The Canadian Pediatric Surgery Network Congenital Diaphragmatic Hernia Evidence Review Project: Developing national guidelines for care

Delivery Room Management of Infants with Surgical Conditions

Delivery room resuscitation of infants with surgical conditions can be complex and depends on an experienced and cohesive multidisciplinary team whose performance is more important than that of any individual team member. Existing resuscitation algorithms were not developed for infants with congenital anomalies, and delivery room resuscitation is largely dictated by expert opinion extrapolating physiologic expectations from infants without anomalies. As prenatal diagnosis rates improve, there is an increased ability to plan for the unique delivery room needs of infants with surgical conditions. In this review, we share expert opinion, including our center's delivery room management for neonatal noncardiac surgical conditions, and highlight knowledge gaps and the need for further studies and evidence-based practice to be incorporated into the delivery room care of infants with surgical conditions. Future research in this area is essential to move from an expert-based approach to a data-driven approach to improve and individualize delivery room resuscitation of infants with surgical conditions.

Delivery Room Resuscitation of Infants with Congenital Diaphragmatic Hernia: Lessons Learned through Video Review

INTRODUCTION

Delivery room (DR) interventions for infants with congenital diaphragmatic hernia (CDH) are not well described. This study sought to describe timing and order of DR interventions and identify system factors impacting CDH DR resuscitations using a human factors framework.

METHODS

Single center observational study of video recorded CDH DR resuscitations documenting timing and order of interventions. The team used the Systems Engineering Initiative for Patient Safety (SEIPS) model to identify system factors impacting DR resuscitations and time to invasive ventilation.

RESULTS

We analyzed 31 video recorded CDH resuscitations. We observed variability in timing and order of resuscitation tasks. The 'Internal Environment' and 'Tasks' components of the SEIPS model were prominent factors affecting resuscitation efficiency; significant room and bed spatial constraints exist, and nurses have a significant task burden. Additionally, endotracheal tube preparation was a prominent barrier to timely invasive ventilation.

CONCLUSION

Video review revealed variation in event timing and order during CDH resuscitations. Standardization of room set-up, equipment, and event order and reallocation of tasks facilitate more efficient intubation and ventilation, representing targets for CDH DR improvement initiatives. This work emphasizes the utility of rigorous human factors review to identify areas for improvement during DR resuscitation.

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.

The impact of a care bundle with an emphasis on hemodynamic assessment on the short-term outcomes in neonates with congenital diaphragmatic hernia

OBJECTIVE

To evaluate the short-term outcomes of implementing a care bundle emphasizing frequent hemodynamic assessments by echocardiography in neonates with congenital diaphragmatic hernia (CDH).

STUDY DESIGN

This was a retrospective cohort study of infants with CDH admitted to a quaternary perinatal unit from January 2013 to March 2021. The primary composite outcome was defined as mortality or use of extracorporeal membrane oxygenation or need for respiratory support at discharge.

RESULTS

We identified 37 and 20 CDH infants in Epoch I and II, respectively. More patch repairs (50% vs. 21.9%, p = 0.035) and echocardiograms (6[4-8] vs. 1[0-5], p = 0.003) were performed in Epoch II. While there were no differences in the primary outcome, there was a reduction in mortality in Epoch II (0% vs. 27%, p = 0.01).

CONCLUSION

With the implementation of a CDH care bundle with an emphasis on hemodynamic assessment, we demonstrated a significant reduction in mortality.

A Scoping Review on Learning Health Networks Available in Pediatric Surgical Specialties

BACKGROUND

Learning health networks (LHN) are consortia of institutions that collaborate and embrace the elements of the learning health system (LHS), including quality improvement, education, research, and stakeholder involvement. Their ultimate goal is rapid information dissemination in clinical care. Pediatric surgical specialties perform unique yet high-impact procedures that could benefit from LHN, thereby improving surgical outcomes and care through LHS approaches. Consequently, health system leaders should be aware of LHN and their importance in enhancing surgical care and improving outcomes. This scoping review aims to map and characterize the existing LHN applied in pediatric surgical specialties.

