Thoracoscopic Patch Repair of Congenital Diaphragmatic Hernia: Can Smaller Incisions Treat Larger Defects?

INTRODUCTION

Thoracoscopic CDH repair is increasingly performed for Type A and small Type B defects that are amenable to primary repair. However, the thoracoscopic approach is controversial for larger defects necessitating a patch due to technical complexity, intraoperative acidosis, and recurrence risk. We aim to compare clinical outcomes between thoracoscopic and open patch repair of Type B/C defects, using a standardized technique.

METHODS

This is a single-center retrospective review of thoracoscopic and open CDH patch repairs January 2017-December 2021. We excluded primary repairs, Type D hernias, repairs on ECMO, recurrent repairs. Various preoperative, intraoperative, and postoperative variables were compared. Primary outcome was recurrence rate. Secondary outcomes included intraoperative pH and pCO2, operative time, and complication rates.

RESULTS

Twenty-nine patients met inclusion criteria (open = 13, thoracoscopic = 16). The open cohort had lower o/e total fetal lung volume (29 vs 41.2%, p = 0.042), higher preoperative peak inspiratory pressures (24 vs 20 cm H2O, p = 0.007), were more frequently Type C defects (92.3 vs 31%, p = 0.002) and had liver "up" in left-sided hernias (46 vs 0%, p < 0.0001). Intraoperatively, median lowest pH and highest pCO2 did not differ; neither did overall median pH or pCO2. Operative times were similar (153 vs 194 min, p = 0.113). No difference in recurrence rates was identified, however postoperative complications were higher in the open group. There were no mortalities.

CONCLUSIONS

Although we demonstrate higher disease severity of patients undergoing open repair, thoracoscopic patch repair for Type B/C defects is safe and effective in patients with favorable physiologic status, alleviating concerns for intraoperative acidosis, operative length, and risk of recurrence.

LEVEL OF EVIDENCE

II.

The role of fetal hemoglobin in the artificial placenta: A premature ovine model

INTRODUCTION

A radical paradigm shift in the treatment of premature infants failing conventional treatment is to recreate fetal physiology using an extracorporeal Artificial Placenta (AP). The aim of this study is to evaluate the effects of changing fetal hemoglobin percent (HbF%) on physiology and circuit function during AP support in an ovine model.

METHODS

Extremely premature lambs (n = 5) were delivered by cesarean section at 117-121 d estimated gestational age (EGA) (term = 145d), weighing 2.5 ± 0.35 kg. Lambs were cannulated using 10-14Fr cannulae for drainage via the right jugular vein and reinfusion via the umbilical vein. Lambs were intubated and lungs were filled with perfluorodecalin to a meniscus with a pressure of 5-8 cm H2O. The first option for transfusion was fetal whole blood from twins followed by maternal red blood cells. Arterial blood gases were used to titrate AP support to maintain fetal blood gas values.

RESULTS

The mean survival time on circuit was 119.6 ± 39.5 h. Hemodynamic parameters and lactate were stable throughout. As more adult blood transfusions were given to maintain hemoglobin at 10 mg/dL, the HbF% declined, reaching 40% by post operative day 7. The HbF% was inversely proportional to flow rates as higher flows were required to maintain adequate oxygen saturation and perfusion.

CONCLUSIONS

Transfusion of adult blood led to decreased fetal hemoglobin concentration during AP support. The HbF% was inversely proportional to flow rates. Future directions include strategies to decrease the priming volume and establishing a fetal blood bank to have blood rich in HbF.

Prenatal Measurements of Congenital Lung Malformations: Can They Predict Postnatal Size?

INTRODUCTION

Prenatally diagnosed congenital lung malformations (CLMs) are monitored via ultrasound and measured by congenital pulmonary airway malformation volume ratios (CVRs) which can predict postnatal respiratory symptoms. This study compared CVR to postnatal lesion size to help guide prenatal counseling.

METHODS

A retrospective chart review evaluated the prenatal imaging and postnatal outcomes for patients who were prenatally diagnosed with CLMs and had a postnatal computed tomography (CT) scan at one institution.

RESULTS

Fifty-seven patients were included. Four had symptoms requiring urgent resection. The remaining were discharged and had clinic follow-up with CT scan to determine next steps: five had no identified lesions, eight had lesions whose diagnosis did not warrant an operation, and 40 had lesions whose diagnosis rendered size a factor in operative decision-making. Of these 40, 26/40 patients (65%) underwent elective resection (median maximum CVR 0.97; median lesion size 4 cm) and 14/40 patients (35%) were observed without resection (median maximum CVR 0.5; median lesion size 3 cm). There was a positive correlation between prenatal CVR and postnatal lesion size, with R-squared = 0.46. Maximum CVRs were better than last CVRs when predicting whether postnatal CT size would fall above or below our institution's level of recommended resection, with an area under the curve of 0.85 and a CVR cut-point of 0.61.

CONCLUSIONS

For newborns with asymptomatic CLMs, higher maximum CVRs correlated with larger size on postnatal CT. A maximum CVR ≤0.6 was correlated with a smaller postnatal CT size that may be eligible for nonoperative management. While these results are not intended to recommend surgery based on higher CVRs alone, this information could potentially be used to reassure expectant parents whose babies' prenatal imaging demonstrate lower maximum CVRs.

Extracorporeal life support without systemic anticoagulation: a nitric oxide-based non-thrombogenic circuit for the artificial placenta in an ovine model

BACKGROUND

Clinical translation of the extracorporeal artificial placenta (AP) is impeded by the high risk for intracranial hemorrhage in extremely premature newborns. The Nitric Oxide Surface Anticoagulation (NOSA) system is a novel non-thrombogenic extracorporeal circuit. This study aims to test the NOSA system in the AP without systemic anticoagulation.

METHODS

Ten extremely premature lambs were delivered and connected to the AP. For the NOSA group, the circuit was coated with DBHD-N2O2/argatroban, 100 ppm nitric oxide was blended into the sweep gas, and no systemic anticoagulation was given. For the Heparin control group, a non-coated circuit was used and systemic anticoagulation was administered.

RESULTS

Animals survived 6.8 ± 0.6 days with normal hemodynamics and gas exchange. Neither group had any hemorrhagic or thrombotic complications. ACT (194 ± 53 vs. 261 ± 86 s; p < 0.001) and aPTT (39 ± 7 vs. 69 ± 23 s; p < 0.001) were significantly lower in the NOSA group than the Heparin group. Platelet and leukocyte activation did not differ significantly from baseline in the NOSA group. Methemoglobin was 3.2 ± 1.1% in the NOSA group compared to 1.6 ± 0.6% in the Heparin group (p < 0.001).

CONCLUSIONS

The AP with the NOSA system successfully supported extremely premature lambs for 7 days without significant bleeding or thrombosis.

IMPACT

The Nitric Oxide Surface Anticoagulation (NOSA) system provides effective circuit-based anticoagulation in a fetal sheep model of the extracorporeal artificial placenta (AP) for 7 days. The NOSA system is the first non-thrombogenic circuit to consistently obviate the need for systemic anticoagulation in an extracorporeal circuit for up to 7 days. The NOSA system may allow the AP to be implemented clinically without systemic anticoagulation, thus greatly reducing the intracranial hemorrhage risk for extremely low gestational age newborns. The NOSA system could potentially be applied to any form of extracorporeal life support to reduce or avoid systemic anticoagulation.

Ethical challenges in first-in-human trials of the artificial placenta and artificial womb: not all technologies are created equally, ethically

Artificial placenta and artificial womb technologies to support extremely premature neonates are advancing toward clinical testing in humans. Currently, no recommendations exist comparing these approaches to guide study design and optimal enrollment eligibility adhering to principles of research ethics. In this paper, we will explore how scientific differences between the artificial placenta and artificial womb approaches create unique ethical challenges to designing first-in-human trials of safety and provide recommendations to guide ethical study design for initial human translation.

The new frontier in ECLS: Artificial placenta and artificial womb for premature infants

Outcomes for extremely low gestational age newborns (ELGANs), defined as <28 weeks estimated gestational age (EGA), remain disproportionately poor. A radical paradigm shift in the treatment of prematurity is to recreate the fetal environment with extracorporeal support and provide an environment for organ maturation using an extracorporeal VV-ECLS artificial placenta (AP) or an AV-ECLS artificial womb (AW). In this article, we will review clinical indications, current approaches in development, ongoing challenges, remaining milestones and ethical considerations prior to clinical translation.

