Bronchopulmonary Dysplasia and Perinatal Characteristics Predict 1-Year Respiratory Outcomes in Newborns Born at Extremely Low Gestational Age: A Prospective Cohort Study

Outpatient clinical care for bronchopulmonary dysplasia: A survey of the BPD collaborative

BACKGROUND

Bronchopulmonary dysplasia, a sequela of preterm birth, is the most common chronic respiratory disorder in infancy, and the second most common in children. Despite this, clinical care remains highly variable with guidelines supported by limited evidence, and do not provide specific guidance for timing of clinical follow-up, echocardiography, modalities of pulmonary function testing, etc. OBJECTIVE/METHODS: To further our understanding of care delivery for BPD, we sought to describe outpatient care patterns at tertiary care centers through survey data from 27 well-established BPD programs.

RESULTS

We observed variability in referral patterns to outpatient BPD clinics, ancillary services provided, indications for follow-up echocardiograms, availability of lung function testing, and criteria for discharge from care.

CONCLUSION

More comprehensive and detailed clinical guidelines similar to other pulmonary diseases such as asthma and cystic fibrosis should be developed to help standardize care and may improve long term outcomes.

Continuous Neuromuscular Blockade for Bronchopulmonary Dysplasia

OBJECTIVE

 Bronchopulmonary dysplasia (BPD) is the most common late morbidity for premature infants. Continuous neuromuscular blockade (CNMB) is suggested for the most unstable phase of BPD, despite no outcome data. We explored the association between duration of CNMB for severe BPD and mortality.

DESIGN

 Medical record review of children <5 years old admitted from 2016 to 2022 with BPD and one or more course of CNMB for ≥14 days.

RESULTS

 Twelve children received a total of 20 episodes of CNMB for ≥14 days (range 14-173 d) during their hospitalization. Most (10/12) were born at <28 weeks' gestation and most (11/12) with birth weight <1,000 g; 7/12 were of Black race/ethnicity. All were hospitalized since birth. Most (10/12) were initially transferred from an outside neonatal intensive care unit (ICU), typically after a >60-day hospitalization (9/12). Half (6/12) of them had a ≥60-day stay in our neonatal ICU before transferring to our pediatric ICU for, generally, ≥90 days (8/12). The primary study outcome was survival to discharge: 2/12 survived. Both had shorter courses of CNMB (19 and 25 d); only one child who died had a course ≤25 days. Just two infants had increasing length Z-scores during hospitalization; only one infant had a final length Z-score > - 2.

CONCLUSION

 In this case series of infants with severe BPD, there were no survivors among those receiving ≥25 days of CNMB. Linear growth, an essential growth parameter for infants with BPD, decreased in most patients. These data do not support the use of ≥25 days of CNMB to prevent mortality in infants with severe BPD.

KEY POINTS

· This is a case series of neuromuscular blockade for severe BPD.. · Neuromuscular blockade did not improve linear growth.. · Ten out of 12 infants who were on prolonged neuromuscular blockade died..

Association between early metabolic acidosis and bronchopulmonary dysplasia/death in preterm infants born at less than 28 weeks' gestation: an observational cohort study

BACKGROUND

Metabolic acidosis occurs frequently during the first postnatal days in extremely preterm infants and is mainly attributed to renal immaturity. Recent studies suggested a link between metabolic acidosis and the development of BPD. The aim of this study was to systematically investigate the association between severe metabolic acidosis during the first two weeks of life and bronchopulmonary dysplasia (BPD) / mortality among preterm infants born before 28 weeks' gestation.

METHODS

Monocentric observational cohort study including 1748 blood gas samples of 138 extremely preterm infants born 2020-2022. Metabolic acidosis was defined as pH < 7.2 with base excess (BE) < -10 mmol/L or standard bicarbonate (SBC) < 12 mmol/L. Primary outcome was BPD and/or death at 36 weeks postmenstrual age.

RESULTS

Fifty-six (40.6%) infants had BPD/death. Metabolic acidosis occurred in 50.0% of infants with BPD/death, compared to 22.0% of BPD-free survivors (p = 0.001) during the first 14 postnatal days. Minimum pH (median 7.12 vs. 7.19, p < 0.001), BE (median -10.9 vs. -9.5 mmol/L, p = 0.005), SBC (median 14.7 vs. 16.1 mmol/L, p < 0.001) were different between the two groups. After adjusting for confounders, pH (postnatal days 2-6), BE (postnatal day 3) and SBC (postnatal days 2-4) were significantly lower in infants with BPD/death. Metabolic acidosis on postnatal days 1-7 was associated with higher odds of BPD (adjusted Odds Ratio (aOR) 3.461, 95% CI 1.325-9.042) and BPD/death (aOR 3.087, 95% CI 1.225-7.778).

CONCLUSIONS

Metabolic acidosis during the first week of life was associated with higher odds of BPD/death in extremely preterm infants.

Interdisciplinary clinical bronchopulmonary dysplasia programs: development, evolution, and maturation

Multidisciplinary bronchopulmonary dysplasia (BPD) programs provide improved and consistent medical management, care of the developing infant, family support, and smoother transitions in care resulting in improved survival, pulmonary, and extra-pulmonary outcomes. This review summarizes the benefits of interdisciplinary BPD management, as well as strategies for initial programmatic development, program growth, and maintenance at centers across the United States factoring in institutional, provider, and parent reported goals that were derived from a consensus conference on BPD management.

Mesenchymal stromal cell extracellular vesicles improve lung development in mechanically ventilated preterm lambs

Novel therapies are needed for bronchopulmonary dysplasia (BPD) because no effective treatment exists. Mesenchymal stromal cell extracellular vesicles (MSC-sEVs) have therapeutic efficacy in a mouse pup neonatal hyperoxia BPD model. We tested the hypothesis that MSC-sEVs will improve lung functional and structural development in mechanically ventilated preterm lambs. Preterm lambs (∼129 days; equivalent to human lung development at ∼28 wk gestation) were exposed to antenatal steroids, surfactant, caffeine, and supported by mechanical ventilation for 6-7 days. Lambs were randomized to blinded treatment with either MSC-sEVs (human bone marrow MSC-derived; 2 × 1011 particles iv; n = 8; 4 F/4 M) or vehicle control (saline iv; 4 F/4 M) at 6 and 78 h post delivery. Physiological targets were pulse oximetry O2 saturation 90-94% ([Formula: see text] 60-90 mmHg), [Formula: see text] 45-60 mmHg (pH 7.25-7.35), and tidal volume 5-7 mL/kg. MSC-sEVs-treated preterm lambs tolerated enteral feedings compared with vehicle control preterm lambs. Differences in weight patterns were statistically significant. Respiratory severity score, oxygenation index, A-a gradient, distal airspace wall thickness, and smooth muscle thickness around terminal bronchioles and pulmonary arterioles were significantly lower for the MSC-sEVs group. S/F ratio, radial alveolar count, secondary septal volume density, alveolar capillary surface density, and protein abundance of VEGF-R2 were significantly higher for the MSC-sEVs group. MSC-sEVs improved respiratory system physiology and alveolar formation in mechanically ventilated preterm lambs. MSC-sEVs may be an effective and safe therapy for appropriate functional and structural development of the lung in preterm infants who require mechanical ventilation and are at risk of developing BPD.NEW & NOTEWORTHY This study focused on potential treatment of preterm infants at risk of developing bronchopulmonary dysplasia (BPD), for which no effective treatment exists. We tested treatment of mechanically ventilated preterm lambs with human mesenchymal stromal cell extracellular vesicles (MSC-sEVs). The results show improved respiratory gas exchange and parenchymal growth of capillaries and epithelium that are necessary for alveolar formation. Our study provides new mechanistic insight into potential efficacy of MSC-sEVs for preterm infants at risk of developing BPD.

Quality Improvement Initiative Enhances Outpatient Pediatric Pulmonology Follow-up for Premature Infants with Bronchopulmonary Dysplasia

Introduction

Bronchopulmonary dysplasia (BPD) is a chronic lung disorder affecting many premature infants. Infants with BPD have higher hospital readmission rates due to respiratory-related morbidity. We aimed to increase the rates of outpatient pulmonary follow-up and attendance of premature babies with moderate and severe BPD to above 85% within 6 months.

Methods

We conducted a quality improvement project at Yale New Haven Children's Hospital. Key interventions included developing a BPD clinical pathway integrated into the electronic medical record to assist providers in correctly classifying BPD severity, assigning the appropriate International Classification of Diseases, 10th Revision code (P27.1), and providing standardized treatment options. The outcome measures included correct diagnosis and classification of BPD, the percentage of patients with BPD scheduled for pediatric pulmonology appointments within 45 days, and the percentage attending those appointments.

