Prolonged extracorporeal membrane oxygenation for children with respiratory failure

Prolonged extracorporeal membrane oxygenation in pediatrics: How long did we wait?

BACKGROUND

In this study, we aimed to evaluate the duration of extracorporeal membrane oxygenation (ECMO) and its effect on outcomes. Also, we sought to identify hospital mortality predictors and determine when ECMO support began to be ineffective.

METHODS

This was a single-center, retrospective cohort study conducted between January 2014 and January 2022. The prolonged ECMO (pECMO) cut-off point was accepted as 14 days.

RESULTS

Thirty-one (29.2%) of 106 patients followed up with ECMO had pECMO. The mean follow-up period of the patients who underwent pECMO was 22 (range, 15-72) days, and the mean age was 75 ± 72 months. According to the results of our heterogeneous study population, life expectancy decreased dramatically towards the 21st day. Hospital mortality predictors were determined in the logistic regression analysis in all ECMO groups in our study as high Pediatric Logistic Organ Dysfunction (PELOD) two score, continuous renal replacement therapy (CRRT) use, and sepsis. The pECMO mortality was 61.2% and the overall mortality was 53.0%, with the highest mortality rate in the bridge-to-transplant group (90.9%) because of lack of organ donation in our country.

CONCLUSIONS

In our study, the PELOD two score, presence of sepsis, and use of CRRT were found to be in the predictors of in-hospital ECMO mortality model. Considering the complications, in the COX regression model analysis, the factors affecting the probability of dying in patients followed under ECMO were found to be bleeding, thrombosis, and thrombocytopenia.

Supporting and Contextualizing Pediatric ECMO Decision-Making Using a Person-Centered Framework

AbstractThere is a critical need to establish a space to engage in careful deliberation amid exciting, important, necessary, and groundbreaking technological and clinical advances in pediatric medicine. Extracorporeal membrane oxygenation (ECMO) is one such technology that began in pediatric settings nearly 50 years ago. And while not void of medical and ethical examination, both the symbolic progression of medicine that ECMO embodies and its multidimensional challenges to patient care require more than an intellectual exercise. What we illustrate, then, is a person-centered framework that incorporates the philosophy and practice of palliative care and care-based ethical approaches. This person-centered framework is valuable for identifying and understanding challenges central to ECMO, guides collaborative decision-making, and recognizes the value of relationships within and between patients, families, healthcare teams, and others who impact and are impacted by ECMO. Specifically, this person-centered approach enables caregivers to provide compassionate and effective support in critical, and often urgent, situations where conflicts may emerge among healthcare team members, families, and other decision makers. By reflecting on three cases based on actual situations, we apply our person-centered framework and identify those aspects that were utilized in and informed this project. We aim to fill a current gap in the pediatric ECMO literature by presenting a person-centered framework that promotes caregiving relationships among hospitalized critically ill children, families, and the healthcare team and is supported through the philosophy and practice of palliative care and clinical ethics.

Seven-day in vivo testing of a novel, low-resistance, pumpless pediatric artificial lung for long-term support

INTRODUCTION

For children with end-stage lung disease that cannot wean from extracorporeal life support (ECLS), a wearable artificial lung would permit extubation and provide a bridge to recovery or transplantation. We evaluate the function of the novel Pediatric MLung-a low-resistance, pumpless artificial lung developed specifically for children-in healthy animal subjects.

METHODS

Adolescent "mini sheep" weighing 12-20 kg underwent left thoracotomy, cannulation of the main pulmonary artery (PA; inflow) and left atrium (outflow), and connection to the MLung.

RESULTS

Thirteen sheep were studied; 6 were supported for 7 days. Mean PA pressure was 23.9 ± 6.9 mmHg. MLung blood flow was 633±258 mL/min or 30.0 ± 16.0% of CO. MLung pressure drop was 4.4 ± 3.4 mmHg. Resistance was 7.2 ± 5.2 mmHg/L/min. Device outlet oxygen saturation was 99.0 ± 3.3% with inlet saturation 53.8 ± 7.3%. Oxygen delivery was 41.1 ± 18.4 mL O₂/min (maximum 84.9 mL/min) or 2.8 ± 1.5 mL O₂/min/kg. Platelet count significantly decreased; no platelet transfusions were required. Plasma free hemoglobin significantly increased only on day 7, at which point 2 of the animals had plasma free hemoglobin levels above 50 mg/dL.

CONCLUSION

The MLung provides adequate gas exchange at appropriate blood flows for the pediatric population in a PA-to-LA configuration. Further work remains to improve the biocompatibility of the device.

LEVEL OF EVIDENCE

N/A.

Necrotizing pneumonia requiring prolonged extracorporeal membrane oxygenation: Pushing the boundaries in pediatric ECMO

Extracorporeal membrane oxygenation (ECMO) is a life‐saving rescue therapy used in acute respiratory failure refractory to invasive mechanical ventilation. Recent studies on positive outcomes of extended ECMO therapy are promising. We describe a case of a 2‐year 8‐month‐old female child with necrotizing pneumonia secondary to Streptococcus pneumoniae, Influenza A, and Mycoplasma pneumoniae, who survived with intact neurological function and no long‐term adverse outcomes after a prolonged ECMO run of 86 days. To the best of our knowledge, this is one of the longer durations of ECMO with transplant‐free survival in a pediatric patient requiring respiratory support with good recovery and a good functional outcome. Allowing time for native lung recovery is pivotal for optimal recovery, despite significant lung injury due to the underlying disease process. With evolving ECMO experience, clinicians may need to re‐consider the conventional maximum duration of ECMO in children with severe respiratory failure on a case‐by‐case basis.

