Conventional Mechanical Ventilation Versus High-frequency Oscillatory Ventilation for Congenital Diaphragmatic Hernia: A Randomized Clinical Trial (The VICI-trial)

Utility of the oxygenation index in management of congenital diaphragmatic hernia: a report from a Thai University Surgical Centre

BACKGROUND

Oxygenation index (OI) is associated with severity of newborn pulmonary hypertension (PH) in congenital diaphragmatic hernia (CDH). Higher OI may indicate worst degree(s) of PH.

OBJECTIVES

This study reports OI dynamic(s) over the first 72 h of life and its correlation with (1) perioperative morbidity and (2) CDH mortality.

METHODS

Medical records of inborn CDH babies during 2002-2022 were examined. OI on Days (s) 1-3 and perioperative OI trends were recorded. Operation (primary vs patch repair) and survival rates (%) were studied.

RESULTS

Fifty-five CDH newborns (54.5% male: 45.5% female)-mean birth GA 37.5 ± 2.7 wks. had a mean birth weight 2813 ± 684 g with prenatal diagnosis in 32.7% cases. 52/55 (94.5%) were intubated at birth and HFOV deployed in 29 (55.8%). Those requiring HFOV had higher OI on DOL1 (24.8 ± 17 vs 10.3 ± 11.5; p < 0.05), DOL 2 (26.3 ± 22.9 vs 6.7 ± 12.1; p < 0.05) and DOL 3 (21.9 ± 33.8 vs 5.5 ± 9.3; p = 0.04). Operation was undertaken in 36/55 (65.5%). Preoperative mortality group had significant higher OI on DOL 2 (42.1 ± 21.0 vs 14.9 ± 9.3; p = 0.04). CDH defects were-Type A N = 27 (75%), Type B N = 7 (19.4%) and Type C N = 2 (5.6%). Overall mortality was 40% (22/55). Statistically significant OI trends were recorded in non-survival vs. survival groups on DOL 1 (31.6 ± 16.8. vs 10.5 ± 9.0; p < 0.05, DOL 2 (38.1 ± 21.9 vs 6.3 ± 7.1; p < 0.05), and DOL 3 (38.8 ± 39.4; p = 0.012).

CONCLUSIONS

OI dynamics are highly predictive for accurate monitoring of CDH cardiorespiratory physiology and crucially may guide ventilatory management as well as timing of surgery.

Cutting into the NICU: Improvements in Outcomes for Neonates with Surgical Conditions

The Children's Hospitals Neonatal Consortium (CHNC), established in 2010, seeks to improve care for infants with medically and surgically complex conditions who are cared for in level IV regional children's hospital NICUs across North America. Through patient-level individual data collection, comparative benchmarking, and multicenter quality improvement work, CHNC has contributed to knowledge and improved outcomes, leveraging novel collaborations between and across institutions. Focusing on antenatal and inpatient care for infants with surgical conditions including congenital diaphragmatic hernia, gastroschisis, and necrotizing enterocolitis, we summarize the progress made in these infants' care. We highlight the ways in which CHNC has enabled multidisciplinary and multicenter collaborations through the facilitation of diagnosis-specific focus groups, which enable comparative observations of outcomes through quality improvement and research initiatives. Finally, we review the importance of postbirth hospitalization needs of these infants and the application of telemedicine in this population.

Association between initial ventilation mode and hospital outcomes for severe congenital diaphragmatic hernia

OBJECTIVE

To determine the association between initial delivery room (DR) ventilator (conventional mechanical ventilation [CMV] versus high frequency oscillatory ventilation [HFOV] and hospital outcomes for infants with severe congenital diaphragmatic hernia (CDH).

STUDY DESIGN

Quasi-experimental design before/after introducing a clinical protocol promoting HFOV. The primary outcome was first blood gas parameters. Secondary outcomes included serial blood gas assessments, ECMO, survival, duration of ventilation, and length of hospitalization.

RESULTS

First pH and CO2 were more favorable in the HFOV group (n = 75) than CMV group (n = 85), median (interquartile range (IQR)) pH 7.18 (7.03, 7.24) vs. 7.05 (6.93, 7.17), adjusted p-value < 0.001; median CO2 62.0 (46.0, 82.0) vs 85.9 (59.0, 103.0), adjusted p-value < 0.001. ECMO, survival, duration of ventilation, and length of hospitalization did not differ between groups in adjusted analysis.

CONCLUSION

Among infants with severe CDH, initial DR HFOV was associated with improved early gas exchange with no adverse differences in hospital outcomes.

Antenatal Administration of Extracellular Vesicles Derived From Amniotic Fluid Stem Cells Improves Lung Function in Neonatal Rats With Congenital Diaphragmatic Hernia

BACKGROUND

The severity of pulmonary hypoplasia is a main determinant of outcome for babies with congenital diaphragmatic hernia (CDH). Antenatal administration of extracellular vesicles derived from amniotic fluid stem cells (AFSC-EVs) has been shown to rescue morphological features of lung development in the rat nitrofen model of CDH. Herein, we evaluated whether AFSC-EV administration to fetal rats with CDH is associated with neonatal improvement in lung function.

METHODS

AFSC-EVs were isolated by ultracentrifugation and characterized by size, morphology, and canonical marker expression. At embryonic (E) day 9.5, dams were gavaged with olive oil (control) or nitrofen to induce CDH. At E18.5, fetuses received an intra-amniotic injection of either saline or AFSC-EVs. At E21.5, rats were delivered and subjected to a tracheostomy for mechanical ventilation (flexiVent system). Groups were compared for lung compliance, resistance, Newtonian resistance, tissue damping and elastance. Lungs were evaluated for branching morphogenesis and collagen quantification.

RESULTS

Compared to healthy control, saline-treated pups with CDH had fewer airspaces, more collagen deposition, and functionally exhibited reduced compliance and increased airway resistance, elastance, and tissue damping. Conversely, AFSC-EV administration resulted in improvement of lung mechanics (compliance, resistance, tissue damping, elastance) as well as lung branching morphogenesis and collagen deposition.

CONCLUSIONS

Our studies show that the rat nitrofen model reproduces lung function impairment similar to that of human babies with CDH. Antenatal administration of AFSC-EVs improves lung morphology and function in neonatal rats with CDH.

LEVEL OF EVIDENCE

N/A (animal and laboratory study).

Neonatal high-frequency oscillatory ventilation: where are we now?

High-frequency oscillatory ventilation (HFOV) is an established mode of respiratory support in the neonatal intensive care unit. Large clinical trial data is based on first intention use in preterm infants with acute respiratory distress syndrome. Clinical practice has evolved from this narrow population. HFOV is most often reserved for term and preterm infants with severe, and often complex, respiratory failure not responding to conventional modalities of respiratory support. Thus, optimal, and safe, application of HFOV requires the clinician to adapt mean airway pressure, frequency, inspiratory:expiratory ratio and tidal volume to individual patient needs based on pathophysiology, lung volume state and infant size. This narrative review summarises the status of HFOV in neonatal intensive care units today, the lessons that can be learnt from the past, how to apply HFOV in different neonatal populations and conditions and highlights potential new advances. Specifically, we provide guidance on how to apply an open lung approach to mean airway pressure, selecting the correct frequency and use of volume-targeted HFOV.