Results

There were 226 patients in our study, including 85 in the baseline period. Correct diagnosis of BPD increased from 49% to 95%, the percentage of scheduled appointments increased from 71.9% to 100%, and the percentage of appointments attended increased from 55.6% to 87.1%.

Conclusions

Our quality improvement initiative improved the accuracy of diagnosis, severity classification, and outpatient pulmonary follow-up of children with moderate and severe BPD.

Approaches to Interdisciplinary Care for Infants with Severe Bronchopulmonary Dysplasia: A Survey of the Bronchopulmonary Dysplasia Collaborative

OBJECTIVE

Bronchopulmonary dysplasia (BPD) remains the most common late morbidity for extremely premature infants. Care of infants with BPD requires a longitudinal approach from the neonatal intensive care unit to ambulatory care though interdisciplinary programs. Current approaches for the development of optimal programs vary among centers.

STUDY DESIGN

We conducted a survey of 18 academic centers that are members of the BPD Collaborative, a consortium of institutions with an established interdisciplinary BPD program. We aimed to characterize the approach, composition, and current practices of the interdisciplinary teams in inpatient and outpatient domains.

RESULTS

Variations exist among centers, including composition of the interdisciplinary team, whether the team is the primary or consult service, timing of the first team assessment of the patient, frequency and nature of rounds during the hospitalization, and the timing of ambulatory visits postdischarge.

CONCLUSION

Further studies to assess long-term outcomes are needed to optimize interdisciplinary care of infants with severe BPD.

KEY POINTS

· Care of infants with BPD requires a longitudinal approach from the NICU to ambulatory care.. · Benefits of interdisciplinary care for children have been observed in other chronic conditions.. · Current approaches for the development of optimal interdisciplinary BPD programs vary among centers..

Urine Desmosine as a Novel Biomarker for Bronchopulmonary Dysplasia and Postprematurity Respiratory Disease in Extremely Preterm or Low Birth Weight Infants

OBJECTIVE

This study aimed to evaluate whether elevated urine desmosine levels at 3 weeks of age were associated with severe radiological findings, bronchopulmonary dysplasia (BPD), and post-prematurity respiratory disease (PRD) in extremely preterm (EP) or extremely low birth weight (ELBW) infants.

STUDY DESIGN

This study recruited 37 EP (22-27 completed weeks) or ELBW (<1,000 g) infants. Urine was collected between 21 and 28 postnatal days, and desmosine was measured using an enzyme-linked immunosorbent assay kit; the urine creatinine level was also measured. Bubbly/cystic lungs were characterized by emphysematous chest X-rays on postnatal day 28. Furthermore, provision of supplemental oxygen or positive-pressure respiratory support at 40 weeks' postmenstrual age defined BPD, and increased medical utilization at 18 months of corrected age defined PRD. The desmosine/creatinine threshold was determined by receiver operating characteristic analysis. The adjusted risk and 95% confidence interval (CI) for elevated urine desmosine/creatinine levels were estimated by logistic regression analysis.

RESULTS

Elevated urine desmosine/creatinine levels higher than the threshold were significantly associated with bubbly/cystic lungs (8/13 [61.5%] vs. 2/24 [8.3%], p = 0.001), BPD (10/13 [76.9%] vs. 8/24 [33.3%], p = 0.02), and PRD (6/13 [46.2%] vs. 2/24 [8.3%], p = 0.01). After adjusting for gestational age, birth weight, and sex, the urine desmosine/creatinine levels were significantly higher in those who were highly at risk of bubbly/cystic lungs (odds ratio [OR], 13.2; 95% CI, 1.67-105) and PRD (OR, 13.8; 95% CI, 1.31-144).

CONCLUSION

Elevated urine desmosine/creatinine levels on the third postnatal week were associated with bubbly/cystic lungs on day 28 and PRD at 18 months of corrected age in EP or ELBW infants.

KEY POINTS

· Urine desmosine was prospectively measured in 3-week-old EP/ELBW infants.. · Elevated urine desmosine levels were associated with emphysematous radiological findings on day 28, PRD at 18 months of corrected age.. · Urine desmosine may be a promising biomarker indicating lung damage in EP/ELBW infants..

Pulmonary Hypertension in Established Bronchopulmonary Dysplasia: Physiologic Approaches to Clinical Care

Preterm infants with bronchopulmonary dysplasia (BPD) are prone to develop pulmonary hypertension (PH). Strong laboratory and clinical data suggest that antenatal factors, such as preeclampsia, chorioamnionitis, oligohydramnios, and placental dysfunction leading to fetal growth restriction, increase susceptibility for BPD-PH after premature birth. Echocardiogram metrics and serial assessments of NT-proBNP provide useful tools to diagnose and monitor clinical course during the management of BPD-PH, as well as monitoring for such complicating conditions as left ventricular diastolic dysfunction, shunt lesions, and pulmonary vein stenosis. Therapeutic strategies should include careful assessment and management of underlying airways and lung disease, cardiac performance, and systemic hemodynamics, prior to initiation of PH-targeted drug therapies.

Insulin-like growth factor-1 replacement therapy after extremely premature birth: An opportunity to optimize lifelong lung health by preserving the natural sequence of lung development

The past decades have seen markedly improved survival of increasingly immature preterm infants, yet major health complications persist. This is particularly true for bronchopulmonary dysplasia (BPD), the chronic lung disease of prematurity, which has become the most common sequelae of prematurity and a significant predictor of respiratory morbidity throughout childhood as well as adult life, neurodevelopmental disability, cardiovascular disease, and even death. The need for novel approaches to reduce BPD and related complications of prematurity has never been more critical. Thus, despite major advances in the use of antenatal steroids, surfactant therapy, and improvements in respiratory support, there is a persistent need for developing therapeutic strategies that more specifically reflect our growing understanding of BPD in the post-surfactant age, or the "new BPD." In contrast with the severe lung injury leading to marked fibroproliferative disease from the past, the "new BPD" is primarily characterized by an arrest of lung development as related to more extreme prematurity. This distinction and the continued high incidence of BPD and related sequelae suggest the need to identify therapies that target critical mechanisms that support lung growth and maturation in conjunction with treatments to improve respiratory outcomes across the lifespan. As the prevention of BPD and its severity remains a primary goal, we highlight the concept from preclinical and early clinical observations that insulin-like growth factor 1 (IGF-1) can potentially support the natural sequence of lung growth as a replacement therapy after preterm birth. Data supporting this hypothesis are robust and include observations that low IGF-1 levels persist after extremely preterm birth in human infants and strong preclinical data from experimental models of BPD highlight the therapeutic benefit of IGF-1 in reducing disease. Importantly, phase 2a clinical data in extremely premature infants where replacement of IGF-1 with a human recombinant human IGF-1 complexed with its main IGF-1 binding protein 3, significantly reduced the most severe form of BPD, which is strongly associated with multiple morbidities that have lifelong consequences. As physiologic replacement therapy of surfactant heralded the success of reducing acute respiratory distress syndrome in preterm infants, the paradigm has the potential to become the platform for discovering the next generation of therapies like IGF-1, which becomes deficient after extremely premature birth where endogenous production by the infant is not sufficient to maintain the physiologic levels adequate to support normal organ development and maturation.

Leveraging transcriptomics to develop bronchopulmonary dysplasia endotypes: a concept paper

IMPACT

Bronchopulmonary dysplasia has multiple definitions that are currently based on phenotypic characteristics. Using an unsupervised machine learning approach, we created BPD subclasses (e.g., endotypes) by clustering whole microarray data. T helper 17 cell differentiation was the most significant pathway differentiating the BPD endotypes.

INTRODUCTION

Bronchopulmonary dysplasia (BPD) is the most common complication of extreme prematurity. Discovery of BPD endotypes in an unbiased format, derived from the peripheral blood transcriptome, may uncover patterns underpinning this complex lung disease.

METHODS

An unsupervised agglomerative hierarchical clustering approach applied to genome-wide expression of profiling from 62 children at day of life five was used to identify BPD endotypes. To identify which genes were differentially expressed across the BPD endotypes, we formulated a linear model based on least-squares minimization with empirical Bayes statistics.

RESULTS

Four BPD endotypes (A, B,C,D) were identified using 7,319 differentially expressed genes. Across BPD endotypes, 5,850 genes had a p value < 0.05 after multiple comparison testing. Endotype A consisted of neonates with a higher gestational age and birthweight. Endotypes B-D included neonates between 25 and 26 weeks and a birthweight range of 640 to 940 g. Endotype D appeared to have a protective role against BPD compared to Endotypes B and C (36% vs. 62% vs. 60%, respectively). The most significant pathway focused on T helper 17 cell differentiation.

CONCLUSION

Bioinformatic analyses can help identify BPD endotypes that associate with clinical definitions of BPD.