A pumpless artificial lung without systemic anticoagulation: The Nitric Oxide Surface Anticoagulation system

BACKGROUND

Artificial lungs have the potential to serve as a bridge to transplantation or recovery for children with end-stage lung disease dependent on extracorporeal life support, but such devices currently require systemic anticoagulation. We describe our experience using the novel Nitric Oxide (NO) Surface Anticoagulation (NOSA) system-an NO-releasing circuit with NO in the sweep gas-with the Pediatric MLung-a low-resistance, pumpless artificial lung.

METHODS

NO flux testing: MLungs (n = 4) were tested using veno-venous extracorporeal life support in a sheep under anesthesia with blood flow set to 0.5 and 1 L/min and sweep gas blended with 100 ppm NO at 1, 2, and 4 L/min. NO and NO₂ were measured in the sweep and exhaust gas to calculate NO flux across the MLung membrane. Pumpless implants: Sheep (20-100 kg, n = 3) underwent thoracotomy and cannulation via the pulmonary artery (device inflow) and left atrium (device outflow) using cannulae and circuit components coated with an NO donor (diazeniumdiolated dibutylhexanediamine; DBHD-N₂O₂) and argatroban. Animals were connected to the MLung with 100 ppm NO in the sweep gas under anesthesia for 24 h with no systemic anticoagulation after cannulation.

RESULTS

NO flux testing: NO flux averaged 3.4 ± 1.0 flux units (x10^-10 mol/cm²/min) (human vascular endothelium: 0.5-4 flux units). Pumpless implants: 3 sheep survived 24 h with patent circuits. MLung blood flow was 716 ± 227 mL/min. Outlet oxygen saturation was 98.3 ± 2.6%. Activated clotting time was 151±24 s. Platelet count declined from 334,333 ± 112,225 to 123,667 ± 7,637 over 24 h. Plasma free hemoglobin and leukocyte and platelet activation did not significantly change.

CONCLUSIONS

The NOSA system provides NO flux across a gas-exchange membrane of a pumpless artificial lung at a similar rate as native vascular endothelium and achieves effective local anticoagulation of an artificial lung circuit for 24 h.

Extracorporeal membrane oxygenation in critically ill neonatal and pediatric patients with acute respiratory failure: a guide for the clinician

Intro: Extracorporeal membrane oxygenation for neonatal and pediatric respiratory failure continues to demonstrate improving outcomes, largely due to advances in technology along with refined management strategies despite mounting patient acuity and complexity. Successful use of ECMO requires thoughtful initiation and candidacy strategies, along with reducing the risk of ventilator induced lung injury and the progression to multiorgan failure.Areas Covered: This review describes current ECMO management strategies for neonatal and pediatric patients with acute refractory respiratory failure and summarizes relevant published literature. ECMO initiation and candidacy, along with ventilator and sedation management, are highlighted. Additionally, rapidly expanding areas of interest such as anticoagulation strategies, transfusion thresholds, rehabilitation on ECMO, and drug pharmacokinetics are described.Expert Opinion: Over the last few decades, published studies supporting ECMO use for acute refractory respiratory failure, along with institutional experience, have resulted in increased utilization although more randomized-controlled trials are needed. Future research should focus on filling the knowledge gaps that remain regarding anticoagulation, transfusion thresholds, ventilator strategies, sedation, and approaches to rehabilitation to subsequently implement into clinical practice. Additionally, efforts should focus on well-designed trials, including population pharmacokinetic studies, to develop dosing recommendations.

Perception of prolonged extracorporeal membrane oxygenation in Europe: an EuroELSO survey

The substantial increase in the number of patients receiving extracorporeal membrane oxygenation over the last decade has led to an evolution of indications and an expansion into wider patient groups. One of the unanticipated benefits of the increase in extracorporeal membrane oxygenation has been a change in the understanding of the natural history of many respiratory diseases. Development in technology and materials, reduced extracorporeal membrane oxygenation-specific complications, and improvement of critical care, in general, have facilitated longer extracorporeal membrane oxygenation runs, and the definition of prolonged extracorporeal membrane oxygenation was recently expanded to continuous support for more than 28 days. This survey aimed to describe European ECMO centers' perception and arbitrary definition of prolonged extracorporeal membrane oxygenation, patient management, and futility. Of 94 center responses, 37% regarded 14-21 days, 30% 21-28 days, and 28% >28 days as prolonged treatment. Bridge to recovery (64%) or to transplantation (20%) was the most common causes. Awake, and ambulation while on extracorporeal membrane oxygenation was reported from 34% of the centers. In case of perceived futility, decision to withdraw was taken in 65% of the centers in agreement between profession and family and in 30% by profession only. One-fourth of the centers did not discontinue support. Large differences prevail among European ECMO centers concerning local perception and patient management in prolonged extracorporeal membrane oxygenation.

Mortality trends in neonatal ECMO for pulmonary hypoplasia: A review of the Extracorporeal Life Support Organization database from 1981 to 2016

BACKGROUND

The purpose of this review is to provide ECMO outcome data for medical personnel who counsel families of patients with pulmonary hypoplasia (PH), often secondary to renal abnormalities. We report diagnoses and outcomes associated with PH in neonates that were treated with ECMO over the past 35 years.

METHODS

Retrospective cohort study using the ELSO database for neonates born between 1981 and 2016 with a primary or secondary diagnosis of PH. Five patient groups were created based on ICD-9 codes. Mortality rates were compared and trends over time were investigated.