Lung-protective ventilation in the management of congenital diaphragmatic hernia

Prioritizing lung-protective ventilation has produced a clear mortality benefit in neonates with congenital diaphragmatic hernia (CDH). While there is a paucity of CDH-specific evidence to support any particular approach to lung-protective ventilation, a growing body of data in adults is beginning to clarify the mechanisms behind ventilator-induced lung injury and inform safer management of mechanical ventilation in general. This review summarizes the adult data and attempts to relate the findings, conceptually, to the CDH population. Critical lessons from the adult studies are that much of the damage done during conventional mechanical ventilation affects normal lung tissue and that most of this damage occurs at the low-volume and high-volume extremes of the respiratory cycle. Consequently, it is important to prevent atelectasis by using sufficient positive end-expiratory pressure while also avoiding overdistention by scaling tidal volume to the amount of functional lung tissue rather than body weight. Paralysis early in acute respiratory distress syndrome improves outcomes, possibly because consistent respiratory mechanics facilitate avoidance of both atelectasis and overdistention-a mechanism that may also apply to the CDH population. Volume-targeted conventional modes may be advantageous in CDH, but determining optimal tidal volume is challenging. Both high-frequency oscillatory ventilation and high-frequency jet ventilation have been used successfully as 'rescue modes' to avoid extracorporeal membrane oxygenation, and a prospective trial comparing the two high-frequency modalities as the primary ventilation strategy for CDH is underway.

The promise and pitfalls of care standardization in congenital diaphragmatic hernia

The aim of standardizing care is to enhance patient outcomes and optimize healthcare delivery by minimizing variations in care and ensuring the efficient allocation of healthcare resources. Despite these potential benefits to patients, healthcare providers and the healthcare system, standardization may also disadvantage these groups. With a specific focus on congenital diaphragmatic hernia, this article will review the promise and pitfalls of standardization, as well as a potential path forward that uses standardization to improve outcomes in this rare and complex disease process.

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.

Congenital diaphragmatic hernia: relationship between defect size and outcome. Experience in a reference centre

INTRODUCTION

Congenital diaphragmatic hernia (CDH) remains a therapeutic challenge. The surgical classification recommended by the Congenital Diaphragmatic Hernia study group (CDHSG), based on the size of the defect, is used for staging in reference centres. Larger defects are associated with poorer outcomes. Our aim was to describe and compare the morbidity at hospital discharge of newborns who underwent surgical correction of CDH at the Juan P. Garrahan, according to the surgical staging of the defect proposed by the CDHSG.

MATERIAL AND METHODS

The study included patients with CDH admitted to the Juan P. Garrahan Hospital between 2012 and 2020, and we analysed the distribution, morbidity and mortality associated with the size of the defect. We carried out a descriptive analysis, calculating measures of central tendency and dispersion, and bivariate and multivariate analyses.

RESULTS

A total of 230 patients with CDH were admitted and 158 underwent surgery. We found that defect sizes C and D sizes were associated with an increased risk of chronic pulmonary disease (CPD) (OR, 5.3; 95% CI, 2.2-13.4; P<.0000), need of extracorporeal membrane oxygenation (OR 3.9; 95% CI, 1.3-12.8; P<.005) and chylothorax (OR, 2.1; 95% CI, 0.8-6.4; P<.10]. The multivariate analysis revealed that a large defect size (C-D) was independently and significantly associated with CPD (OR 4.19; 95% CI, 1.76-9.95).

CONCLUSION

Staging the defect according to de CDHSG classification during surgery allows the application of uniform management criteria and the prediction of patient outcomes and complications during the hospital stay.

Beyond Bronchopulmonary Dysplasia: A Comprehensive Review of Chronic Lung Diseases in Neonates

In neonates, pulmonary diseases such as bronchopulmonary dysplasia and other chronic lung diseases (CLDs) pose significant challenges due to their complexity and high degree of morbidity and mortality. This review discusses the etiology, pathophysiology, clinical presentation, and diagnostic criteria for these conditions, as well as current management strategies. The review also highlights recent advancements in understanding the pathophysiology of these diseases and evolving strategies for their management, including gene therapy and stem cell treatments. We emphasize how supportive care is useful in managing these diseases and underscore the importance of a multidisciplinary approach. Notably, we discuss the emerging role of personalized medicine, enabled by advances in genomics and precision therapeutics, in tailoring therapy according to an individual's genetic, biochemical, and lifestyle factors. We conclude with a discussion on future directions in research and treatment, emphasizing the importance of furthering our understanding of these conditions, improving diagnostic criteria, and exploring targeted treatment modalities. The review underscores the need for multicentric and longitudinal studies to improve preventative strategies and better understand long-term outcomes. Ultimately, a comprehensive, innovative, and patient-centered approach can enhance the quality of care and outcomes for neonates with CLDs.

Chest radiographic thoracic areas and respiratory outcomes in infants with anterior abdominal wall defects

OBJECTIVES

Infants with anterior abdominal wall defects (AWD) can suffer from pulmonary complications. Our aims were to determine if the chest radiographic thoracic areas (CRTAs) on day one differed between infants with exomphalos or gastroschisis, whether this related to differing severity of outcomes and if they were lower than those of controls indicating abnormal antenatal lung growth.

METHODS

A review of infants with exomphalos or gastroschisis born between January 2004 and January 2023 was conducted. The control group was term, newborn infants ventilated for poor respiratory drive at birth. Chest radiographs on day one were analysed and the highest CRTA in the first 24 h after birth for each infant included in the analysis.

RESULTS

The 127 infants with gastroschisis had a lower gestational age and birthweight than the 62 exomphalos infants and 130 controls (all p<0.001) The CRTAs of the controls were greater than the CRTAs of the exomphalos and the gastroschisis infants (p = 0.001). The median CRTA corrected for birthweight was lower in the exomphalos infants [688, IQR 568-875 mm2/kg] than the gastroschisis infants [813, IQE 695-915 mm2/kg] No gastroschisis infant developed bronchopulmonary dysplasia (BPD). A CRTA of 1759 mm2 had a sensitivity of 81 % and specificity of 71 % in predicting BPD in infants with exomphalos.

CONCLUSIONS

Infants with gastroschisis or exomphalos had lower CRTAs than controls suggesting both groups had abnormal antenatal lung development. The CRTA was lower in the exomphalos infants who also had worse respiratory outcomes, hence CRTA assessment may a useful prognostic aid.

Prevalence and early surgical outcome of congenital diaphragmatic hernia in the Netherlands: a population-based cohort study from the European Pediatric Surgical Audit

BACKGROUND

Congenital diaphragmatic hernia (CDH) is a rare birth defect with substantial mortality. This study aims to generate a population-based overview of CDH care and outcomes in the Netherlands. Moreover, it assesses interhospital variations between the two Dutch CDH expert centres.

METHODS

This study uses data from the Dutch branch of the European Pediatric Surgical Audit, a prospective clinical audit for congenital anomalies. Data of all patients with CDH treated between 2014 and 2021 were included for epidemiological analysis. For comparative analyses, patients presenting after the neonatal period or not treated in the two CDH expert centres were excluded. Identified interhospital variations were assessed using regression analysis.

RESULTS

In the study period, 283 children with CDH were born, resulting in a national prevalence rate of 2.06/10 000 live births. The patient population, treatment and outcomes at 1 year were comparable between the hospitals, except for length of hospital stay. Regression analysis identified the treating hospital as the strongest significant predictor thereof. Other factors associated with longer length of stay include the presence of other malformations, intrathoracic liver position on prenatal ultrasound, extracorporeal membrane oxygenation treatment, patch repair, complicated postoperative course and discharge to home rather than to another care facility.

CONCLUSION

Outcomes of CDH care throughout the Netherlands are comparable. However, the length of stay differed between the two hospitals, also when adjusting for other covariates. Further qualitative analysis to explain this interhospital variation is indicated. Our findings underscore the potential of clinical auditing as a quality measurement tool in rare conditions.