Updates in Neonatal Extracorporeal Membrane Oxygenation and the Artificial Placenta

Extracorporeal life support, initially performed in neonates, is now commonly used for both pediatric and adult patients requiring pulmonary and/or cardiac support. Data suggests the clinical feasibility of Extracorporeal Membrane Oxygenation for premature infants (29-33 weeks estimated gestational age [EGA]). For extremely premature infants less than 28 weeks EGA, an artificial placenta has been developed to recreate the fetal environment. This approach is investigational but clinical translation is promising. In this article, we discuss the current state and advances in neonatal and "preemie Extracorporeal Membrane Oxygenation" and the development of an artificial placenta and its potential use in extremely premature infants.

Milestones for clinical translation of the artificial placenta

Despite significant advances in the treatment of prematurity, premature birth results in significant mortality and morbidity. In particular, extremely low gestational age newborns (ELGANs) defined as <28 weeks estimated gestational age (EGA) suffer from disproportionate mortality and morbidity. A radical paradigm shift in the treatment of prematurity is to recreate fetal physiology using an extracorporeal VV-ECLS artificial placenta (AP) or an AV-ECLS artificial womb (AW). Over the past 15 years, tremendous advances have been made in the laboratory confirming long-term support and organ protection and ongoing development. The major milestones to clinical application are miniaturization, anticoagulation, clinical risk stratification, specialized critical care protocols, a regulatory path and a strategy and platform to translate technology to the bedside. Currently, several groups are addressing the remaining milestones for clinical translation.

Being small for gestational age is not an independent risk factor for mortality in neonates with congenital diaphragmatic hernia: a multicenter study

BACKGROUND

Congenital diaphragmatic hernia (CDH) accounts for 8% of all major congenital anomalies. Neonates who are small for gestational age (SGA) generally have a poorer prognosis. We sought to identify risk factors and variables associated with outcomes in neonates with CDH who are SGA in comparison to neonates who are appropriate for gestational age (AGA).

METHODS

We used the multicenter Diaphragmatic Hernia Research & Exploration Advancing Molecular Science (DHREAMS) study to include neonates enrolled from 2005 to 2019. Chi-squared or Fisher's exact tests were used to compare categorical variables and t tests or Wilcoxon rank sum for continuous variables. Cox model analyzed time to event outcomes and logistic regression analyzed binary outcomes.

RESULTS

589 neonates were examined. Ninety were SGA (15.3%). SGA patients were more likely to be female (p = 0.003), have a left sided CDH (p = 0.05), have additional congenital anomalies and be diagnosed with a genetic syndrome (p < 0.001). On initial single-variable analysis, SGA correlated with higher frequency of death prior to discharge (p < 0.001) and supplemental oxygen requirement at 28 days (p = 0.005). Twice as many SGA patients died before repair (12.2% vs 6.4%, p = 0.04). Using unadjusted Cox model, the risk of death prior to discharge among SGA patients was 1.57 times the risk for AGA patients (p = 0.029). There was no correlation between SGA and need for ECMO, pulmonary hypertensive medication at discharge or oxygen at discharge. After adjusting for confounding variables, SGA no longer correlated with mortality prior to discharge or incidence of unrepaired defects but remained significant for oxygen requirement at 28 days (p = 0.03).

CONCLUSION

Infants with CDH who are SGA have worse survival and poorer lung function than AGA infants. However, the outcome of SGA neonates is impacted by other factors including gestational age, genetic syndromes, and particularly congenital anomalies that contribute heavily to their poorer prognosis.

Image-based prenatal predictors correlate with postnatal survival, extracorporeal life support use, and defect size in left congenital diaphragmatic hernia

OBJECTIVE

To evaluate the association between prenatal imaging predictors of patients with left-sided congenital diaphragmatic hernia (LCDH) and postnatal outcomes.

STUDY DESIGN

CDH study group data were reviewed for LCDH infants born 2015-2019. Prenatal ultrasound (US) and magnetic resonance imaging (MRI) data were collected and correlated with postnatal information including CDHSG defect size (A through D or non-repair (NR)).

RESULTS

In total, 929 LCDH patients were included. Both US and MRI imaging predictors correlated with postnatal survival (72.2%) and ECLS use (29.6%). Logistic regression models confirmed increased survival and decreased ECLS use with larger values for all predictors. Importantly, all prenatal values evaluated showed no significant difference between defect size D and NR patients.

CONCLUSIONS

This is the largest cohort of LCDH patients and demonstrates that prenatal imaging factors correlate with postnatal outcomes and confirms that patients in the non-repair group are prenatally similar to type D defects.

Hepatic Function in Premature Lambs Supported by the Artificial Placenta and Total Parenteral Nutrition

The artificial placenta (AP) promotes organ development and reduces organ injury in a lamb model of extreme prematurity. This study evaluates hepatic outcomes after AP support with total parenteral nutrition (TPN) administration. Premature lambs (116-121 days estimated gestational age; term = 145) were cannulated for 7 days of AP support. Lambs received TPN with SMOFlipid (n = 7) or Intralipid (n = 5). Liver function and injury were compared between the two groups biochemically and histologically. Groups were compared by ANOVA with Tukey's multiple comparisons or linear-mixed effects models. From baseline to day 7, total bilirubin (Intralipid 2.6 ± 2.3 to 7.9 ± 4.4 mg/dl; SMOFlipid 0.3 ± 0.1 to 5.5 ± 2.3 mg/dl), alanine aminotransferase, and gamma-glutamyl transferase increased in both groups ( p < 0.001 for all). Direct bilirubin (0.3 ± 0.2 to 1.8 ± 1.4 mg/dl; p = 0.006) and AST (27 ± 5 to 309 ± 242 mg/dl; p < 0.001) increased in SMOFlipid group (not measured in Intralipid group). On liver histology, Intralipid showed more cholestasis than SMOFlipid; both groups showed more than tissue controls. The Intralipid group alone showed hepatocyte injury and had more congestion than controls. Lambs supported by the AP with TPN administration maintain normal hepatic function and sustain minimal hepatic injury. SMOFlipid is associated with decreased cholestasis and hepatic injury versus Intralipid.

Care Levels for Fetal Therapy Centers

Fetal therapies undertaken to improve fetal outcome or to optimize transition to neonate life often entail some level of maternal, fetal, or neonatal risk. A fetal therapy center needs access to resources to carry out such therapies and to manage maternal, fetal, and neonatal complications that might arise, either related to the therapy per se or as part of the underlying fetal or maternal condition. Accordingly, a fetal therapy center requires a dedicated operational infrastructure and necessary resources to allow for appropriate oversight and monitoring of clinical performance and to facilitate multidisciplinary collaboration between the relevant specialties. Three care levels for fetal therapy centers are proposed to match the anticipated care complexity, with appropriate resources to achieve an optimal outcome at an institutional and regional level. A level I fetal therapy center should be capable of offering fetal interventions that may be associated with obstetric risks of preterm birth or membrane rupture but that would be very unlikely to require maternal medical subspecialty or intensive care, with neonatal risks not exceeding those of moderate prematurity. A level II center should have the incremental capacity to provide maternal intensive care and to manage extreme neonatal prematurity. A level III therapy center should offer the full range of fetal interventions (including open fetal surgery) and be able manage any of the associated maternal complications and comorbidities, as well as have access to neonatal and pediatric surgical intervention including indicated surgery for neonates with congenital anomalies.

A single institution's experience with the management of peripheral bronchial atresia

PURPOSE

Peripheral bronchial atresia is a pulmonary abnormality diagnosed on postnatal computed tomography after prenatal imaging reveals a congenital lung lesion. Debate regarding management of this abnormality prompted us to review our institution's practice patterns and outcomes.

METHODS

All patients diagnosed with bronchial atresia were assessed from 6/2014 to 7/2020. Pediatric radiologists were surveyed to delineate computed tomography criteria used to diagnose peripheral bronchial atresia. Criteria were applied in an independent blinded review of postnatal imaging. Data for patients determined to have peripheral bronchial atresia and at least an initial pediatric surgical evaluation were analyzed.