RESULTS

Thirty-three percent of the 1385 patients survived to discharge. Congenital diaphragmatic hernia (CDH) patients had significantly higher mortality than PH patients secondary to renal dysplasia (p < 0.001). Mortality decreased significantly over time for all groups (p < 0.001). The proportion of patients alive at discharge increased over time for CDH patients (p < 0.001), whereas survival decreased for patients with PH secondary to renal dysplasia (p = 0.012).

CONCLUSIONS

Neonates with PH that require ECMO have high mortality rates, which have generally decreased over the past 35 years; however, mortality for neonates with PH secondary to renal dysplasia continues to increase. We speculate that the apparent rise in mortality for these patients is because of changes in patient selection subsequent to improvements in non-ECMO ventilatory support.

LEVEL OF EVIDENCE

II.

Combination of polycarboxybetaine coating and factor XII inhibitor reduces clot formation while preserving normal tissue coagulation during extracorporeal life support

Blood contact with high surface area medical devices, such as dialysis and extracorporeal life support (ECLS), induces rapid surface coagulation. Systemic anticoagulation, such as heparin, is thus necessary to slow clot formation, but some patients suffer from bleeding complications. Both problems might be reduced by 1) replacing heparin anticoagulation with artificial surface inhibition of the protein adsorption that initiates coagulation and 2) selective inhibition of the intrinsic branch of the coagulation cascade. This approach was evaluated by comparing clot formation and bleeding times during short-term ECLS using zwitterionic polycarboxybetaine (PCB) surface coatings combined with either a potent, selective, bicyclic peptide inhibitor of activated Factor XII (FXII900) or standard heparin anticoagulation. Rabbits underwent venovenous ECLS with small sham oxygenators for 60 min using three means of anticoagulation (n = 4 ea): (1) PCB coating + FXII900 infusion, (2) PCB coating + heparin infusion with an activated clotting time of 220-300s, and (3) heparin infusion alone. Sham oxygenator blood clot weights in the PCB + FXII900 and PCB + heparin groups were 4% and 25% of that in the heparin group (p < 10^-6 and p < 10^-5), respectively. At the same time, the bleeding time remained normal in the PCB + FXII900 group (2.4 ± 0.2 min) but increased to 4.8 ± 0.5 and 5.1 ± 0.7 min in the PCB + heparin and heparin alone groups (p < 10^-4 and 0.01). Sham oxygenator blood flow resistance was significantly lower in the PCB + FXII900 and PCB + heparin groups than in the heparin only group (p < 10^-6 and 10^-5). These results were confirmed by gross and scanning electron microscopy (SEM) images and fibrinopeptide A (FPA) concentrations. Thus, the combined use of PCB coating and FXII900 markedly reduced sham oxygenator coagulation and tissue bleeding times versus the clinical standard of heparin anticoagulation and is a promising anticoagulation method for clinical ECLS.

Beyond Frontiers: Feasibility and Outcomes of Prolonged Veno-Venous Extracorporeal Membrane Oxygenation in Severe Acute Respiratory Distress Syndrome

Extracorporeal membrane oxygenation (ECMO) use in acute respiratory failure is increasing. We aim to compare characteristics and outcomes of patients with prolonged (≥21 days) veno-venous (VV) ECMO runs (pECMO), to patients with short (<21 days) VV ECMO runs (sECMO). The observational retrospective single-center study compared patients who received VV ECMO from January 2018 to June 2019 at Prince Mohamed Bin Abdulaziz Center in Riyadh, Saudi Arabia. Forty-three patients were supported with VV ECMO during the study period, of whom 37 are included as six patients were still receiving ECMO at time of data collection: 24 sECMO and 13 pECMO patients. Baseline characteristics and comorbidities were similar except pECMO patients were older and had a lower P/F ratio (61 [58-68] vs. 71[58-85.5], p = 0.05). Survival to hospital discharge (69% vs. 83%, p = 0.32; pECMO vs. sECMO) and 90 day survival (62% vs. 75%, p = 0.413; pECMO vs. sECMO) were similar among groups. At 1 year follow-up, all patients were still alive and independently functioning except for one patient in the pECMO group who required a walking aid related to trauma. In this single-center study, patients requiring pECMO had similar short- and long-term survival to those requiring sECMO duration.

Pediatric and neonatal extracorporeal life support: current state and continuing evolution

The use of extracorporeal life support (ECLS) for the pediatric and neonatal population continues to grow. At the same time, there have been dramatic improvements in the technology and safety of ECLS that have broadened the scope of its application. This article will review the evolving landscape of ECLS, including its expanding indications and shrinking contraindications. It will also describe traditional and hybrid cannulation strategies as well as changes in circuit components such as servo regulation, non-thrombogenic surfaces, and paracorporeal lung-assist devices. Finally, it will outline the modern approach to managing a patient on ECLS, including anticoagulation, sedation, rehabilitation, nutrition, and staffing.

Surfactant therapy to facilitate weaning in paediatric patients dependent on extacorporeal membrane oxygenation

We are reporting two paediatric cases with severe adenoviral acute respiratory distress syndrome with viral counts of 308 and 119 million copies/mL respectively, who required venoarterial extracorporeal membrane oxygenation (ECMO) support for nearly 3 weeks. They were static on ECMO and had shown a complete lack of response to all therapeutic interventions aimed at decreasing ECMO support. To facilitate weaning from ECMO, they received 2-3 doses of surfactant. This led to dramatic improvement in pulmonary compliance, oxygenation and chest X-ray. They were both weaned off ECMO within 24 hours of receiving surfactant. Surfactant was well tolerated, with no adverse effects. In both cases, weaning from ECMO was possible only after surfactant administration. From our experience, we conclude that surfactant administration is a potentially safe and effective treatment modality that helps weaning from ECMO and should be considered in patients who are dependent on ECMO for long duration.