Prediction of bronchopulmonary dysplasia by the chest radiographic thoracic area on day one in infants with exomphalos

OBJECTIVES

To determine if infants with exomphalos had abnormal antenatal lung growth as indicated by lower chest radiographic thoracic areas (CRTA) on day one compared to controls and whether the CRTA could predict the development of bronchopulmonary dysplasia (BPD).

METHODS

Infants with exomphalos cared for between January 2004 and January 2023 were included. The controls were term, newborn infants ventilated for absent respiratory drive at birth, without lung disease and had no supplemental oxygen requirement by 6 h of age. The radiographs were imported as digital image files by Sectra PACS software (Sectra AB, Linköping, Sweden). Free-hand tracing of the perimeter of the thoracic area was undertaken and the CRTA calculated by the software.

RESULTS

Sixty-four infants with exomphalos and 130 controls were included. Infants with exomphalos had a lower median (IQR) CRTA (1,983 [1,657-2,471] mm2) compared to controls (2,547 [2,153-2,932] mm2, p<0.001). Following multivariable regression analysis, infants with exomphalos had lower CRTAs compared to controls (p=0.001) after adjusting for differences in gestational age and male sex. In the exomphalos group, the CRTAs were lower in those who developed BPD (n=14, 1,530 [1,307-1,941] mm2) compared to those who did not (2,168 [1,865-2,672], p<0.001). Following multivariable regression analysis, the CRTA was associated with BPD development (p=0.021) after adjusting for male sex and gestational age.

CONCLUSIONS

Lower CRTAs on day one in the exomphalos infants compared to the controls predicted BPD development.

Diaphragmatic Defects in Infants: Acute Management and Repair

Congenital diaphragmatic hernia (CDH) is a complex and highly variable disease process that should be treated at institutions with multidisciplinary teams designed for their care. Treatment in the neonatal period focuses on pulmonary hypoplasia, pulmonary hypertension, and cardiac dysfunction. Extracorporeal membrane oxygenation (ECMO) can be considered in patients refractory to medical management. Repair of CDH early during the ECMO course seems to improve mortality compared with other times for surgical intervention. The choice of surgical approach to CDH repair should consider the patient's physiologic status and the surgeon's familiarity with the operative approaches available, recognizing the pros/cons of each technique.

Diagnosis and management of congenital diaphragmatic hernia: a 2023 update from the Canadian Congenital Diaphragmatic Hernia Collaborative

OBJECTIVE

The Canadian Congenital Diaphragmatic Hernia (CDH) Collaborative sought to make its existing clinical practice guideline, published in 2018, into a 'living document'.

DESIGN AND MAIN OUTCOME MEASURES

Critical appraisal of CDH literature adhering to Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. Evidence accumulated between 1 January 2017 and 30 August 2022 was analysed to inform changes to existing or the development of new CDH care recommendations. Strength of consensus was also determined using a modified Delphi process among national experts in the field.

RESULTS

Of the 3868 articles retrieved in our search that covered the 15 areas of CDH care, 459 underwent full-text review. Ultimately, 103 articles were used to inform 20 changes to existing recommendations, which included aspects related to prenatal diagnosis, echocardiographic evaluation, pulmonary hypertension management, surgical readiness criteria, the type of surgical repair and long-term health surveillance. Fifteen new CDH care recommendations were also created using this evidence, with most related to the management of pain and the provision of analgesia and neuromuscular blockade for patients with CDH.

CONCLUSIONS

The 2023 Canadian CDH Collaborative's clinical practice guideline update provides a management framework for infants and children with CDH based on the best available evidence and expert consensus.

The role of extracorporeal life support and timing of repair in infants with congenital diaphragmatic hernia

Extracorporeal life support (ECLS) serves as a rescue therapy for patients with congenital diaphragmatic hernia (CDH) and severe cardiopulmonary failure, and only half of these patients survive to discharge. This costly intervention has a significant complication risk and is reserved for patients with the most severe disease physiology refractory to maximal cardiopulmonary support. Some contraindications to ECLS do exist such as coagulopathy, lethal chromosomal or congenital anomaly, very preterm birth, or very low birth weight, but many of these limits are being evaluated through further research. Consensus guidelines from the past decade vary in recommendations for ECLS use in patients with CDH but this therapy appears to have a survival benefit in the most severe subset of patients. Improved outcomes have been observed for patients treated at high-volume centers. This review details the evolving literature surrounding management paradigms for timing of CDH repair for patients receiving preoperative ECLS. Most recent data support early repair following cannulation to avoid non-repair which is uniformly fatal in this population. Longer ECLS runs are associated with decreased survival, and patient physiology should guide ECLS weaning and eventual decannulation rather than limiting patients to arbitrary run lengths. Standardization of care across centers is a major focus to limit unnecessary costs and improve short-term and long-term outcomes for these complex patients.

Diagnosis, management and long term cardiovascular outcomes of phenotypic profiles in pulmonary hypertension associated with congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a developmental defect of the diaphragm resulting in herniation of viscera into the chest. This condition is characterized by pulmonary hypoplasia, pulmonary hypertension (PH) and cardiac ventricular dysfunction. PH is a key component of the pathophysiology of CDH in neonates and contributes to morbidity and mortality. Traditionally, PH associated with CDH (CDH-PH) is thought to be secondary to increased pulmonary arterial resistance and vasoreactivity resulting from pulmonary hypoplasia. Additionally, there is increasing recognition of associated left ventricular hypoplasia, dysfunction and elevated end diastolic pressure resulting in pulmonary venous hypertension in infants with CDH. Thus, hemodynamic management of these infants is complex and cautious use of pulmonary vasodilators such as inhaled nitric oxide (iNO) is warranted. We aim to provide an overview of different phenotypic profiles of CDH associated PH and potential management options based on current evidence and pathophysiology.

Role of practice standardization in outcome optimization for CDH

Standardization of care seeks to improve patient outcomes and healthcare delivery by reducing unwanted variations in care as well as promoting the efficient and effective use of healthcare resources. There are many types of standardization, with clinical practice guidelines (CPGs), based on a stringent assessment of evidence and expert consensus, being the hallmark of high-quality care. This article outlines the history of CPGs, their benefits and shortcomings, with a specific focus on standardization efforts as it relates to congenital diaphragmatic hernia management.

Early Ventilator Management for Infants With Congenital Diaphragmatic Hernia: Impact of a Standardized Clinical Practice Guideline

BACKGROUND

Infants with congenital diaphragmatic hernia (CDH) experience high morbidity and mortality due to pulmonary arterial hypertension and hypoplasia. Mechanical ventilation is a central component of CDH management. Our objective was to evaluate the impact of a standardized clinical practice guideline (implemented in January 2012) on ventilator management for infants with CDH, and associate management changes with short-term outcomes, specifically extracorporeal membrane oxygenation (ECMO) utilization and survival to discharge.

METHODS

We conducted a retrospective pre-post study of 103 CDH infants admitted from January 2007-July 2021, divided pre- (n = 40) and post-guideline (n = 63). Clinical outcomes, ventilator settings, and blood gas values in the first 7 days of mechanical ventilation were compared between the pre- and post-guideline cohorts.

RESULTS

Post-guideline, ECMO utilization decreased (11% vs 38%, p = 0.001) and survival to discharge improved (92% vs 68%, p = 0.001). More post-guideline patients remained on conventional mechanical ventilation without need for escalation to high-frequency ventilation or ECMO, and had higher pressures and PaCO2 with lower FiO2 and PaO2 (p < 0.05).

CONCLUSIONS

Standardized ventilator management optimizing pressures for adequate lung expansion and minimizing oxygen toxicity improves outcomes for infants with CDH.