RESULTS

Twenty-eight patients with bronchial atresia received at least an initial pediatric surgical evaluation. Expectant management was planned for 22/28 (79%) patients. Two patients transitioned from an expectant management strategy to an operative strategy for recurrent respiratory infections; final pathology revealed bronchial atresia in both. Six patients were initially managed operatively; final pathology revealed bronchial atresia (n = 3) or congenital lobar overinflation (n = 3).

CONCLUSIONS

Peripheral bronchial atresia can be safely managed expectantly. A change in symptoms is suspicious for alternate lung pathology, warranting further workup and consideration for resection.

LEVEL OF EVIDENCE

Level IV.

Neonatal pneumothorax in congenital diaphragmatic hernia: Be wary of high ventilatory pressures

Background

Patients with congenital diaphragmatic hernia (CDH) require invasive respiratory support and higher ventilator pressures may be associated with barotrauma. We sought to evaluate the risk factors associated with pneumothorax in CDH neonates prior to repair.

Methods

We retrospectively reviewed newborns born with CDH between 2014 and 2019 who developed a pneumothorax, and we matched these cases to patients with CDH without pneumothorax.

Results

Twenty-six patients were included (n=13 per group). The pneumothorax group required extracorporeal life support (ECLS) more frequently (85% vs 54%, p=0.04), particularly among type A/B defects (31% vs 7%, p=0.01). The pneumothorax group had higher positive end-expiratory pressure (PEEP) within 1 hour of birth (p=0.02), at pneumothorax diagnosis (p=0.003), and at ECLS (p=0.02). The pneumothorax group had a higher mean airway pressure (Paw) at birth (p=0.01), within 1 hour of birth (p=0.01), and at pneumothorax diagnosis (p=0.04). Using multiple logistic regression with cluster robust SEs, higher Paw (OR 2.2, 95% CI 1.08 to 3.72, p=0.03) and PEEP (OR 1.8, 95% CI 1.15 to 3.14, p=0.007) were associated with an increased risk of developing pneumothorax. There was no difference in survival (p=0.09).

Conclusions

Development of a pneumothorax in CDH neonates is independently associated with higher Paw and higher PEEP. A pneumothorax increases the likelihood of treated with ECLS, even with smaller defect.

Rare and de novo variants in 827 congenital diaphragmatic hernia probands implicate LONP1 as candidate risk gene

Congenital diaphragmatic hernia (CDH) is a severe congenital anomaly that is often accompanied by other anomalies. Although the role of genetics in the pathogenesis of CDH has been established, only a small number of disease-associated genes have been identified. To further investigate the genetics of CDH, we analyzed de novo coding variants in 827 proband-parent trios and confirmed an overall significant enrichment of damaging de novo variants, especially in constrained genes. We identified LONP1 (lon peptidase 1, mitochondrial) and ALYREF (Aly/REF export factor) as candidate CDH-associated genes on the basis of de novo variants at a false discovery rate below 0.05. We also performed ultra-rare variant association analyses in 748 affected individuals and 11,220 ancestry-matched population control individuals and identified LONP1 as a risk gene contributing to CDH through both de novo and ultra-rare inherited largely heterozygous variants clustered in the core of the domains and segregating with CDH in affected familial individuals. Approximately 3% of our CDH cohort who are heterozygous with ultra-rare predicted damaging variants in LONP1 have a range of clinical phenotypes, including other anomalies in some individuals and higher mortality and requirement for extracorporeal membrane oxygenation. Mice with lung epithelium-specific deletion of Lonp1 die immediately after birth, most likely because of the observed severe reduction of lung growth, a known contributor to the high mortality in humans. Our findings of both de novo and inherited rare variants in the same gene may have implications in the design and analysis for other genetic studies of congenital anomalies.

Development of an artificial placenta for support of premature infants: narrative review of the history, recent milestones, and future innovation

Over 50 years ago, visionary researchers began work on an extracorporeal artificial placenta to support premature infants. Despite rudimentary technology and incomplete understanding of fetal physiology, these pioneering scientists laid the foundation for future work. The research was episodic, as medical advances improved outcomes of premature infants and extracorporeal life support (ECLS) was introduced for the treatment of term and near-term infants with respiratory or cardiac failure. Despite ongoing medical advances, extremely premature infants continue to suffer a disproportionate burden of mortality and morbidity due to organ immaturity and unintended iatrogenic consequences of medical treatment. With advancing technology and innovative approaches, there has been a resurgence of interest in developing an artificial placenta to further diminish the mortality and morbidity of prematurity. Two related but distinct platforms have emerged to support premature infants by recreating fetal physiology: a system based on arteriovenous (AV) ECLS and one based on veno-venous (VV) ECLS. The AV-ECLS approach utilizes only the umbilical vessels for cannulation. It requires immediate transition of the infant at the time of birth to a fluid-filled artificial womb to prevent umbilical vessel spasm and avoid gas ventilation. In contradistinction, the VV-ECLS approach utilizes the umbilical vein and the internal jugular vein. It would be applied after birth to infants failing maximal medical therapy or preemptively if risk stratified for high mortality and morbidity. Animal studies are promising, demonstrating prolonged support and ongoing organ development in both systems. The milestones for clinical translation are currently being evaluated.

Switching to centrifugal pumps may decrease hemolysis rates among pediatric ECMO patients

Recent advances in ECLS technology have led to the adoption of centrifugal pumps for the majority of patients worldwide. Despite several advantages of centrifugal pumps, they remain controversial because a number of studies have shown increased rates of hemolysis. The aim of this study was to assess the impact of transitioning from roller to centrifugal pumps on hemolysis rates at our center. A retrospective analysis of all pediatric ECMO patients at a single center between 2005 and 2017 was undertaken. Hemolysis was defined as a plasma free hemoglobin >50 mg/dL. Multivariable logistic regression was performed correcting for several factors to determine risk factors for hemolysis and analyze outcomes among patients with hemolysis. Significant findings were those with p < 0.05. A total of 590 patients were identified during the study period. Multivariable logistic regression for risk factors for hemolysis showed roller pumps (OR 1.92, CI 1.11–3.33) and ECMO duration (OR 1.002 per hour, CI 1.00–1.01) to be significant factors. Rates of hemolysis significantly improved following conversion from roller to centrifugal pumps, with significantly lower rates of hemolysis in 2012, 2015, 2016, and 2017 when compared to the historical average with roller pumps from 2005 to 2009 (34.7%). Additionally, hemolysis was associated with an increased risk of death (OR 3.59, CI 2.05–6.29) when correcting for other factors. These data suggest decreasing rates of hemolysis with centrifugal pumps compared to roller pumps. Since hemolysis was also associated with increased risk of death, these data support the switch from roller to centrifugal pumps at ECMO centers.

Predicting lethal pulmonary hypoplasia in congenital diaphragmatic hernia (CDH): Institutional experience combined with CDH registry outcomes

BACKGROUND

The Severe Pulmonary Hypoplasia and Evaluation for Resuscitative Efforts (SPHERE) protocol was developed to attempt to identify CDH patients with likely lethal pulmonary hypoplasia. We present our experience with this protocol and utilize the CDH Registry to critically assess the protocol.

METHODS

SPHERE patients identified based on prenatal imaging (10/2009-1/2018) were offered ECMO if meeting postnatal physiologic criteria, while others received comfort measures. Within the CDH Registry, patients with suspected severe CDH were identified and separated into "passed" (lowest pCO2 ≤100) versus "failed" (lowest pCO2 >100) groups.

RESULTS

Of 23 SPHERE patients, 57% (13/23) passed criteria for ECMO and survival was 46% (6/13) in that cohort. Of 4912 patients in the CDH Registry, 265 met criteria. There was no difference in survival rates between those that "passed" (122/227; 54%) versus "failed" (18/38; 47%). However, the latter had longer ECMO runs and more required ventilator/ECMO support at 30 days. Amongst survivors, the "failed" group had longer hospital stays and more frequently required tube feeds at discharge.

CONCLUSIONS

The SPHERE protocol did not predict mortality in the CDH Registry. However, our data suggest resource utilization is significant when unable to reach pCO2 ≤100 despite resuscitation. Morbidity remains high in this group.