Neonatal respiratory extracorporeal membrane oxygenation and primary diagnosis: trends between two decades

OBJECTIVE

Examine changing neonatal respiratory extracorporeal membrane oxygenation (ECMO) practice trends and outcomes.

STUDY DESIGN

Retrospective cohort study comparing neonatal respiratory ECMO in the 1990 and 2010 decades (1994-1995 and 2014-2015). Patients ≤ 30 days of life, reported to the Extracorporeal Life Support Organization registry, were included.

RESULTS

Four thousand one hundred and twenty-five patients met inclusion criteria. ECMO cases decreased by 33%. The primary ECMO diagnosis changed significantly over time (p < 0.0001). Survival to discharge decreased (76 vs 67%, p < 0.0001) and ECMO duration increased (131 vs 158 h, p < 0.001). Lung recovery was the most common reason to discontinue ECMO although family request for withdrawal and a diagnosis considered "incompatible with life" was increasingly common in the 2010s.

CONCLUSION

Although the use of ECMO for neonatal respiratory diagnoses has decreased over time, its use has increased for patients with more complex diagnoses and ECMO duration is longer. ECMO continues to be an important supportive therapy, improved understanding of which patients would benefit most is needed.

Extra-corporeal membrane oxygenation in paediatric acute respiratory distress syndrome: overrated or underutilized?

Extracorporeal membrane oxygenation (ECMO) is a modified form of cardiopulmonary bypass which may provide support for severe cardiorespiratory failure including paediatric acute respiratory distress syndrome (PARDS). While ECMO was initially demonstrated to successfully support neonates with severe respiratory failure, the use of ECMO has expanded rapidly to support both paediatric and adult respiratory failure. Extracorporeal Life Support Organization (ELSO) registry data shows that the use of ECMO for paediatric respiratory failure has expanded rapidly over the past decades with increasing use of venovenous ECMO. Despite the increasing complexity of children supported by ECMO for ARDS, outcomes have remained consistent with survival to hospital discharge greater than 50%. ECMO complications are still common and potentially devastating, especially neurological complications. There is grade 1 evidence to support the use of ECMO in both neonatal and adult respiratory failure but evidence in paediatric respiratory failure is confined to case series and case-control studies. While there are no published guidelines for use of ECMO in PARDS, in particular no clearly defined inclusion and exclusion criteria, current evidence suggests that children with severe ARDS may benefit from ECMO support, with survival to hospital discharge equivalent or better than conventional management in children with severe ARDS.

De novo lung biofabrication: clinical need, construction methods, and design strategy

Chronic lung disease is the 4th leading cause of death in the United States. Due to a shortage of donor lungs, alternative approaches to support failing, native lungs have been attempted, including mechanical ventilation and various forms of artificial lungs. However, each of these support methods causes significant complications when used for longer than a few days and are thus not capable of long-term support. For artificial lungs, complications arise due to interactions between the artificial materials of the device and the blood of the recipient. A potential new approach is the fabrication of lungs from biological materials, such that the gas exchange membranes provide a more biomimetic blood-contacting interface. Recent advancements with three-dimensional, soft-tissue biofabrication methods and the engineering of thin, basement membranes demonstrate the potential of fabricating a lung scaffold from extracellular matrix materials. This scaffold could then be seeded with endothelial and epithelial cells, matured within a bioreactor, and transplanted. In theory, this fully biological lung could provide improved, long-term biocompatibility relative to artificial lungs, but significant work is needed to perfect the organ design and construction methods. Like artificial lungs, biofabricated lungs do not need to follow the shape and structure of a native lung, allowing for simpler manufacture. However, various functional requirements must still be met, including stable, efficient gas exchange for a period of years. Design decisions depend on the disease state, how the organ is implanted, and the latest biofabrication methods available in a rapidly evolving field.

Outcomes and associated ethical considerations of long-run pediatric ECMO at a single center institution

PURPOSE

Survival of neonatal and pediatric patients undergoing extracorporeal membrane oxygenation (ECMO) ≥ 21 days has not been well described. We hypothesized that patients would have poor survival and increased long-term complications.

METHODS

Retrospective, single center, review and case analysis. Tertiary-care university children's hospital including neonatal, pediatric and cardiac intensive care units. After institutional review board approval, the charts of all patients < 18 years of age undergoing ECMO for ≥ 21 continuous days were performed, and they were compared to comparative patients undergoing shorter runs. Overall survival, incidence of complications, and post-discharge recovery were recorded.

RESULTS

Overall survival was 36% in patients undergoing ≥ 21 days of ECMO (N = 14). 5/8 patients with cardiopulmonary failure from acquired etiologies survived versus 0/6 patients with congenital anomalies. 1/5 survivors achieved complete recovery with no neurologic deficits. The remaining survivors suffer from multiple medical and neurodevelopmental morbidities.

CONCLUSION

ECMO support for ≥ 21 days is associated with poor survival, particularly in neonates with congenital anomalies. Long-term outcomes for survivors ought to be carefully weighed and discussed with parents given the high incidence of neurologic morbidities in this population.

Risk factors for mortality in paediatric cardiac ICU patients managed with extracorporeal membrane oxygenation

BACKGROUND

Veno-arterial extracorporeal membrane oxygenation is frequently used in patients with cardiac disease. We evaluated short-term outcomes and identified factors associated with hospital mortality in cardiac patients supported with veno-arterial extracorporeal membrane oxygenation.