LEVEL OF EVIDENCE

III.

Mechanical ventilation in special populations

Optimal respiratory support can only be achieved if the ventilator strategy utilized for each individual patient at any given point in the evolution of their disease process is tailored to the underlying pathophysiology. The critically ill newborn infant requires individualized patient care when it comes to mechanical ventilation. This can only occur if the clinician has a good understanding of the different pathophysiologies of a variety of conditions that can lead to respiratory failure. In this chapter we describe the key pathophysiological features of bronchopulmonary dysplasia, meconium aspiration syndrome and lung hypoplasia syndromes with emphasis on congenital diaphragmatic hernia. We review available evidence to guide management an provide specific recommendations for pathophysiologically-based mechanical ventilation support.

Neonatal high frequency ventilation: Current trends and future directions

High frequency ventilation (HFV) in neonates has been in use for over forty years. Some early HFV ventilators are no longer available, but high frequency oscillatory ventilation (HFOV) and jet ventilators (HFJV) continue to be commonly employed. Advanced HFOV models available outside of the United States are much quieter and easier to use, and are available as options on many conventional ventilators, providing important improvements such as tidal volume measurement and targeting. HFJV excels in treating air leak and non-homogenous lung disease and is often used for other diseases as well. High frequency non-invasive ventilation (hfNIV) is a novel application of HFV that remains under investigation. Similar to bubble CPAP, hfNIV has been applied with a variety of high-frequency ventilators. Efficacy and safety of hfNIV with any device have not yet been established. This article describes the current approaches to these HFV therapies and stresses the importance of understanding how each device works and what disease processes may respond best to the technology employed.

Respiratory function testing for guiding ventilator mode conversion in congenital diaphragmatic hernia

INTRODUCTION

For patients with a congenital diaphragmatic hernia, conventional mechanical ventilation (CMV) and high-frequency oscillatory ventilation (HFOV) are used in initial ventilatory management. HFOV has recently been recommended as a rescue therapy; however, we use HFOV for initial ventilation management, with a preoperative challenge test for CMV conversion and respiratory function testing at the time of CMV conversion. We aimed to compare patient characteristics between CMV conversion- and HFOV-preferred treatment groups.

METHODS

Ventilator settings and blood gases were retrospectively evaluated pre- and post-CMV conversion, and respiratory function tests for compliance of the respiratory system (Crs) and for resistance of the respiratory system (Rrs) were performed during the trial to CMV conversion.

RESULTS

No differences were observed between the CMV conversion- and HFOV-preferred groups regarding gestational age, birth weight, and observed/expected lung area-to-head circumference ratios. The median Crs (ml/cmH2 O/kg) and Rrs (cmH2 O･kg/L/s) in the CMV conversion- and HFOV-preferred groups was 0.42 versus 0.53 (p = .44) and 467 versus 327 (p = .045), respectively. The pre and posttrial amount of change in blood gas levels and ventilator parameters in the CMV conversion- and HFOV-preferred groups were as follows: mean airway pressure, -2.0 versus 0 cmH2 O; partial pressure of carbon dioxide, 6.1 versus 2.9 Torr; alveolar-arterial oxygen difference, -39.5 versus -50 Torr; and oxygenation index, -1.0 versus -0.6; respectively.

CONCLUSION

Respiratory function tests were useful in tailoring ventilator settings. Patients with high Rrs values responded better to CMV conversion.

Congenital Diaphragmatic Hernia: Pulmonary Hypertension and Pulmonary Vascular Disease

This review provides a comprehensive summary of the current understanding of pulmonary hypertension (PH) in congenital diaphragmatic hernia, outlining the underlying pathophysiologic mechanisms, methods for assessing PH severity, optimal management strategies, and prognostic implications.

Congenital diaphragmatic hernia: quality improvement using a maximal lung protection strategy and early surgery-improved survival

To evaluate the effectiveness of a novel protocol, adopted in our institution, as a quality improvement project for congenital diaphragmatic hernia (CDH). A maximal lung protection (MLP) protocol was implemented in 2019. This strategy included immediate use of high-frequency oscillatory ventilation (HFOV) after birth, during the stay at the Neonatal Intensive Care Unit (NICU), and during surgical repair. HFOV strategy included low distending pressures and higher frequencies (15 Hz) with subsequent lower tidal volumes. Surgical repair was performed early, within 24 h of birth, if possible. A retrospective study of all inborn neonates prenatally diagnosed with CDH and without major associated anomalies was performed at the NICU of Schneider Children's Medical Center of Israel between 2009 and 2022. Survival rates and pulmonary outcomes of neonates managed with MLP were compared to the historical standard care cohort. Thirty-three neonates were managed with the MLP protocol vs. 39 neonates that were not. Major adverse outcomes decreased including death rate from 46 to 18% (p = 0.012), extracorporeal membrane oxygenation from 39 to 0% (p < 0.001), and pneumothorax from 18 to 0% (p = 0.013).

CONCLUSION

 MLP with early surgery significantly improved survival and additional adverse outcomes of neonates with CDH. Prospective randomized studies are necessary to confirm the findings of the current study.

WHAT IS KNOWN

• Ventilator-induced lung injury was reported as the main cause of mortality in neonates with congenital diaphragmatic hernia (CDH). • Conventional ventilation is recommended by the European CDH consortium as the first-line ventilation modality; timing of surgery is controversial.

WHAT IS NEW

• A maximal lung protection strategy based on 15-Hz high-frequency oscillatory ventilation with low distending pressures as initial modality and early surgery significantly reduced mortality and other outcomes.

High-Frequency Positive Pressure Ventilation as Primary Rescue Strategy for Patients with Congenital Diaphragmatic Hernia: A Comparison to High-Frequency Oscillatory Ventilation

OBJECTIVE

The aim of this article was to evaluate high-frequency positive pressure ventilation (HFPPV) compared with high-frequency oscillatory ventilation (HFOV) as a rescue ventilation strategy for patients with congenital diaphragmatic hernia (CDH). HFPPV is a pressure-controlled conventional ventilation method utilizing high respiratory rate and low positive end-expiratory pressure.

STUDY DESIGN

Seventy-seven patients diagnosed with CDH from January 2005 to September 2019 who were treated with stepwise progression from HFPPV to HFOV versus only HFOV were included. Fisher's exact test and the Kruskal-Wallis test were used to compare outcomes.

RESULTS

Patients treated with HFPPV + HFOV had higher survival to discharge (80 vs. 50%, p = 0.007) and to surgical intervention (95.6 vs. 68.8%, p = 0.003), with average age at repair 2 days earlier (p = 0.004). Need for extracorporeal membrane oxygenation (p = 0.490), inhaled nitric oxide (p = 0.585), supplemental oxygen (p = 0.341), and pulmonary hypertension medications (p = 0.381) were similar.

CONCLUSION

In CDH patients who fail respiratory support with conventional ventilation, HFPPV may be used as an intermediary mode of rescue ventilation prior to HFOV without adverse effects.

KEY POINTS

· HFPPV may be used as an intermediary mode of rescue ventilation prior to HFOV without adverse effect.. · HFPPV is more widely available and can mitigate the limitations faced when using HFOV.. · HFPPV allows for intra- or interhospital transfer of neonates with CDH..

