Pumpless arteriovenous extracorporeal membrane oxygenation: A novel mode of respiratory support in a lamb model of congenital diaphragmatic hernia

Update on Management and Outcomes of Congenital Diaphragmatic Hernia

Infants with congenital diaphragmatic hernia (CDH) benefit from comprehensive multidisciplinary teams that have experience in caring for the unique and complex issues associated with CDH. Despite prenatal referral to specialized high-volume centers, advanced ventilation strategies and pulmonary hypertension management, and extracorporeal membrane oxygenation, mortality and morbidity remain high. These infants have unique and complex issues that begin in fetal and infant life, but persist through adulthood. Here we will review the literature and share our clinical care pathway for neonatal care and follow up. While many advances have occurred in the past few decades, our work is just beginning to continue to improve the mortality, but also importantly the morbidity of CDH.

ECMO for premature neonates- Are we there yet?

Despite ECMO being a well-accepted and established life-saving support for newborns, prematurity (<34 weeks of gestation) and low birth weight <2.0 kg are still considered relative contraindications due to the fear of intracranial bleeding complications. In the last decades, outcome in extracorporeal life support for pre-term babies has improved, and morbidity dominated by intracranial bleedings has decreased. With the introduction of new methodologies and technological development, the current ELSO guideline for ECMO (GA >34 w, BW > 2.0 kg) deserves to be challenge. The authors suggest that Prem-ECMO (GA 32-33) could be considered when restricted to experienced high-volume neonatal ECMO centers, with closed monitoring and rigorous reporting to the ELSO registry, providing close targeting of oxygen delivery for prevention of retinopathy and being active participants in continuous development of technology and devices for improved biocompatibility for use in the neonate.

Expanding neonatal ECMO criteria: When is the premature neonate too premature

Extracorporeal membrane oxygenation (ECMO) is a universally accepted and life-saving therapy for neonates with respiratory or cardiac failure that is refractory to maximal medical management. Early studies found unacceptable risks of mortality and morbidities such as intracranial hemorrhage among premature and low birthweight neonates, leading to widely accepted ECMO inclusion criteria of gestational age ≥34 weeks and birthweight >2 kg. Although contemporary data is lacking, the most recent literature demonstrates increased survival and decreased rates of intracranial hemorrhage in premature neonates who are supported with ECMO. As such, it seems like the right time to push the boundaries of ECMO on a case-by-case basis beginning with neonates 32-34 weeks GA in large volume centers with careful neurodevelopmental follow-up to better inform practices changes on this select population.

The fetal lamb model of congenital diaphragmatic hernia shows altered cerebral perfusion using contrast enhanced ultrasound

BACKGROUND

Neurodevelopmental impairment is common in survivors of congenital diaphragmatic hernia (CDH). Altered cerebral perfusion in utero may contribute to abnormal brain development in CDH patients.

METHODS

5 fetal lambs with surgical left-CDH and 5 controls underwent transuterine cranial Doppler and contrast enhanced ultrasound (CEUS). Global and regional perfusion metrics were obtained. Biometric and perfusion data were compared between groups via nonparametric Mann Whitney U test and Spearman's rank order correlation.

RESULTS

No significant differences in cerebral Doppler measurements were identified between groups. By CEUS, CDH animals demonstrated significantly decreased global brain perfusion and increased transit time. With focal regions-of-interest (ROIs), there was a tendency towards decreased perfusion in the central/thalamic region in CDH but not in the peripheral brain parenchyma. Transit time was significantly increased in both ROIs in CDH, whereas flux rate was decreased in the central/thalamic region but not the peripheral brain parenchyma. Biometric CDH severity was correlated to perfusion deficit. There was no difference in cardiomyocyte histology.

CONCLUSION

The fetal lamb model of CDH shows altered cerebral perfusion as measured by CEUS, correlating to disease severity. This suggests a physiological abnormality in fetal cerebrovascular perfusion that may contribute to abnormal brain development and neurodevelopmental impairment in survivors.