Dose-dependent impact of human milk feeding on tidal breathing flow-volume loop parameters across the first 2 years of life in extremely low-birth-weight infants: a cohort study

The purpose of this study is to test the hypothesis that higher consumption of human milk (HM) in preterm infants with birth weight (BW) <1000 g is associated with improved lung function in a dose-dependent manner over the first 2 years of corrected age (CA). This retrospective study at an academic medical center included infants with BW <1000g. They had lung function assessment by the tidal breathing flow-volume loop (TBFVL) follow-up visits at 0-3-, 3-6-, 6-12-, 12-18-, and 18-24-month CA. One hundred eighty infants were included in the study with a mean (SD) gestational age 26.5 (1.90) weeks and BW 772.4 (147.0) g, 50% were female, and 60% developed BPD. 62.8% of infants received HM during the NICU stay. According to a general linear model (including GA, being small for GA (SGA), sex, human milk percentage, sepsis, and BPD), on average, each week of GA resulted in a higher tPTEF/tE of 1.24 (p = 0.039) and being SGA in a lower tPTEF/tE of 5.75 (p = 0.013) at 0-3-month CA. A higher percentage of human milk out of the total enteral intake was associated with better tPTEF/tE z-scores at 0-3 months (p = 0.004) and 18-24 months of CA (p = 0.041). BPD diagnosis was associated with a relevantly worse tPTEF/tE z-score at 6-12 months of CA (p = 0.003).

CONCLUSION

Preterm infants with higher consumption of HM had significantly less airway obstruction across the first 2 years, suggesting that human milk may contribute in a dose-dependent manner to improve lung function in early childhood in former preterm infants born ELBW.

WHAT IS KNOWN

• Human milk feeding reduces the risk of prematurity-related morbidities, including necrotizing enterocolitis, sepsis, lower respiratory tract infections, and BPD. Both exclusive and partial human milk feeding appear to be associated with a lower risk of BPD in preterm infants.

WHAT IS NEW

• This cohort study of 180 preterm infants with birth weight < 1000 g found that exposure to human milk during hospitalization improves airway obstruction markers tPTEF/tE z-score over the first 2 years of corrected age in a dose-dependent manner.

To Trach or Not To Trach: Long-term Tracheostomy Outcomes in Infants with BPD

See Bonus NeoBriefs videos and downloadable teaching slides Infants born preterm who are diagnosed with bronchopulmonary dysplasia (BPD) demonstrate a wide spectrum of illness severity. For infants with the most severe forms of BPD, safe discharge from the hospital may only be possible by providing long-term ventilation via a surgically placed tracheostomy. Though tracheostomy placement in infants with BPD is infrequent, recent reports suggest that rates of tracheostomy placement are increasing in this population. Even though there are known respiratory and neurodevelopmental risks associated with tracheostomy placement, no evidence-based criteria or consensus clinical practice guidelines exist to inform tracheostomy placement in this growing and vulnerable population. An incomplete knowledge of long-term post-tracheostomy outcomes in infants with BPD may unduly bias medical decision-making and family counseling regarding tracheostomy placement. This review aims to summarize our current knowledge of the epidemiology and long-term outcomes of tracheostomy placement in infants with BPD to provide a family-centered framework for tracheostomy counseling.

Identifying Barriers and Facilitators to Care for Infants with Bronchopulmonary Dysplasia After NICU Discharge: A Prospective Study of Parents and Clinical Stakeholders

Objective

Understand barriers and facilitators to follow-up care for infants with bronchopulmonary dysplasia (BPD).

Methods

Qualitative study of parents and clinical stakeholders caring for infants with BPD. The interview guide was developed by a mother of a former 23-week preterm infant, neonatologist, pulmonologist, nurse, and qualitative researcher. Purposive sampling obtained a heterogenous sociodemographic and professional cohort. Subjects discussed their experience with BPD, barriers to care, caregiver quality of life and health education. Interviews were audio-recorded, transcribed and coded. Thematic analysis was used.

Results

Eighteen parents and 20 stakeholders completed interviews. Family-level themes included pragmatic barriers like transportation being multi-faceted; and caregiving demands straining mental health. System-level themes included caregiver education needing to balance process needs with future trajectories; and integration of primary care, specialty care, and community supports.

Conclusions

Individual and system barriers impact follow-up for infants with BPD. This conceptual framework can be used to measure and improve care.

Pulmonary phenotypes of bronchopulmonary dysplasia in the preterm infant

Bronchopulmonary dysplasia (BPD) remains the most common complication of premature birth, imposing a significant and potentially life-long burden on patients and their families. Despite advances in our understanding of the mechanisms that contribute to patterns of lung injury and dysfunctional repair, current therapeutic strategies remain non-specific with limited success. Contemporary definitions of BPD continue to rely on clinician prescribed respiratory support requirements at specific time points. While these criteria may be helpful in broadly identifying infants at higher risk of adverse outcomes, they do not offer any precise information regarding the degree to which each compartment of the lung is affected. In this review we will outline the different pulmonary phenotypes of BPD and discuss important features in the pathogenesis, clinical presentation, and management of these frequently overlapping scenarios.

Endothelial to mesenchymal transition in neonatal hyperoxic lung injury: role of sex as a biological variable

Bronchopulmonary dysplasia (BPD) is characterized by an arrest in alveolarization, abnormal vascular development, and variable interstitial fibroproliferation in the premature lung. Endothelial to mesenchymal transition (EndoMT) may be a source of pathological fibrosis in many organ systems. Whether EndoMT contributes to the pathogenesis of BPD is not known. We tested the hypothesis that pulmonary endothelial cells will show increased expression of EndoMT markers upon exposure to hyperoxia and that sex as a biological variable will modulate differences in expression. Wild-type (WT) and Cdh5-PAC CreERT2 (endothelial reporter) neonatal male and female mice (C57BL6) were exposed to hyperoxia (0.95 [Formula: see text]) either during the saccular stage of lung development (95% [Formula: see text]; postnatal day 1-5 [PND1-5]) or through the saccular and early alveolar stages of lung development (75% [Formula: see text]; PND1-14). Expression of EndoMT markers was measured in whole lung and endothelial cell mRNA. Sorted lung endothelial cells (from room air- and hyperoxia-exposed lungs) were subjected to bulk RNA-Seq. We show that exposure of the neonatal lung to hyperoxia leads to upregulation of key markers of EndoMT. Furthermore, using lung sc-RNA-Seq data from neonatal lung we were able to show that all endothelial cell subpopulations including the lung capillary endothelial cells show upregulation of EndoMT-related genes. Markers related to EndoMT are upregulated in the neonatal lung upon exposure to hyperoxia and show sex-specific differences. Mechanisms mediating EndoMT in the injured neonatal lung can modulate the response of the neonatal lung to hyperoxic injury and need further investigation.NEW & NOTEWORTHY We show that neonatal hyperoxia exposure increased EndoMT markers in the lung endothelial cells and this biological process exhibits sex-specific differences.

Characteristics of home oxygen therapy for preterm infants with bronchopulmonary dysplasia in China: results of a multicenter cohort study

BACKGROUND

Home oxygen therapy (HOT) is indicated upon discharge in some preterm infants with severe bronchopulmonary dysplasia (BPD). There is a lack of evidence-based consensus on the indication for HOT among these infants. Because wide variation in the institutional use of HOT exists, little is known about the role of regional social-economic level in the wide variation of HOT.

METHODS

This was a secondary analysis of Chinese Neonatal Network (CHNN) data from January 1, 2019 to December 31, 2019. Infants at gestational ages < 32 weeks, with a birth weight < 1500 g, and with moderate or severe BPD who survived to discharge from tertiary hospitals located in 25 provinces were included in this study. Infants with major congenital anomalies and those who were discharged against medical advice were excluded.

RESULTS

Of 1768 preterm infants with BPD, 474 infants (26.8%) were discharged to home with oxygen. The proportion of HOT use in participating member hospitals varied from 0 to 89%, with five of 52 hospitals' observing proportions of HOT use that were significantly greater than expected, with 14 hospitals with observing proportions significantly less than expected, and with 33 hospitals with appropriate proportions. We noted a negative correlation between different performance groups of HOT and median GDP per capita (P = 0.04).

CONCLUSIONS

The use of HOT varied across China and was negatively correlated with the levels of provincial economic levels. A local HOT guideline is needed to address the wide variation in HOT use with respect to different regional economic levels in countries like China.

Association between red blood cell transfusion and bronchopulmonary dysplasia: a systematic review and meta-analysis

Background

We aimed to determine the association between red blood cell transfusions (RBCT) and bronchopulmonary dysplasia (BPD) in neonates.