Unique Cardiopulmonary Interactions in Congenital Diaphragmatic Hernia: Physiology and Therapeutic Implications

Congenital diaphragmatic hernia (CDH) results in abdominal contents entering the thoracic cavity, affecting both cardiac and pulmonary development. Maldevelopment of the pulmonary vasculature occurs within both the ipsilateral lung and the contralateral lung. The resultant bilateral pulmonary hypoplasia and associated pulmonary hypertension are important components of the pathophysiology of this disease that affect outcomes. Despite prenatal referral to specialized high-volume centers, advanced ventilation strategies, pulmonary hypertension management, and the option of extracorporeal membrane oxygenation, overall CDH mortality remains between 25% and 30%. With increasing recognition that cardiac dysfunction plays a large role in morbidity and mortality in patients with CDH, it becomes imperative to understand the different clinical phenotypes, thus allowing for individual patient-directed therapies. Further research into therapeutic interventions that address the cardiopulmonary interactions in patients with CDH may lead to improved morbidity and mortality outcomes.

Comparison of conventional mechanical ventilation and high-frequency oscillatory ventilation in congenital diaphragmatic hernias: a systematic review and meta-analysis

Outcomes of conventional mechanical ventilation (CMV) and high-frequency oscillatory ventilation (HFOV) in patients with congenital diaphragmatic hernia (CDH) were compared through a systematic review and meta-analysis. Outcome measures included mortality and incidence of chronic lung disease (CLD). Odds ratio (OR) and 95% confidence interval (95%CI) were evaluated. Subgroup analyses were performed according to the strategy for applying HFOV in CDH patients. Group A: CMV was initially applied in all CDH patients, and HFOV was applied in unstable patients. Group B: chronologically analyzed. (CMV and HFOV era) Group C: CMV or HFOV was used as the initial MV. Of the 2199 abstracts screened, 15 full-text articles were analyzed. Regarding mortality, 16.7% (365/2180) and 32.8% (456/1389) patients died in CMV and HFOV, respectively (OR, 2.53; 95%CI 2.12-3.01). Subgroup analyses showed significantly worse, better, and equivalent mortality for HFOV than that for CMV in group A, B, and C, respectively. CLD occurred in 32.4% (399/1230) and 49.3% (369/749) patients in CMV and HFOV, respectively (OR, 2.37; 95%CI 1.93-2.90). The evidence from the literature is poor. Mortality and the incidence of CLD appear worse after HFOV in children with CDH. Cautious interpretation is needed due to the heterogeneity of each study.

Pathological findings in congenital diaphragmatic hernia on necropsy studies: A single-center case series

INTRODUCTION

Congenital diaphragmatic hernia (CDH) is associated with high mortality rates and significant pulmonary morbidities. The objective of this study was to delineate the histopathological features observed in necropsies of CDH patients and correlate these with their clinical manifestations.

METHODS

We retrospectively reviewed the postmortem findings and corresponding clinical characteristics in eight CDH cases from 2017 to July 2022.

RESULTS

The median survival time was 46 (8-624) hours. Autopsy reports showed that diffuse alveolar damage (congestion and hemorrhage) and hyaline membrane formation were the primary pathological lung changes observed. Notably, despite significant reduction in lung volume, the lung development appeared normal in 50% of the cases, while lobulated deformities were present in three (37.5%) cases. All patients displayed a large patent ductus arteriosus (PDA) and a patent foramen ovale, resulting in increased right ventricle (RV) volume, and myocardial fibers appeared slightly congested and swollen. The pulmonary vessels indicated thickening of the arterial media and adventitia. Lung hypoplasia and diffuse lung damage resulted in impaired gas exchange, while PDA and pulmonary hypertension led to RV failure, subsequent organ dysfunction and ultimately death.

CONCLUSIONS

Patients with CDH typically succumb to cardiopulmonary failure, a condition driven by a complex interplay of pathophysiological factors. This complexity accounts for the unpredictable response to currently available vasodilators and ventilation therapies.

Post-natal prognostic factors in CDH: experience of 11 years in a referral center in Brazil

OBJECTIVE

To describe post-natal risk factors associated with death in Newborns (NB) with Congenital Diaphragmatic Hernia (CDH) in a Brazilian reference center.

METHODS

In this retrospective cohort study, post-natal clinical factors of all NB diagnosed with CDH were reviewed in an 11-year period (2007‒2018). The primary outcome was death. Secondary outcomes included clinical features, prognostic indexes, type of mechanical ventilation, complications during hospitalization and surgical repair.

RESULTS

After applying the exclusion criteria, the authors analyzed 137 charts. Overall mortality was 59% (81/137), and the highest rates were observed for low-birth-weight NB (87%), syndromic phenotype (92%), and those with major malformations (100%). Prognostic indexes such as Apgar, SNAPPE-II and 24hOI (best oxygenation index in 24 hours) were all associated with poor evolution. In a multivariate analysis, only birth weight and 24hOI were statistically significant risk factors for mortality, with a reduction in mortality risk of 17.1% (OR = 0.829, 95% IC 0.72‒0.955, p = 0.009) for each additional 100g at birth and an increase by 26.5% (OR = 1.265, 95% IC 1.113‒1.436, p = 0.0003) for each unitary increase at the 24hOI.

CONCLUSION

Prognostic indexes are an important tool for predicting outcomes and improving resource allocation. Post-natal risk factors may be more suitable for settings where antenatal diagnosis is not universal. Classical risk factors, such as prematurity, low birth weight, higher need for supportive care, and poorer prognostic indexes were associated with mortality in our CDH population.

High frequency jet ventilation for congenital diaphragmatic hernia

BACKGROUND

The optimal role of high frequency jet ventilation (HFJV) in lung protective stabilization of congenital diaphragmatic hernia (CDH) remains uncertain. We aimed to describe our center's experience with HFJV as both a rescue (following failed stabilization with CMV) and primary ventilation mode in the management of CDH.

METHODS

Liveborn CDH patients treated from 2013 to 2021 in a single institution were reviewed. We compared 3 groups based on their primary and last ventilation mode prior to surgery: CMV (Group 1); HFJV (Group 2); and CMV/HFJV (Group 3). Outcomes included a composite primary outcome (≥1 of mortality, need for ECMO or need for supplemental O2 at discharge), total invasive ventilation days and development of pneumothorax. A descriptive analysis including univariate group comparisons was performed. Multivariate logistic regression models investigating the relationship between mode of ventilation and the primary outcome adjusted by potentially confounding covariates were constructed.

RESULTS

56 patients (32 Group 1, 18 Group 2, 6 Group 3) were analyzed. Group 2 and 3 patients had more severe disease based on liver position, SNAP-II score, pulmonary hypertension severity, need for inotropic support, CDHSG defect size and need for patch repair. There were no group differences in survival, need for ECMO, or pneumothorax occurrence, although infants receiving HFJV required longer invasive ventilation and had a greater need for O2 at discharge. Multivariate logistic regression revealed no associations between mode of ventilation and outcome.

CONCLUSIONS

HFJV appears effective, both for CMV rescue and as a primary ventilation strategy in high risk CDH.

LEVEL OF EVIDENCE

Level IV.

Mortality in Congenital Diaphragmatic Hernia: A Multicenter Registry Study of Over 5000 Patients Over 25 Years

OBJECTIVE

To determine if risk-adjusted survival of patients with CDH has improved over the last 25 years within centers that are long-term, consistent participants in the CDH Study Group (CDHSG).

SUMMARY BACKGROUND DATA

The CDHSG is a multicenter collaboration focused on evaluation of infants with CDH. Despite advances in pediatric surgical and intensive care, CDH mortality has appeared to plateau. Herein, we studied CDH mortality rates amongst long-term contributors to the CDHSG.