METHODS

A systematic literature search was performed on Medline, EMBASE, and Scopus up to June 2022, with an update search conducted in May 2023. Additionally, Google Scholar, ProQuest and inquiry from topic experts were used for cross-referencing relevant review articles to identify grey literature. This scoping review was conducted and reported according to the PRISMA-scoping review extension.

RESULTS

A total of 56 publications for 19 LHN were identified and included in this scoping review. Out of 19 identified LHN in pediatric surgical specialties, 18 were organized in North America. Eight of the networks are related to pediatric general surgery and another eight were related to pediatric transplantation. The 16 out of 19 LHN were initiated after 2001. To date, only eight of the LHNs generated reports of comparative improved outcomes.

CONCLUSION

This scoping review provides an overview of the available LHNs in pediatric surgical specialties. Over the past decade, several pediatric surgical specialties have embraced the principles of learning health systems, forming inter-institutional collaborations that utilize information technology to generate big data on patient-level clinical information, engage in quality improvement cycles, adopt evidence-based practices, and actively involve patients and stakeholders.

LEVEL OF EVIDENCE

IV.

Update on Management and Outcomes of Congenital Diaphragmatic Hernia

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

Successful extracorporeal membrane oxygenation for postoperative cardiopulmonary failure in newborns with congenital diaphragmatic hernia: case reports and literature reviews

Introduction

Congenital diaphragmatic hernia (CDH) is a structural defect caused by inadequate fusion of the pleuroperitoneal membrane that forms the diaphragm, allowing peritoneal viscera to protrude into the pleural cavity. Up to 30% of newborns with CDH require extracorporeal membrane oxygenation (ECMO) support. As with all interventions, the risks and benefits of ECMO must be carefully considered in these patients. Cardiopulmonary function has been shown to worsen rather than improve after surgical CDH repair. Even after a detailed perioperative assessment, sudden cardiopulmonary failure after surgery is dangerous and requires timely and effective treatments.

Method

Three cases of cardiopulmonary failure after surgical CDH treatment in newborns have been reported. ECMO support was needed for these three patients and was successfully discontinued. We report our treatment experience.

Conclusion

ECMO is feasible for the treatment of postoperative cardiopulmonary failure in newborns with CDH.

Postnatal care setting and survival after fetoscopic tracheal occlusion for severe congenital diaphragmatic hernia: A systematic review and meta-analysis

BACKGROUND

Fetoscopic endoluminal tracheal occlusion (FETO) was recently shown to improve postnatal survival in a multicenter, randomized controlled trial of infants with severe congenital diaphragmatic hernia (CDH). However, the external validity of this study remains unclear given a lack of standardization in postnatal management approaches. The purpose of this study was to evaluate the impact of an integrated prenatal and postnatal care setting on survival outcomes in severe CDH after FETO.

STUDY DESIGN

A systematic review, meta-analysis, and individual participant analysis of FETO outcomes in severe CDH were conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The primary outcome was survival to discharge. Subgroup analyses of patients managed in integrated versus nonintegrated settings were performed to identify predictors of outcome.

RESULTS

The review generated five studies (n = 192) for the meta-analysis of FETO versus expectant prenatal management. These data revealed a significant survival benefit after FETO that was restricted to an integrated setting (OR 2.97, 95% Confidence Interval 1.69-4.26). There were nine studies (n = 150) for the individual participant analysis, which showed that FETO managed in an integrated setting had significantly increased survival rates when compared to FETO treated in a nonintegrated setting (70.7% vs. 45.7%, p = 0.003). Multi-level logistic regression identified increased availability of extracorporeal membrane oxygenation (ECMO) as the strongest determinant of postnatal survival (OR=18.8, p = 0.049).

CONCLUSION

This systematic review shows that institutional integration of prenatal and postnatal care is associated with the highest overall survival in children with severe CDH. These data highlight the importance of a standardized, multidisciplinary approach, including access to ECMO, as a critical postnatal component in optimizing FETO outcomes in CDH.

