Persistent hypoplasia of the lung after repair of congenital diaphragmatic hernia

Ventilator strategies in congenital diaphragmatic hernia

This review focuses on contemporary mechanical ventilator practices used in the initial management of neonates born with congenital diaphragmatic hernia (CDH). Both conventional and non-conventional ventilation modes in CDH are reviewed. Special emphasis is placed on the rationale for gentle ventilation and the current evidence-based clinical practice guidelines that are recommended for supporting these fragile infants. The interplay between CDH lung hypoplasia and other key cardiopulmonary elements of the disease, namely a reduced pulmonary vascular bed, abnormal pulmonary vascular remodeling, and left ventricular hypoplasia, are discussed. Finally, we provide insights into future avenues for mechanical ventilator research in CDH.

Surfactant Therapy in Congenital Diaphragmatic Hernia and Fetoscopic Endoluminal Tracheal Occlusion

INTRODUCTION

Congenital diaphragmatic hernia (CDH) is a complex pathology with severe pulmonary morbidity. Administration of surfactant in CDH is controversial, and the advent of fetoscopic endoluminal tracheal occlusion (FETO) has added further complexity. While FETO has been shown to improve survival outcomes, there are risks of prematurity and potential surfactant deficiency. We aim to evaluate the characteristics and outcomes of surfactant administration for CDH infants and elucidate potential benefits or risks in this unique population.

METHODS

A single-center retrospective cohort review of patients with unilateral CDH from September 2015 to July 2022 was performed. Demographics, prognostic perinatal imaging features, and outcomes were collected. Patients were stratified by surfactant administration and history of FETO. Data were analyzed with descriptive statistics, two-sample t-tests, chi-squared analyses, and logistic regression.

RESULTS

Of 105 included patients, 19 (18%) underwent FETO and 25 (24%) received surfactant. Overall, surfactant recipients were born at earlier gestational ages and lower birthweights regardless of FETO history. Surfactant recipients possessed significantly worse prenatal prognostic features such as observed to expected total fetal lung volume, observed to expected lung to head ratio, and percent liver herniation. In CDH patients without FETO history, surfactant recipients demonstrated worse outcomes than nonrecipients. This association is notably absent in the FETO population, where surfactant recipients have more favorable survival and comparable outcomes. When controlling for defect severity or surfactant usage, as a proxy for respiratory status, surfactant recipients that underwent FETO trended toward improved survival and decreased ECMO use.

CONCLUSIONS

Surfactant administration is not associated with increased morbidity and mortality and may be beneficial in CDH patients that have undergone FETO.

Review of the Evaluation of Pulmonary Hypoplasia as an Important Determinant of Clinical Outcomes in Infants with Congenital Diaphragmatic Hernia

Pulmonary hypoplasia is one of main causes of neonatal mortality and morbidity in patients with congenital diaphragmatic hernia. With most cases diagnosed prenatally, the emphasis is put on prediction of the severity of this defect. Several attempts are made to reduce the mortality and provide optimal prenatal and postnatal care. Appropriate estimation of risk of pulmonary hypoplasia also provides an important inclusion criterion for prenatal intervention. The main tool used for the detection and prediction of pulmonary hypoplasia is ultrasound, with an increasing number of available formulas to estimate the risk of occurrence of this phenomenon and complication associated with it. For most of the formulas used in this measurement method, the main limitations are either gestational-age dependency or limited research. Other imaging methods used to assess the risk of pulmonary hypoplasia involve magnetic resonance imaging and vascular assessment of affected lungs. The limitation in these remains the limited accessibility. Currently, the most widely used indexes are observed-to-expected lungs-to-head ratio and presence of liver herniation. These are the 2 most commonly used measurement methods, as they are the basis for patient qualification for fetoscopic endoluminal tracheal occlusion. This article aims to review the evaluation of pulmonary hypoplasia or hypoplastic lung disease as an important determinant of clinical outcomes in infants with congenital diaphragmatic hernia. In this review, we emphasize the importance of early prenatal diagnosis of congenital diaphragmatic hernia and present a summary of different methods of prenatal risk assessment of lung hypoplasia in congenital diaphragmatic hernia.

Characterization of the congenital diaphragmatic hernia model in C57BL/6J fetal mice: a step toward lineage tracing experiments

PURPOSE

Lineage tracing is key to study the fate of individual cells and their progeny especially in developmental biology. To conduct these studies, we aimed to establish a reproducible model of CDH in the most commonly used genetic background strain that is C57BL/6J mice.

METHODS

CDH was induced in C57BL/6J dams by maternal administration of nitrofen + bisdiamine at E8.5. Fetuses from olive oil-gavaged mothers served as controls. Lungs from CDH and control fetuses were compared for (1) growth via radial airspace count (RAC), mean linear intercept (MLI) and gene expression for Fgf10, Nrp1, and Ctnnb1; (2) maturation (Pdpn, Spc, Ager, Abca3, Eln, Acta2, Pdgfra) via gene and protein expression; (3) vascularization via gene and protein expression (CD31, Vegfa, Vegfr1/2, Epas1, Enos).

STATISTICS

unpaired t-test or Mann-Whitney test.

RESULTS

Nitrofen + bisdiamine administration resulted in 36% left-sided CDH (31% mortality). CDH fetuses had hypoplastic lungs and impaired growth (lower RAC, higher MLI, lower Fgf10, Nrp1, Ctnnb1), maturation (decreased Pdpn, Ager, Eln gene expression), and vascularization (decreased Cd31, Vegfr1/2; Epas1 and Enos). Lower protein expression was confirmed for PDPN, ELN and CD31.

CONCLUSION

Modeling CDH in C57BL/6J mouse fetuses is effective in reproducing the classical CDH hallmarks. This model will be critical for lineage tracing experiments.

Treatment with Amniotic Fluid Stem Cell Extracellular Vesicles Promotes Fetal Lung Branching and Cell Differentiation at Canalicular and Saccular Stages in Experimental Pulmonary Hypoplasia Secondary to Congenital Diaphragmatic Hernia

Pulmonary hypoplasia secondary to congenital diaphragmatic hernia (CDH) is characterized by impaired branching morphogenesis and differentiation. We have previously demonstrated that administration of extracellular vesicles derived from rat amniotic fluid stem cells (AFSC-EVs) rescues development of hypoplastic lungs at the pseudoglandular and alveolar stages in rodent models of CDH. Herein, we tested whether AFSC-EVs exert their regenerative effects at the canalicular and saccular stages, as these are translationally relevant for clinical intervention. To induce fetal pulmonary hypoplasia, we gavaged rat dams with nitrofen at embryonic day 9.5 and demonstrated that nitrofen-exposed lungs had impaired branching morphogenesis, dysregulated signaling pathways relevant to lung development (FGF10/FGFR2, ROBO/SLIT, Ephrin, Neuropilin 1, β-catenin) and impaired epithelial and mesenchymal cell marker expression at both stages. AFSC-EVs administered to nitrofen-exposed lung explants rescued airspace density and increased the expression levels of key factors responsible for branching morphogenesis. Moreover, AFSC-EVs rescued the expression of alveolar type 1 and 2 cell markers at both canalicular and saccular stages and restored markers of club, ciliated epithelial, and pulmonary neuroendocrine cells at the saccular stage. AFSC-EV-treated lungs also had restored markers of lipofibroblasts and PDGFRA+ cells to control levels at both stages. EV tracking showed uptake of AFSC-EV RNA cargo throughout the fetal lung and an mRNA-miRNA network analysis identified that several miRNAs responsible for regulating lung development processes were contained in the AFSC-EV cargo. These findings suggest that AFSC-EV-based therapies hold potential for restoring fetal lung growth and maturation in babies with pulmonary hypoplasia secondary to CDH.