METHODS

A retrospective review of patients supported with veno-arterial extracorporeal membrane oxygenation at a university-affiliated children's hospital was performed.

RESULTS

A total of 253 patients with cardiac disease managed with extracorporeal membrane oxygenation were identified; survival to discharge was 48%, which significantly improved from 39% in an earlier era (1995-2001) (p=0.01). Patients were categorised into surgical versus non-surgical groups on the basis of whether they had undergone cardiac surgery before or not, respectively. The most common indication for extracorporeal membrane oxygenation was extracorporeal cardiopulmonary resuscitation: 96 (51%) in the surgical group and 45 (68%) in the non-surgical group. In a multiple covariate analysis, single-ventricle physiology (p=0.01), duration of extracorporeal membrane oxygenation (p&lt;0.01), and length of hospital stay (p=0.03) were associated with hospital mortality. Weekend or night shift cannulation was associated with mortality in non-surgical patients (p=0.05).

CONCLUSION

We report improvement in survival compared with an earlier era in cardiac patients supported with extracorporeal membrane oxygenation. Single-ventricle physiology continues to negatively impact survival, along with evidence of organ dysfunction during extracorporeal membrane oxygenation, duration of extracorporeal membrane oxygenation, and length of stay.

Sepsis and Pediatric Acute Respiratory Distress Syndrome

The epidemiology of the acute respiratory distress syndrome (ARDS) in pediatric sepsis is poorly defined. With significant data extrapolated from adult studies in sepsis and ARDS, sometimes with uncertain applicability, better pediatric-specific guidelines and dedicated investigations are warranted. The recent publication of a consensus definition for pediatric ARDS (PARDS) is the first step in addressing this knowledge gap. The aim of this review is to frame our current understanding of PARDS as it relates to pediatric sepsis, encompassing epidemiology, pathophysiology, and management. We argue that addressing the role of PARDS in pediatric sepsis requires significant attention to details with respect to how PARDS and sepsis are defined to accurately describe their epidemiology, natural history, and outcomes. Finally, we highlight certain aspects of PARDS management as they relate to the septic child and offer suggestion for future directions in this field.

An overview of medical ECMO for neonates

Extracorporeal membrane oxygenation (ECMO), a life-saving therapy for respiratory and cardiac failure, was first used in neonates in the 1970s. The indications and criteria for ECMO have changed over the years, but it continues to be an important option for those who have failed other medical therapies. Since the Extracorporeal Life Support Organization (ELSO) Registry was established in 1989, more than 29,900 neonates have been placed on ECMO for respiratory failure, with 84% surviving their ECMO course, and 73% surviving to discharge or transfer. In this chapter, we will review the basics of ECMO, patient characteristics and criteria, patient management, ECMO complications, special uses of neonatal ECMO, and patient outcomes.

Prolonged extracorporeal membrane oxygenation for pediatric necrotizing pneumonia due to Streptococcus pneumonia and influenza H1N1 co-infection: how long should we wait for native lung recovery?

Most children with severe respiratory failure require extracorporeal membrane oxygenation (ECMO) for 7-10 days. However, some may need prolonged duration ECMO (> 14 days). To date, no consensus exists on how long to wait for native lung recovery. Here we report the case of a 3-year-old boy who developed severe necrotizing pneumonia requiring venovenous (VV) ECMO after 19 days of mechanical ventilation. In the first 4 weeks of his ECMO run, he showed no lung aeration, requiring total extracorporeal support. However, after we started strategies for promoting lung recovery such as daily prone positioning and regular use of toilet bronchoscopy and inhalative DNAse to clear secretions, by week five his tidal volumes gradually increased and he was successfully decannulated after 43 days. Moreover, we decided not to proceed to a surgical removal of the necrotic lung area. At present, he is 1-year post discharge and has fully recovered. This report shows that unexpected native lung recovery is possible even after prolonged loss of lung function and that a previous healthy lung can recover from apparent irreversible lung injury.

Improving Long-Term Outcomes After Extracorporeal Membrane Oxygenation: From Observational Follow-Up Programs Toward Risk Stratification

Since the introduction of extracorporeal membrane oxygenation (ECMO), more neonates and children with cardiorespiratory failure survive. Interest has therefore shifted from reduction of mortality toward evaluation of long-term outcomes and prevention of morbidity. This review addresses the changes in ECMO population and the ECMO-treatment that may affect long-term outcomes, the diagnostic modalities to evaluate neurological morbidities and their contributions to prognostication of long-term outcomes. Most follow-up data have only become available from observational follow-up programs in neonatal ECMO-survivors. The main topics are discussed in this review. Recommendations for long-term follow up depend on the presence of neurological comorbidity, the nature and extent of the underlying disease, and the indication for ECMO. Follow up should preferably be offered as standard of care, and in an interdisciplinary, structured and standardized way. This permits evaluation of outcome data and effect of interventions. We propose a standardized approach and recommend that multiple domains should be evaluated during long-term follow up of neonates and children who needed extracorporeal life support.

Intrapulmonary Percussive Ventilation as an Airway Clearance Technique during Venoarterial Extracorporeal Life Support in an Infant with Pertussis

Initiation of extracorporeal life support (ECLS) is often followed by complete opacification of pulmonary parenchyma and volume loss. The optimal mechanical ventilator management and lung recruitment strategy of a pediatric patient requiring extracorporeal membrane oxygenation is not known. We present a case of a 4-week old infant who developed a severe pertussis infection requiring ECLS. The severity of his illness and pertussis infection-associated intraluminal bronchiole obstruction made medical management challenging. In addition to lung protection ventilator strategies and bronchoscopy, intrapulmonary percussive ventilation was initiated to facilitate lung recruitment. This was associated with precipitous incremental improvement in lung compliance and eventual liberation from venoarterial ECLS.