Variation across centers in standardized mortality ratios for congenital diaphragmatic hernia receiving extracorporeal life support

BACKGROUND

We sought to elucidate the degree of variation across centers by calculating center-specific standardized mortality ratios (SMRs) for infants with congenital diaphragmatic hernia (CDH) requiring extracorporeal life support (ECLS).

METHODS

The Extracorporeal Life Support Organization (ELSO) registry data (2000-2019) were used to estimate SMRs. Center-specific SMRs and their 95% confidence intervals (CIs) were used to identify centers with mortality as significantly worse (SW), significantly better (SB), or not different (ND) relative to the median standardized mortality rate.

RESULTS

We identified 4,223 neonates with CDH from 109 centers. SMRs were risk-adjusted for pre-ECLS case-mix (birthweight, sex, race, 5 min Apgar, blood gases, gestational age, hernia side, prenatal diagnosis, pre-ECLS arrest, and comorbidities). Observed (unadjusted) mortality rates across centers varied substantially (range: 14.3%-90.9%; interquartile range [IQR]: 42.9%-62.1%). Thirteen centers (11.9%) had SB SMRs< 1 (SMR 0.52 to 0.84), 7 centers (6.4%) had SW SMRs>1 (SMR 1.25 to 1.43), and 89 centers (81.7%) had SMRs ND relative to the median SMR rate across all centers (i.e., SMR not different from one). Descriptive analyses demonstrated that SB centers had a lower proportion of cases with renal complications, infectious complications and discontinuation of ECLS owing to complications, as well as differences in pre-ECLS treatments and timing of CDH repair, compared to SW and ND centers.

CONCLUSION

This study specifically identified ECLS centers with higher and lower survival for patients with CDH, which may serve as a benchmark for institutional quality improvement. Future studies are needed to identify those specific processes at those centers that leads to favorable outcomes with the goal of improving care globally.

LEVEL OF EVIDENCE

Level III.

Impact of fetal treatments for congenital diaphragmatic hernia on lung development

The extent of lung hypoplasia impacts the survival and severity of morbidities associated with congenital diaphragmatic hernia (CDH). The alveoli of CDH infants and in experimental models of CDH have thickened septa with fewer type II pneumocytes and capillaries. Fetal treatments of CDH-risk preterm birth. Therefore, treatments must aim to balance the need for increased gas exchange surface area with the restoration of pulmonary epithelial type II cells and the long-term respiratory and neurodevelopmental consequences of prematurity. Achievement of sufficient lung development in utero for successful postnatal transition requires adequate intra-thoracic space for lung growth, maintenance of sufficient volume and appropriate composition of fetal lung fluid, regular fetal breathing movements, appropriate gas exchange area, and ample surfactant production. The review aims to examine the rationale for current and future therapeutic strategies to improve postnatal outcomes of infants with CDH.

The maternal-fetal transfer of passive immunity as a mechanism of transplacental nanoparticle drug delivery for prenatal therapies

Nanoparticles administered into the maternal circulation and across the placenta are a potential clinical therapy to treat congenital diseases. The mechanism by which nanoparticles can safely cross the placenta for targeted drug delivery to the fetus remains poorly understood. We demonstrate that the maternal-fetal transfer of passive immunity through the neonatal Fc Receptor (FcRn) can induce the transplacental transfer of chitosan nanoparticles modifed with IgG antibodies (414 ± 27 nm). The transfer of FITC-tagged IgG-modified chitosan nanoparticles was 2.8 times higher (p = 0.0264) compared to similarly-sized unmodified chitosan nanoparticles (375 ± 17 nm). Co-administration of free IgG competitively diminished the transplacental transfer of IgG-modified nanoparticles, yet unmodified nanoparticles remained unaffected. Colocalization of the FcRn and the IgG-modified chitosan nanoparticles were observed with confocal microscopy. Barrier function before and after nanoparticle administration remained intact as determined by TEER (75-79 Ω cm²) and immmunofluorescence of ZO-1 tight junction proteins. The results provide insight into the clinical applications of nanoparticles for prenatal therapies using the mechanism of the maternal-fetal transfer of passive immunity.

