Prevention of Bronchopulmonary Dysplasia: A Summary of Evidence-Based Strategies

Identification of serum metabolite biomarkers in premature infants with bronchopulmonary dysplasia: protocol for a multicentre prospective observational cohort study

INTRODUCTION

Bronchopulmonary dysplasia (BPD) is one of the most common and significant complications of preterm birth. It ultimately leads to a decrease in the quality of life for preterm infants and impacts their long-term health. Early prediction and timely intervention are crucial to halting the development of BPD. This study aims to identify the biomarkers that can predict the early occurrence and development of BPD by screening serum metabolites in preterm infants. This will provide strong support for the early prediction of BPD and targeted interventions in future research.

METHODS AND ANALYSIS

This is a prospective, multicentre, open-label, observational cohort study spanning 3 years. It will be conducted in six major neonatal intensive care units in Shenzhen, China, involving preterm infants born at gestational ages <32 weeks. Demographic data and treatment information will be collected prospectively. Serum samples will be collected at five distinct time points: within 24 hours after birth, at 1 week, 2 weeks, 28 days and at 36 weeks postmenstrual age. These samples will undergo analysis using liquid chromatography-tandem mass spectrometry for untargeted metabolomics studies. Participants will be categorised into BPD and non-BPD groups based on their final diagnosis, and metabolite differences between these groups will be analysed. The study aims to enrol 1500 preterm infants with gestational ages <32 weeks over 3 years. A three-step analysis strategy-discovery, validation and clinical testing-will be used to identify and validate the clinical utility of novel biomarkers. Additionally, a nested case-control study will be conducted, matching participants 1:1 with a control group sharing similar BPD risk factors.

ETHICS AND DISSEMINATION

Our protocol has been approved by the Medical Ethics Committees of all participating hospitals, including Peking University Shenzhen Hospital, Shenzhen People's Hospital, Shenzhen Baoan Women's and Children's Hospital, Longgang District Maternity and Child Healthcare Hospital, Nanshan Maternity and Child Healthcare Hospital and Shenzhen Luohu People's Hospital. We will disseminate our study results through academic conferences and peer-reviewed public journals.

TRIAL REGISTRATION NUMBER

ChiCTR2400081615.

Early postnatal corticosteroids in preventing mortality and bronchopulmonary dysplasia: the pivotal importance of selecting an appropriate treated population

This study explores the efficacy of early systematic postnatal corticosteroids (PCS) in reducing bronchopulmonary dysplasia (BPD) and mortality among preterm infants, focusing on identifying the populations most likely to benefit. Although PCS has been extensively studied for its anti-inflammatory effects in preventing BPD, the ideal target population remains unclear. This meta-analysis included 26 randomized controlled trials (RCTs) focusing exclusively on systemic intravenous PCS. Studies were stratified by baseline BPD or mortality rates in control groups (< 50%, 50-65%, and > 65%). Results indicated that PCS effectiveness in reducing BPD or mortality was significantly associated with baseline risk, with rate differences (RD) for BPD or mortality of - 0.03 (95% CI - 0.08, 0.01) in lower-risk groups (< 50%), - 0.07 (95% CI - 0.12, - 0.01) in moderate-risk groups (50-65%), and - 0.18 (95% CI - 0.32, - 0.04) in high-risk groups (> 65%). Linear logistic analysis demonstrated a significant trend, with higher baseline event rates in control groups associated with a more substantial RD (RD ~ rates in controls, R2 = 0.228, p = 0.014). Both dexamethasone and hydrocortisone showed similar trends.

CONCLUSION

These findings underscore that the baseline event rates in the control group are potentially correlated with the efficacy of PCS in preventing BPD or mortality, offering more precise guidance beyond the general "high-risk" category and supporting baseline risk stratification for more targeted PCS therapy in clinical practice.

WHAT IS KNOWN

• Early postnatal corticosteroids (PCS) have been widely studied for their anti-inflammatory effects in preventing bronchopulmonary dysplasia (BPD) in preterm infants. • Determining the optimal target population for PCS remains challenging due to varying baseline risks and associated neurodevelopmental concerns.

WHAT IS NEW

• Stratifying infants by baseline BPD or mortality rates reveals that PCS shows greater efficacy in high-risk groups, particularly those with baseline event rates above 50%. • Considering baseline risk stratification represents a key direction for future clinical decision-making.

Estimating the effect of diuretics and inhaled corticosteroids for evolving bronchopulmonary dysplasia in preterm infants

BACKGROUND

Off-label treatment of extremely preterm infants with diuretics and inhaled corticosteroids (ICS) for evolving bronchopulmonary dysplasia (BPD) is common. Their effectiveness in reducing mortality or BPD severity, and optimal treatment timing, are unclear.

OBJECTIVES

To determine whether diuretic treatment or ICS administration for infants with early evolving (between 10-27 days postnatal) and progressively evolving (28th-day-36th-week postnatal) BPD are independently associated with reduced mortality and moderate or severe BPD at 36-weeks postmenstrual age (PMA).