METHODS

We divided registry data into 5-year intervals, with Era 1 (E1) beginning in 1995, and analyzed multiple variables (operative strategy, defect size, and mortality) to assess evolution of disease characteristics and severity over time. For mortality analyses, patients were risk stratified using a validated prediction score based on 5-minute Apgar (Apgar5) and birth weight. A risk-adjusted, observed to expected (O:E) mortality model was created using E1 as a reference.

RESULTS

5203 patients from 23 centers with >22years of participation were included. Birth weight, Apgar5, diaphragmatic agenesis, and repair rate were unchanged over time (all P > 0.05). In E5 compared to E1, minimally invasive and patch repair were more prevalent, and timing of diaphragmatic repair was later (all P < 0.01). Overall mortality decreased over time: E1 (30.7%), E2 (30.3%), E3 (28.7%), E4 (26.0%), E5 (25.8%) ( P = 0.03). Risk-adjusted mortality showed a significant improvement in E5 compared to E1 (OR 0.78, 95% CI 0.62-0.98; P = 0.03). O:E mortality improved over time, with the greatest improvement in E5.

CONCLUSIONS

Risk-adjusted and observed-to-expected CDH mortality have improved over time.

Respiratory physiology during NAVA ventilation in neonates born with a congenital diaphragmatic hernia: The "NAVA-diaph" pilot study

BACKGROUND

Neurally adjusted ventilatory assist (NAVA) is a ventilatory mode that delivers synchronized ventilation, proportional to the electrical activity of the diaphragm (EAdi). Although it has been proposed in infants with a congenital diaphragmatic hernia (CDH), the diaphragmatic defect and the surgical repair could alter the physiology of the diaphragm.

AIM

To evaluate, in a pilot study, the relationship between the respiratory drive (EAdi) and the respiratory effort in neonates with CDH during the postsurgical period under either NAVA ventilation or conventional ventilation (CV).

METHODS

This prospective physiological study included eight neonates admitted to a neonatal intensive care unit with a diagnosis of CDH. EAdi, esophageal, gastric, and transdiaphragmatic pressure, as well as clinical parameters, were recorded during NAVA and CV (synchronized intermittent mandatory pressure ventilation) in the postsurgical period.

RESULTS

EAdi was detectable and there was a correlation between the ΔEAdi (maximal - minimal values) and the transdiaphragmatic pressure (r = 0.26, 95% confidence interval [CI] [0.222; 0.299]). There was no significant difference in terms of clinical or physiological parameters during NAVA compared to CV, including work of breathing.

CONCLUSION

Respiratory drive and effort were correlated in infants with CDH and therefore NAVA is a suitable proportional mode in this population. EAdi can also be used to monitor the diaphragm for individualized support.

Variability for Age at Successful Extubation in Infants with Congenital Diaphragmatic Hernia

OBJECTIVE

The objective of this study was to characterize clinical factors associated with successful extubation in infants with congenital diaphragmatic hernia.

STUDY DESIGN

Using the Children's Hospitals Neonatal Database, we identified infants with congenital diaphragmatic hernia from 2017 to 2020 at 32 centers. The main outcome was age in days at the time of successful extubation, defined as the patient remaining extubated for 7 consecutive days. Unadjusted Kaplan-Meier and multivariable Cox proportional hazards ratio equations were used to estimate associations between clinical factors and the main outcome. Observations occurred through 180 days after birth.

RESULTS

There were 840 eligible neonates with a median gestational age of 38 weeks and birth weight of 3.0 kg. Among survivors (n = 693), the median age at successful extubation was 15 days (interquartile range [IQR]: 8-29 days, 95th percentile: 71 days). For nonsurvivors (n = 147), the median age at death was 21 days (IQR: 11-39 days, 95th percentile: 110 days). Center (adjusted hazards ratio: 0.22-15, P < .01), low birth weight, intrathoracic liver position, congenital heart disease, lower 5-minute Apgar score, lower pH upon admission to Children's Hospitals Neonatal Database center, and use of extracorporeal support were independently associated with older age at successful extubation. Tracheostomy was associated with multiple failed extubations.

CONCLUSION

Our findings suggest that infants who have not successfully extubated by about 3 months of age may be candidates for tracheostomy with chronic mechanical ventilation or palliation. The variability of timing of successful extubation among our centers supports the development of practice guidelines after validating clinical criteria.

Validation of disease-specific biomarkers for the early detection of bronchopulmonary dysplasia

OBJECTIVE

To demonstrate and validate the improvement of current risk stratification for bronchopulmonary dysplasia (BPD) early after birth by plasma protein markers (sialic acid-binding Ig-like lectin 14 (SIGLEC-14), basal cell adhesion molecule (BCAM), angiopoietin-like 3 protein (ANGPTL-3)) in extremely premature infants.

METHODS AND RESULTS

Proteome screening in first-week-of-life plasma samples of n = 52 preterm infants <32 weeks gestational age (GA) on two proteomic platforms (SomaLogic^®, Olink-Proteomics^®) confirmed three biomarkers with significant predictive power: BCAM, SIGLEC-14, and ANGPTL-3. We demonstrate high sensitivity (0.92) and specificity (0.86) under consideration of GA, show the proteins' critical contribution to the predictive power of known clinical risk factors, e.g., birth weight and GA, and predicted the duration of mechanical ventilation, oxygen supplementation, as well as neonatal intensive care stay. We confirmed significant predictive power for BPD cases when switching to a clinically applicable method (enzyme-linked immunosorbent assay) in an independent sample set (n = 25, p < 0.001) and demonstrated disease specificity in different cohorts of neonatal and adult lung disease.

CONCLUSION

While successfully addressing typical challenges of clinical biomarker studies, we demonstrated the potential of BCAM, SIGLEC-14, and ANGPTL-3 to inform future clinical decision making in the preterm infant at risk for BPD.

TRIAL REGISTRATION

Deutsches Register Klinische Studien (DRKS) No. 00004600; https://www.drks.de .

IMPACT

The urgent need for biomarkers that enable early decision making and personalized monitoring strategies in preterm infants with BPD is challenged by targeted marker analyses, cohort size, and disease heterogeneity. We demonstrate the potential of the plasma proteins BCAM, SIGLEC-14, and ANGPTL-3 to identify infants with BPD early after birth while improving the predictive power of clinical variables, confirming the robustness toward proteome assays and proving disease specificity. Our comprehensive analysis enables a phase-III clinical trial that allows full implementation of the biomarkers into clinical routine to enable early risk stratification in preterms with BPD.

Minimally Invasive Fetal Surgery and the Next Frontier

Most patients with congenital anomalies do not require prenatal intervention. Furthermore, many congenital anomalies requiring surgical intervention are treated adequately after birth. However, there is a subset of patients with congenital anomalies who will die before birth, shortly after birth, or experience severe postnatal complications without fetal surgery. Fetal surgery is unique in that an operation is performed on the fetus as well as the pregnant woman who does not receive any direct benefit from the surgery but rather lends herself to risks, such as hemorrhage, abruption, and preterm labor. The maternal risks involved with fetal surgery have limited the extent to which fetal interventions may be performed but have, in turn, led to technical innovations that have significantly advanced the field. This review will examine congenital abnormalities that can be treated with minimally invasive fetal surgery and introduce the next frontier of prenatal management of fetal surgical pathology.