Work of breathing at different tidal volume targets in newborn infants with congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) results in varying degrees of pulmonary hypoplasia. Volume targeted ventilation (VTV) is a lung protective strategy but the optimal target tidal volume in CDH infants has not previously been studied. The aim of this study was to test the hypothesis that low targeted volumes would be better in CDH infants as determined by measuring the work of breathing (WOB) in CDH infants, at three different targeted tidal volumes. A randomised cross-over study was undertaken. Infants were eligible for inclusion in the study after surgical repair of their diaphragmatic defect. Targeted tidal volumes of 4, 5, and 6 ml/kg were each delivered in random order for 20-min periods with 20-min periods of baseline ventilation between. WOB was assessed and measured by using the pressure-time product of the diaphragm (PTPdi). Nine infants with a median gestational age at birth of 38 + 4 (range 36 + 4-40 + 6) weeks and median birth weight 3202 (range 2855-3800) g were studied. The PTPdi was higher at 4 ml/kg than at both 5, p = 0.008, and 6 ml/kg, p = 0.012.

CONCLUSION

VTV of 4 ml/kg demonstrated an increased PTPdi compared to other VTV levels studied and should be avoided in post-surgical CDH infants.

WHAT IS KNOWN

• Lung injury secondary to mechanical ventilation increases the mortality and morbidity of infants with CDH. • Volume targeted ventilation (VTV) reduces 'volutrauma' and ventilator-induced lung injury in other neonatal intensive care populations.

WHAT IS NEW

• A randomised cross-over trial was carried out investigating the response to different VTV levels in infants with CDH. • Despite pulmonary hypoplasia being a common finding in CDH, a VTV of 5ml/kg significantly reduced the work of breathing in infants with CDH compared to a lower VTV level.

Factors to Consider to Study Preductal Oxygen Saturation Targets in Neonatal Pulmonary Hypertension

There are potential benefits and risks to the infant with higher and lower oxygen saturation (SpO₂) targets, and the ideal range for infants with pulmonary hypertension (PH) remains unknown. Targeting high SpO₂ can promote pulmonary vasodilation but cause oxygen toxicity. Targeting lower SpO₂ may increase pulmonary vascular resistance, especially in the presence of acidosis and hypothermia. We will conduct a randomized pilot trial to compare two ranges of target preductal SpO₂ in late-preterm and term infants with hypoxic respiratory failure (HRF) and acute pulmonary hypertension (aPH) of the newborn. We will assess the reliability of a newly created HRF/PH score that could be used in larger trials. We will assess trial feasibility and obtain preliminary estimates of outcomes. Our primary hypothesis is that in neonates with PH and HRF, targeting preductal SpO₂ of 95-99% (intervention) will result in lower pulmonary vascular resistance and pulmonary arterial pressures, and lower the need for pulmonary vasodilators (inhaled nitric oxide-iNO, milrinone and sildenafil) compared to targeting SpO₂ at 91-95% (standard). We also speculate that a higher SpO₂ target can potentially induce oxidative stress and decrease response to iNO (oxygenation and pulmonary vasodilation) for those patients that still require iNO in this range. We present considerations in planning this trial as well as some of the details of the protocol design (Clinicaltrials.gov (NCT04938167)).

Vena Cava Thrombosis after Congenital Diaphragmatic Hernia Repair: Multivariate Analysis of Potential Risk Factors

INTRODUCTION

 The treatment of newborns with congenital diaphragmatic hernia (CDH) is associated with a significant complication rate. Information on major thrombotic complications and their incidence in newborns with CDH is lacking. The aims of our analysis were to evaluate the frequency of vena cava thrombosis and to determine its predictors within a consecutive series of patients with CDH.