Autophagy is Impaired in Fetal Hypoplastic Lungs and Rescued by Administration of Amniotic Fluid Stem Cell Extracellular Vesicles

RATIONALE

Pulmonary hypoplasia secondary to congenital diaphragmatic hernia (CDH) is characterized by reduced branching morphogenesis, which is responsible for poor clinical outcomes. Administration of amniotic fluid stem cell extracellular vesicles (AFSC-EVs) rescues branching morphogenesis in rodent fetal models of pulmonary hypoplasia. Herein, we hypothesized that AFSC-EVs exert their regenerative potential by affecting autophagy, a process required for normal lung development.

OBJECTIVES

To evaluate autophagy in hypoplastic lungs throughout gestation and establish whether AFSC-EV administration improves branching morphogenesis through autophagy-mediated mechanisms.

METHODS

EVs were isolated from c-kit+ AFSC conditioned medium by ultracentrifugation and characterized by size, morphology, and EV marker expression. Branching morphogenesis was inhibited in rat fetuses by nitrofen administration to dams and in human fetal lung explants by blocking RAC1 activity with NSC23766. Expression of autophagy activators (BECN1 and ATG5) and adaptor (SQSTM1) was analyzed in vitro (rat and human fetal lung explants) and in vivo (rat fetal lungs). Mechanistic studies on rat fetal primary lung epithelial cells were conducted using inhibitors for microRNA-17 and -20a contained in the AFSC-EV cargo and known to regulate autophagy.

MEASUREMENTS AND MAIN RESULTS

Rat and human models of fetal pulmonary hypoplasia showed reduced autophagy at different developmental stages. AFSC-EV administration restored autophagy levels in both pulmonary hypoplasia models by transferring miR-17~92 cluster members contained in the EV cargo.

CONCLUSIONS

AFSC-EV treatment rescues branching morphogenesis partly by restoring autophagy through miRNA cargo transfer. This study enhances our understanding of pulmonary hypoplasia pathogenesis and creates new opportunities for fetal therapeutic intervention in CDH babies. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Fetal lung regeneration using stem cell-derived extracellular vesicles: A new frontier for pulmonary hypoplasia secondary to congenital diaphragmatic hernia

The poor outcomes of babies with congenital diaphragmatic hernia (CDH) are directly related to pulmonary hypoplasia, a cosndition characterized by impaired lung development. Although the pathogenesis of pulmonary hypoplasia is not fully elucidated, there is now evidence that CDH patients have missing or dysregulated microRNAs (miRNAs) that regulate lung development. A prenatal therapy that supplements these missing/dysregulated miRNAs could be a strategy to rescue normal lung development. Extracellular vesicles (EVs), also known as exosomes when of small dimensions, are lipid-bound nanoparticles that can transfer their heterogeneous cargo (proteins, lipids, small RNAs) to target cells to induce biological responses. Herein, we review all studies that show evidence for stem cell-derived EVs as a regenerative therapy to rescue normal development in CDH fetal lungs. Particularly, we report studies showing that administration of EVs derived from amniotic fluid stem cells (AFSC-EVs) to models of pulmonary hypoplasia promotes fetal lung growth and maturation via transfer of miRNAs that are known to regulate lung developmental processes. We also describe that stem cell-derived EVs exert effects on vascular remodeling, thus possibly preventing postnatal pulmonary hypertension. Finally, we discuss future perspectives and challenges to translate this promising stem cell EV-based therapy to clinical practice. This article is protected by copyright. All rights reserved.

Small Extracellular Vesicles from Human Amniotic Fluid Samples as Promising Theranostics

Since the first evidence that stem cells can provide pro-resolving effects via paracrine secretion of soluble factors, growing interest has been addressed to define the most ideal cell source for clinical translation. Leftover or clinical waste samples of human amniotic fluid obtained following prenatal screening, clinical intervention, or during scheduled caesarean section (C-section) delivery at term have been recently considered an appealing source of mesenchymal progenitors with peculiar regenerative capacity. Human amniotic fluid stem cells (hAFSC) have been demonstrated to support tissue recovery in several preclinical models of disease by exerting paracrine proliferative, anti-inflammatory and regenerative influence. Small extracellular vesicles (EVs) concentrated from the hAFSC secretome (the total soluble trophic factors secreted in the cell-conditioned medium, hAFSC-CM) recapitulate most of the beneficial cell effects. Independent studies in preclinical models of either adult disorders or severe diseases in newborns have suggested a regenerative role of hAFSC-EVs. EVs can be eventually concentrated from amniotic fluid (hAF) to offer useful prenatal information, as recently suggested. In this review, we focus on the most significant aspects of EVs obtained from either hAFSC and hAF and consider the current challenges for their clinical translation, including isolation, characterization and quantification methods.

Nanotechnology-based Approaches and Investigational Therapeutics against COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the novel coronavirus responsible for the current global pandemic, which first emerged in December 2019. This coronavirus has affected 217 countries worldwide, most of which have enacted non-remedial preventive measures, such as nationwide lockdowns, work from home, travel bans, and social isolation. Pharmacists, doctors, nurses, technologists, and other healthcare professionals have played pivotal roles during this pandemic. Unfortunately, confirmed drugs have not been identified for the treatment of patients with coronavirus disease 2019 (COVID-19) caused by SARSCoV2; however, favipiravir and remdesivir have been reported as promising antiviral drugs. Some vaccines have already been developed, and vaccination is ongoing globally. Various nanotechnologies are currently being developed in many countries for preventing SARS-CoV-2 spread and treating COVID-19 infections. In this article, we present an overview of the COVID-19 pandemic situation and discuss nanotechnology-based approaches and investigational therapeutics for COVID-19.

Mechanical Ventilation During Chronic Lung Disease

For infants with the most severe forms of chronic lung disease, regardless of etiology, chronic mechanical ventilation can provide stability, reduce acute respiratory events, and alleviate increased work of breathing. This approach prioritizes the baby's growth and development during early life. Once breathing comfortably, these infants can tolerate developmental therapies with the goal of achieving the best neurocognitive outcomes possible.

Fetal lung underdevelopment is rescued by administration of amniotic fluid stem cell extracellular vesicles in rodents

Fetal lung underdevelopment, also known as pulmonary hypoplasia, is characterized by decreased lung growth and maturation. The most common birth defect found in babies with pulmonary hypoplasia is congenital diaphragmatic hernia (CDH). Despite research and clinical advances, babies with CDH still have high morbidity and mortality rates, which are directly related to the severity of lung underdevelopment. To date, there is no effective treatment that promotes fetal lung growth and maturation. Here, we describe a stem cell-based approach in rodents that enhances fetal lung development via the administration of extracellular vesicles (EVs) derived from amniotic fluid stem cells (AFSCs). Using fetal rodent models of pulmonary hypoplasia (primary epithelial cells, organoids, explants, and in vivo), we demonstrated that AFSC-EV administration promoted branching morphogenesis and alveolarization, rescued tissue homeostasis, and stimulated epithelial cell and fibroblast differentiation. We confirmed this regenerative ability in in vitro models of lung injury using human material, where human AFSC-EVs obtained following good manufacturing practices restored pulmonary epithelial homeostasis. Investigating EV mechanism of action, we found that AFSC-EV beneficial effects were exerted via the release of RNA cargo. MicroRNAs regulating the expression of genes involved in lung development, such as the miR17-92 cluster and its paralogs, were highly enriched in AFSC-EVs and were increased in AFSC-EV-treated primary lung epithelial cells compared to untreated cells. Our findings suggest that AFSC-EVs hold regenerative ability for underdeveloped fetal lungs, demonstrating potential for therapeutic application in patients with pulmonary hypoplasia.