Extracorporeal membrane oxygenation for pediatric cardiac arrest

Extracorporeal cardiopulmonary resuscitation (ECPR) remains a promising treatment for pediatric patients in cardiac arrest unresponsive to traditional cardiopulmonary resuscitation. With venoarterial extracorporeal support, blood is drained from the right atrium, oxygenated through the extracorporeal circuit, and transfused back to the body, bypassing the heart and lungs. The use of artificial oxygenation and perfusion thus provides the body a period of hemodynamic stability, while allowing resolution of underlying disease processes. Survival rates for ECPR patients are higher than those for traditional cardiopulmonary resuscitation (CPR), although neurological outcomes require further investigation. The impact of duration of CPR and length of treatment with extracorporeal membrane oxygenation vary in published reports. Furthermore, current guidelines for the initiation and use of ECPR are limited and may lead to confusion about appropriate use of this support. Many ethical concerns arise with this advanced form of life support. More often than not, the dilemma is not whether to withhold ECPR, but rather when to withdraw it. Although clinicians must decide if ECPR is appropriate and when further intervention is futile, the ultimate burden of choice is left to the patient's caregivers. Offering support and guidance to the patient's family as well as the patient is essential.

Surfactant Administration During Pediatric Extracorporeal Membrane Oxygenation

Administering surfactant during pediatric extracorporeal membrane oxygenation (ECMO) may influence important clinical variables but has been insufficiently described. Ninety-six courses of ECMO from our center were retrospectively assessed, and 89 surfactant doses were identified during 37 ECMO courses. Surfactant administration was associated with a respiratory indication for ECMO and increased durations of ECMO and positive pressure ventilation. Hospital survival was 64.9% (24) in surfactant-treated ECMO courses and 72.9% (43) otherwise (p = 0.41). Dynamic compliance of the respiratory system (Cdyn; shown as least squares mean [standard error] in ml/cm H2O/kg by mixed-effects modeling) increased significantly from 0.34 (0.03) before surfactant to 0.40 (0.03) within 12 hours (p = 0.023) and to 0.45 (0.03) within 24 hours (p < 0.001) of surfactant administration. Other mechanical ventilator parameters, ECMO settings, and arterial blood gas results did not differ significantly after surfactant administration. Among surfactant recipients, significantly increased Cdyn was observed in the nonsurgical group (n = 20) but not in the cardiac surgery group (n = 17). In conclusion, respiratory system compliance is increased after surfactant administration and noncardiac surgical patients may preferentially benefit from this therapy. Surfactant administration was associated with longer durations of mechanical support, but not with unfavorable mortality.

Pore-Scale Modeling of Non-Newtonian Shear-Thinning Fluids in Blood Oxygenator Design

This paper reviews and further develops pore-scale computational flow modeling techniques used for creeping flow through orthotropic fiber bundles used in blood oxygenators. Porous model significantly reduces geometrical complexity by taking a homogenization approach to model the fiber bundles. This significantly simplifies meshing and can avoid large time-consuming simulations. Analytical relationships between permeability and porosity exist for Newtonian flow through regular arrangements of fibers and are commonly used in macroscale porous models by introducing a Darcy viscous term in the flow momentum equations. To this extent, verification of analytical Newtonian permeability–porosity relationships has been conducted for parallel and transverse flow through square and staggered arrangements of fibers. Similar procedures are then used to determine the permeability–porosity relationship for non-Newtonian blood. The results demonstrate that modeling non-Newtonian shear-thinning fluids in porous media can be performed via a generalized Darcy equation with a porous medium viscosity decomposed into a constant term and a directional expression through least squares fitting. This concept is then investigated for various non-Newtonian blood viscosity models. The proposed methodology is conducted with two different porous model approaches, homogeneous and heterogeneous, and validated against a high-fidelity model. The results of the heterogeneous porous model approach yield improved pressure and velocity distribution which highlights the importance of wall effects.

High-frequency percussive ventilation and bronchoscopy during extracorporeal life support in children

Variables affecting duration of pediatric extracorporeal life support (ECLS) are poorly defined. Prior analyses suggested increased mortality risk with prolonged ECLS. Lung recruitment strategies with improved secretion mobilization may shorten ECLS duration. High frequency percussive ventilation (HFPV) has been used, predominantly in inhalational injury, as a mode of ventilation to improve secretion clearance. We describe the application of HFPV and therapeutic bronchoscopies in pediatric ECLS and evaluate outcomes with a same-center historical control population. After May 2011, all children (n = 14) on ECLS were managed with HFPV during extracorporeal support (HFPV cohort). This group's demographics and outcomes were compared with ECLS patients in our unit immediately before the utilization of HFPV (pre-HFPV cohort, n = 22). The HFPV and pre-HFPV cohorts had similar demographics and utilization of venoarterial ECLS. In univariate analysis, the HFPV group underwent more bronchoscopies and experienced more ECLS-free days (days alive and off ECLS) at 30 and 60 days. In multivariate analysis, use of HFPV was independently associated with ECLS-free days. We conclude that use of HFPV and bronchoscopies during ECLS for respiratory failure was associated with an increase in ECLS-free days and that this association should be prospectively evaluated.