MATERIALS AND METHODS

 We retrospectively analyzed charts of all neonates of our department that underwent CDH repair from 2007 to 2021, focusing on vena cava thrombosis. Vena cava thrombosis was diagnosed sonographically and classified as complete or partial venous occlusion. Complete occlusion was confirmed by cavography. Variables evaluated were CDH side, liver position, central vein line, surgical approach, and extracorporeal membrane oxygenation (ECMO). Univariate and multivariate tests were utilized.

RESULTS

 Among 57 neonates who underwent CDH repair, vena cava thrombosis was diagnosed in 14 (24.6%), seven of whom had complete occlusion of the vena cava. Factors associated with vena cava thrombosis were femoral or saphenous venous catheter (p = 0.044), right sided CDH (p = 0.027) and chylothorax (p < 0.0001). ECMO was not associated with vena cava thrombosis. Seven patients (50%) with vena cava thrombosis were treated interventionally with angioplasty and seven (50%) conservatively with anticoagulation only. Mortality was not higher in patients with compared with patients without vena cava thrombosis.

CONCLUSION

 The incidence of vena cava thrombosis in newborns with CDH in our series is high. Routine postoperative abdominal sonography focusing on vena cava thrombosis is mandatory in all patients with CDH. Patients who developed vena cava thrombosis were more likely to develop chylothorax after CDH repair. Considering the good outcome of medical therapy of partial vena cava thrombosis, it may be discussed whether low dose anticoagulation may be provided to all newborns with CDH.

When to say no to inhaled nitric oxide in neonates?

Inhaled nitric oxide (iNO) was approved for use in critically ill term and near-term neonates (>34 weeks gestational age) in 1999 for hypoxic respiratory failure (HRF) with evidence of pulmonary hypertension. In 2011 and 2014, the National Institutes of Health and American Academy of Pediatrics respectively recommended against the use of iNO in preterm infants <34 weeks. However, these guidelines were based on trials conducted with varying inclusion criteria and outcomes. Recent guidelines from the American Thoracic Society/American Heart Association, the Pediatric Pulmonary Hypertension Network (PPHNet) and European Pediatric Pulmonary Vascular Disease Network recommend the use of iNO in preterm neonates with HRF with confirmed pulmonary hypertension. This review discusses the available evidence for off-label use of iNO. Preterm infants with prolonged rupture of membranes and pulmonary hypoplasia appear to respond to iNO. Similarly, preterm infants with physiology of pulmonary hypertension with extrapulmonary right-to-left shunts may potentially have an oxygenation response to iNO. An overview of relative and absolute contraindications for iNO use in neonates is provided. Absolute contraindications to iNO use include a ductal dependent congenital heart disease where systemic circulation is supported by a right-to-left ductal shunt, severe left ventricular dysfunction and severe congenital methemoglobinemia. In preterm infants, we do not recommend the routine use of iNO in HRF due to parenchymal lung disease without pulmonary hypertension and prophylactic use to prevent bronchopulmonary dysplasia. Future randomized trials evaluating iNO in preterm infants with pulmonary hypertension and/or pulmonary hypoplasia are warranted. (233/250 words).

Outcomes of Preterm Infants With Congenital Heart Defects After Early Surgery: Defining Risk Factors at Different Time Points During Hospitalization