Diaphragmatic Hernia as a Prenatal Feature of Glycosylphosphatidylinositol Biosynthesis Defects and the Overlap With Fryns Syndrome - Literature Review

Fryns syndrome is an autosomal recessive multiple congenital anomaly syndrome, with diaphragmatic defects and secondary lung hypoplasia as cardinal features. Despite it was reported first in 1979, its exact etiology has not been established to date. With this review, we would like to draw attention to the prenatal presentation of multiple congenital anomalies syndromes, resulting from defects in the synthesis of glycosylphosphatidylinositol anchors, to be considered in a prenatal assessment of fetuses with DH and Fryns-like phenotype.

Computed tomography based measurements to evaluate lung density and lung growth after congenital diaphragmatic hernia

Emphysema-like-change of lung is one aspect of lung morbidity in children after congenital diaphragmatic hernia (CDH). This study aims to evaluate if the extent of reduced lung density can be quantified through pediatric chest CT examinations, if side differences are present and if emphysema-like tissue is more prominent after CDH than in controls. Thirty-seven chest CT scans of CDH patients (mean age 4.5 ± 4.0 years) were analyzed semi-automatically and compared to an age-matched control group. Emphysema-like-change was defined as areas of lung density lower than - 950 HU in percentage (low attenuating volume, LAV). A p-value lower than 0.05 was regarded as statistically significant. Hypoattenuating lung tissue was more frequently present in the ipsilateral lung than the contralateral side (LAV 12.6% vs. 5.7%; p < 0.0001). While neither ipsilateral nor contralateral lung volume differed between CDH and control (p > 0.05), LAV in ipsilateral (p = 0.0002), but not in contralateral lung (p = 0.54), was higher in CDH than control. It is feasible to quantify emphysema-like-change in pediatric patients after CDH. In the ipsilateral lung, low-density areas are much more frequently present both in comparison to contralateral and to controls. Especially the ratio of LAV ipsilateral/contralateral seems promising as a quantitative parameter in the follow-up after CDH.

Evaluation of Pulmonary Hypoplasia in Various Congenital Anomalies with a Comparison of Two Conventional Methods of Assessment: Radial Alveolar Count (RAC) and Lung Weight: Body Weight Ratio (LBW)

OBJECTIVE

Pulmonary hypoplasia is common in the perinatal period and causes death in newborn infants. It is commonly associated with a number of malformation syndromes. Various parameters are used to estimate pulmonary hypoplasia at fetal autopsy including Lung Weight Body Weight ratio (LW:BW), Radial Alveolar Count (RAC) and DNA estimation.

MATERIAL AND METHOD

This study was carried out as a retrospective analysis of 108 lung specimens of fetuses with congenital anomalies for a period of five years. All terminated fetuses with anomalies were received with 10% formalin. An inverted Y-shaped incision was made on the fetus to remove the lungs. Lung weight and body weight were measured and the ratio was calculated. Morphometric estimation of RAC was done microscopically by counting the number of alveoli using the Q capture software. RAC was calculated based on gestational age.

RESULTS

Among the restrictive lung diseases, pulmonary hypoplasia by the LW:BW ratio was prevalent in 43% while the same by RAC was 19%. Similarly, pulmonary hypoplasia by the LW:BW ratio was prevalent in 35% while the same by RAC was 26% among cases with non restrictive lung diseases. Oligohydramnios showed the highest prevalence of pulmonary hypoplasia (23.7%), followed by renal anomalies (16.9%) and CNS anomalies (15.2%).

CONCLUSION

Pulmonary hypoplasia is a common occurrence in many congenital anomalies, premature rupture of membranes, and hydrops fetalis. Identifying the anomaly during the intrauterine period will help to anticipate and accordingly manage the baby in the postpartum period. Early diagnosis of correctable condition like oligohydramnios will also help in the early intervention and prevention of pulmonary hypoplasia.

Impacts of Respiratory Muscle Training on Respiratory Functions, Maximal Exercise Capacity, Functional Performance, and Quality of Life in School-Aged Children with Postoperative Congenital Diaphragmatic Hernia

Objectives

Congenital diaphragmatic hernia (CDH) is a birth defect affecting the respiratory functions, functional performance, and quality of life (QOL) in school-aged children. Rarely have studies been conducted to evaluate the impacts of respiratory muscle training on school-aged children with postoperative CDH. The current study was designed to evaluate the impacts of respiratory muscle training on respiratory function, maximal exercise capacity, functional performance, and QOL in these children.

Methods

This study is a randomized control study. 40 children with CDH (age: 9-11 years) were assigned randomly into two groups. The first group conducted an incentive spirometer exercise combined with inspiratory muscle training (study group, n = 20), whereas the second group conducted only incentive spirometer exercise (control group, n = 20), thrice weekly for twelve consecutive weeks. Respiratory functions, maximal exercise capacity, functional performance, and pediatric quality of life inventory (PedsQL) were assessed before and after the treatment program. Results. Regarding the posttreatment analysis, the study group showed significant improvements in all outcome measures (FVC%, p < 0.001; FEV1%, p = 0.002; VO₂max, p = 0.008; VE/VCO₂ slope, p = 0.002; 6-MWT, p < 0.001; and PedsQL, p < 0.001), whereas the control group did not show significant changes (p > 0.05).

Conclusion

Respiratory muscle training may improve respiratory functions, maximal exercise capacities, functional performance, and QOL in children with postoperative CDH. Clinical commendations have to be considered to include respiratory muscle training in pulmonary rehabilitation programs in children with a history of CDH.

Therapy at 30 days of life predicts lung function at 6 to 12 months in infants with congenital diaphragmatic hernia

INTRODUCTION

Congenital diaphragmatic hernia (CDH) is associated with variable degrees of lung hypoplasia. Pulmonary support at 30 days postnatal age was found to be the strongest predictor of inpatient mortality and morbidity among CDH infants and was also associated with higher pulmonary morbidity at 1 and 5 years. It is not known, however, if there is a relationship between the need for medical therapy at 30 days of life and subsequent abnormalities in lung function as reflected in infant pulmonary function test (iPFT) measurements.

OBJECTIVE

We hypothesized that CDH infants who require more intensive therapy at 30 days would have more abnormal iPFT values at the time of their first infant pulmonary function study, reflecting the more severe spectrum of lung hypoplasia.

METHODS

A single-institution chart review of all CDH survivors who were enrolled in a Pulmonary Hypoplasia Program (PHP) through July 2019, and treated from 2002 to 2019 was performed. All infants were divided into groups based on their need for noninvasive (supplemental oxygen, high flow therapy, noninvasive mechanical ventilation) or invasive (mechanical ventilation, extracorporeal membrane oxygenation) respiratory assistance, bronchodilators, diuretic use, and pulmonary hypertension (PH) therapy (inhaled and/or systemic drugs) at 30 days. Descriptive and statistical analyses were performed between groups comparing subsequent lung function measurements.