Methods

A systematic review and meta-analysis were conducted using data obtained from literature search of PubMed, Embase, and Web of Science from their inception till May 1, 2022. Two reviewers independently selected potentially relevant studies, and after data extraction, they assessed the methodological quality of the included studies using the Newcastle-Ottawa scale. Data were pooled using random-effects models in Review Manager 5.3. Subgroup-analysis was performed based on the number of transfusions and adjusted results.

Results

Of the 1,011 identified records, 21 total case-control, cross-sectional, and cohort studies were selected, which included a total of 6,567 healthy controls and 1,476 patients with BPD. The pooled unadjusted odds ratio ([OR], 4.01; 95% confidence interval [CI] 2.31-6.97) and adjusted OR (5.11; 95% CI 3.11-8.4) showed significant association between RBCT and BPD. A substantial heterogeneity was noted, which could be due to different variables controlled for in each study. The subgroup analysis showed that heterogeneity may be partially explained by the extent of transfusion.

Conclusion

The association between BPD and RBCT remains unclear based on the current data due to the substantial heterogeneity among the results. Well-designed studies are still needed in the future.

Sociodemographic factors associated with tracheostomy and mortality in bronchopulmonary dysplasia

OBJECTIVES

We sought to investigate how race, ethnicity, and socioeconomic status relate to tracheostomy insertion and post-tracheostomy mortality among infants with bronchopulmonary dysplasia (BPD).

METHODS

The Vizient Clinical Database/Resource Manager was queried to identify infants born ≤32 weeks with BPD admitted to US hospitals from January 2012 to December 2020. Markers of socioeconomic status were linked to patient records from the Agency for Healthcare Research and Quality's Social Determinants of Health Database. Regression models were used to assess trends in annual tracheostomy insertion rate and odds of tracheostomy insertion and post-tracheostomy mortality, adjusting for sociodemographic and clinical factors.

RESULTS

There were 40,021 ex-premature infants included in the study, 1614 (4.0%) of whom received a tracheostomy. Tracheostomy insertion increased from 2012 to 2017 (3.1%-4.1%), but decreased from 2018 to 2020 (3.3%-1.6%). Non-Hispanic Black infants demonstrated a 25% higher odds (aOR 1.25, 1.09-1.43) and Hispanic infants demonstrated a 20% lower odds (aOR 0.80, 0.65-0.96) of tracheostomy insertion compared with non-Hispanic White infants. Patients receiving public insurance had increased odds of tracheostomy insertion (aOR 1.15, 1.03-1.30), but there was no relation between other metrics of socioeconomic status and tracheostomy insertion within our cohort. In-hospital mortality among the tracheostomy-dependent was 14.1% and was not associated with sociodemographic factors.

CONCLUSIONS

Disparities in tracheostomy insertion are not accounted for by differences in socioeconomic status or the presence of additional neonatal morbidities. Post-tracheostomy mortality does not demonstrate the same relationships. Further investigation is needed to explore the source and potential mitigators of the identified disparities.

Environmental influences on child health outcomes: cohorts of individuals born very preterm

The National Institutes of Health's Environmental influences on Child Health Outcomes (ECHO) Program was designed to address solution-oriented research questions about the links between children's early life environment and their risks of pre-, peri-, and post-natal complications, asthma, obesity, neurodevelopmental disorders, and positive health. Children born very preterm are at increased risk for many of the outcomes on which ECHO focuses, but the contributions of environmental factors to this risk are not well characterized. Three ECHO cohorts consist almost exclusively of individuals born very preterm. Data provided to ECHO from cohorts can be used to address hypotheses about (1) differential risks of chronic health and developmental conditions between individuals born very preterm and those born at term; (2) health disparities across social determinants of health; and (3) mechanisms linking early-life exposures and later-life outcomes among individuals born very preterm. IMPACT: The National Institutes of Health's Environmental Influences on Child Health Outcomes Program is conducting solution-oriented research on the links between children's environment and health. Three ECHO cohorts comprise study participants born very preterm; these cohorts have enrolled, to date, 1751 individuals born in 14 states in the U.S. in between April 2002 and March 2020. Extensive data are available on early-life environmental exposures and child outcomes related to neurodevelopment, asthma, obesity, and positive health. Data from ECHO preterm cohorts can be used to address questions about the combined effects of preterm birth and environmental exposures on child health outcomes.

Outcomes of infants with severe bronchopulmonary dysplasia who received tracheostomy and home ventilation

OBJECTIVE

To describe the survival rate, timing of liberation from the ventilator, and factors favorable for decannulation among infants with severe bronchopulmonary dysplasia (sBPD) who received tracheostomy.

METHODS

Demographics and clinical outcomes were obtained through retrospective chart review of 98 infants with sBPD who were born between 2004 and 2017, received tracheostomy at <1 year of age, and were followed in the Infant Tracheostomy and Home Ventilator clinic up to 4 years of age.

RESULTS

The number of infants with sBPD who received tracheostomy increased significantly over the study period. The median age at tracheostomy was 4 months (IQR 3, 5) or 43 weeks corrected gestational age; the median age at NICU discharge was 7 months (IQR 6, 9). At 48 months of age, all subjects had been liberated from the ventilator, at a median age of 24 months (IQR 18, 29); 52% had been decannulated with a median age at decannulation of 32 months (IQR 26, 39). Only 1 (1%) infant died. Multivariate logistic regression showed infants who were White, liberated from the ventilator by 24 months of age and have public insurance had significantly greater odds of being decannulated by 48 months of age. Tracheobronchomalacia was associated with decreased odds of decannulation.

CONCLUSION

Infants with sBPD who received tracheostomy had an excellent survival rate. Liberation from home ventilation and decannulation are likely to occur by 4 years of age.

Neonatal respiratory support related to lung function abnormalities in school-age children with bronchopulmonary dysplasia

OBJECTIVE

To elucidate the relationship between abnormal lung function (LF) at school age and neonatal respiratory support in very low birth weight children with bronchopulmonary dysplasia (BPD).

STUDY DESIGN

We retrospectively examined 78 BPD children whose LF was evaluated at 8-9 years. LF abnormalities were defined by reduced values of spirometric parameters. Adjusted odds ratios (aORs) for abnormal LF by the type and postmenstrual age (PMA) of respiratory support were calculated using logistic regression analysis after controlling perinatal factors.

RESULTS

Overall, 24 (31%) patients had LF abnormalities. Antenatal steroid use was associated with a decreased risk of abnormal LF [aOR, 0.31; 95% CI, 0.09-0.92]. Requiring positive-pressure support at 37 weeks' PMA correlated with abnormal LF [aOR, 4.58; 95% CI, 1.15-21.90]; whereas only low-flow oxygen at any PMA did not.

CONCLUSION

Requiring positive-pressure support at 37 weeks' PMA could be an indicator of abnormal LF at school age.

Lung Function of Preterm Children Parsed by a Polygenic Risk Score for Adult COPD

BACKGROUND: Chronic obstructive pulmonary disease (COPD) in adults is a result of environmental risk factors and genetic factors. Polygenic COPD risk scores are highly predictive for lung function in adults. We hypothesized that a polygenic COPD risk score is also predictive for lung function in children who are born preterm. METHODS: Infants with a birth weight of less than 1500 g (n=17,394) were enrolled in the German Neonatal Network. Among these children, we included those with chip genotyping and 5-year follow-up assessment (n=1957) in this analysis. A polygenic COPD risk score derived in adults with COPD was calculated on the basis of 1,637,882 single-nucleotide polymorphisms associated with forced expiratory volume within 1 second (FEV1) and 1,179,331 single-nucleotide polymorphisms associated with FEV1/FVC (forced vital capacity). This score was related to FEV1, FVC, and FEV1/FVC z scores by linear regression analysis. RESULTS: At a mean age at follow-up of 5.8±0.4 years, the polygenic COPD risk score was strongly associated with FEV1 (−0.05 z score/decile, P=6.5 × 10−9) and FEV1/FVC (−0.07 z score/decile, P=4.4 × 10−11) but not FVC. Children in the 10th decile of the polygenic COPD risk score — that is, those at the highest risk — had a mean FEV1 z score of −1.74 (±1.1), indicating lower lung function by these measures and higher rates of obstructive bronchitis. CONCLUSIONS: The upper deciles of a polygenic COPD risk score derived in adults identified a subgroup of children who were born preterm and who are at high risk for obstructive pulmonary disease of prematurity. This finding supports the notion that COPD-associated genes strongly impact lung function in premature children. (Funded by the German Federal Ministry of Education and Research.)

COVID-19 restrictions and hygiene measures reduce the rates of respiratory infections and wheezing among preterm infants

BACKGROUND AND AIM

During the 2020 and 2021 Italian COVID-19 pandemic social restrictions and strict hygiene measures were recommended to limit the spread of SARS-CoV-2. We aimed to assess whether rates of respiratory infections and wheezing in preterm infants have changed during the pandemic.