Background: Compared with those born at term gestation, infants with complex congenital heart defects (CCHD) who were delivered before 37 weeks gestational age and received neonatal open-heart surgery (OHS) have poorer neurodevelopmental outcomes in early childhood. We aimed to describe the growth, disability, functional, and neurodevelopmental outcomes in early childhood of preterm infants with CCHD after neonatal OHS. Prediction models were evaluated at various timepoints during hospitalization which could be useful in the management of these infants. Study Design: We studied all preterm infants with CCHD who received OHS within 6 weeks of corrected age between 1996 and 2016. The Western Canadian Complex Pediatric Therapies Follow-up Program completed multidisciplinary comprehensive neurodevelopmental assessments at 2-year corrected age at the referral-site follow-up clinics. We collected demographic and acute-care clinical data, standardized age-appropriate outcome measures including physical growth with calculated z-scores; disabilities including cerebral palsy, visual impairment, permanent hearing loss; adaptive function (Adaptive Behavior Assessment System-II); and cognitive, language, and motor skills (Bayley Scales of Infant and Toddler Development-III). Multiple variable logistic or linear regressions determined predictors displayed as Odds Ratio (OR) or Effect Size (ES) with 95% confidence intervals. Results: Of 115 preterm infants (34 ± 2 weeks gestation, 2,339 ± 637 g, 64% males) with CCHD and OHS, there were 11(10%) deaths before first discharge and 21(18%) deaths by 2-years. Seven (6%) neonates had cerebral injuries, 7 had necrotizing enterocolitis; none had retinopathy of prematurity. Among 94 survivors, 9% had cerebral palsy and 6% had permanent hearing loss, with worse outcomes in those with syndromic diagnoses. Significant predictors of mortality included birth weight z-score [OR 0.28(0.11,0.72), P = 0.008], single-ventricle anatomy [OR 5.92(1.31,26.80), P = 0.021], post-operative ventilation days [OR 1.06(1.02,1.09), P = 0.007], and cardiopulmonary resuscitation [OR 11.58 (1.97,68.24), P = 0.007]; for adverse functional outcome in those without syndromic diagnoses, birth weight 2,000-2,499 g [ES -11.60(-18.67, -4.53), P = 0.002], post-conceptual age [ES -0.11(-0.22,0.00), P = 0.044], post-operative lowest pH [ES 6.75(1.25,12.25), P = 0.017], and sepsis [ES -9.70(-17.74, -1.66), P = 0.050]. Conclusions: Our findings suggest preterm neonates with CCHD and early OHS had significant mortality and morbidity at 2-years and were at risk for cerebral palsy and adverse neurodevelopment. This information may be important for management, parental counseling and the decision-making process.

Basic and translational science advances in congenital diaphragmatic hernia

Congenital Diaphragmatic Hernia (CDH) is a birth defect that is characterized by lung hypoplasia, pulmonary hypertension and a diaphragmatic defect that allows herniation of abdominal organs into the thoracic cavity. Although widely unknown to the public, it occurs as frequently as cystic fibrosis (1:2500). There is no monogenetic cause, but different animal models revealed various biological processes and epigenetic factors involved in the pathogenesis. However, the pathobiology of CDH is not sufficiently understood and its mortality still ranges between 30 and 50%. Future collaborative initiatives are required to improve our basic knowledge and advance novel strategies to (prenatally) treat the abnormal lung development. This review focusses on the genetic, epigenetic and protein background and the latest advances in basic and translational aspects of CDH research.

First steps in the development of a liquid biopsy in situ hybridization protocol to determine circular RNA biomarkers in rat biofluids

PURPOSE

Epigenetic factors are involved in the pathogenesis of congenital diaphragmatic hernia (CDH). Circular RNAs (circRNAs) are epigenetic regulators amenable to biomarker profiling. Here, we aimed to develop a liquid biopsy protocol to detect pathognomonic circRNA changes in biofluids.

METHODS

Our protocol is adapted from the existing BaseScope™ in situ hybridization technique. Rat biofluids were fixed in a gelatin-coated 96-well plate with formalin. Probes were designed to target circRNAs with significant fold change in nitrofen-induced CDH. FastRED fluorescence was assessed using a plate reader and confirmed with confocal microscopy. We tested maternal serum and amniotic fluid samples from control and nitrofen-treated rats.

RESULTS

We detected circRNAs in rat serum and amniotic fluid from control and CDH (nitrofen-treated) rats using fluorescent readout. CircRNA signal was observed in fixed biofluids as fluorescent punctate foci under confocal laser scanning microscopy. This was confirmed by comparison to BaseScope™ lung tissue sections. Signal was concentration dependent and DNase resistant.