Ambulatory extracorporeal membrane oxygenation as a bridge to lung transplantation: walking while waiting

The proportion of critically ill patients awaiting lung transplantation has increased since the implementation of the Lung Allocation Score (LAS) in 2005. Critically ill patients comprise a sizable proportion of wait-list mortality and are known to experience increased posttransplant complications. These critically ill patients have been successfully bridged to lung transplantation with extracorporeal membrane oxygenation (ECMO), but historically these patients have required excessive sedation, been immobile, and have had difficult functional recovery in the posttransplant period and high mortality. One solution to the deconditioning often seen in critically ill patients is the implementation of rehabilitation and ambulation while awaiting transplantation on ECMO. Ambulatory ECMO programs of this nature have been developed in an attempt to provide rehabilitation, physical therapy, and minimization of sedation prior to lung transplantation to improve both surgical and posttransplant outcomes. Favorable outcomes have been reported using this novel approach, but how and where this strategy should be implemented remain unclear. In this commentary, we review the currently available literature for ambulation and rehabilitation during ECMO support as a bridge to lung transplantation, discuss future directions for this technology, and address the important issues of resource allocation and regionalization of care as they relate to ambulatory ECMO.

The outcomes of children with pediatric acute respiratory distress syndrome: proceedings from the Pediatric Acute Lung Injury Consensus Conference

OBJECTIVE

To provide additional details and evidence behind the recommendations for outcomes assessment of patients with pediatric acute respiratory distress syndrome from the Pediatric Acute Lung Injury Consensus Conference.

DESIGN

Consensus conference of experts in pediatric acute lung injury.

METHODS

A panel of 27 experts met over the course of 2 years to develop a taxonomy to define pediatric acute respiratory distress syndrome and to make recommendations regarding treatment and research priorities. The outcomes subgroup comprised four experts. When published data were lacking, a modified Delphi approach emphasizing strong professional agreement was used.

RESULTS

The Pediatric Acute Lung Injury Consensus Conference experts developed and voted on a total of 151 recommendations addressing the topics related to pediatric acute respiratory distress syndrome, seven of which related to outcomes after pediatric acute respiratory distress syndrome. All seven recommendations had strong agreement. Children with acute respiratory distress syndrome continue to have a high mortality, specifically, in relation to certain comorbidities and etiologies related to pediatric acute respiratory distress syndrome. Comorbid conditions, such as an immunocompromised state, increase the risk of mortality even further. Likewise, certain etiologies, such as non-pulmonary sepsis, also place children at a higher risk of mortality. Significant long-term effects were reported in adult survivors of acute respiratory distress syndrome: diminished lung function and exercise tolerance, reduced quality of life, and diminished neurocognitive function. Little knowledge of long-term outcomes exists in children who survive pediatric acute respiratory distress syndrome. Characterization of the longer term consequences of pediatric acute respiratory distress syndrome in children is vital to help identify opportunities for improved therapeutic and rehabilitative strategies that will lessen the long-term burden of pediatric acute respiratory distress syndrome and improve the quality of life in children.

CONCLUSIONS

The Consensus Conference developed pediatric-specific recommendations for pediatric acute respiratory distress syndrome regarding outcome measures and future research priorities. These recommendations are intended to promote optimization and consistency of care for children with pediatric acute respiratory distress syndrome and identify areas of uncertainty requiring further investigation.

Prolonged extracorporeal membrane oxygenator support among neonates with acute respiratory failure: a review of the Extracorporeal Life Support Organization registry

The objective of this study was to identify types of neonatal diseases associated with prolonged (≥21 days) extracorporeal membrane oxygenation (ECMO), characteristics of survivors and nonsurvivors among those requiring prolonged ECMO, and factors associated with mortality. Data were obtained from the Extracorporeal Life Support Organization registry over the period from January 1, 1998, through December 31, 2011, for all neonates (age <31 days), with respiratory failure as the indication for ECMO. The primary outcome was survival to hospital discharge. Survivors and nonsurvivors were compared for 1) patient demographics, 2) primary diagnosis, 3) pre-ECMO clinical course and therapies, and 4) ECMO course and associated complications. The most common diagnosis associated with prolonged ECMO support in neonates is congenital diaphragmatic hernia (CDH; 69%). Infants with meconium aspiration syndrome had the highest survival rate (71%) compared with other diagnoses analyzed (26.3%; p < 0.001). Nonsurvivors were more likely to experience complications on ECMO, and multivariate analysis showed that the need for inotropes while on ECMO support (odds ratio, 2.2 [95% confidence interval, 1.3-3.7]; p = 0.003) was independently associated with mortality. Neonates requiring prolonged ECMO support have a 24% survival to discharge. Many of these cases involve CDH. Complications are common with prolonged ECMO, but only receipt of inotropes was shown to be independently associated with mortality. This report may help guide clinical decision making and family counseling for neonates requiring prolonged ECMO support.

Existing data analysis in pediatric critical care research

Our objectives were to review and categorize the existing data sources that are important to pediatric critical care medicine (PCCM) investigators and the types of questions that have been or could be studied with each data source. We conducted a narrative review of the medical literature, categorized the data sources available to PCCM investigators, and created an online data source registry. We found that many data sources are available for research in PCCM. To date, PCCM investigators have most often relied on pediatric critical care registries and treatment- or disease-specific registries. The available data sources vary widely in the level of clinical detail and the types of questions they can reliably answer. Linkage of data sources can expand the types of questions that a data source can be used to study. Careful matching of the scientific question to the best available data source or linked data sources is necessary. In addition, rigorous application of the best available analysis techniques and reporting consistent with observational research standards will maximize the quality of research using existing data in PCCM.