METHODS

Single center, retrospective study. Preterm infants in the first 6 months of life discharged home prior to (Period 1, January 2017 - December 2019) or during the pandemic (Period 2, January 2020 - March 2021) were compared. Rates of respiratory infection and wheezing in preterm infants with or without bronchopulmonary dysplasia (BDP) were assessed.

RESULTS

During period 2 premature infants had lower rates of respiratory infections (36 out of 55 in Period 1 vs 11 out of 28 in Period 2, P=0.023) and wheezing (20 out of 55 in Period 1 vs 1 out of 28 in Period 2, P=0.001). This difference remained significant when infants with BPD (all grades) were analyzed separately (respiratory infections 26 out of 40 in Period 1 vs 7 out of 24 in Period 2, P=0.005; wheezing 16 out of 40 in Period 1 vs 1 out of 24 in Period 2, P=0.001). In contrast, respiratory infections and wheezing in preterm infants without BPD did not change after pandemic.

CONCLUSIONS

Episodes of respiratory infections and wheezing among preterm infants were reduced during pandemic. We highlight the importance of proper family education for preventing respiratory tract infections in preterm infants with BPD, beyond the extraordinary conditions of the COVID-19 pandemic.

Comparison of New Bronchopulmonary Dysplasia Definitions on Long-Term Outcomes in Preterm Infants

OBJECTIVE

To compare the discriminative performances of the 2018 National Institutes of Health (NIH) and the 2019 Jensen definitions of bronchopulmonary dysplasia (BPD) with the 2001 NIH definition on adverse neurodevelopmental and respiratory outcomes at 2 years and 5 years corrected age.

STUDY DESIGN

In this single-center retrospective cohort study, outcomes of infants born at <30 weeks of gestational age were collected. The 3 definitions of BPD were compared by adding the different definitions to the National Institute of Child Health and Human Development's outcome prediction model for neurodevelopmental impairment (NDI) or death. Discriminative performance was compared for both outcomes at 2 years and 5 years corrected age by calculating the areas under the receiver operating characteristic curve and z-statistics.

RESULTS

The presence of BPD and its severity were determined in 584 infants. There were considerable shifts in BPD grading among the different definitions. At both time points, all BPD definition models had comparable discriminating power for NDI and respiratory morbidity, with one exception. Compared with the 2001 NIH definition, the 2018 NIH definition had less predictive power for the neurologic outcome at 2 years corrected age.

CONCLUSIONS

Our comparison of the 3 BPD definitions shows similar discriminative performance on long term neurodevelopmental and respiratory outcomes at 2 years and 5 years corrected age.

Prediction of extubation failure among low birthweight neonates using machine learning

OBJECTIVE

To develop machine learning models predicting extubation failure in low birthweight neonates using large amounts of clinical data.

STUDY DESIGN

Retrospective cohort study using MIMIC-III, a large single-center, open-source clinical dataset. Logistic regression and boosted-tree (XGBoost) models using demographics, medications, and vital sign and ventilatory data were developed to predict extubation failure, defined as reintubation within 7 days.

RESULTS

1348 low birthweight (≤2500 g) neonates who received mechanical ventilation within the first 7 days were included, of which 350 (26%) failed a trial of extubation. The best-performing model was a boosted-tree model incorporating demographics, vital signs, ventilator parameters, and medications (AUROC 0.82). The most important features were birthweight, last FiO2, average mean airway pressure, caffeine use, and gestational age.

CONCLUSIONS

Machine learning models identified low birthweight ventilated neonates at risk for extubation failure. These models will need to be validated across multiple centers to determine generalizability of this tool.

Comparison of Definitions for Bronchopulmonary Dysplasia: A Cohort Study

We aimed to compare the definitions of National Institute of Child Health and Human Development (NICHD) for bronchopulmonary dysplasia (BPD) for determining the incidences, and predicting late death and respiratory outcome. This retrospective cohort study included infants born at<32 weeks' gestation who survived up to 36 weeks' postmenstrual age (PMA). Infants were classified as having BPD or no BPD per thedefinitions of NICHD 2001 and 2018. The incidences of BPD were 49 and 32% according to the 2001 and 2018 NICHD definitions. Gestational age, birth weight and intubation after birth were associated with BPD by both definitions. The NICHD 2018 definition displayed similar sensitivity (100%) and negative predictive value (100%), and higher specificity (70 vs. 52%) for predicting death after 36 weeks' PMA; a higher specificity (72 vs. 53%), comparable negative predictive value (77 vs.76%), but lower sensitivity for predicting adverse respiratory outcome within 12 months corrected age compared with the NICHD 2001 definition. The NICHD 2018 definition is as powerful as the 2001 definition for predicting late death and seems to be a better indicator for long-term respiratory outcome. The use of supplemental oxygen or oxygen plus respiratory support should be considered while predicting both late death and long-term respiratory outcome.

Prematurity-associated wheeze: current knowledge and opportunities for further investigation

Prematurity-associated wheeze is a common complication of preterm birth, with significant impact on the health and healthcare utilization of former preterm infants. This wheezing phenotype remains poorly understood and difficult to predict. This review will discuss the current state of the literature on prematurity-associated wheeze. We will discuss etiology and pathophysiology, and offer two conceptual models for the pathogenesis of this complex condition. This review will also identify current methods of ascertainment, and discuss the strengths and limitations of each. We will explore research-backed approaches to prevention and management, and finally suggest both pre-clinical and clinical avenues for investigation. An in-depth understanding of prematurity-associated wheeze will aid clinicians in its diagnosis and management, and inspire scientists to pursue much-needed further study into causes and prevention of this common and impactful condition. IMPACT: There is no recent, concise review on the current state of research on prematurity-associated wheeze, which is a rapidly evolving area of study. This article highlights causal models of wheeze, methods of ascertainment, management strategies for the clinician, and opportunities for further research for the physician scientist.

Prospective Risk Stratification Identifies Healthcare Utilization Associated with Home Oxygen Therapy for Infants with Bronchopulmonary Dysplasia

OBJECTIVE

To test whether prospective classification of infants with bronchopulmonary dysplasia identifies lower-risk infants for discharge with home oxygen who have fewer rehospitalizations by 1 year after neonatal intensive care unit discharge.

STUDY DESIGN

This is a prospective single-center cohort that included infants from 2016 to 2019 with bronchopulmonary dysplasia, defined as receiving respiratory support at 36 weeks of postmenstrual age. "Lower-risk" infants were receiving ≤2 L/min nasal cannula flow, did not have pulmonary hypertension or airway comorbidities, and had blood gas partial pressure of carbon dioxide <70 mm Hg. We compared 3 groups by discharge status: lower-risk room air, lower-risk home oxygen, and higher-risk home oxygen. The primary outcome was rehospitalization at 1 year postdischarge, and the secondary outcomes were determined by the chart review and parent questionnaire.

RESULTS

Among 145 infants, 32 (22%) were lower-risk discharged in room air, 49 (32%) were lower-risk using home oxygen, and 64 (44%) were higher-risk. Lower-risk infants using home oxygen had rehospitalization rates similar to those of lower-risk infants on room air (18% vs 16%, P = .75) and lower rates than higher-risk infants (39%, P = .018). Lower-risk infants using home oxygen had more specialty visits (median 10, IQR 7-14 vs median 6, IQR 3-11, P = .028) than those on room air. Classification tree analysis identified risk status as significantly associated with rehospitalization, along with distance from home to hospital, inborn, parent-reported race, and siblings in the home.

CONCLUSIONS

Prospectively identified lower-risk infants discharged with home oxygen had fewer rehospitalizations than higher-risk infants and used more specialty care than lower-risk infants discharged in room air.

Racial disparities in the development of comorbid conditions after preterm birth: A narrative review

Despite recognition and attempts to reduce racial disparities in perinatal outcomes, Black infants are still disproportionately represented among those who are born preterm. Postnatal investigations of racial disparities in comorbidities and outcomes after preterm birth are increasing, although their results and interpretations are conflicting. In the present review, we 1.) identify important methodological limitations of that literature 2.) summarize the conflicting literature investigating racial disparities, specifically Black-white differences, in postnatal comorbidities and outcomes after preterm birth 3.) describe mechanisms by which racism operates to contextualize our understanding to inform future work to actively reduce disparities in preterm birth and subsequently, its complications.