LEVEL OF EVIDENCE

Level III ANNOTATION OF CHANGES: Institutional Review Board Approval at University of Michigan (HUM00031524 and HUM00044010) TYPE OF STUDY: Retrospective Review.

Fetal Surgery in the Primate 4.0: A New Technique 30 Years Later

INTRODUCTION

Open fetal surgery requires a hemostatic hysterotomy that minimizes membrane separation. For over 30 years, the standard of care for hysterotomy in the gravid uterus has been the AutoSuture Premium Poly CS*-57 stapler.

OBJECTIVE

In this study, we sought to test the feasibility of hysterotomy in a rhesus monkey model with the Harmonic ACE®+7 Shears.

METHODS

A gravid rhesus monkey underwent midgestation hysterotomy at approximately 90 days of gestation (2nd trimester; term = 165 ± 10 days) using the Harmonic ACE®+7 Shears. A two-layer uterine closure was completed and the dam was monitored by ultrasound intermittently throughout the pregnancy. At 58 days after hysterotomy (near term), a final surgery was performed to evaluate the uterus and hysterotomy site.

RESULTS

A 3.5-cm hysterotomy was completed in 2 min 7 s. The opening was hemostatic and the membranes were sealed. Immediately after closure and throughout the pregnancy, ultrasound revealed intact membranes without separation and normal amniotic fluid levels. At term, the scar was well healed without signs of thinning or dehiscence.

CONCLUSIONS

The Harmonic ACE®+7 Shears produced a hemostatic midgestation hysterotomy with membrane sealing in the rhesus monkey model. Importantly, healing was acceptable.

Discordant prenatal ultrasound and fetal MRI in CDH: wherein lies the truth?

PURPOSE

Prenatal risk assessment of congenital diaphragmatic hernia (CDH) relies on prenatal ultrasound (U/S) and fetal magnetic resonance imaging (MRI). When the modalities differ in prognosis, it is unclear which is more reliable.

METHODS

Retrospective chart review identified cases of prenatally diagnosed CDH from 4/2010-6/2018 meeting inclusion criteria. Demographic, radiologic, and postnatal outcomes data were collected. Ultrasound- versus MRI-based prognosis (mild, moderate, and severe) was compared with clinical outcomes. Kappa measures compared congruency in disease severity scaling between imaging modalities, while logistic regression and receiver operating characteristics curves compared the ability of each modality to predict outcomes.

RESULTS

Forty-two patients met criteria. Both U/S- and MRI-based prognosis categories differentiated for survival. MRI categories differentiated for ECMO use, surgical repair, and defect type. O/e TFLV better discriminated for survivors and defect type than o/e LHR. Seventeen (40.5%) had discordant prenatal prognostic categories. In 13/17 (76.5%), o/e TFLV predicted higher severity when compared to o/e LHR, but sample size was insufficient to compare accuracy in cases of discordance.

CONCLUSIONS

Clinical outcomes suggest fetal MRI may more accurately predict severe pulmonary hypoplasia compared to prenatal ultrasound. Our analysis suggests fetal MRI is a valuable adjunct in the prenatal evaluation of CDH.

LEVEL OF EVIDENCE

Level III.

TYPE OF STUDY

Retrospective Review.

Likely damaging de novo variants in congenital diaphragmatic hernia patients are associated with worse clinical outcomes

Purpose

Congenital diaphragmatic hernia (CDH) is associated with significant mortality and long-term morbidity in some but not all individuals. We hypothesize monogenic factors that cause CDH are likely to have pleiotropic effects and be associated with worse clinical outcomes.

Methods

We enrolled and prospectively followed 647 newborns with CDH and performed genomic sequencing on 462 trios to identify de novo variants. We grouped cases into those with and without likely damaging (LD) variants and systematically assessed CDH clinical outcomes between the genetic groups.

Results

Complex cases with additional congenital anomalies had higher mortality than isolated cases (P=8×10⁻⁶). Isolated cases with LD variants had similar mortality to complex cases and much higher mortality than isolated cases without LD (P=3×10⁻³). The trend was similar with pulmonary hypertension at 1 month. Cases with LD variants had an estimated 12–17 points lower scores on neurodevelopmental assessments at 2 years compared to cases without LD variants, and this difference is similar in isolated and complex cases.

Conclusion

We found that the LD genetic variants are associated with higher mortality, worse pulmonary hypertension, and worse neurodevelopment outcomes compared to non-LD variants. Our results have important implications for prognosis, potential intervention and long-term follow up for children with CDH.

Recurrent endobronchial inflammatory myofibroblastic tumors: Novel treatment options

Endobronchial inflammatory myofibroblastic tumors (IMTs) rarely occur in children younger than 10 years of age and have intermediate malignant potential. A 7-year-old girl initially presented with pneumonia. After failing outpatient treatment, she re-presented in status asthmaticus. Computed tomography showed a left mainstem endobronchial mass which was resected bronchoscopically. Pathology was consistent with IMT. Surveillance bronchoscopy identified a recurrence. Despite a left upper lobectomy, recurrence led to further treatment with celecoxib and argon plasma coagulation. Follow-up bronchoscopy revealed complete resolution. She remains disease and symptom-free at her six-year follow-up.

Comparative outcomes of right versus left congenital diaphragmatic hernia: A multicenter analysis

BACKGROUND

Congenital diaphragmatic hernia (CDH) occurs in 1 out of 2500-3000 live births. Right-sided CDHs (R-CDHs) comprise 25% of all CDH cases, and data are conflicting on outcomes of these patients. The aim of our study was to compare outcomes in patients with right versus left CDH (L-CDH).

METHODS

We analyzed a multicenter prospectively enrolled database to compare baseline characteristics and outcomes of neonates enrolled from January 2005 to January 2019 with R-CDH vs. L-CDH.

RESULTS

A total of 588, 495 L-CDH, and 93 R-CDH patients with CDH were analyzed. L-CDHs were more frequently diagnosed prenatally (p=0.011). Lung-to-head ratio was similar in both cohorts. R-CDHs had a lower frequency of primary repair (p=0.022) and a higher frequency of need for oxygen at discharge (p=0.013). However, in a multivariate analysis, need for oxygen at discharge was no longer significantly different. There were no differences in long-term neurodevelopmental outcomes assessed at two year follow up. There was no difference in mortality, need for ECMO, pulmonary hypertension, or hernia recurrence.

CONCLUSION

In this large series comparing R to L-CDH patients, we found no significant difference in mortality, use of ECMO, or pulmonary complications. Our study supports prior studies that R-CDHs are relatively larger and more often require a patch or muscle flap for repair.

TYPE OF STUDY

Prognosis study LEVEL OF EVIDENCE: Level II.

Safety of delayed decannulation of venoarterial cannulas in patients with congenital diaphragmatic hernia

BACKGROUND

The practice of "cutting-away" from venoarterial extracorporeal life support (ECLS) and leaving indwelling heparinized cannulas prior to decannulation is controversial. This study aims to determine the safety and efficacy of this strategy in patients with congenital diaphragmatic hernia (CDH) who require ECLS.

METHODS

A single-center retrospective review of electronic health records was performed on all patients with CDH who underwent elective ECLS decannulation between January 2014 and September 2018. Descriptive statistics are presented as medians with interquartile range.

RESULTS

Seventy-three percent (19/26) of patients who underwent venoarterial ECLS for CDH were electively decannulated. After a median ECLS run of 10.7 days [6.1-19.5], patients were "cut-away" for a median of 26 h [19.8-43] prior to decannulation. One patient required re-initiation at 36 h for a pulmonary hypertensive crisis (5%). There were no major bleeding or embolic events while "cut-away", and four (21%) patients had clots removed from the cannulas without clinical sequelae. One patient was recannulated 16 days following initial decannulation.

CONCLUSIONS

Our data suggests that "cutting-away" from ECLS in patients with congenital diaphragmatic hernia is safe and allows a period of observation without significant complications. This strategy may be particularly helpful in patients at risk for recannulation, but better prognostic criteria are needed.

LEVEL OF EVIDENCE

Level IV.

TYPE OF STUDY

Treatment Study.

Calculating Observed-to-Expected Total Fetal Lung Volume in CDH Fetuses in Twin Gestation: Is There a Better Way?