Extracorporeal membrane oxygenation for pediatric respiratory failure: History, development and current status

Extracorporeal membrane oxygenation (ECMO) is currently used to support patients of all ages with acute severe respiratory failure non-responsive to conventional treatments, and although initial use was almost exclusively in neonates, use for this age group is decreasing while use in older children remains stable (300-500 cases annually) and support for adults is increasing. Recent advances in technology include: refinement of double lumen veno-venous (VV) cannulas to support a large range of patient size, pumps with lower prime volumes, more efficient oxygenators, changes in circuit configuration to decrease turbulent flow and hemolysis. Veno-arterial (VA) mode of support remains the predominant type used; however, VV support has lower risk of central nervous injury and mortality. Key to successful survival is implementation of ECMO before irreversible organ injury develops, unless support with ECMO is used as a bridge to transplant. Among pediatric patients treated with ECMO mortality varies by pulmonary diagnosis, underlying condition, other non-pulmonary organ dysfunction as well as patient age, but has remained relatively unchanged overall (43%) over the past several decades. Additional risk factors associated with death include prolonged use of mechanical ventilation (> 2 wk) prior to ECMO, use of VA ECMO, older patient age, prolonged ECMO support as well as complications during ECMO. Medical evidence regarding daily patient management specifically related to ECMO is scant, it usually mirrors care recommended for similar patients treated without ECMO. Linkage of the Extracorporeal Life Support Organization dataset with other databases and collaborative research networks will be required to address this knowledge deficit as most centers treat only a few pediatric respiratory failure patients each year.

Extracorporeal membrane oxygenation for neonatal and pediatric respiratory failure: an evidence-based review of the past decade (2002-2012)

OBJECTIVE

To provide a comprehensive evidence-based review of extracorporeal membrane oxygenation for neonatal and pediatric respiratory failure.

DATA SOURCE

A thorough computerized bibliographic search of the clinical literature regarding the use of extracorporeal membrane oxygenation in the neonatal and pediatric populations.

STUDY SELECTION

Clinical trials published between January 1, 2002, and October 1, 2012, including "extracorporeal membrane oxygenation" or "ECMO" and limited to studies involving humans aged 0-18 years. Trials focused on extracorporeal membrane oxygenation for cardiac indications were excluded from this study, unless the study was evaluating ancillary therapies in conjunction with extracorporeal membrane oxygenation.

DATA EXTRACTION

Studies were evaluated for inclusion based on reporting of patient outcomes and/or strategic considerations, such as cannulation strategies, timing of extracorporeal membrane oxygenation utilization, and ancillary therapies.

DATA SYNTHESIS

Pertinent data are summarized, and the available data are objectively classified based on the value of the study design from which the data are obtained.

CONCLUSIONS

Despite a large number of published extracorporeal membrane oxygenation studies, there remains a paucity of high-quality clinical trials. The available data support continued use of extracorporeal membrane oxygenation for respiratory failure refractory to conventional therapy for neonatal and pediatric patients without significant comorbidities. Further research is needed to better quantify the benefit of extracorporeal membrane oxygenation and the utility of many therapies commonly applied to extracorporeal membrane oxygenation patients.

Recurrent or prolonged mechanical circulatory support: bridge to recovery or road to nowhere?

Remarkable outcomes have been reported after prolonged mechanical circulatory support in the pediatric population, but there is yet no clear delineation of the duration beyond which supporting a child becomes futile. The likelihood of survival in patients supported on extracorporeal membrane oxygenation for respiratory failure decreases with the length of support. However, extracorporeal membrane oxygenation can be successfully used in these patients for long periods (weeks to months) provided adequate support is maintained without complications. This is not the case with cardiac failure and mechanical circulatory support.Extracorporeal membrane oxygenation is usually the initial form of mechanical circulatory support used in patients with primary refractory myocardial dysfunction. There is evidence and consensus that if the patient shows no signs of recovery after a maximum duration of 2 weeks, he or she should be transitioned to a ventricular assist device, which allows prolonged support. In post-cardiac surgery patients, survival is only anecdotal beyond 12 days of extracorporeal membrane oxygenation support, and myocardial recovery is exceptionally rare after this time period unless new diagnoses and management strategies are formulated.Repeat extracorporeal membrane oxygenation should generally not be offered to patients unless it is established that support was withdrawn prematurely or a new intervention is planned. Repeat extracorporeal membrane oxygenation may achieve some improvement in early survival, but the long-term outcomes of survivors are so poor that these attempts cannot be generally recommended unless organ transplantation is an option.

[Particularities of ECMO in acute respiratory distress syndrome in pediatrics]

Les techniques de circulation extracorporelle sont utilisées en pédiatrie dans les syndromes de détresse respiratoire aiguë (SDRA) les plus graves depuis les années 1980. Les données du registre international de l’Extracorporeal Life Support Organization révèlent plus 5 000 enfants placés en extracorporeal membrane oxygenation (ECMO) en 2012 avec une augmentation du nombre de cas annuels depuis l’épidémie de 2009. La survie, de 56 %, est stable alors que le nombre d’enfants avec des comorbidités augmente grâce aux améliorations apportées au matériel. Bien que nous ne disposions pas d’études randomisées, ces résultats encouragent à proposer l’ECMO dans l’arsenal thérapeutique du SDRA de l’enfant. Si les techniques veinoveineuses doivent être privilégiées dans les affections respiratoires, l’ECMO veinoartérielle peut être nécessaire et reste d’une utilisation fréquente chez l’enfant (50 % des cas). En pédiatrie, les particularités techniques sont liées d’une part aux particularités physiologiques de l’enfant et d’autre part aux contraintes dues au matériel proposé selon les différentes catégories d’âge. L’ECMO est une technique de recours lourde qui nécessite une expertise à la fois technique et pédiatrique spécialisée en raison de ce terrain particulier.