RESULTS

A total of 382 infants (median gestational age [GA] 38.4 [interquartile range (IQR) = 37.1-39] weeks, 41.8% female, 70.9% Caucasian) with CDH were enrolled in the PHP through July 2019, and 118 infants underwent iPFT. The median age of the first iPFT was 6.6 (IQR = 5.3-11.7) months. Those requiring any pulmonary support at 30 days had a higher functional residual capacity (FRC) (z) (P = .03), residual volume (RV) (z) (P = .008), ratio of RV to total lung capacity (RV/TLC) (z) (P = .0001), and ratio of FRC to TLC (FRC/TLC) (z) (P = .001); a lower forced expiratory volume at 0.5 seconds (FEV0.5) (z) (P = .03) and a lower respiratory system compliance (Crs) (P = .01) than those who did not require any support. Similarly, those requiring diuretics and/or PH therapy at 30 days had higher fractional lung volumes, lower forced expiratory flows and Crs than infants who did not require such support (P < .05).

CONCLUSIONS

Infants requiring any pulmonary support, diuretics and/or PH therapy at 30 postnatal days have lower forced expiratory flows and higher fractional lung volumes, suggesting a greater degree of lung hypoplasia. Our study suggests that the continued need for PH, diuretic or pulmonary support therapy at 30 days can be used as additional risk-stratification measurements for evaluation of infants with CDH.

Congenital diaphragmatic hernia: current management strategies from antenatal diagnosis to long-term follow-up

Congenital diaphragmatic hernia (CDH) is a developmental birth defect consisting of a diaphragmatic defect and abnormal lung development. CDH complicates 2.3-2.8 per 10,000 live births. Despite efforts to standardize clinical practice, management of CDH remains challenging. Frequent re-evaluation of clinical practices in CDH reveals that management of CDH is evolving from one of postnatal stabilization to prenatal optimization. Translational research reveals promising avenues for in utero therapeutic intervention, including fetoscopic endoluminal tracheal occlusion. These remain highly experimental and demand improved antenatal diagnostics. Timely diagnosis of CDH and identification of severely affected fetuses allow time for delivery planning or in utero therapeutics. Optimal perinatal care and surgical treatment strategies are highly debated. Improved CDH mortality rates have placed increased emphasis on identifying and monitoring the long-term sequelae of disease throughout childhood and into adulthood. We review the current management strategies for CDH, highlighting where progress has been made, and where future developments have the potential to revolutionize care in this vulnerable patient population.

Fetal tracheal occlusion for congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) remains one of the most elusive birth defects to treat. Despite greater knowledge of disease and advances in technology, approximately one-third of CDH children born today still die. Consequently, clinicians and researchers have struggled to find the optimal treatment strategies for CDH. Without further innovations in postnatal treatment, many have focused an antenatal approach to improve pulmonary function. Fetoscopic Endoluminal Tracheal Occlusion (FETO) for CDH has evolved to the bedside after decades of research. While still under clinical investigation, FETO remains a promising adjunct to the treatment of CDH.

Endoplasmic reticulum stress response is activated in pulmonary hypoplasia secondary to congenital diaphragmatic hernia, but is decreased by administration of amniotic fluid stem cells

PURPOSE

Pulmonary hypoplasia secondary to congenital diaphragmatic hernia (CDH) is characterized by impaired epithelial homeostasis. Recently, amniotic fluid stem cells (AFSCs) have been shown to promote growth in hypoplastic lungs of rat fetuses with CDH. Herein, we investigated whether CDH hypoplastic lungs mount an endoplasmic reticulum (ER) stress response and whether AFSCs could re-establish pulmonary epithelial homeostasis.

METHODS

Primary epithelial cells were isolated from fetal rat lungs at E14.5 from control and nitrofen-exposed dams at E9.5. Nitrofen-exposed epithelial cells were grown in medium alone or co-cultured with AFSCs. Epithelial cell cultures were compared for apoptosis (TUNEL), cytotoxicity (LIVE/DEAD assay), proliferation (5'EdU), and ER stress (CHOP, Bcl-2) using one-way ANOVA (Dunn's post-test).

RESULTS

Compared to control, nitrofen-exposed epithelial cells had increased cytotoxicity and apoptosis, reduced proliferation, and activated ER stress. AFSCs restored apoptosis, proliferation, and ER stress back to control levels, and significantly reduced cytotoxicity.

CONCLUSIONS

This study shows for the first time that ER stress-induced apoptosis is activated in the pulmonary epithelium of hypoplastic lungs from fetuses with CDH. AFSC treatment restores epithelial cellular homeostasis by attenuating the ER stress response and apoptosis, by increasing proliferation and migration ability, and by reducing cytotoxicity.

Evaluation of Neonatal Lung Volume Growth by Pulmonary Magnetic Resonance Imaging in Patients with Congenital Diaphragmatic Hernia

OBJECTIVE

To evaluate postnatal lung volume in infants with congenital diaphragmatic hernia (CDH) and determine if a compensatory increase in lung volume occurs during the postnatal period.

STUDY DESIGN

Using a novel pulmonary magnetic resonance imaging method for imaging neonatal lungs, the postnatal lung volumes in infants with CDH were determined and compared with prenatal lung volumes obtained via late gestation magnetic resonance imaging.

RESULTS

Infants with left-sided CDH (2 mild, 9 moderate, and 1 severe) were evaluated. The total lung volume increased in all infants, with the contralateral lung increasing faster than the ipsilateral lung (mean ± SD: 4.9 ± 3.0 mL/week vs 3.4 ± 2.1 mL/week, P = .005). In contrast to prenatal studies, the volume of lungs of infants with more severe CDH grew faster than the lungs of infants with more mild CDH (Spearman's ρ=-0.086, P = .01). Although the contralateral lung volume grew faster in both mild and moderate groups, the majority of total lung volume growth in moderate CDH came from increased volume of the ipsilateral lung (42% of total lung volume increase in the moderate group vs 32% of total lung volume increase in the mild group, P = .09). Analysis of multiple clinical variables suggests that increased weight gain was associated with increased compensatory ipsilateral lung volume growth (ρ = 0.57, P = .05).

CONCLUSIONS

These results suggest a potential for postnatal catch-up growth in infants with pulmonary hypoplasia and suggest that weight gain may increase the volume growth of the more severely affected lung.

Pulmonary hypoplasia

To survive the transition to extrauterine life, newborn infants must have lungs that provide an adequate surface area and volume to allow for gas exchange. The dynamic activities of fetal breathing movements and accumulation of lung luminal fluid are key to fetal lung development throughout the various phases of lung development and growth, first by branching morphogenesis, and later by septation. Because effective gas exchange is essential to survival, pulmonary hypoplasia is among the leading findings on autopsies of children dying in the newborn period. Management of infants born prematurely who had disrupted lung development, especially at the pre-glandular or canalicular periods, may be challenging, but limited success has been reported. Growing understanding of stem cell biology and mechanical development of the lung, and how to apply them clinically, may lead to new approaches that will lead to better outcomes for these patients.