BACKGROUND

Congenital diaphragmatic hernia (CDH) is a potentially lethal birth defect, and identifying prenatal predictors of outcome is important. Observed-to-expected total fetal lung volume (o/e TFLV) has been shown to be a predictor of severity and useful in risk stratification but is variable due to different TFLV formulas.

OBJECTIVES

To calculate o/e TFLV for CDH patients part of a twin gestation using the unaffected sibling as an internal control and comparing these values to those calculated using published formulas for TFLV.

METHODS

Seven twin gestations with one fetus affected by CDH were identified between 2006 and 2017. The lung volume for each twin was calculated using magnetic resonance imaging (MRI), and o/e TFLV was calculated using the unaffected twin's TFLV. This percentage was then compared to the o/e TFLV calculated using published formulas.

RESULTS

Lung volumes in the unaffected twins were within normal ranges at the lower end of the spectrum. No single TFLV formula was found to correlate perfectly. Intraclass correlation coefficient estimate was most consistent for o/e TFLV calculated with the Meyers formula and supported by Bland-Altman plots.

CONCLUSIONS

O/e TFLV measured in CDH/non-CDH twin gestations using the unaffected sibling demonstrated agreement with o/e TFLV calculated using the Meyers formula. We urge the fetal community to standardize the method, use, and interpretation of fetal MRI in the prenatal evaluation of CDH.

Prenatal Dilated Rectum: Do We Need to Worry?

BACKGROUND

Advances in prenatal imaging is increasing detection of abnormally dilated bowel. There is no literature to date defining the criteria for a dilated rectum or its association with postnatal pathology. The aim of this study is to investigate the clinical significance of a prenatally identified dilated rectum.

METHODS

A retrospective review was performed of all cases of "dilated bowel" on prenatal ultrasound between January 2000 and December 2017 at a single institution. We excluded ventral wall defects from review and sought to include only cases of a prominent or dilated rectum. Collected data included prenatal bowel measurements, postnatal diagnoses, need for surgical intervention, and outcomes. Descriptive statistics were applied.

RESULTS

One hundred and ninety-three cases of prenatal "dilated bowel" were identified in which 12 (6.2%) had specifically visualized a prominent or dilated rectum. Nine of these (75.0%) had no rectal or intestinal abnormality on postnatal evaluation and were discharged feeding and defecating normally. The remaining three cases exhibited clinical pathology necessitating additional management: (1) meconium plug, (2) jejunal atresia with cecal perforation, and (3) rectal perforation with retroperitoneal abscess. All three had rectal biopsies with identification of ganglionated submucosa.

CONCLUSIONS

Although a prenatal dilated rectum is a normal variant in the vast majority of cases, it may be associated with a gastrointestinal abnormality requiring surgical intervention. Interestingly, there were no cases of Hirschsprung's disease or anorectal malformations in this cohort. These results, in conjunction with continued efforts to identify and define rectal dilation, are useful for prenatal counseling and postnatal evaluation.

Diagnostic accuracy of imaging studies in congenital lung malformations

BACKGROUND

Although fetal ultrasound, fetal MRI and postnatal CT are now widely used in the evaluation of congenital lung malformations (CLM), their diagnostic accuracy remains undefined.

OBJECTIVE

To correlate prenatal and postnatal imaging studies with pathological data after CLM resection.

DESIGN

Retrospective, descriptive case series study.

SETTING

A North American tertiary care centre.

PATIENTS

One hundred and three consecutive lung resections for a suspected CLM between 1 January 2005 and 31 December 2015.

MAIN OUTCOME MEASURES

Diagnostic accuracy of imaging diagnosis compared with pathological evaluation.

RESULTS

Pathological diagnoses included congenital pulmonary airway malformation ((CPAM) n=45, 44%), bronchopulmonary sequestration (BPS; n=25, 24%), CPAM/BPS hybrid lesions (n=22, 21%) and pleuropulmonary blastoma (n=2, 2%). Fetal ultrasound detected 85 (82.5%) lesions and correctly diagnosed whether or not a lesion was a CPAM in 75% of cases (sensitivity 93%, specificity 32%). Fetal MRI had a similar concordance rate (73%) but was superior in correctly determining whether a systemic feeding vessel was present in 80% of cases (sensitivity 71%, specificity 88%) compared with an ultrasound accuracy rate of 72% (sensitivity 49%, specificity 93%). By comparison, postnatal CT correctly diagnosed whether a CPAM was present in 84% of cases (sensitivity 86%, specificity 77%) and whether a systemic feeding vessel was present in 90% of cases (sensitivity 92%, specificity 88%).

CONCLUSIONS

Fetal ultrasound remains an important tool in the detection and evaluation of congenital lung malformations. However, it does not correctly predict histology in approximately 25% of prenatally detected CLMs and remains limited by relatively poor sensitivity for systemic feeding vessels pathognomic for a bronchopulmonary sequestration. These data suggest the importance of obtaining additional cross-sectional imaging, preferably a postnatal CT scan, in all patients to help counsel families and to guide in the optimal management of these lesions.

Splenic development and injury in premature lambs supported by the artificial placenta

INTRODUCTION

The purpose of this study is to evaluate splenic effects during artificial placenta (AP) support.

METHODS

AP lambs (118-121 d, n = 14) were delivered and placed on the AP support for a goal of 10-14 days. Cannulation used right jugular drainage and umbilical vein reinfusion. Early (ETC; 115-120 d; n = 7) and late (LTC; 125-131 d; n = 7) tissue controls were delivered and immediately sacrificed. Spleens were formalin fixed, H&E stained, and graded for injury, response to inflammation, and extramedullary hematopoiesis (EMH). CD68 and CD163 stains were used to assess for macrophage activation and density. Clinical variables were correlated with splenic scores. Groups were compared using Fisher's Exact Test and descriptive statistics. p < 0.05 indicated significance.

RESULTS

Mean survival for AP lambs was 12 ± 5 d. There was no necrosis found in any of the groups. Vascular congestion and sinusoidal histiocytosis did not significantly differ between AP and control groups (p = 0.72; p = 0.311). There were significantly more pigmented macrophages (p = 0.008), CD163 (p = <0.001), and CD68 (p = <0.001) stained cells in the AP group. ETC and LTC demonstrated more EMH than AP spleens (p = <0.001).

CONCLUSIONS

During AP support, spleens appear to develop normally and exhibit an appropriate inflammatory response. After initiation of AP support, EMH transitions away from the spleen.

STUDY TYPE

Research Paper/Therapeutic Potential.

LEVEL OF EVIDENCE

N/A.

An Early Investigation into Possible Alternatives to Stapled Hysterotomy in Open Fetal Surgery

PURPOSE

We hypothesized that surgical energy could be used to create hysterotomies in open fetal surgery.

STUDY DESIGN

Initial studies compared the LigaSure Impact and Harmonic ACE + 7 Shears in the efficiency of hysterotomy and thermal damage. Pregnant ewes at an estimated gestational age (EGA) of 116 to 120 days (term = 145; n = 7) underwent hysterotomy using either device. Hysterotomy edges were resected, and thermal injury extent was determined by histopathological assessment. Upon determining a superior device, subsequent studies compared this to the AutoSuture Premium Poly CS*-57 Stapler in uterine healing. Pregnant ewes (n = 6) at an EGA of 87 to 93 days underwent 6-cm hysterotomy in each gravid horn with either the stapler (n = 5) or Harmonic (n = 5) followed by closure and animal recovery. After 37 to 42 days, uterine healing was assessed by evaluating tensile strength and histopathology.

RESULTS

Thermal damage was more extensive with the LigaSure (n = 11 hysterotomies) than with the Harmonic (n = 11; 5.6 ± 1 vs. 3.1 ± 0.6 mm; p < 0.0001);therefore, the Harmonic was selected for healing studies. Gross scar appearance and tensile strength were the same between the Harmonic and stapler. The stapler caused more fibrosis (4/7 samples with "moderate" fibrosis vs. 0/8 with the Harmonic; p = 0.02).

CONCLUSION

The Harmonic ACE + 7 caused less thermal injury than the LigaSure Impact and performed similar to the CS*-57 Stapler in uterine healing with continued gestation.