CONCLUSION

We successfully adapted BaseScope™ to detect circRNAs in rat biofluids: serum and amniotic fluid. We detected signal from probes targeted to circRNAs that are dysregulated in rat CDH. This work establishes the preliminary feasibility of circRNA detection in prenatal diagnostics.

Prenatal prediction of survival in congenital diaphragmatic hernia: An audit of postnatal outcomes

PURPOSE

Effective antenatal counseling in congenital diaphragmatic hernia (CDH) relies on proper measurement of prognostic indices. This quality initiative audited the accuracy of prenatal imaging with postnatal outcomes at two tertiary pediatric referral centers.

METHODS

Prenatal lung-head ratio (LHR) and total fetal lung volume (TFLV) for CDH patients treated between 2006 and 2017 were retrieved. Study inclusion required at least one LHR or TFLV measurement between 24 and 32 weeks gestational age. Postnatal outcomes [mortality, extracorporeal life support (ECLS) need, patch repair, persistent pulmonary hypertension, oxygen requirement at 28 days] were abstracted from the Canadian Pediatric Surgery Network (CAPSNet) database and local chart review. Univariate and descriptive analyses were conducted.

RESULTS

Eighty-two of 121 eligible CDH patients (68%) were included. Overall mortality, ECLS rates, and patch repair were 33%, 12.5%, and 45%, respectively. Lower LHR values correlated with increased rates of each outcome and persisted despite multiple measurements. Values obtained were higher than those in published schemata. LHR values >45% were most associated with survival, avoidance of ECLS, and primary repair. TFLV values only correlated with mortality and patch repair.

CONCLUSIONS

This audit confirms that LHR and TFLV values predict CDH outcomes. However, absolute values obtained require careful interpretation and internal review.

LEVEL OF EVIDENCE

IV.

Role of ECMO in congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is typified morphologically by failure of diaphragmatic development with accompanying lung hypoplasia and persistent pulmonary hypertension of the newborn (PPHN). Patients who have labile physiology and low preductal saturations despite optimal ventilatory and inotropic support may be considered for extracorporeal membrane oxygenation (ECMO). Systematic reviews into the benefits of ECMO in CDH concluded that any benefit is unclear. Few randomised trials exist to demonstrate clear benefit and guide management. However, ECMO may have its uses in those that have reversibility of their respiratory disease. A few centres and networks have demonstrated an increase in survival rate by post hoc analysis (based on a difference in referral patterns with the availability of ECMO) in their series. One issue may be that of careful patient selection with regard to reversibility of pathophysiology. At present, there is no single test or prognostication that predicts reversibility of PPHN and criteria for referral for ECMO is undergoing continued refinement. Overall survival is similar between cannulation modes. There is no consensus on the time limit for ECMO runs. The optimal timing of surgery for patients on ECMO is difficult to definitively establish, but it seems that repair at an early stage (with careful perioperative management) is becoming less of a taboo, and may improve outcome and help with either coming off ECMO or decisions on withdrawal later. The provision of ECMO will continue to be evaluated, and prospective randomised trial are needed to help answer question of patient selection and management.

Congenital diaphragmatic hernia: The role of multi-institutional collaboration and patient registries in supporting best practice

Among congenital malformations, congenital diaphragmatic hernia (CDH) is distinguished by its relatively low occurrence rate, need for resource intensive, integrated multidisciplinary care, and widespread variation in practice and outcome. Although randomized controlled trials (RCTs) are considered the gold standard for generating evidence, they are poorly suited to the study of a condition like CDH due to challenges in illness severity adjustment, unpredictability in clinical course and the impact limitations of studying a single intervention at a time. An alternative to RCTs for comparative effectiveness research for CDH is the patient registry, which aggregates multi-institutional condition-specific patient level data into a large CDH-specific database for the dual purposes of collaborative research and quality improvement across participating sites. This article discusses patient registries from the perspective of structure, data collection and management, and privacy protection that guide the use of registry data to support collaborative, multidisciplinary research. Two CDH-specific registries are described as illustrative examples of the "value proposition" of registries in improving the evidence basis for best practices for CDH.