Premature and Extracorporeal Life Support: Is it Time? A Systematic Review

Early preterm birth < 34 gestational weeks (GA) and birth weight (BW) <2 kg are relative contraindications for extracorporeal membrane oxygenation (ECMO). However, with improved technology, ECMO is presently managed more safely and with decreasing complications. Thus, these relative contraindications may no longer apply. We performed a systematic review to evaluate the existing literature on ECMO in early and late (34-37 GA) prematurity focusing on survival to hospital discharge and the complication intracranial hemorrhage (ICH). Data sources: MEDLINE, PubMed, Web of Science, Embase, and the Cochrane Database. Only publications in the English language were evaluated. Of the 36 included studies, 23 were related to ECMO support for respiratory failure, 10 for cardiac causes, and four for congenital diaphragmatic hernia (CDH). Over the past decades, the frequency of ICH has declined (89-21%); survival has increased in both early prematurity (25-76%), and in CDH (33-75%), with outcome similar to late prematurity (48%). The study was limited by an inherent risk of bias from overlapping single-center and registry data. Both the risk of ICH and death have decreased in prematurely born treated with ECMO. We challenge the 34 week GA time limit for ECMO and propose an international task force to revise current guidelines. At present, gestational age < 34 weeks might no longer be considered a contraindication for ECMO in premature neonates.

The horizon of pediatric cardiac critical care

Pediatric Cardiac Critical Care (PCCC) is a challenging discipline where decisions require a high degree of preparation and clinical expertise. In the modern era, outcomes of neonates and children with congenital heart defects have dramatically improved, largely by transformative technologies and an expanding collection of pharmacotherapies. Exponential advances in science and technology are occurring at a breathtaking rate, and applying these advances to the PCCC patient is essential to further advancing the science and practice of the field. In this article, we identified and elaborate on seven key elements within the PCCC that will pave the way for the future.

Conventional revolution: the ethical implications of the natural progress of neonatal intensive care to artificial wombs

Research teams have used extra-uterine systems (Biobags) to support premature fetal lambs and to bring them to maturation in a way not previously possible. The researchers have called attention to possible implications of these systems for sustaining premature human fetuses in a similar way. Some commentators have pointed out that perfecting these systems for human fetuses might alter a standard expectation in abortion practices: that the termination of a pregnancy also (inevitably) entails the death of the fetus. With Biobags, it might be possible, some argue, that no woman has the right to expect that outcome if the technology is able to sustain fetal life after an abortion. In order to protect the expectation that the termination of a pregnancy always entails the death of the fetus, Elizabeth Romanis has argued that fetuses sustained in Biobags have a status different than otherwise 'born' children. In support of that view, she argues that these 'gestatelings' are incapable of independent life. This argument involves a misunderstanding of the gestational support involved, as well as a misapprehension of neonatology practice. Here, we argue that any human fetus sustained in a Biobag would be as 'independent' as any other premature infant, and just as 'born'. Neonatologists would seem to have certain presumptive moral responsibilities toward any human fetus gestating in a Biobag. It remains a separate question whether the perfection and widespread application of Biobags for premature human beings would or should alter the expectation that ending a pregnancy also entails fetal death.

Reconsidering ECMO in Premature Neonates

Extracorporeal membrane oxygenation (ECMO) is a life-saving intervention for neonates with respiratory failure or congenital cardiac disease refractory to maximal medical management. Early studies showed high rates of mortality and morbidities among preterm and low birthweight (BW) neonates, leading to widely accepted ECMO inclusion criteria of gestational age (GA) ≥34 weeks and BW >2 kg. In recent years, publications involving neonates of 32-34 weeks GA have reported improved survival and decreased intracranial hemorrhage. As such, ECMO should be considered on a case-by-case basis in premature neonates as long as the risks are understood.

The role of ECMO in the management of congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is the most common indication for extra-corporeal membrane oxygenation (ECMO) for neonatal respiratory failure. CDH management is evolving with advanced prenatal diagnostic imaging modalities. The risk profiles of infants receiving ECMO for CDH are shifting towards higher risk. Many clinicians are developing and following clinical practice guidelines to standardize and optimize the care of CDH neonates. Despite these efforts, there are significant differences in the practice patterns among ECMO centers as to how and when they choose to initiate ECMO for CDH, when they believe repair is safe, as well as many other nuances that are based on center experience or style. The purpose of this report is to summarize our current understanding of the new and recent developments regarding management of infants with CDH managed with ECMO.