Cerebral Oxygenation of Premature Lambs Supported by an Artificial Placenta

An artificial placenta (AP) using venovenous extracorporeal life support (VV-ECLS) could represent a paradigm shift in the treatment of extremely premature infants. However, AP support could potentially alter cerebral oxygen delivery. We assessed cerebral perfusion in fetal lambs on AP support using near-infrared spectroscopy (NIRS) and carotid arterial flow (CAF). Fourteen premature lambs at estimated gestational age (EGA) 130 days (term = 145) underwent cannulation of the right jugular vein and umbilical vein with initiation of VV-ECLS. An ultrasonic flow probe was placed around the right carotid artery (CA), and a NIRS sensor was placed on the scalp. Lambs were not ventilated. CAF, percentage of regional oxygen saturation (rSO2) as measured by NIRS, hemodynamic data, and blood gases were collected at baseline (native placental support) and regularly during AP support. Fetal lambs were maintained on AP support for a mean of 55 ± 27 hours. Baseline rSO2 on native placental support was 40% ± 3%, compared with a mean rSO2 during AP support of 50% ± 11% (p = 0.027). Baseline CAF was 27.4 ± 5.4 ml/kg/min compared with an average CAF of 23.7 ± 7.7 ml/kg/min during AP support. Cerebral fractional tissue oxygen extraction (FTOE) correlated negatively with CAF (r = -0.382; p < 0.001) and mean arterial pressure (r = -0.425; p < 0.001). FTOE weakly correlated with systemic O2 saturation (r = 0.091; p = 0.017). Cerebral oxygenation and blood flow in premature lambs are maintained during support with an AP. Cerebral O2 extraction is inversely related to carotid flow and is weakly correlated with systemic O2 saturation.

Pulmonary Hypertension in Patients with Congenital Diaphragmatic Hernia: Does Lung Size Matter?

PURPOSE

 The relationship between pulmonary hypoplasia and pulmonary arterial hypertension (PHTN) in patients with congenital diaphragmatic hernia (CDH) remains ill-defined. We hypothesized that prenatal estimates of lung size would directly correlate with PHTN severity.

METHODS

 Infants with isolated CDH (born 2004-2015) at a single institution were included. Estimates of lung size included observed-to-expected LHR (o:eLHR) and %-predicted lung volumes (PPLV = observed/predicted volumes). The primary outcome was severity of PHTN (grade 0-3) on echocardiography performed between day of life 3 and 30.

RESULTS

 Among 62 patients included, there was 32% mortality and 65% ECMO utilization. PPLV (odds ratio [OR] = 0.94 per 1 grade in PHTN severity, 95% confidence interval [CI] = 0.89-0.98, p < 0.01) and o:eLHR (OR = 0.97, 95% CI = 0.94-0.99, p < 0.01) were significantly associated with PHTN grade. Among patients on ECMO, PPLV (OR = 0.92, 95% CI = 0.84-0.99, p = 0.03) and o:eLHR (OR = 0.95, 95% CI = 0.92-0.99, p = 0.01) were more strongly associated with PHTN grade. PPLV and o:eLHR were significantly associated with the use of inhaled nitric oxide (iNO) (OR = 0.90, 95% CI = 0.83-0.98, p = 0.01 and OR = 0.94, 95% CI = 0.91-0.98, p < 0.01, respectively) and epoprostenol (OR = 0.91, 95% CI = 0.84-0.99, p = 0.02 and OR = 0.93, 95% CI = 0.89-0.98, p < 0.01, respectively).

CONCLUSION

 Among infants with isolated CDH, PPLV, and o:eLHR were significantly associated with PHTN severity, especially among patients requiring ECMO. Prenatal lung size may help predict postnatal PHTN and associated therapies.

De novo variants in congenital diaphragmatic hernia identify MYRF as a new syndrome and reveal genetic overlaps with other developmental disorders

Congenital diaphragmatic hernia (CDH) is a severe birth defect that is often accompanied by other congenital anomalies. Previous exome sequencing studies for CDH have supported a role of de novo damaging variants but did not identify any recurrently mutated genes. To investigate further the genetics of CDH, we analyzed de novo coding variants in 362 proband-parent trios including 271 new trios reported in this study. We identified four unrelated individuals with damaging de novo variants in MYRF (P = 5.3x10(-8)), including one likely gene-disrupting (LGD) and three deleterious missense (D-mis) variants. Eight additional individuals with de novo LGD or missense variants were identified from our other genetic studies or from the literature. Common phenotypes of MYRF de novo variant carriers include CDH, congenital heart disease and genitourinary abnormalities, suggesting that it represents a novel syndrome. MYRF is a membrane associated transcriptional factor highly expressed in developing diaphragm and is depleted of LGD variants in the general population. All de novo missense variants aggregated in two functional protein domains. Analyzing the transcriptome of patient-derived diaphragm fibroblast cells suggest that disease associated variants abolish the transcription factor activity. Furthermore, we showed that the remaining genes with damaging variants in CDH significantly overlap with genes implicated in other developmental disorders. Gene expression patterns and patient phenotypes support pleiotropic effects of damaging variants in these genes on CDH and other developmental disorders. Finally, functional enrichment analysis implicates the disruption of regulation of gene expression, kinase activities, intra-cellular signaling, and cytoskeleton organization as pathogenic mechanisms in CDH.

The artificial placenta: Continued lung development during extracorporeal support in a preterm lamb model

PURPOSE

An artificial placenta (AP) utilizing extracorporeal life support (ECLS) could avoid the harm of mechanical ventilation (MV) while allowing the lungs to develop.

METHODS

AP lambs (n = 5) were delivered at 118 days gestational age (GA; term = 145 days) and placed on venovenous ECLS (VV-ECLS) with jugular drainage and umbilical vein reinfusion. Lungs remained fluid-filled. After 10 days, lambs were ventilated. MV control lambs were delivered at 118 ("early MV"; n = 5) or 128 days ("late MV"; n = 5), and ventilated. Compliance and oxygenation index (OI) were calculated. After sacrifice, lungs were procured and H&E-stained slides scored for lung injury. Slides were also immunostained for PDGFR-α and α-actin; alveolar development was quantified by the area fraction of alveolar septal tips staining double-positive for both markers.

RESULTS

Compliance of AP lambs was 2.79 ± 0.81 C_dyn compared to 0.83 ± 0.19 and 3.04 ± 0.99 for early and late MV, respectively. OI in AP lambs was lower than early MV lambs (6.20 ± 2.10 vs. 36.8 ± 16.8) and lung injury lower as well (1.8 ± 1.6 vs. 6.0 ± 1.2). Double-positive area fractions were higher in AP lambs (0.012 ± 0.003) than early (0.003 ± 0.0005) and late (0.004 ± 0.002) MV controls.

CONCLUSIONS

Lung development continues and lungs are protected from injury during AP support relative to mechanical ventilation.

LEVEL OF EVIDENCE

n/a (basic/translational science).

Is there a best approach for extracorporeal life support cannulation: a review of the extracorporeal life support organization

BACKGROUND

Neurologic complications are common, and amongst the most devastating complications in pediatric patients undergoing extracorporeal life support (ECLS). Carotid artery cannulation (CAN) has been associated with an increase in these complications, thereby shaping practices to avoid this approach in most pediatric patients in which other cannulation approaches are viable.

METHODS

A retrospective review of children (0-18years) in the ELSO database was undertaken from 1989 through 2013. Multivariate logistic regression analysis of rates of stroke and other neurologic complications based on cannulation technique was undertaken, adjusting for patient factors including age, underlying disease process, and severity of illness.

RESULTS

A total of 30,282 ECLS runs were found in the database. CAN was associated with higher rates of stroke (5.15% vs 3.74%) and overall neurologic complications. However, when correcting for patient factors, including age, underlying disease process, and support type, CAN was not associated with an increased rate of neurologic complications or stroke (p>0.05 for both).

CONCLUSION

When correcting for patient related factors CAN is not associated with an increase in stroke or neurologic compilcations. CAN should be re-examined as a cannulation technique for older pediatric patients.

LEVEL OF EVIDENCE

III.

Gastrointestinal mucosal development and injury in premature lambs supported by the artificial placenta

BACKGROUND

An Artificial Placenta (AP) utilizing extracorporeal life support (ECLS) could revolutionize care of extremely premature newborns, but its effects on gastrointestinal morphology and injury need investigation.