Lung ultrasound score follows the chronic pulmonary insufficiency of prematurity trajectory in early infancy

Extremely preterm birth is associated with a high risk of chronic pulmonary insufficiency of prematurity (CPIP). Lung ultrasound score (LUS) proved capable to characterise CPIP progression beyond the acute setting, but still, post-discharge data remain lacking. We hypothesised a priori that LUS in both BPD and no-BPD infants declines with postnatal age from birth through early infancy. This observational retrospective cohort study included preterm infants < 32 gestational weeks, who underwent the follow-up for CPIP. LUS was assessed from birth to 8 months postnatal age, over antero-lateral (LUS) and posterior (pLUS) pulmonary areas, placing the transducer longitudinally over the midclavicular and midaxillary lines and medial to the scapular line respectively. Extended LUS (eLUS) including LUS and pLUS was calculated. The primary outcome was LUS time course. Secondary outcomes included the correlation between LUS and pLUS. Sixty-two infants were included: 22 (35.5%) in the BPD group and 40 (64.5%) in the no-BPD group. BPD group infants were smaller (weight 841 g (± 228) vs 1226 (± 328), p < 0.001) and younger (26.8 weeks (± 2.0) vs 28.9 (± 1.9), p < 0.001). LUS declined over time in the entire population (ß =  - 1.75, p < 0.001) and in both no-BPD and BPD groups (ß =  - 1.64, p < 0.001 and ß =  - 1.93, p < 0.001, respectively). eLUS declined correspondingly (p < 0.001). LUS and likewise eLUS were significantly different between BPD and no-BPD groups over time (p < 0.001).  Conclusion: LUS trajectory progressively decreased from birth to early infancy. BPD cohort tracked higher, implying a worse respiratory status. pLUS had a similar timepoint course, adding no further information to LUS. To the best of our knowledge, this is the first study that describes preterm LUS time course after discharge. LUS may help track the CPIP progression. What is Known: • Extremely preterm birth is associated with high risk of chronic pulmonary insufficiency of prematurity (CPIP). • Several studies investigated the ability of lung ultrasound score (LUS) to characterize CPIP progression beyond the acute setting, still post-discharge data remain lacking. What is New: • LUS trajectory progressively decreases from birth to early infancy; BPD cohort tracks higher, implying a worse respiratory status. pLUS has similar timepoint course, adding no further information to LUS. • The use of LUS may contribute to better characterising and monitoring CPIP in BPD and no-BPD infants.

Long-term burden of respiratory complications associated with extreme prematurity: An analysis of US Medicaid claims

BACKGROUND

Infants born extremely premature (EP) (<28 weeks gestational age) are at high risk of complications, particularly bronchopulmonary dysplasia (BPD), which can develop into chronic lung disease (CLD).

METHODS

The burden of respiratory complications in EP infants up to 2 years corrected age (CA) was evaluated using real-world data from the US Medicaid program. Data recorded between 1997 and 2018 on EP infants without major congenital malformations were collected from Medicaid records of six states. EP infants were divided into three cohorts: BPD, CLD, and without BPD or CLD. The incidence of respiratory conditions, respiratory medication use, and healthcare resource utilization were compared between the BPD cohort and CLD cohort versus the cohort without BPD or CLD, using unadjusted and adjusted generalized linear models.

RESULTS

A total of 4462 EP infants were identified (17.4% of all premature infants in the database). Of these, BPD and CLD were diagnosed in 61.9% and 72.1%, respectively, and 14.5% were diagnosed with neither BPD nor CLD. Compared with infants without BPD or CLD, infants with BPD or CLD had more complications and a longer length of birth hospitalization stay. Respiratory distress syndrome was the most frequently reported complication (94.6%, 92.5%, and 82.3% of EP infants in the BPD, CLD, and without BPD or CLD cohorts, respectively). After the birth hospitalization, respiratory conditions, respiratory medication use, and incidence rates of rehospitalizations, emergency room visits, and outpatient visits were higher for infants with BPD or CLD. Rehospitalization occurred in 50.5%, 51.6%, and 27.3% of EP infants with BPD, CLD, or without BPD or CLD, respectively; most hospitalizations occurred for respiratory-related reasons.

CONCLUSION

In this analysis of a large population of EP infants up to 2 years CA, respiratory conditions were prevalent after the birth hospitalization and were associated with high rates of medication and healthcare resource utilization.

Association of Racial Disparities With In-Hospital Outcomes in Severe Bronchopulmonary Dysplasia

Importance

Bronchopulmonary dysplasia (BPD) is the most common serious morbidity of preterm birth. Short-term respiratory outcomes for infants with the most severe forms of BPD are highly variable. The mechanisms that explain this variability remain unknown and may be mediated by racial disparities.

Objective

To determine the association of maternal race with death and length of hospital stay in a multicenter cohort of infants with severe BPD.

Design, Setting, and Participants

This multicenter cohort study included preterm infants enrolled in the BPD Collaborative registry from January 1, 2015, to July 19, 2021, involving 8 BPD Collaborative centers located in the US. Included patients were born at less than 32 weeks' gestation, had a diagnosis of severe BPD as defined by the 2001 National Institutes of Health Consensus Criteria, and were born to Black or White mothers.

Exposures

Maternal race: Black vs White.

Main Outcomes and Measures

Death and length of hospital stay.

Results

Among 834 registry infants (median [IQR] gestational age, 25 [24-27] weeks; 492 male infants [59%]) meeting inclusion criteria, the majority were born to White mothers (558 [67%]). Death was observed infrequently in the study cohort (32 [4%]), but Black maternal race was associated with an increased odds of death (adjusted odds ratio, 2.1; 95% CI, 1.2-3.5) after adjusting for center. Black maternal race was also significantly associated with length of hospital stay (adjusted between-group difference, 10 days; 95% CI, 3-17 days).

Conclusions and Relevance

In a multicenter severe BPD cohort, study results suggest that infants born to Black mothers had increased likelihood of death and increased length of hospital stay compared with infants born to White mothers. Prospective studies are needed to define the sociodemographic mechanisms underlying disparate health outcomes for Black infants with severe BPD.

Insurance coverage and respiratory morbidities in bronchopulmonary dysplasia

INTRODUCTION

Preterm infants and young children with bronchopulmonary dysplasia (BPD) are at increased risk for acute care utilization and chronic respiratory symptoms during early life. Identifying risk factors for respiratory morbidities in the outpatient setting could decrease the burden of care. We hypothesized that public insurance coverage was associated with higher acute care usage and respiratory symptoms in preterm infants and children with BPD after initial neonatal intensive care unit (NICU) discharge.

METHODS

Subjects were recruited from BPD clinics at 10 tertiary care centers in the United States between 2018 and 2021. Demographics and clinical characteristics were obtained through chart review. Surveys for clinical outcomes were administered to caregivers.

RESULTS

Of the 470 subjects included in this study, 249 (53.0%) received employer-based insurance coverage and 221 (47.0%) received Medicaid as sole coverage at least once between 0 and 3 years of age. The Medicaid group was twice as likely to have sick visits (adjusted odd ratio [OR]: 2.06; p = 0.009) and emergency department visits (aOR: 2.09; p = 0.028), and three times more likely to be admitted for respiratory reasons (aOR: 3.04; p = 0.001) than those in the employer-based group. Additionally, those in the Medicaid group were more likely to have nighttime respiratory symptoms (aOR: 2.62; p = 0.004).

CONCLUSIONS

Children with BPD who received Medicaid coverage were more likely to utilize acute care and have nighttime respiratory symptoms during the first 3 years of life. More comprehensive studies are needed to determine whether the use of Medicaid represents a barrier to accessing care, lower socioeconomic status, and/or a proxy for detrimental environmental exposures.

The association between pulmonary vascular disease and respiratory improvement in infants with type I severe bronchopulmonary dysplasia

OBJECTIVE

To describe the association between echocardiographic measures of pulmonary vascular disease and time to respiratory improvement among infants with Type I severe bronchopulmonary dysplasia (sBPD).

STUDY DESIGN

We measured the pulmonary artery acceleration time indexed to the right ventricular ejection time (PAAT/RVET) and right ventricular free wall longitudinal strain (RVFWLS) at 34-41 weeks' postmenstrual age. Cox-proportional hazards models were used to estimate the relationship between the PAAT/RVET, RVFWLS, and the outcome: days from 36 weeks' postmenstrual age to room-air or discharge with oxygen (≤0.5 L/min).

RESULT

For 102 infants, the mean PAAT/RVET and RVFWLS were 0.27 ± 0.06 and -22.63 ± 4.23%. An abnormal measurement was associated with an increased time to achieve the outcome (PAAT/RVET: 51v24, p < 0.0001; RVFWLS; 62v38, p = 0.0006). A normal PAAT/RVET was independently associated with a shorter time to outcome (aHR = 2.04, 1.11-3.76, p = 0.02).

CONCLUSION

The PAAT/RVET may aid in anticipating timing of discharge in patients with type I severe BPD.

Identification of Premature Infants at High Risk of Late Respiratory Diseases: A Retrospective Cohort Study

Aim

To identify infants with very low birth weight at risk of late respiratory diseases after discharge.