Hyperpolarized Gas Magnetic Resonance Lung Imaging in Children and Young Adults

The assessment of early pulmonary disease and its severity can be difficult in young children, as procedures such as spirometry cannot be performed on them. Computed tomography provides detailed structural images of the pulmonary parenchyma, but its major drawback is that the patient is exposed to ionizing radiation. In this context, magnetic resonance imaging (MRI) is a promising technique for the evaluation of pediatric lung disease, especially when serial imaging is needed. Traditionally, MRI played a small role in evaluating the pulmonary parenchyma. Because of its low proton density, the lungs display low signal intensity on conventional proton-based MRI. Hyperpolarized (HP) gases are inhaled contrast agents with an excellent safety profile and provide high signal within the lung, allowing for high temporal and spatial resolution imaging of the lung airspaces. Besides morphologic information, HP MR images also offer valuable information about pulmonary physiology. HP gas MRI has already made new contributions to the understanding of pediatric lung diseases and may become a clinically useful tool. In this article, we discuss the HP gas MRI technique, special considerations that need to be made when imaging children, and the role of MRI in 2 of the most common chronic pediatric lung diseases, asthma and cystic fibrosis. We also will discuss how HP gas MRI may be used to evaluate normal lung growth and development and the alterations occurring in chronic lung disease of prematurity and in patients with a congenital diaphragmatic hernia.

Antenatal predictors of outcome in prenatally diagnosed congenital diaphragmatic hernia (CDH)

BACKGROUND

Pulmonary hypoplasia is the main cause of mortality in isolated congenital diaphragmatic hernia (CDH) and its prediction is paramount when counseling parents. We sought to identify antenatal parameters that predicted neonatal mortality in CDH.

METHOD

Search was conducted in MEDLINE, EMBASE, Cochrane Database of Systematic reviews, PubMed, Scopus, and Web of Science on the ability of lung-to-head ratio (LHR), observed-to-expected LHR (o/e LHR), total fetal lung volume (TFLV), o/e TFLV, percentage predicted lung volume (PPLV) and degree of liver herniation to predict neonatal morbidity and mortality in fetuses with CDH. Primary outcome was perinatal survival and secondary was the use of extracorporeal membrane oxygenation (ECMO).

RESULTS

Until April 2016, 1067 articles were found, of which 22 were included in our meta-analysis. This showed that the odds of survival with LHR <1.0 and liver herniation on ultrasound were 0.14 (CI 0.10-0.27) and 0.21 (CI 0.13-0.35) respectively. Mean LHR, o/e LHR, absolute TFLV, o/e TFLV, PPLV and liver herniation all predicted survival, however o/e LHR and o/e TFLV performed best in this prediction. When the longest diameter measurement method was used, the o/e TFLV (summary area under curve (AUC) 0.8) was slightly superior to o/e LHR (summary AUC 0.78). This difference disappeared when LHR was measured by the trace method. The most discriminatory threshold for O/E LHR and O/E TFLV was 25%. LHR <1 was predictive of extracorporeal life support (ECLS) use.

CONCLUSION

O/E LHR, o/e TFLV (thresholds of 25%) and liver herniation are good predictors of mortality in CDH.

LEVEL OF EVIDENCE

Level II Type of study: Systematic review and meta-analysis.

Enhanced Pulmonary Vascular and Alveolar Development via Prenatal Administration of a Slow-Release Synthetic Prostacyclin Agonist in Rat Fetal Lung Hypoplasia

Lung hypoplasia and pulmonary hypertension are the major causes of mortality in neonates with congenital diaphragmatic hernia (CDH). Although the prostaglandin pathway plays a pivotal role in lung development, the reported efficacy of postnatal prostaglandin agonist treatment is suboptimal. We hypothesized that prenatal treatment with ONO-1301SR, a slow-release form of a novel synthetic prostacyclin agonist with thromboxane inhibitory activity, might enhance the development of lungs exhibiting hypoplasia in the fetal period. On embryonic day (E) 9.5, nitrofen was given to pregnant Sprague-Dawley rats to establish a CDH-related lung hypoplasia model, whereas normal rats received the vehicle only. The same day, either ONO-1301SR or a placebo was also randomly administered. On E21.5, the fetuses of the normal group and those exhibiting CDH were analyzed. Prenatal ONO-1301SR administration had no influence on the incidence of nitrofen-induced CDH. The lung-to-body weight ratio in the CDH+ONO group was greater than that in the CDH group. Histologically, the medial wall in the CDH+ONO group was two-thirds thinner than that in the CDH group. In addition, the number of Ttf-1-positive cells and the capillary density were ≥1.5 times greater in the CDH+ONO group than in the CDH group, and this increase was associated with higher expression of vascular endothelial growth factor and stromal cell-derived factor in the CDH+ONO group, suggesting enhanced development of the alveolar and capillary networks. Thus, prenatal ONO-1301SR was protective against the progression of lung hypoplasia associated with CDH in a nitrofen-induced rat model, indicating the potential of this treatment for pathologies exhibiting lung hypoplasia.

Risk of Readmission for Wheezing during Infancy in Children with Congenital Diaphragmatic Hernia

RATIONALE

Congenital diaphragmatic hernia (CDH) is associated with a high incidence of respiratory problems, even after initial hospital discharge. These problems are likely to lead to re-hospitalization during infancy, although actual frequency of readmissions is unknown.

OBJECTIVE

We aimed to determine the rate of hospitalization for wheezing in infants with CDH between the time of initial discharge and 24 months of age, and to identify factors associated with readmission.

METHODS

Data about infants with CDH born in three French reference tertiary centers between January 2009 and March 2013 who were alive at hospital discharge, were extracted from a prospective national database.

RESULTS

Ninety-two children were identified, and 86 were included in the analysis. In total, 116 wheezing episodes requiring a doctor's visit occurred in 50 infants (58%) before 24 months of age. Twenty-two children (26%) were readmitted at least once for wheezing exacerbations. RSV was present in 6 of 15 (40%) of children with available nasal samples at first readmission, and 1 of 5 (20%) at second readmission. Thoracic herniation of the liver, low gestational age, longer initial hospitalization, need for oxygen therapy at home, and eczema were all significantly associated with readmission for wheezing exacerbations. Fifty-three infants (62%) received palivizumab prophylaxis, but there was no association with the overall rate of readmission for wheezing exacerbations or RSV-related hospitalization.

CONCLUSIONS

The rate of readmission for wheezing among infants with CDH is high, and significantly influenced by several prenatal and neonatal factors. Palivizumab prophylaxis was not associated with the rate of readmission.

Pulmonary ventilation and micro-structural findings in congenital diaphragmatic hernia

BACKGROUND

With increasing survival of patients with more severe forms of congenital diaphragmatic hernia (CDH) and risk of long-term respiratory morbidity, studies on lung morphology are needed. We used hyperpolarised (3) He MRI and anatomical (1) H MRI in a cohort of young adult CDH patients to image regional lung ventilation and microstructure, focusing on morphological and micro-structural (alveolar) abnormalities.

METHODS

Nine patients with left-sided CDH, born 1975-1993, were studied. Regional ventilation was imaged with hyperpolarised (3) He MRI, and the (3) He apparent diffusion coefficient (ADC) was computed separately for the ipsilateral and contralateral lungs. (1) H MRI was used to image lung anatomy, total lung volume and motion during free-breathing.

RESULTS

(3) He MRI showed ventilation abnormalities in six patients, ranging from a single ipsilateral ventilation defect (3 patients) to multiple ventilation defects in both lungs (one patient treated with extra corporeal membrane oxygenation). In eight patients, (3) He ADC values for the ipsilateral lung were significantly higher than those for the contralateral lung.