METHODS

Lambs (116-121days GA, term=145; n=5) were delivered by C-section, cannulated for ECLS, had total parenteral nutrition (TPN) provided, and were supported for 7days before euthanasia. Early and Late Tissue Controls (ETC, n=5 and LTC, n=5) delivered at 115-121days and 125-131days, respectively, were immediately sacrificed. Standardized jejunal samples were formalin-fixed for histology. Crypt depth (CD), villus height (VH), and VH:CD ratios were measured. Measurements also included enterocyte proliferation (Ki-67), Paneth cell count (Lysozyme), and injury scores (H&E). ANOVA and Chi Square were used with p<0.05 considered significant.

RESULTS

CD, VH, and VH:CD were similar between groups (p>0.05). AP demonstrated more enterocyte proliferation (95.7±21.8) than ETC (49.4±23.4; p=0.003) and LTC (66.1+11.8; p=0.04), and more Paneth cells (81.7±17.5) than ETC (41.6±7.0; p=0.0005) and LTC (40.7±8.2, p=0.0004). Presence of epithelial injury and congestion in the bowel of all groups were not statistically different. No villus atrophy or inflammation was present in any group.

CONCLUSIONS

This suggests preserved small bowel mucosal architecture, high cellular turnover, and minimal evidence of injury.

STUDY TYPE

Research paper/therapeutic potential.

LEVEL OF EVIDENCE

N/A.

Effects of an artificial placenta on brain development and injury in premature lambs

PURPOSE

We evaluated whether brain development continues and brain injury is prevented during Artificial Placenta (AP) support utilizing extracorporeal life support (ECLS).

METHODS

Lambs at EGA 118days (term=145; n=4) were placed on AP support (venovenous ECLS with jugular drainage and umbilical vein reinfusion) for 7days and sacrificed. Early (EGA 118; n=4) and late (EGA 127; n=4) mechanical ventilation (MV) lambs underwent conventional MV for up to 48h and were sacrificed, and early (n=5) and late (n=5) tissue control (TC) lambs were sacrificed at delivery. Brains were harvested, formalin-fixed, rehydrated, and studied by magnetic resonance imaging (MRI). The gyrification index (GI), a measure of cerebral folding complexity, was calculated for each brain. Diffusion-weighted imaging was used to determine fractional anisotropy (FA) and apparent diffusion coefficient (ADC) in multiple structures to assess white matter (WM) integrity.

RESULTS

No intracranial hemorrhage was observed. GI was similar between AP and TC groups. ADC and FA did not differ between AP and late TC groups in any structure. Compared to late MV brains, AP brains demonstrated significantly higher ADC (0.45±0.08 vs. 0.27±0.11, p=0.02) and FA (0.61±0.04 vs. 0.44±0.05; p=0.006) in the cerebral peduncles.

CONCLUSIONS

After 7days of AP support, WM integrity is preserved relative to mechanical ventilation.

TYPE OF STUDY

Research study.

Comparison of early versus delayed strategies for repair of congenital diaphragmatic hernia on extracorporeal membrane oxygenation

PURPOSE

For the last seven years, our institution has repaired infants with CDH that require ECMO early after cannulation. Prior to that, we attempted to decannulate before repair, but repaired on ECMO if we were unable to wean after two weeks. This study compares those strategies.

METHODS

From 2002 to 2016, 65 infants with CDH required ECMO. 67.7% were repaired on ECMO, and 27.7% were repaired after decannulation. Data were compared between patients repaired ≤5days after cannulation ("early protocol", n=30) and >5days after cannulation or after de-cannulation ("late protocol", n=35). We used Cox regression to assess differences in outcomes between groups.

RESULTS

Survival for the early and late protocol groups was 43.3% and 68.8%, respectively (p=0.0485). For patients that were successfully decannulated before repair, survival was 94.4%. Moreover, the early repair protocol was associated with prolongation of ECMO (16.8±7.4 vs. 12.6±6.8days, p=0.0216). After multivariate regression, the early repair protocol was an independent predictor of both mortality (HR=3.48, 95% CI=1.28-9.45, p=0.015) and days on ECMO (IRR=1.39, 95% CI=1.07-1.79, p=0.012). All bleeding occurred in patients repaired on ECMO (29.5%, 13/44).

CONCLUSIONS

Our data suggest that protocolized CDH repair early after ECMO cannulation may be associated with increased mortality and prolongation of ECMO. However, early repair is not necessarily harmful for those patients who would otherwise be unable to wean from ECMO before repair. Further work is needed to better move towards individualized patient care.

TYPE OF STUDY

Treatment Study.

LEVEL OF EVIDENCE

Level III.

Perfluorocarbons Prevent Lung Injury and Promote Development during Artificial Placenta Support in Extremely Premature Lambs

BACKGROUND

Extremely premature neonates suffer high morbidity and mortality. An artificial placenta (AP) using extracorporeal life support (ECLS) is a promising therapy.

OBJECTIVES

We hypothesized that intratracheal perfluorocarbon (PFC) instillation during AP support would reduce lung injury and promote lung development relative to intratracheal amniotic fluid or crystalloid.

METHODS

Lambs at an estimated gestational age (EGA) 116-121 days (term 145 days) were placed on venovenous ECLS with jugular drainage and umbilical vein reinfusion and intubated. Airways were managed by the instillation of amniotic fluid and tracheal occlusion (TO; n = 4), or lactated Ringer's (LR; n = 4) or perfluorodecalin (a PFC) without occlusion (n = 4). After 7 days, the animals were sacrificed. Early (EGA 116-121 days) and late (EGA 125-131 days) tissue control lambs were delivered and sacrificed. Lungs were formalin-inflated to 30 cm H2O and sectioned for histology. Injury was scored by an unbiased pathologist. Slides were immunostained for PDGFR-α and α-actin; development was quantified by the area fraction of double-positive tips. Surfactant protein-C (SP-C) concentration in bronchoalveolar lavage fluid was quantified using ELISA.

RESULTS

Total injury scores were lower in PFC lungs (1.8 ± 1.7) than in TO (6.5 ± 2.1; p = 0.01) and LR lungs (5.5 ± 2.4; p = 0.01). The area fraction of double-positive alveolar tips appeared higher in PFC lungs than in TO lungs (0.18 ± 0.007 vs. 0.008 ± 0.004; p = 0.07). SP-C concentration was higher in PFC lungs than in TO lungs (37.9 ± 7.6 vs. 20.0 ± 5.4 pg/mL; p = 0.005), and both early (12.4 ± 1.7 g/mL; p = 0.007) and late tissue control lungs (15.1 ± 5.0 pg/mL; p = 0.0008).

CONCLUSION

During AP support, intratracheal PFC prevents lung injury and promotes normal lung development better than crystalloid or amniotic fluid with TO.

A definition of gentle ventilation in congenital diaphragmatic hernia: a survey of neonatologists and pediatric surgeons

Ventilation practices have changed significantly since the initial reports in the mid 1980 of successful use of permissive hypercapnia and spontaneous ventilation [often called gentle ventilation (GV)] in infants with congenital diaphragmatic hernia (CDH). However, there has been little standardization of these practices or of the physiologic limits that define GV. We sought to ascertain among Diaphragmatic Hernia Research and Exploration; Advancing Molecular Science (DHREAMS) centers' GV practices in the neonatal management of CDH. Pediatric surgeons and neonatologists from DHREAMS centers completed an online survey on GV practices in infants with CDH. The survey gathered data on how individuals defined GV including ventilator settings, blood gas parameters and other factors of respiratory management. A total of 87 respondents, from 12 DHREAMS centers completed the survey for an individual response rate of 53% and a 92% center response rate. Approximately 99% of the respondents defined GV as accepting higher carbon dioxide (PCO2) and 60% of the respondents also defined GV as accepting a lower pH. There was less consensus about the use of sedation and neuromuscular blocking agents in GV, both within and across the centers. Acceptable pH and PCO2 levels are broader than the goal ranges. Despite a lack of formal standardization, the results suggest that GV practice is consistently defined as the use of permissive hypercapnia with mild respiratory acidosis and less consistently with the use of sedation and neuromuscular blocking agents. GV is the reported practice of surveyed neonatologists and pediatric surgeons in the respiratory management of infants with CDH.