METHODS

We examined neonates born before 28 weeks' gestation and admitted to neonatal intensive care units on postnatal Day 0 between 2006 and 2016 using data collected during routine care recorded within the Paediatric Health Information System (PHIS). An early evolving BPD cohort consisted of infants treated with oxygen, positive pressure or mechanical ventilation at 10 days postnatal. The progressively evolving BPD cohort consisted of infants treated with these modalities at 28 days. In new users, we evaluated the effect of diuretic and ICS treatment on mortality or BPD severity at 36 weeks PMA, adjusting for time-dependent confounding by respiratory status using marginal structural models.

RESULTS

Early evolving BPD was present in 10,135 patients; progressively evolving BPD in 11,728. New diuretic exposure during early evolving BPD (adjusted risk ratio [aRR] 0.77, 95% confidence interval [CI] 0.65, 0.93) was associated with decreased mortality or moderate/severe BPD risk. New diuretics (aRR 0.86, 95% CI 0.75, 0.99) during progressively evolving BPD between 28-days-36-weeks PMA were less strongly associated with mortality or moderate/severe BPD reduction. There was no strong association for ICS in patients with early evolving (aRR: 1.40; 95% CI: 0.79, 2.51) or progressively evolving BPD (aRR 1.16, 95% CI 0.95, 1.49).

CONCLUSION

Diuretics, but not ICS, for evolving BPD were associated with mortality and BPD risk reduction.

Managing established bronchopulmonary dysplasia without using routine blood gas measurements

OBJECTIVE

Routine blood gas measurements are common in infants with severe bronchopulmonary dysplasia (sBPD) and are a noxious stimulus. We developed a guideline-driven approach to evaluate the care of infants with sBPD without routine blood gas sampling in the chronic phase of NICU care (after diagnosis at 36 weeks PMA).

STUDY DESIGN

We examined blood gas utilization and outcomes in our sBPD inpatient care unit using data collected between 2014 and 2020.

RESULTS

485 sBPD infants met inclusion criteria, and 303 (62%) never had a blood gas obtained after 36 weeks PMA. In infants who had blood gas measurements, the median number of total blood gases per patient was only 4 (IQR 1-10). We did not identify adverse effects on hospital outcomes in patients without routine blood gas measurements.

CONCLUSIONS

We found that patients with established BPD could be managed without routine blood gas analyses after 36 weeks PMA.

Changes in ventilation modes in the last decade and their impact on the prevalence of bronchopulmonary dysplasia in preterm infants

BACKGROUND

Less invasive forms of ventilation have evolved aiming to decrease bronchopulmonary dysplasia (BPD) morbidity. It is unclear whether changes in ventilation practices have been associated with improvements in respiratory outcomes.

OBJECTIVE

To examine the changes in ventilation modes in preterm neonates between two periods during the last decade and their impact on BPD prevalence.

METHODS

A retrospective chart review of very low birth weight infants and those born at less than 32 weeks gestation hospitalized during two periods: the years 2012-2013 and 2018-2019. The primary outcome was the prevalence of BPD. Study variables included the mode and duration of ventilation, duration of oxygen need, and perinatal clinical parameters.

RESULTS

Four hundred eighty-one infants were enrolled. Between the two study periods, a significant increase was observed in invasive (33%-47%, p = 0.002), and noninvasive ventilation rates (44%-72%, p < 0.001). The average duration of noninvasive ventilation increased significantly (from 9.24 to 14.08 days, p = 0.016). The total duration of respiratory support remained unchanged. The overall prevalence of moderate and severe BPD at 36 weeks corrected age remained approximately 40% in preterm infants born at less than 28 weeks gestation.

CONCLUSION

The increasing use of non-invasive ventilation was not accompanied by a reduction in the use of invasive ventilation, nor by a reduced prevalence of BPD. The high prevalence of BPD remains a significant problem in extreme prematurity. Other interventions, in addition to less aggressive ventilation, need to be explored.

The association between BMI trajectories and bronchopulmonary dysplasia among very preterm infants

OBJECTIVE

To investigate the association between change in body mass index (BMI) from birth to 36 weeks gestation (ΔBMI) and bronchopulmonary dysplasia (BPD) among infants born <30 weeks gestation.

METHODS

This was a multicenter retrospective cohort study (2015-2018) of infants born <30 weeks gestation and alive at ≥34 weeks corrected. Main exposure was a change in BMI z score from birth to 36 weeks corrected age grouped into quartiles of change. Association between ΔBMI z scores and BPD was assessed using generalized linear mixed models.

RESULTS

Among 772 included infants, 51% developed BPD. From birth to 36 weeks CGA, the weight z score of infants with BPD decreased less than for BPD-free infants, despite a greater decrease in length z score and similar caloric intake resulting in increases in BMI z score (median [IQR], 0.16 [-0.64; 1.03] vs -0.29 [-1.03; 0.49]; P < 0.01). In the adjusted analysis, higher ΔBMI z score quartiles were associated with higher odds of BPD (Q3 vs Q2, AOR [95% CI], 2.02 [1.23; 3.31] and Q4 vs Q2, AOR [95% CI], 2.00 [1.20; 3.34]).