CONCLUSIONS

Functional and micro-structural changes persist into adulthood in most CDH patients. Ipsilateral elevated (3) He ADC values are consistent with enlargement of mean dimensions of the confining lung micro-structure at the alveolar level.

Correlation of Observed-to-Expected MRI Fetal Lung Volume and Ultrasound Lung-to-Head Ratio at Different Gestational Times in Fetuses With Congenital Diaphragmatic Hernia

OBJECTIVE

The purpose of this study is to compare the observed-to-expected MRI fetal lung volume and the observed-to-expected ultrasound lung-to-head ratio intraindividually for prediction of survival, the need for extracorporeal membrane oxygenation (ECMO) therapy, and the development of chronic lung disease (CLD) at different times of gestation (< 28, 28-32, and > 32 weeks) in fetuses with congenital diaphragmatic hernia (CDH), and to analyze the intraindividual correlation of observed-to-expected MRI fetal lung volume and observed-to-expected ultrasound lung-to-head ratio.

MATERIALS AND METHODS

Two hundred one fetuses were included in our study. Observed-to-expected MRI fetal lung volume and observed-to-expected ultrasound lung-to-head ratio were calculated for 270 MRI and ultrasound examinations performed within 72 hours of each other. The prognostic accuracy of observed-to-expected MRI fetal lung volume and observed-to-expected ultrasound lung-to-head ratio was assessed by performing ROC analysis. Correlation was determined using linear regression analysis.

RESULTS

The results revealed statistically significant differences between the observed-to-expected MRI fetal lung volume and observed-to-expected ultrasound lung-to-head ratio for the prediction of survival, the need for ECMO therapy, and the development of CLD in fetuses with left-sided CDH (p ≤ 0.0444), with the highest prognostic accuracy for survival (AUC = 0.863). Observed-to-expected MRI fetal lung volume and observed-to-expected ultrasound lung-to-head ratio correlated statistically significantly (p < 0.0001) for left-sided CDH with correlation coefficients (r) of 0.71, 0.71, and 0.56 for early, intermediate, and late times of gestation, respectively. The correlation was not statistically significant at any time for right-sided CDH (p ≥ 0.3947; r ≤ 0.26).

CONCLUSION

Observed-to-expected MRI fetal lung volume and observed-to-expected ultrasound lung-to-head ratio are valuable prognostic parameters for prenatal prediction of survival, the need for ECMO therapy, and the development of CLD in fetuses with left-sided CDH at all times of gestation. Observed-to-expected MRI fetal lung volume and observed-to-expected ultrasound lung-to-head ratio correlate statistically significantly for left-sided CDH, and the correlation is best before 32 weeks' gestation, but they do not correlate statistically significantly for right-sided CDH.

A review of congenital diaphragmatic hernia

Background: Congenital diaphragmatic hernia (CDH) is a simple diaphragmatic defect that is seen frequently in antenatal scans. Though the surgical repair is relatively easy in the neonate, the mortality is high due to pulmonary hypoplasia and pulmonary vascular changes.

Materials and Methods: The goals of prenatal imaging are to establish the diagnosis. Assessment in a tertiary scanning center would identify prognostic factors which assist in counselling and planning antenatal management. However, the pulmonary hypoplasia associated with the CDH in moderate and severe cases makes the prognosis poor.

Conclusions: Fetal intervention such as, fetal tracheal occlusion, is being trialled and may change the outcomes in the future.

An association between pulmonary hypertension and impaired lung function in infants with congenital diaphragmatic hernia

RATIONALE

Infants with congenital diaphragmatic hernia (CDH) can develop pulmonary hypertension (PH) from decreased number and abnormal muscularization of pulmonary arteries. Normally pulmonary vascular growth and remodeling parallel airspace growth and alveolarization, which exhibits a wide morphologic variation in CDH.

AIM

To assess whether infants with CDH and PH have greater abnormalities in infant pulmonary function testing (IPFT) compared to those without PH.

METHODS

We reviewed results of IPFTs and echocardiograms performed on infants with CDH from 2004 to June 2011. Lung volumes, forced flows and tidal mechanics were standardized according to available reference values. Comparisons between infants with and without PH were performed using linear regression, adjusting for potential confounders.

MAIN RESULTS

Sixty-six infants were included; 18 had PH and 48 did not. Z-score values for functional residual capacity (FRC), residual volume (RV), FRC/total lung capacity (TLC), and RV/TLC were significantly higher in infants with CDH and PH compared to those without PH. Z-score values for forced flows including forced expiratory volume in the first 0.5 sec (FEV0.5) and FEV0.5/forced vital capacity were significantly lower in infants with CDH and PH compared to those without PH. For 29 infants studied on ≥2 occasions, the slopes of FRC, RV, and TLC versus length were significantly higher in those with persistent PH compared to those without.

CONCLUSIONS

Infants with CDH and persistent PH demonstrate greater airspace overdistension with growth compared to those without. Therapies that modify disrupted pulmonary vascular and alveolar formation could potentially improve future care of these patients.

Controversies in the management of severe congenital diaphragmatic hernia

Despite years of progress in perinatal care, severe congenital diaphragmatic hernia (CDH) remains a clinical challenge. Controversies include almost every facet of clinical care: the definition of severe CDH by prenatal and postnatal criteria, fetal surgical intervention, ventilator management, pulmonary hypertension management, use of extracorporeal membrane oxygenation, surgical considerations, and long-term follow-up. Breakthroughs are likely only possible by sharing of experience, collaboration between institutions and innovative therapies within well-designed multicenter clinical trials.

Comparison of ultrasound and magnetic resonance imaging parameters in predicting survival in isolated left-sided congenital diaphragmatic hernia

OBJECTIVE

To compare test characteristics of ultrasound- and magnetic resonance imaging (MRI)-derived parameters in predicting newborn survival in cases of isolated left-sided congenital diaphragmatic hernia (CDH).

METHODS

This was a retrospective study involving 85 fetuses with an isolated left CDH. All had detailed prenatal evaluation, prenatal care, delivery and postnatal care at a single institution. Ultrasound images were reviewed to allow calculation of the lung-to-head ratio (LHR) and the observed/expected LHR (O/E-LHR), and MRI images were reviewed to determine the observed/expected total lung volume (O/E-TLV) and the percent herniated liver (%HL). Univariable logistic regression was used to evaluate each parameter for its ability to predict survival. Receiver-operating characteristics (ROC) curves were constructed and test characteristics were determined for each parameter as a predictor of survival.

RESULTS

The overall survival for all fetuses included was 65%. Pseudo-R(2) values for all parameters were similar and were statistically significant as predictors of survival, with %HL having the highest pseudo-R(2) , of 0.28. ROC curve analysis showed ultrasound-determined parameters (LHR and O/E-LHR) to have a similar area under the curve (AUC), of 0.70, whilst MRI parameters (O/E-TLV and %HL) had AUC values of 0.82 and 0.84, respectively. At ROC-curve-determined cut-off values, MRI parameters had better test characteristics than did ultrasound parameters. At a standardized 5% false-positive rate, %HL performed best, with a sensitivity of 0.54 and a specificity of 0.95. At clinically employed cut-off values, sensitivity was similar for all parameters but MRI parameters provided the best combination of sensitivity and specificity, as evidenced by better likelihood ratios.

CONCLUSIONS

A variety of measures have been proposed as antenatal predictors of survival in CDH. Ultrasound parameters function at a similar level, whereas MRI-determined parameters appear to offer better predictive value.