Pushing the boundaries of ECLS: Outcomes in <34 week EGA neonates

PURPOSE

Extracorporeal life support (ECLS) is usually reserved for infants ≥34weeks estimated gestational age (EGA) owing to concerns about increased mortality and incidence of intracranial hemorrhage (ICH). We sought to characterize survival, rates of ICH, and complications in <34week EGA neonates placed on ECLS.

METHODS

752 neonates of EGA 29-34weeks were identified in the Extracorporeal Life Support Organization (ELSO) Registry (1976-2008). Data analyzed included birthweight, survival, pre-ECLS conditions, ventilatory parameters and complications (including ICH and other neurological outcomes). Data were compared using t-test, Chi-square and logistic regression analyses.

RESULTS

When compared to survival rates of 34week EGA neonates (58%), survival was statistically different for 29-33week EGA (48%, p=0.05). No significant difference in ICH incidence was seen between the 29-33week and 34week groups (21% vs. 17%, respectively), but a significant difference was seen in the incidence of cerebral infarct between groups (22% for 29-33weeks vs. 16% for 34weeks; p=0.03). ICH and survival did not correlate with EGA during logistic regression analysis.

CONCLUSIONS

Though rates of survival and cerebral infarction were worse at 29-33weeks EGA compared with 34weeks, these differences were modest and may be clinically acceptable. This suggests that EGA<34weeks may not be an absolute contraindication to use of ECLS.

LEVEL OF EVIDENCE

III.

Mutations in BMPR2 are not present in patients with pulmonary hypertension associated with congenital diaphragmatic hernia

BACKGROUND

Congenital diaphragmatic hernia (CDH) is a prevalent major congenital anomaly with significant morbidity and mortality. Thirty to 40% mortality in CDH is largely attributed to pulmonary hypoplasia and pulmonary hypertension (PH). We hypothesized that the underlying genetic risk factors for hereditary PH are shared with CDH associated PH.

METHODS

Participants were recruited as part of the Diaphragmatic Hernia Research & Exploration; Advancing Molecular Science (DHREAMS) study, a prospective cohort of neonates with a diaphragmatic defect enrolled from 2005 to 2012. PH affected patients with available DNA for sequencing had one of the following: moderate or severe PH on echocardiography at 3months of age; moderate of severe PH at 1month of age with death occurring prior to the 3month echocardiogram; or on PH medications at 1month of age. We sequenced the coding regions of the hereditary PH genes bone morphogenetic protein receptor type II (BMPR2), caveolin 1 (CAV1) and potassium channel subfamily K, member 3 (KCNK3) to screen for mutations.

RESULTS

There were 29 CDH patients with PH including 16 males and 13 females. Sequencing of BMPR2, CAV1, and KCNK3 coding regions did not identify any pathogenic variants in these genes.

TYPE OF STUDY

Prognosis study LEVEL OF EVIDENCE: Level IV.

Avalon catheters in pediatric patients requiring ECMO: Placement and migration problems

PURPOSE

The Avalon dual-lumen venovenous catheter has several advantages, but placement techniques and management have not been adequately addressed in the pediatric population. We assessed our institutional outcomes and complications using the Avalon catheter in children.

METHODS

We reviewed all pediatric patients who had Avalon catheters placed for respiratory failure at our institution, excluding congenital heart disease patients, from April 2009 to March 2016. All patients were managed using our standard ECMO protocol, and cannula position was followed by daily chest x-ray and intermittent echocardiography (ECHO). Data included demographics, diagnosis, PRISM3 predicted mortality, ECMO duration, complications, and survival. The primary outcome was the need for catheter repositioning.

RESULTS

Twenty-five patients were included, with mean age 8.3±6.9years and 15±22days of ECMO support. Overall survival was 68% (17/25). Fourteen patients (56%) underwent placement with fluoroscopy in addition to ultrasound and ECHO, primarily after 2013. Overall, thirteen patients (52%) had problems with cannula malposition. 9 of these (69%) required cannula repositioning. Three of 14 (21%) cannulas placed with fluoroscopy required repositioning, compared to 7/11 (64%) placed without fluoroscopy (p=0.05).

CONCLUSIONS

Complications are common with the Avalon catheter in children. Safe percutaneous access requires ultrasound guidance, and use of intraoperative fluoroscopy in addition to echocardiography decreases malposition rates.

LEVEL OF EVIDENCE

IV (Prognosis study).

Outcomes of fetuses with primary hydrothorax that undergo prenatal intervention (prenatal intervention for hydrothorax)

BACKGROUND

Primary hydrothorax is a congenital anomaly affecting 1 in 10,000-15,000 pregnancies. The natural history of this condition is variable with some fetuses having spontaneous resolution and others showing progression. The associated pulmonary hypoplasia leads to increased perinatal morbidity and mortality. Optimal prenatal intervention remains controversial.

METHODS

After obtaining the Institutional Review Board approval, a retrospective review of all patients evaluated for a fetal pleural effusion in the Fetal Diagnosis and Treatment Center at The University of Michigan, between 2006 and 2016 was performed. Cases with secondary etiologies for an effusion or when families decided to pursue elective termination were excluded.

RESULTS

Pleural effusions were identified in 175 patients. Primary hydrothorax was diagnosed in 15 patients (8%). The effusions were bilateral in 13/15 cases (86%) and 10/15 (66%) had hydrops at presentation. All 15 patients with primary hydrothorax underwent prenatal intervention. Thoracentesis was performed in 14/15 cases (93%). Shunt placement was performed in 10/15 cases (66%). Shunt migration was seen in four patients (40%) and all of these underwent prenatal shunt replacement. Overall survival was 76%. The rates of prematurity and preterm premature rupture of membranes were 69% and 35%, respectively.

CONCLUSIONS

Fetal intervention for the treatment of primary hydrothorax is effective, and it appears to confer a survival advantage. Both the fetuses and the mothers tolerated the procedures well. Preterm labor and preterm premature rupture of membranes remain an unsolved problem. Further studies are needed to understand the mechanisms behind the development of fetal hydrothorax.

Hepatoduodenal ligament teratoma with immature elements

Pediatric germ cell tumors comprise 1-3% of all malignant pediatric tumors and are found in variable locations. We present the case of a term 3.7 kg neonate who was found to have a giant liver mass at birth, later determined to be an immature teratoma arising from the hepatoduodenal ligament. This case report and images add to the limited literature a very rare presentation of a teratoma.

Prenatally diagnosed severe CDH: mortality and morbidity remain high

PURPOSE

This study sought to evaluate prenatal markers' ability to predict severe congenital diaphragmatic hernia(CDH) and assess this subgroup's morbidity and mortality.

METHODS

A retrospective review was performed between 2006 and 2014. Prenatal criteria for severe CDH included: liver herniation, lung-to-head ratio (LHR) <1 on prenatal ultrasound and/or observed-to-expected LHR (o/eLHR) <25%, and/or observed-to-expected total lung volume (o/eTLV) <25% on fetal MRI. Postnatal characteristics included: mortality, ECMO utilization, patch closure, persistent suprasystemic pulmonary hypertension (PHtn), O2 requirement at discharge, and few ventilator-free days in the first 60. Statistics performed used unpaired t-test, p<0.05 significant.

RESULTS

Overall, 47.5%(29/61) of patients with prenatally diagnosed, isolated CDH met severe criteria. Mean LHR: 1.04±0.35, o/eLHR: 31±10% and o/eTLV: 20±7%. Distribution was 72% LCDH, 24% R-CDH. Overall survival: 38%. ECMO requirement: 92%. Patch rate: 91%. Mean ventilator-free days in 60: 7.1±14. Supplemental oxygen at discharge was required in 27%. In this prenatally diagnosed severe cohort, 58%(15/26) had persistent PHtn post-ECMO requiring inhaled nitric oxide±epoprostenol. Comparing patients with and without PHtn: mean ECMO duration 18±10 days versus 9±7 days (p=0.01) and survival 20% versus 72% (p=0.006).

CONCLUSION

A combination of prenatal markers accurately identified severe CDH patients. Outcomes of this group remain poor and persistent PHtn contributes significantly to mortality.