Early origins of respiratory disease

Chronic respiratory morbidity is unfortunately common in childhood, particularly in those born very prematurely or with congenital anomalies affecting pulmonary development and those with sickle cell disease. Our research group, therefore, has focused on the early origins of chronic respiratory disease. This has included assessing antenatal diagnostic techniques and potentially therapeutic interventions in infants with congenital diaphragmatic hernia. Undertaking physiological studies, we have increased the understanding of the premature baby's response to resuscitation and evaluated interventions in the delivery suite. Mechanical ventilation modes have been optimised and randomised controlled trials (RCTs) with short- and long-term outcomes undertaken. Our studies highlighted respiratory syncytial virus lower respiratory tract infections (LRTIs) and other respiratory viral LRTIs had an adverse impact on respiratory outcomes of prematurely born infants, who we demonstrated have a functional and genetic predisposition to respiratory viral LRTIs. We have described the long-term respiratory outcomes for children with sickle cell disease and importantly identified influencing factors. In conclusion, it is essential to undertake long term follow up of infants at high risk of chronic respiratory morbidity if effective preventative strategies are to be developed.

Right to left ventricular volume ratio is associated with mortality in congenital diaphragmatic hernia

BACKGROUND

Congenital diaphragmatic hernia (CDH) is associated with high neonatal mortality. We performed this study to test the hypothesis that left ventricular (LV) and right ventricular (RV) volumes assessed by three-dimensional echocardiography may be associated with mortality in CDH.

METHODS

This study was a single-center retrospective cohort study involving 35 infants with CDH. RV and LV end-diastolic volume (RVEDV and LVEDV, respectively) were measured by three-dimensional echocardiography and were corrected by birth body weight (BBW) on day 1. RVEDV/BBW, LVEDV/BBW, and LVEDV/RVEDV were compared between CDH survivors and non-survivors. Receiver-operating characteristic curve analysis was performed to assess the predictive ability for mortality of the echocardiographic parameters.

RESULTS

Comparing CDH non-survivors (n = 6) with survivors (n = 29), respectively, RVEDV/BBW was significantly larger (2.54 ± 0.33 vs 1.86 ± 0.35 ml/kg; P < 0.01), LVEDV/BBW was significantly smaller (0.86 ± 0.21 vs 1.22 ± 0.33 ml/kg; P < 0.001), and LVEDV/RVEDV was significantly lower (0.34 ± 0.06 vs 0.66 ± 0.18; P < 0.001). The area under the curve for LVEDV/RVEDV was the largest (0.98).

CONCLUSIONS

Three-dimensional echocardiographic volume imbalance between the RV and LV was remarkable in CDH non-survivors. The LVEDV/RVEDV ratio may be associated with mortality in CDH.

IMPACT

Mortality with congenital diaphragmatic hernia (CDH) is high, and evaluating left and right ventricular structures and functions may be helpful in assessing the prognosis. Three-dimensional (3D) echocardiography indicated that the left ventricular end-diastolic volume/right ventricular end-diastolic volume ratio within 24 h after birth was associated with mortality in CDH infants. The usefulness of this ratio should be validated in prospective multicenter studies involving larger numbers of patients.

Congenital diaphragmatic hernia survival in an English regional ECMO center

Introduction

Congenital diaphragmatic hernia (CDH) remains a cause of neonatal death. Our aims are to describe contemporary rates of survival and the variables associated with this outcome, contrasting these with our study of two decades earlier and recent reports.

Materials and methods

A retrospective review of all infants diagnosed in a regional center between January 2000 and December 2020 was performed. The outcome of interest was survival. Possible explanatory variables included side of defect, use of complex ventilatory or hemodynamic strategies (inhaled nitric oxide (iNO), high-frequency oscillatory ventilation (HFOV), extracorporeal membrane oxygenation (ECMO), and Prostin), presence of antenatal diagnosis, associated anomalies, birth weight, and gestation. Temporal changes were studied by measuring outcomes in each of four consecutive 63-month periods.

Results

A total of 225 cases were diagnosed. Survival was 60% (134 of 225). Postnatal survival was 68% (134 of 198 liveborn), and postrepair survival was 84% (134 of 159 who survived to repair). Diagnosis was made antenatally in 66% of cases. Variables associated with mortality were the need for complex ventilatory strategies (iNO, HFOV, Prostin, and ECMO), antenatal diagnosis, right-sided defects, use of patch repair, associated anomalies, birth weight, and gestation. Survival has improved from our report of a prior decade and did not vary during the study period. Postnatal survival has improved despite fewer terminations. On multivariate analysis, the need for complex ventilation was the strongest predictor of death (OR=50, 95% CI 13 to 224, p<0.0001), and associated anomalies ceased to be predictive.

Conclusions

Survival has improved from our earlier report, despite reduced numbers of terminations. This may be related to increased use of complex ventilatory strategies.

One Size Does Not Fit All: Congenital Diaphragmatic Hernia Management in Neonates

Congenital diaphragmatic hernia (CDH) results from abnormal development of the diaphragm during fetal life, allowing abdominal organs to herniate through the defect into the thorax. Stunted lung growth is associated with pulmonary hypoplasia and pulmonary hypertension, which are the primary sources of morbidity and mortality for this population. Despite strides in neonatal and surgical care, the management of neonates with CDH remains challenging. Optimal treatment strategies are still largely unknown. Many centers utilize gentle ventilation, permissive hypercapnia, and pulmonary hypertension treatment inclusive of nitric oxide, sildenafil, or epoprostenol, delayed surgical repair, and extracorporeal membrane oxygenation (ECMO). Evidence-based guidelines are needed to enhance CDH care practices and better outcomes. The successful management of CDH is a collaborative team effort from the prenatal to the postnatal period and beyond.

Management of the CDH patient on ECLS

Congenital diaphragmatic hernia (CDH) is the most common indication for respiratory extracorporeal life support (ECLS) in neonates. The survival rate of CDH neonates treated with ECLS is 50%, and this figure has remained relatively stable over the last few decades. This is likely because the current population of CDH neonates who require ECLS have a higher risk profile [1]. The management of neonates with CDH has evolved over time to emphasize postnatal stabilization, gentle ventilation, and multi-modal treatment of pulmonary hypertension. In order to minimize practice variation, many centers have adopted CDH-specific clinical practice guidelines, however care is not standardized between different centers and outcomes vary [3]. The purpose of this review is to summarize our current understanding of issues central to the care of neonates with CDH treated with ECLS and specifically highlight how the use of the Extracorporeal Life Support Organization (ELSO) data have added to our understanding of CDH.

Surgical Management of Congenital Diaphragmatic Hernia

Congenital diaphragmatic hernia (CDH) is a challenging surgical disease that requires complex preoperative, perioperative, and postoperative care. Survival depends on successful reduction and repair of the defect, and numerous complex decisions must be made regarding timing and preparation for surgery. This review describes the challenges and controversies inherent to surgical CDH care and provides recommendations for management based on the most recent evidence.

The use of neurally-adjusted ventilatory assist (NAVA) for infants with congenital diaphragmatic hernia (CDH)

OBJECTIVES

Newborns with congenital diaphragmatic hernia (CDH) can have complex respiratory problems which are worsened by ventilatory induced lung injury. Neurally adjusted ventilator assist (NAVA) is a potentially promising ventilation mode for this population, as it can result in improved patient-ventilator interactions and provision of adequate gas exchange at lower airway pressures.

CONTENT

A literature review was undertaken to provide an overview of NAVA and examine its role in the management of infants with CDH.

SUMMARY

NAVA in neonates has been used in CDH infants who were stable on ventilatory support or being weaned from mechanical ventilation and was associated with a reduction in the level of respiratory support.

OUTLOOK

There is, however, limited evidence regarding the efficacy of NAVA in infants with CDH, with only short-term benefits being investigated. A prospective, multicentre study with long term follow-up is required to appropriately assess NAVA in this population.