Cord blood endothelial colony-forming cells from newborns with congenital diaphragmatic hernia

Endothelial colony-forming cells (ECFCs) are decreased in the cord blood of preterm infants with moderate-to-severe bronchopulmonary dysplasia. We quantified ECFCs from infants with congenital diaphragmatic hernia, a neonatal disorder with severe lung hypoplasia. Unlike newborns who develop bronchopulmonary dysplasia, those with congenital diaphragmatic hernia had increased and highly-proliferative cord blood ECFCs.

Management of prenatally diagnosed congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a congenital anomaly that presents with a broad spectrum of severity that is dependent upon components of pulmonary hypoplasia and pulmonary hypertension. While advances in neonatal care have improved the overall survival of CDH in experienced centers, mortality and morbidity remain high in a subset of CDH infants with severe CDH. Prenatal predictors have been refined for the past two decades and are the subject of another review in this issue. So far, all randomized trials comparing prenatal intervention to standard postnatal therapy have shown no benefit to prenatal intervention. Although recent non-randomized reports of success with fetoscopic endoluminal tracheal occlusion (FETO) and release are promising, prenatal therapy should not be widely adopted until a well-designed prospective randomized trial demonstrating efficacy is performed. The increased survival and subsequent morbidity of CDH survivors has resulted in the need to provide resources for the long-term follow up and support of the CDH population.

Use of ultrasound and MRI for evaluation of lung volumes in fetuses with isolated left congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is an anomaly that results in lung hypoplasia and pulmonary hypertension. The lungs of the CDH fetus have an abnormal architecture, with fewer bronchial branches and decreased number of arteries and veins, factors which result in pulmonary compromise postnatally. The goal of this review is to evaluate prenatal prognostic factors in the fetus with isolated left CDH, with particular emphasis on fetal MRI. These imaging indicators may be used to provide health professionals and the parents with the most accurate information about fetal prognosis.

Lung function at follow-up of infants with surgically correctable anomalies

Infants with congenital diaphragmatic hernia (CDH) or anterior wall defects (AWD) can suffer abnormal antenatal lung growth, the risk, however, may be greater for CDH infants. The objectives of this study were to test the hypothesis that following surgical correction, CDH infants would have worse lung function at follow-up than AWD infants and to determine whether fetal lung volume (FLV) results correlated with the lung function results at follow-up. Thirteen infants with CDH and 13 infants with AWD had lung function measurements at a median age of 11 (range 6-24) months; 17 of the infants had had their FLV assessed. Lung function was assessed by plethysmographic measurement of lung volume (FRCpleth) and airway resistance (Raw). In addition, functional residual capacity was assessed by a helium gas dilution technique (FRCHe); tidal breathing parameters (T(PTEF) :Te) and compliance and resistance of the respiratory system (Crs and Rrs, respectively) were also determined. FLV was assessed using three-dimensional (3D) ultrasound and virtual organ computer aided analysis. The CDH compared to the AWD infants had a higher median FRCpleth (41 ml/kg vs. 37 ml/kg, P = 0.043) and a lower median Crs (1.45 ml/cm H(2) O/kg vs. 2.78 ml/cm H(2) O/kg, P = 0.041). FRCpleth results correlated significantly with FLV results (r = 0.721, P < 0.001). In conclusion, infants with CDH had significantly different lung function at follow-up than AWD infants. Our findings suggest FLV results may predict lung function abnormalities at follow-up in infants with surgically correctable anomalies.

Genetic, host, and environmental interactions in a 19 year old with severe chronic obstructive lung disease; observations regarding the pathophysiology of airflow obstruction

A case of a 19-year-old with severe chronic obstructive pulmonary disease is presented. This case illustrates genetic (severe alpha-1 antitrypsin deficiency) and host factors (such as developmental diaphragmatic hernia and the innate response to injury), and environmental (high oxidative stress and lung injury) interactions that lead to severe chronic obstructive lung disease. The development of chronic lung disease was caused by lung injury under high oxidative and inflammatory conditions in the setting of a diaphragmatic hernia. In the absence of normal alpha-1 antitrypsin levels, a pro-elastolytic environment in the early period of lung growth enhanced the development of severe hyperinflation and precocious airflow obstruction.

Prospective longitudinal evaluation of lung function during the first year of life after repair of congenital diaphragmatic hernia

OBJECTIVE

To evaluate lung function and respiratory morbidity prospectively during the first year of life in patients with congenital diaphragmatic hernia and to study the effect of extracorporeal membrane oxygenation therapy.

DESIGN

Prospective longitudinal cohort study.

SETTING

Outpatient clinic of a tertiary-level pediatric hospital.

PATIENTS

The cohort of 43 infants included 12 patients treated with extracorporeal membrane oxygenation. Evaluation was at 6 and 12 months; 33 infants were evaluated at both time points.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Maximal expiratory flow at functional residual capacity and functional residual capacity were measured with Masterscreen Babybody. Z-scores were calculated for maximal expiratory flow at functional residual capacity. Mean maximal expiratory flow at functional residual capacity values at 6 and 12 months were significantly below the expected values (mean z-score -1.4 and -1.5, respectively) without a significant change between both time points. Values did not significantly differ between extracorporeal membrane oxygenation and nonextracorporeal membrane oxygenation-treated patients. Functional residual capacity values were generally high, 47% were above the suggested normal range, and did not change significantly over time. Mean functional residual capacity values in extracorporeal membrane oxygenation-treated patients were significantly higher than in nonextracorporeal membrane oxygenation-treated patients (p = .006). The difference (5.1 mL/kg ± 1.8 SE) did not change significantly between the two time points. Higher mean airway pressure and longer duration of ventilation were associated with higher functional residual capacity. None of the perinatal characteristics was associated with maximal expiratory flow at functional residual capacity. Mean weight z-scores were significantly below zero at both time points (p < .001). Mean weight z-score in extracorporeal membrane oxygenation-treated patients were lower than in nonextracorporeal membrane oxygenation-treated patients (p = .046).

CONCLUSIONS

Infants with congenital diaphragmatic hernia have decreased expiratory flows and increased functional residual capacity within the first year of life. Extracorporeal membrane oxygenation-treated patients with congenital diaphragmatic hernia may have more respiratory morbidity and concomitant growth impairment. Close follow-up beyond the neonatal period is therefore required.

Long term respiratory outcomes of congenital diaphragmatic hernia, esophageal atresia, and cardiovascular anomalies

Intrathoracic congenital malformations may be associated with long-term pulmonary morbidity. This certainly is the case for congenital diaphragmatic hernia, esophageal atresia and cardiac and aortic arch abnormalities. These conditions have variable degrees of impaired development of both the airways and lung vasculature, with a postnatal impact on lung function and bronchial reactivity. Pulmonary complications are themselves frequently associated to non-pulmonary morbidities, including gastrointestinal and orthopaedic complications. These are best recognized in a structured multidisciplinary follow-up clinic so that they can be actively managed.

Prospective longitudinal evaluation of lung function during the first year of life after extracorporeal membrane oxygenation

OBJECTIVE

To collect longitudinal data on lung function in the first year of life after extracorporeal membrane oxygenation and to evaluate relationships between lung function and perinatal factors. Longitudinal data on lung function in the first year of life after extracorporeal membrane oxygenation are lacking.

DESIGN

Prospective longitudinal cohort study.

SETTING

Outpatient clinic of a tertiary level pediatric hospital.