Methods

This retrospective longitudinal study included 388 preterm infants with gestational age of < 32 weeks and birth weight of < 1,500 g and evaluated perinatal information, assessments performed while in the neonatal intensive care unit, and longitudinal follow-up via questionnaire until the corrected gestational age of 18-24 months.

Results

The mean birth weight and gestational age were 1,191.2 ± 191.8 g and 29.1 ± 1.4 weeks, respectively. Sixty-four (16.5%) infants developed late respiratory diseases after discharge to the corrected gestational age of 18-24 months. Univariate analyses showed that gestational age, birth weight, respiratory support, oxygen use, bronchopulmonary dysplasia diagnosed at 36 weeks' postmenstrual age and length of hospital stay were associated with late respiratory diseases. After adjusting for covariates, respiratory support was significantly associated with serious respiratory morbidities to 18-24 months corrected gestational age. With each day of respiratory support, the odds of late respiratory diseases increased by 1.033-fold.

Conclusion

Respiratory support was associated with increased odds of developing late respiratory diseases during early childhood, which may be an early predictor to late respiratory morbidities. Thus, it is imperative to identify a safe and effective strategy to prevent chronic dependency on respiratory support.

Aberrant newborn T cell and microbiota developmental trajectories predict respiratory compromise during infancy

Neonatal immune-microbiota co-development is poorly understood, yet age-appropriate recognition of - and response to - pathogens and commensal microbiota is critical to health. In this longitudinal study of 148 preterm and 119 full-term infants from birth through one year of age, we found that postmenstrual age or weeks from conception is a central factor influencing T cell and mucosal microbiota development. Numerous features of the T cell and microbiota functional development remain unexplained; however, by either age metric and are instead shaped by discrete perinatal and postnatal events. Most strikingly, we establish that prenatal antibiotics or infection disrupt the normal T cell population developmental trajectory, influencing subsequent respiratory microbial colonization and predicting respiratory morbidity. In this way, early exposures predict the postnatal immune-microbiota axis trajectory, placing infants at later risk for respiratory morbidity in early childhood.

Noninvasive Respiratory Severity Indices Predict Adverse Outcomes in Bronchopulmonary Dysplasia

OBJECTIVE

To test the hypothesis that elevated respiratory severity indices will identify patients with severe bronchopulmonary dysplasia (BPD) at the greatest risk for adverse in-hospital outcomes.

STUDY DESIGN

This was a retrospective cohort study. A modified respiratory severity score (mean airway pressure × fraction of inspired oxygen) and a modified pulmonary score (respiratory support score × fraction of inspired oxygen + sum of medication scores) were calculated in a consecutive cohort of patients ≥36 weeks of postmenstrual age with severe BPD admitted to a referral center between 2010 and 2018. The association between each score and the primary composite outcome of death/prolonged length of stay (>75th percentile for cohort) was assessed using area under the receiver operator characteristic curve (AUROC) analysis and logistic regression. Death and the composite outcome death/tracheostomy were analyzed as secondary outcomes.

RESULTS

In 303 patients, elevated scores were significantly associated with increased adjusted odds of death/prolonged length of stay: aOR 1.5 (95% CI 1.3-1.7) for the modified respiratory severity score and aOR 11.5 (95% CI 5.5-24.1) for the modified pulmonary score. The modified pulmonary score had slightly better discrimination of death/prolonged length of stay when compared with the modified respiratory severity score, AUROC 0.90 (95% CI 0.85-0.94) vs 0.88 (95% CI 0.84-0.93), P = .03. AUROCs for death and death/tracheostomy did not differ significantly when comparing the modified respiratory severity score with the modified pulmonary score.

CONCLUSIONS

In our referral center, the modified respiratory severity score or the modified pulmonary score identified patients with established severe BPD at the greatest risk for death/prolonged length of stay, death, and death/tracheostomy.

Extreme prematurity: Risk and resiliency

Individuals born extremely preterm (before 28 weeks of gestation) comprise only about 0.7% of births in the United States and an even lower proportion in other high resource countries. However, these individuals account for a disproportionate number of children with cerebral palsy, intellectual deficit, autism spectrum disorder, attention deficit hyperactivity disorder, and epilepsy. This review describes two large multiple center cohorts comprised of individuals born extremely preterm: the EPICURE cohort, recruited 1995 in the United Kingdom and the Republic of Ireland, and the Extremely Low Gestational Age Newborn (ELGAN), recruited 2002-2004 in five states in the United States. The primary focus of these studies has been neurodevelopmental disorders, but also of interest are growth, respiratory illness, and parent- and self-reported global health and well-being. Both of these studies indicate that among individuals born extremely preterm the risks of most neurodevelopmental disorders are increased. Early life factors that contribute to this risk include perinatal brain damage, some of which can be identified using neonatal head ultrasound, bronchopulmonary dysplasia, and neonatal systemic inflammation. Prenatal factors, particularly the family's socioeconomic position, also appear to contribute to risk. For most adverse outcomes, the risk is higher in males. Young adults born extremely preterm who have neurodevelopmental impairment, as compared to those without such impairment, rate their quality of life lower. However, young adults born extremely preterm who do not have neurodevelopmental impairments rate their quality of life as being similar to that of young adults born at term. Finally, we summarize the current state of interventions designed to improve the life course of extremely premature infants, with particular focus on efforts to prevent premature birth and on postnatal efforts to prevent adverse neurodevelopmental outcomes.

Antenatal mesenchymal stromal cell extracellular vesicle treatment preserves lung development in a model of bronchopulmonary dysplasia due to chorioamnionitis

Antenatal stressors such as chorioamnionitis (CA) increase the risk for bronchopulmonary dysplasia (BPD). Studies have shown that experimental BPD can be ameliorated by postnatal treatment with mesenchymal stromal cell-derived extracellular vesicles (MEx). However, the antenatal efficacy of MEx to prevent BPD is unknown. To determine whether antenatal MEx therapy attenuates intrauterine inflammation and preserves lung growth in a rat model of CA-induced BPD. At embryonic day (E)20, rat litters were treated with intra-amniotic injections of saline, endotoxin (ETX) to model chorioamnionitis, MEx, or ETX plus MEx followed by cesarean section delivery with placental harvest at E22. Placental and lung evaluations were conducted at day 0 and day 14, respectively. To assess the effects of ETX and MEx on lung growth in vitro, E15 lung explants were imaged for distal branching. Placental tissues from ETX-exposed pregnancies showed increased expression of inflammatory markers NLRP-3 and IL-1ß and altered spiral artery morphology. In addition, infant rats exposed to intrauterine ETX had reduced alveolarization and pulmonary vessel density (PVD), increased right ventricular hypertrophy (RVH), and decreased lung mechanics. Intrauterine MEx therapy of ETX-exposed pups reduced inflammatory cytokines, normalized spiral artery architecture, and preserved distal lung growth and mechanics. In vitro studies showed that MEx treatment enhanced distal lung branching and increased VEGF and SPC gene expression. Antenatal MEx treatment preserved distal lung growth and reduced intrauterine inflammation in a model of CA-induced BPD. We speculate that MEx may provide a novel therapeutic strategy to prevent BPD due to antenatal inflammation.

Pulmonary function tests in extremely low gestational age infants at one year of age

RATIONALE

Identifying neonatal and post-discharge exposures among extremely low gestational age newborns (ELGANs) that drive increased pulmonary morbidity and abnormal lung function at 1 year of age proves challenging.

OBJECTIVE

The NIH-sponsored Prematurity and Respiratory Outcomes Program (PROP), evaluated infant pulmonary function tests (iPFTs) at 1 year corrected age to determine which demographic and clinical factors are associated with abnormal lung function.

METHODS

iPFTs were performed on a PROP subcohort of 135 participants following Institutional Review Board (IRB)-approved written consent. Demographic data, Neonatal Intensive Care Unit (NICU) clinical care, and post-NICU exposures were analyzed for association with iPFTs.

MAIN RESULTS

A significant decrease in forced expiratory volume at 0.5 s (FEV_0.5 ) and/or forced expiratory flows at 75% of forced vital capacity (FEF₇₅ ), were associated with male sex and African American race. Clinical factors including longer duration of ventilatory support, exposure to systemic steroids, and weight less than the 10th percentile at 36 weeks postmenstrual age were also associated with airflow obstruction, whereas supplemental oxygen requirement and bronchopulmonary dysplasia were not. Additionally, the need for respiratory medications, technology, or hospitalizations during the first year, ascertained by a quarterly survey, were the only post-NICU factors associated with decreased FEV_0.5 and FEF₇₅ . Only 7% of infants had reversible airflow obstruction.

