorporeal membrane oxygenation. A single-center retrospective analysis from a prospective observational database assessing the incidence of acute kidney injury in children undergoing extracorporeal membrane oxygenation, the use of continuous renal replacement therapy and its association with outcomes was performed. One hundred children were studied. Creatinine was normal in 33.3% of children at the beginning of extracorporeal membrane oxygenation, between 1.5 and 2 times its baseline levels in 18.4% of children (stage I acute kidney injury), between 2 and 3 times baseline levels (stage II) in 20.7%, and over 3 times baseline levels or requiring continuous renal replacement therapy (stage III) in 27.6% of the patients. Eighteen patients were on continuous renal replacement therapy before the beginning of extracorporeal membrane oxygenation, 81 required continuous renal replacement therapy during extracorporeal membrane oxygenation, and 38 after weaning from extracorporeal membrane oxygenation, but none of them did at discharge from the pediatric intensive care unit. Fifty-one children survived to pediatric intensive care unit discharge. Mortality was lower in children with normal kidney function or with stage I acute kidney injury at the beginning of extracorporeal membrane oxygenation than in those with stage II or III acute kidney injury (33.3% vs 58.3%, p = 0.021). Mortality in children requiring continuous renal replacement therapy during extracorporeal membrane oxygenation was 54.3% and 21.1% in the rest of patients (p < 0.01). We conclude that kidney function is significantly impaired in a high percentage of children undergoing extracorporeal membrane oxygenation and many of them are treated with continuous renal replacement therapy. Patients treated with continuous renal replacement therapy have a higher mortality than those with normal kidney function or stage I acute kidney injury at the beginning of extracorporeal membrane oxygenation. Most patients surviving to pediatric intensive care unit discharge recover normal renal function after weaning from extracorporeal membrane oxygenation.

Mortality of Critically Ill Children Requiring Continuous Renal Replacement Therapy: Effect of Fluid Overload, Underlying Disease, and Timing of Initiation

OBJECTIVE

To identify risk factors associated with mortality in critically ill children requiring continuous renal replacement therapy.

DESIGN

Retrospective observational study based on a prospective registry.

SETTING

Tertiary and quaternary referral 30-bed PICU.

PATIENTS

Critically ill children undergoing continuous renal replacement therapy were included in the study.

INTERVENTIONS

Continuous renal replacement therapy.

MEASUREMENTS AND MAIN RESULTS

Overall mortality was 36% (n = 58) among the 161 patients treated with continuous renal replacement therapy during the study period and was significantly higher in patients on extracorporeal membrane oxygenation (47.5%, 28 of 59) than in patients not requiring extracorporeal membrane oxygenation (28.4%, 29 of 102; p = 0.022). According to the admission diagnosis, we found the highest mortality in patients with onco-hematologic disease (77.8%) and the lowest in patients with renal disease (5.6%). Based on multivariate logistic regression analysis, the presence of higher severity of illness score at admission (adjusted odds ratio, 1.49; 95% CI, 1.18-1.89; p < 0.001), onco-hematologic disease (odds ratio, 17.10; 95% CI, 4.10-72.17; p < 0.001), fluid overload 10%-20% (odds ratio, 3.83; 95% CI, 1.33-11.07; p = 0.013), greater than 20% (odds ratio, 15.03; 95% CI, 4.03-56.05; p < 0.001), and timing of initiation of continuous renal replacement therapy (odds ratio, 1.01; 95% CI, 1.00-1.01; p = 0.040) were independently associated with mortality. In our population, the odds of dying increases by 1% for every hour of delay in continuous renal replacement therapy initiation from ICU admission.

CONCLUSIONS

Mortality in children requiring continuous renal replacement therapy remains high and seems to be related to the underlying disease, the severity of illness, and the degree of fluid overload. In critically ill children at high risk for developing acute kidney injury and fluid overload, earlier initiation of continuous renal replacement therapy might result in decreased mortality.