Use of intraoperative high frequency oscillatory ventilation in neonates with pulmonary hypoplasia

High-frequency oscillatory ventilation (HFOV) is a ventilatory modality widely used in neonatal intensive care units. Its main indication is restrictive lung pathology with difficult gas exchange using conventional mechanical ventilation (CMV). Patients receiving CMV require high intensity care, and immature lungs can be at risk for barotrauma and volutrauma. The few studies that have explored the use of HFOV in the operating room are mainly limited to HFVO during congenital diaphragmatic hernia repair. Limited experience of this ventilatory method in the operating room may be a disadvantage for the anesthesiologist. However, it is important to remember the benefits of this technique as a lung protection strategy. We report two cases of neonatal pulmonary hypoplasia of different etiology in which good oxygenation and ventilation was achieved with intraoperative HFOV.

High-frequency oscillatory ventilation versus conventional ventilation in the respiratory management of term neonates with a congenital diaphragmatic hernia: a retrospective cohort study

Conventional mechanical ventilation (CMV) has been recommended as the first-line mode of respiratory support for neonates born with a congenital diaphragmatic hernia (CDH). However, older studies suggested that protective high-frequency oscillatory ventilation (HFOV) with low-mean airway pressure (MAP) may limit lung injury. We aimed to compare low-MAP HFOV with CMV in neonates with CDH in terms of patient outcomes. This retrospective cohort study was conducted in two French neonatal intensive care units: center 1 mainly used CMV, and center 2 mainly used HFOV with a low MAP. All term neonates with CDH born between 2010 and 2018 in these two centers were included. The primary outcome was the duration of oxygen therapy. Secondary outcomes were survival and duration of mechanical ventilation. A total of 170 patients (105 in center 1, 65 in center 2) were included. In center 2, 96% of patients were ventilated with HFOV versus 19% in center 1. After adjustment for perinatal data, there was no significant difference regarding duration of oxygen therapy (SHR 0.83, 95% CI [0.55-1.23], p = 0.35) or survival (HR 1.73, 95% CI [0.64-4.64], p = 0.28). Center 2 patients required longer mechanical ventilation and sedation.

CONCLUSION

First-line mode of mechanical ventilation was not associated with the duration of oxygen therapy or survival in neonates with CDH.

WHAT IS KNOWN

• Recommendations were given in favour of using the conventional mechanical ventilation in first intention in neonates with a congenital diaphragmatic hernia, since High frequency oscillation (HFO) has been associated with a higher morbidity.

WHAT IS NEW

• No differences between HFO and conventional mechanical ventilation were observed concerning the length of oxygen supply and the survival..

Mechanical properties of the premature lung: From tissue deformation under load to mechanosensitivity of alveolar cells

Many preterm infants require mechanical ventilation as life-saving therapy. However, ventilation-induced overpressure can result in lung diseases. Considering the lung as a viscoelastic material, positive pressure inside the lung results in increased hydrostatic pressure and tissue compression. To elucidate the effect of positive pressure on lung tissue mechanics and cell behavior, we mimic the effect of overpressure by employing an uniaxial load onto fetal and adult rat lungs with different deformation rates. Additionally, tissue expansion during tidal breathing due to a negative intrathoracic pressure was addressed by uniaxial tension. We found a hyperelastic deformation behavior of fetal tissues under compression and tension with a remarkable strain stiffening. In contrast, adult lungs exhibited a similar response only during compression. Young’s moduli were always larger during tension compared to compression, while only during compression a strong deformation-rate dependency was found. In fact, fetal lung tissue under compression showed clear viscoelastic features even for small strains. Thus, we propose that the fetal lung is much more vulnerable during inflation by mechanical ventilation compared to normal inspiration. Electrophysiological experiments with different hydrostatic pressure gradients acting on primary fetal distal lung epithelial cells revealed that the activity of the epithelial sodium channel (ENaC) and the sodium-potassium pump (Na,K-ATPase) dropped during pressures of 30 cmH₂O. Thus, pressures used during mechanical ventilation might impair alveolar fluid clearance important for normal lung function.

Operative repair in congenital diaphragmatic hernia: How long do we really need to wait?

OBJECTIVE

To analyze preoperative cardiopulmonary support and define preoperative stability relative to timing of surgical repair for CDH neonates not on ECMO.

STUDY DESIGN

We retrospectively analyzed repeated measures of oxygenation index (OI; Paw*FiO₂×100/PaO₂) among 158 neonates for temporal preoperative trends. We defined physiologic stability using OI and characterized ventilator days and discharge age relative to delay in repair beyond physiologic stability.

RESULTS

The OI in the first 24 h of life was temporally reliable and representative of the preoperative mean (ICC 0.70, 95% CI 0.61-0.77). A pre-operative OI of ≤ 9.4 (AUC 0.95) was predictive of survival. Surgical delay after an OI ≤ 9.4 resulted in increased ventilator days (1.4, 95% CI 1.1-1.9) and discharge age (1.5, 95% CI 1.2-2.0). When prospectively applied to a subsequent cohort, an OI ≤ 9.4 was again reflective of physiologic stability prior to repair.

CONCLUSION

OI values are temporally reliable and change minimally after 24 h age. Delay in surgical repair of CDH beyond initial stability increases ventilator days and discharge age without a survival benefit.

LEVEL OF EVIDENCE

Prognosis study, Level III.

The effect of high-frequency oscillatory ventilator combined with pulmonary surfactant in the treatment of neonatal respiratory distress syndrome

OBJECTIVE

To investigate the efficacy of high-frequency oscillatory ventilation (HFOV) combined with pulmonary surfactant (PS) in the treatment of neonatal respiratory distress syndrome (NRDS).

METHODS

This study is a retrospective clinical study. Seventy-two NRDS neonates were selected as the subjects from November 2019 to November 2020, and divided into observation group (40 cases, HFOV treatment) and control group (32 cases, conventional mechanical ventilation treatment). All cases were treated with PS and comprehensive treatment. The therapeutic effect, arterial partial pressure of oxygen (PaO2), arterial partial pressure of carbon dioxide (PaCO2), Percentage of inhaled oxygen concentration (FiO2), mean arterialpressure, oxygenation index (OI), and complications were compared in the 2 groups.

RESULTS

The total effective rate of the observation group was 90.0%, significantly higher than that of the control group. After treatment, the observation group has higher PaO2 levels and lower levels of PaCO2, mean arterial pressure, FiO2, and OI than the control group. There was no significant difference in the incidence of complications between the 2 groups.

CONCLUSION

HFOV combined with PS has a significant effect on NRDS, which can improve the arterial blood gas index without increasing the incidence of complications.

Impact of Time Point of Extracorporeal Membrane Oxygenation on Mortality and Morbidity in Congenital Diaphragmatic Hernia: A Single-Center Case Series

Since there are no data available on the influence of the time point of ECMO initiation on morbidity and mortality in patients with congenital diaphragmatic hernia (CDH), we investigated whether early initiation of ECMO after birth is associated with a beneficial outcome in severe forms of CDH. All neonates with CDH admitted to our institution between 2010 until 2020 and undergoing ECMO treatment were included in this study and divided into four different groups: (1) ECMO initiation < 12 h after birth (n = 143), (2) ECMO initiation between 12−24 h after birth (n = 31), (3) ECMO initiation between 24−120 h after birth (n = 48) and (4) ECMO initiation > 120 h after birth (n = 14). The mortality rate in the first (34%) and fourth group (43%) was high and in the second group (23%) and third group (12%) rather low. The morbidity, characterized by chronic lung disease (CLD), did not differ significantly in the three groups; only patients in which ECMO was initiated >120 h after birth had an increased rate of severe CLD. Our data, although not randomized and limited due to small study groups, suggest that very early need for ECMO and ECMO initiation > 120 h after birth is associated with increased mortality.