CONCLUSIONS

Neonatal demographic factors, respiratory support in the NICU, and a history of greater post-NICU medical utilization for respiratory disease had the strongest association with lower lung function at 1 year in ELGANs.

Extracallosal Structural Connectivity Is Positively Associated With Language Performance in Well-Performing Children Born Extremely Preterm

Children born extremely preterm (<28 weeks gestation) are at risk for language delay or disorders. Decreased structural connectivity in preterm children has been associated with poor language outcome. Previously, we used multimodal imaging techniques to demonstrate that increased functional connectivity during a stories listening task was positively associated with language scores for preterm children. This functional connectivity was supported by extracallosal structural hyperconnectivity when compared to term-born children. Here, we attempt to validate this finding in a distinct cohort of well-performing extremely preterm children (EPT, n = 16) vs. term comparisons (TC, n = 28) and also compare this to structural connectivity in a group of extremely preterm children with a history of language delay or disorder (EPT-HLD, n = 8). All participants are 4-6 years of age. We perform q-space diffeomorphic reconstruction and functionally-constrained structural connectometry (based on fMRI activation), including a novel extension enabling between-groups comparisons with non-parametric ANOVA. There were no significant differences between groups in age, sex, race, ethnicity, parental education, family income, or language scores. For EPT, tracks positively associated with language scores included the bilateral posterior inferior fronto-occipital fasciculi and bilateral cerebellar peduncles and additional cerebellar white matter. Quantitative anisotropy in these pathways accounted for 55% of the variance in standardized language scores for the EPT group specifically. Future work will expand this cohort and follow longitudinally to investigate the impact of environmental factors on developing language networks and resiliency in the preterm brain.

Effects of postnatal hydrocortisone on cytokine profile in extremely preterm infants

BACKGROUND

Systemic hydrocortisone administration has been widely used in preterm infants who are at risk of bronchopulmonary dysplasia (BPD). However, the effects of hydrocortisone on cytokine profiles have not been examined. We aimed to investigate the effects of postnatal hydrocortisone treatment on serum cytokine levels in extremely preterm infants.

METHODS

This is a retrospective study of 29 extremely preterm infants born at <28 weeks of gestational age. We obtained serum from blood samples collected during an early phase (5-20 days) and a late phase (28-60 days) after birth. We measured the levels of proinflammatory cytokines (tumor necrosis factors α and β, interleukin (IL)-1β, and IL-6), T-helper (Th) 1 cytokines (interferon-γ, IL-2, and IL-12p70), Th2 cytokines (IL-4, IL-5, and IL-10), Th17 cytokine IL-17A, and chemokine IL-8. The cytokine levels between the early and late phases were compared between infants who received postnatal hydrocortisone and those who did not.

RESULTS

Thirteen infants (45%) received systemic hydrocortisone treatment at a median age of 15 days (IQR: 10.0-21.5) after birth due to respiratory deterioration. The percentage of BPD was higher in the steroid group than in the non-steroid group (P = 0.008). The ratio of IL-6 for the late-to-early phase was significantly lower in the steroid group than in the non-steroid group (P = 0.04). The concentration of the other cytokines remained unchanged between the phases.

CONCLUSIONS

Although the postnatal hydrocortisone treatment provided for respiratory deterioration did not prevent the BPD development, hydrocortisone treatment might suppress IL-6 overproduction in extremely preterm infants.

Outpatient Respiratory Management of Infants, Children, and Adolescents with Post-Prematurity Respiratory Disease: An Official American Thoracic Society Clinical Practice Guideline

Background: Premature birth affects millions of neonates each year, placing them at risk for respiratory disease due to prematurity. Bronchopulmonary dysplasia is the most common chronic lung disease of infancy, but recent data suggest that even premature infants who do not meet the strict definition of bronchopulmonary dysplasia can develop adverse pulmonary outcomes later in life. This post-prematurity respiratory disease (PPRD) manifests as chronic respiratory symptoms, including cough, recurrent wheezing, exercise limitation, and reduced pulmonary function. This document provides an evidence-based clinical practice guideline on the outpatient management of infants, children, and adolescents with PPRD. Methods: A multidisciplinary panel of experts posed questions regarding the outpatient management of PPRD. We conducted a systematic review of the relevant literature. The Grading of Recommendations, Assessment, Development, and Evaluation approach was used to rate the quality of evidence and the strength of the clinical recommendations. Results: The panel members considered the strength of each recommendation and evaluated the benefits and risks of applying the intervention. In formulating the recommendations, the panel considered patient and caregiver values, the cost of care, and feasibility. Recommendations were developed for or against three common medical therapies and four diagnostic evaluations in the context of the outpatient management of PPRD. Conclusions: The panel developed recommendations for the outpatient management of patients with PPRD on the basis of limited evidence and expert opinion. Important areas for future research were identified.

Patho-mechanisms of the origins of bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) continues to be one of the most common complications of prematurity, despite significant advancement in neonatology over the last couple of decades. The new BPD is characterized histopathologically by impaired lung alveolarization and dysregulated vascularization. With the increased survival of extremely preterm infants, the risk for the development of BPD remains high, emphasizing the continued need to understand the patho-mechanisms that play a role in the development of this disease. This brief review summarizes recent advances in our understanding of the maldevelopment of the premature lung, highlighting recent research in pathways of oxidative stress-related lung injury, the role of placental insufficiency, growth factor signaling, the extracellular matrix, and microRNAs.

Differences in clinical and laboratory biomarkers for short and long-term respiratory outcomes in preterm neonates

BACKGROUND

Pulmonary outcome of premature neonates has focused more on short-term than long-term respiratory morbidities.

OBJECTIVE

Describe risk factors/biomarkers associated with short-term (bronchopulmonary dysplasia [BPD]) (supplemental oxygen use at 36 weeks postmenstrual age [PMA]) and longer-term (chronic respiratory morbidity [CRM]) (respiratory related symptoms, medications, medical/emergency visits, hospitalizations at 6-12 months corrected gestational age [CGA]) respiratory outcomes in a longitudinal cohort.

DESIGN/METHODS

Neonates born at 24-29-week gestation were prospectively followed to 6-12-month CGA. Associations between clinical and laboratory risk factors/biomarkers of BPD and CRM were explored.

RESULTS

Of 86 subjects, 94% survived. Outcomes were available for 89% at 36-week PMA (BPD present in 42% of infants) and 72% at 6-12-month CGA (CRM present in 47% of infants). For the 54 infants with known outcomes for both BPD and CRM, diagnoses were discordant in 41%. BPD was associated with lower birthweight and birthweight Z-score for GA, lower Apgar scores, more surfactant doses, higher SNAPPE-II scores, highest Day 1 inspired oxygen concentration, Day 7 oxygen use, prolonged ventilatory support, bacteremia, necrotizing enterocolitis, and treated patent ductus arteriosus. CRM was associated with lower Apgar scores, Day 7 oxygen use and higher urine vascular endothelial growth factor. Patterns of plasma and urine lipid oxidation products differed in the two outcomes.

CONCLUSION

In this hypothesis generating and exploratory study, BPD and CRM were associated with different risk factors/biomarker patterns. Concordance between these two outcomes was weak. Strategies for reducing CRM should be studied in cohorts identified by appropriate early risk factors/biomarkers.

Effect of human milk and other neonatal variables on lung function at three months corrected age

OBJECTIVE

To evaluate the impact of human milk and different neonatal variables on tidal breathing flow-volume loop (TBFVL) parameters within three months' corrected age (CA) in infants born ≤32 wks or weighing <1500 g.

METHODS

We retrospectively studied 121 infants with gestational age (GA) ≤ 32 weeks or birth weight (BW) <1500 gr who had lung function assessment within three months' CA by TBFVL analysis between June 2009 and April 2018. We investigated the impact of GA, gender, being Small for GA (SGA), sepsis, days of mechanical ventilation (MV) and human milk feeding (HMF) on later respiratory function, both in the entire group and according to BW ( ≤1000 g and >1000 g).

RESULTS

The mean(SD) z-score for tidal volume (Vt) and time to peak expiratory flow to expiratory time (tPTEF/tE) were respectively -4.3 (2.5) and -0.8 (2.0) for the overall population with no significant differences between infants <1000 g or ≥1000 g. The mean(SD) Vt standardized for body weight was 6.2(2.0) ml/kg. Being female was associated with better Vt/Kg, whereas longer MV or being born SGA were associated with worst tPTEF/tE. For infants with BW < 1000 gr, tPTEF/tE was positively associated with HMF.

CONCLUSION

An early TBFVL assessment within three months' CA already reveals lung function alteration in preterm infants. Being female is associated with better Vt/Kg, while longer duration of MV or being born SGA negatively affect tPTEF/tE. The positive association between HMF and better tPTEF/tE in infants with BW <1000 g has emerged, which deserves further investigation.