Neonatal Cardiac ECMO in 2019 and Beyond

Worldwide, the use of Extracorporeal Membrane Oxygenation (ECMO) for cardiac failure has been steadily increasing in the neonatal population and has become a widely accepted modality. Especially in centers caring for children with (congenital) heart disease, ECMO is now an essential part of care available for those with severe heart failure as a bridge to recovery, long term mechanical support, or transplantation. Short-term outcomes depend very much on indication. Hospital survival is ~40% for all neonatal cardiac ECMO patients combined. ECMO is being used for pre- and/or post-operative stabilization in neonates with congenital heart disease and in neonates with medical heart disease such as myocarditis, cardiomyopathy or refractory arrhythmias. ECMO use during resuscitation (ECPR) or for sepsis is summarized elsewhere in this special edition of Frontiers in Pediatrics. In this review article, we will discuss the indications for neonatal cardiac ECMO, the difficult process of patients' selection and identifying the right timing to initiate ECMO, as well as outline pros and cons for peripheral vs. central cannulation. We will present predictors of mortality and, very importantly, predictors of survival: what can be done to improve the outcomes for your patients. Furthermore, an overview of current insights regarding supportive care in neonatal cardiac ECMO is given. Additionally, we will address issues specific to neonates with single ventricle physiology on ECMO, for example cannulation strategies and the influence of shunt type (Blalock-Taussig shunt vs. "right ventricle to pulmonary artery" shunt). We will not only focus on short term outcomes, such as hospital survival, but also on the importance of long-term neuro-developmental outcomes, and we will end this review with suggestions for future research.

Neonatal Extracorporeal Life Support: A Review of Nutrition Considerations

Critically ill neonates who require extracorporeal life support have particular nutrition needs. These infants require prescription of aggressive, early nutrition support by knowledge providers. Understanding the unique metabolic demands and nutrition requirements of these fragile patients is paramount, particularly if additional therapies such as aggressive diuretic regimens or continuous renal replacement therapy are used concurrently. Although the American Society for Parenteral and Enteral Nutrition has published guidelines for this population, a review of each nutrition component is warranted because few studies exist specific to this population. Long-term complications in survivors of neonatal extracorporeal life support, particularly in patients with select diagnoses such as congenital diaphragmatic hernia, can be significant and must be recognized and anticipated. This review focuses on recognizing the nutrition needs of neonatal patients requiring extracorporeal life support, appraising the available data to guide selection of an appropriate mode of nutrition delivery, and describing the anticipated long-term nutrition implications of extracorporeal life support provision during the neonatal period.

The role of fluid overload in the prediction of outcome in acute kidney injury

Our understanding of the epidemiology and the impact of acute kidney injury (AKI) and fluid overload on outcomes has improved significantly over the past several decades. Fluid overload occurs commonly in critically ill children with and without associated AKI. Researchers in pediatric AKI have been at the forefront of describing the impact of fluid overload on outcomes in a variety of populations. A full understanding of this topic is important as fluid overload represents a potentially modifiable risk factor and a target for intervention. In this state-of-the-art review, we comprehensively describe the definition of fluid overload, the impact of fluid overload on kidney function, the impact of fluid overload on the diagnosis of AKI, the association of fluid overload with outcomes, the targeted therapy of fluid overload, and the impact of the timing of renal replacement therapy on outcomes.

Extracorporeal Membrane Oxygenation for Severe Pediatric Respiratory Failure

Extracorporeal membrane oxygenation (ECMO) was developed initially in the 1960s to support refractory respiratory failure in addition to the cardiac support inherent in a venoarterial bypass circuit. Early successes occurred predominantly in the neonatal population with subsequent randomized controlled trials and comprehensive reviews concluding therapeutic efficacy for ECMO in neonatal respiratory failure. In contrast, the evidence supporting ECMO for respiratory failure in children is less definitive. However, although pediatric randomized controlled trials have not been completed, sufficient evidence in support of ECMO as a beneficial therapy for pediatric respiratory failure exists. The acceptance of clinical utility and benefit from ECMO for pediatric ARDS and the trend toward increasing venovenous ECMO use have led to its inclusion in the Pediatric Acute Lung Injury Consensus Conference as a strongly agreed upon recommendation for severe pediatric ARDS. However, the Pediatric Acute Lung Injury Consensus Conference recommendations supporting the use of ECMO for pediatric ARDS highlight the lack of evidence-based selection criteria when determining ECMO candidacy in pediatric patients with ARDS. Ultimately, decisions to proceed with ECMO and the concomitant risk of potential life-threatening complications must consider multiple factors that balance potential risks and likelihood of benefit, pre-morbid conditions and impact on potential post-ECMO quality of life, candidacy for lung transplantation, and patient and family goals of care. This review will discuss ECMO for the support of pediatric respiratory failure, ventilator management during ECMO, considerations impacting timing of decannulation, and developing techniques.