PATIENTS

The cohort consisted of 64 infants; 33 received extracorporeal membrane oxygenation for meconium aspiration syndrome, 14 for congenital diaphragmatic hernia, four for sepsis, six for persistent pulmonary hypertension of the neonate, and seven for respiratory distress syndrome of infancy. Evaluation was at 6 mos and 12 mos; 39 infants were evaluated at both time points .

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Functional residual capacity and forced expiratory flow at functional residual capacity were measured and expressed as z score. Mean (sem) functional residual capacities in z score were 0.0 (0.2) and 0.2 (0.2) at 6 mos and 12 mos, respectively. Mean (sem) forced expiratory flow was significantly below average (z score = 0) (p < .001) at 6 mos and 12 mos: -1.1 (0.1) and -1.2 (0.1), respectively. At 12 mos, infants with diaphragmatic hernia had a functional residual capacity significantly above normal: mean (sem) z score = 1.2 (0.5).

CONCLUSIONS

Infants treated with extracorporeal membrane oxygenation have normal lung volumes and stable forced expiratory flows within normal range, although below average, within the first year of life. There is reason to believe, therefore, that extracorporeal membrane oxygenation either ameliorates the harmful effects of mechanical ventilation or somehow preserves lung function in the very ill neonate.

Bronchopulmonary innervation defects in infants and rats with congenital diaphragmatic hernia

INTRODUCTION

Pulmonary morbidity in survivors of congenital diaphragmatic hernia (CDH) is caused by hypoplasia, barotraumas, or other reasons. We have previously shown deficient tracheal innervation in rats with CDH. Now we examine whether bronchopulmonary innervation is also abnormal in both infants and rats with CDH.

MATERIAL AND METHODS

Sections of E15, E18, and E21 rat lungs were immunostained for Protein gene product 9.5 and S100 antibodies. Similar immunostaining was performed on tissue from infants dying from CDH (n = 6) and other causes (n = 6) with Neurofilament, S100, and Rearranged during transfection antibodies. Nerve trunks/bronchus were counted, and the proportion of glial and RET-positive cells/bronchial surface was calculated. Glial cell-line derived neurotrophic factor protein and mRNA were measured in rat lungs.

RESULTS

Nerve trunks/bronchus were decreased in infants and rat fetuses with CDH. In contrast, glial and RET-positive cells/bronchial surface were increased in infants and rats with CDH. Both lungs were equally affected. GDNF protein was high, whereas GDNF mRNA was decreased in preterm animals with CDH.

CONCLUSIONS

The lungs of infants and rats with CDH have decreased neural components compensated by increased supporting glial cells and persistence high expression of RET and GDNF protein. Because bronchopulmonary innervation controls airway smooth muscle, vessels, and glandular secretions, it is tempting to hypothesize that these deficiencies might play a role in respiratory morbidity in CDH.

Management of prenatally diagnosed congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a congenital anomaly that presents with a broad spectrum of severity dependent upon components of pulmonary hypoplasia and pulmonary hypertension. While advances in neonatal care have improved the overall survival of CDH in experienced centers, mortality and morbidity remain high in a subset of CDH infants with severe CDH. The most important prenatal predictor of outcome in left-sided CDH is liver position. More precise and reproducible prenatal predictive parameters need to be developed to allow standardization of results between centers and appropriate design of clinical trials in CDH. Thus far, all randomized trials comparing prenatal intervention to standard postnatal therapy have shown no benefit to prenatal intervention. Although recent non-randomized reports of success with balloon tracheal occlusion (and release) are promising, prenatal therapy should not be widely adopted until a well-designed prospective randomized trial demonstrating efficacy is performed. The increased survival and subsequent morbidity of CDH survivors has resulted in the need to provide resources for the long-term follow-up and support of the CDH population.

The long-term follow-up of patients with a congenital diaphragmatic hernia: a broad spectrum of morbidity

Congenital diaphragmatic hernia (CDH) is a life-threatening anomaly with a mortality rate of approximately 40-50%, depending on case selection. It has been suggested that new therapeutic modalities such as nitric oxide (NO), high frequency oxygenation (HFO) and extracorporal membrane oxygenation (ECMO) might decrease mortality associated with pulmonary hypertension and the sequelae of artificial ventilation. When these new therapies indeed prove to be beneficial, a larger number of children with severe forms of CDH might survive, resulting in an increase of CDH-associated complications and/or consequences. In follow-up studies of infants born with CDH, many complications including pulmonary damage, cardiovascular disease, gastro-intestinal disease, failure to thrive, neurocognitive defects and musculoskeletal abnormalities have been described. Long-term pulmonary morbidity in CDH consists of obstructive and restrictive lung function impairments due to altered lung structure and prolonged ventilatory support. CDH has also been associated with persistent pulmonary vascular abnormalities, resulting in pulmonary hypertension in the neonatal period. Long-term consequences of pulmonary hypertension are unknown. Gastro-esophageal reflux disease (GERD) is also an important contributor to overall morbidity, although the underlying mechanism has not been fully understood yet. In adult CDH survivors incidence of esophagitis is high and even Barrett's esophagus may ensue. Yet, in many CDH patients a clinical history compatible with GERD seems to be lacking, which may result in missing patients with pathologic reflux disease. Prolonged unrecognized GERD may eventually result in failure to thrive. This has been found in many young CDH patients, which may also be caused by insufficient intake due to oral aversion and increased caloric requirements due to pulmonary morbidity. Neurological outcome is determined by an increased risk of perinatal and neonatal hypoxemia in the first days of life of CDH patients. In patients treated with ECMO, the incidence of neurological deficits is even higher, probably reflecting more severe hypoxemia and the risk of ECMO associated complications. Many studies have addressed the substantial impact of the health problems described above, on the overall well-being of CDH patients, but most of them concentrate on the first years after repair and only a few studies focus on the health-related quality of life in CDH patients. Considering the scattered data indicating substantial morbidity in long-term survivors of CDH, follow-up studies that systematically assess long-term sequelae are mandatory. Based on such studies a more focused approach for routine follow-up programs may be established.

Comparison of fetal lung area to head circumference ratio with lung volume in the prediction of postnatal outcome in diaphragmatic hernia

OBJECTIVES

To compare prediction of postnatal survival in isolated diaphragmatic hernia by prenatal two-dimensional (2D) versus three-dimensional (3D) sonographic assessment of the contralateral lung.

METHODS

The lung area to head circumference ratio (LHR) of the contralateral lung was measured and expressed as a percentage of the normal mean for gestation (O/E) in 47 fetuses with isolated diaphragmatic hernia at 26 (range, 21-36) weeks of gestation. The lung area was measured by tracing the limits of the lungs (LHR trace) and by multiplying the longest diameter by its perpendicular (LHR diameters). The contralateral lung volume was measured by the Virtual Organ Computer-Aided anaLysis method and the O/E was calculated. Regression analysis was used to determine the significance of the LHRs and volume in the prediction of postnatal survival.

RESULTS

The survival rate was 59.6% (28 of 47). There were significant associations between O/E LHR trace and O/E LHR diameters, and between each O/E LHR and O/E volume, but multiple regression analysis demonstrated that significant prediction of survival was provided only by O/E LHR trace and intrathoracic herniation of the liver.

CONCLUSIONS

In diaphragmatic hernia prenatal prediction of postnatal outcome is better by 2D measurement of LHR trace than it is by 3D measurement of lung volume.