CONCLUSION

Among preterm infants, an increase in BMI z score from birth to 36 weeks corrected is associated with higher odds of BPD.

IMPACT

Preterm infants with evolving lung disease often experience disproportionate growth in the neonatal period. In this multicenter cohort study, increases in BMI z score from birth to 36 weeks CGA were associated with higher odds of BPD. Despite similar caloric intake, infants with BPD had a higher weight- but lower length-for-age, resulting in higher BMI z score compared to BPD-free infants. This suggests that infants with evolving BPD may require different growth and nutritional targets compared to BPD-free infants.

Role of endoplasmic reticulum stress in impaired neonatal lung growth and bronchopulmonary dysplasia

Myeloperoxidase (MPO), oxidative stress (OS), and endoplasmic reticulum (ER) stress are increased in the lungs of rat pups raised in hyperoxia, an established model of bronchopulmonary dysplasia (BPD). However, the relationship between OS, MPO, and ER stress has not been examined in hyperoxia rat pups. We treated Sprague-Dawley rat pups with tunicamycin or hyperoxia to determine this relationship. ER stress was detected using immunofluorescence, transcriptomic, proteomic, and electron microscopic analyses. Immunofluorescence observed increased ER stress in the lungs of hyperoxic rat BPD and human BPD. Proteomic and morphometric studies showed that tunicamycin directly increased ER stress of rat lungs and decreased lung complexity with a BPD phenotype. Previously, we showed that hyperoxia initiates a cycle of destruction that we hypothesized starts from increasing OS through MPO accumulation and then increases ER stress to cause BPD. To inhibit ER stress, we used tauroursodeoxycholic acid (TUDCA), a molecular chaperone. To break the cycle of destruction and reduce OS and MPO, we used N-acetyl-lysyltyrosylcysteine amide (KYC). The fact that TUDCA improved lung complexity in tunicamycin- and hyperoxia-treated rat pups supports the idea that ER stress plays a causal role in BPD. Additional support comes from data showing TUDCA decreased lung myeloid cells and MPO levels in the lungs of tunicamycin- and hyperoxia-treated rat pups. These data link OS and MPO to ER stress in the mechanisms mediating BPD. KYC's inhibition of ER stress in the tunicamycin-treated rat pup's lung provides additional support for the idea that MPO-induced ER stress plays a causal role in the BPD phenotype. ER stress appears to expand our proposed cycle of destruction. Our results suggest ER stress evolves from OS and MPO to increase neonatal lung injury and impair growth and development. The encouraging effect of TUDCA indicates that this compound has the potential for treating BPD.

Implementation of neurally adjusted ventilatory assist and high flow nasal cannula in very preterm infants in a tertiary level NICU

Preterm infants treated with invasive ventilation are often affected by bronchopulmonary dysplasia, brain structure alterations, and later neurodevelopmental impairment. We studied the implementation of neurally adjusted ventilatory assist (NAVA) and high flow nasal cannula (HFNC) in a level III neonatal unit, and its effects on pulmonary and central nervous system outcomes. This retrospective cohort study included 193 surviving infants born below 32 weeks of gestation in preimplementation (2007-2008) and postimplementation (2016-2017) periods in a single study center in Finland. The proportion of infants requiring invasive ventilation decreased from 67% in the pre- to 48% in the postimplementation period (p = 0.009). Among infants treated with invasive ventilation, 68% were treated with NAVA after its implementation. At the same time, the duration of invasive ventilation of infants born at or below 28 weeks increased threefold compared with the preimplementation period (p = 0.042). The postimplementation period was characterized by a gradual replacement of nasal continuous positive airway pressure (nCPAP) with HFNC, earlier discontinuation of nCPAP, but a longer duration of positive pressure support. The proportion of normal magnetic resonance imaging (MRI) findings at term corrected age increased from 62% to 84% (p = 0.018). Cognitive outcome improved by one standard score between the study periods (p = 0.019). NAVA was used as the primary mode of ventilation in the postimplementation period. During this period, invasive ventilation time was significantly prolonged. HFNC led to a decrease in the use of nCPAP. The change in the respiratory support might have contributed to the improvement in brain MRI findings and cognitive outcomes.

Pharmacotherapy in Bronchopulmonary Dysplasia: What Is the Evidence?

Bronchopulmonary Dysplasia (BPD) is a multifactorial disease affecting over 35% of extremely preterm infants born each year. Despite the advances made in understanding the pathogenesis of this disease over the last five decades, BPD remains one of the major causes of morbidity and mortality in this population, and the incidence of the disease increases with decreasing gestational age. As inflammation is one of the key drivers in the pathogenesis, it has been targeted by majority of pharmacological and non-pharmacological methods to prevent BPD. Most extremely premature infants receive a myriad of medications during their stay in the neonatal intensive care unit in an effort to prevent or manage BPD, with corticosteroids, caffeine, and diuretics being the most commonly used medications. However, there is no consensus regarding their use and benefits in this population. This review summarizes the available literature regarding these medications and aims to provide neonatologists and neonatal providers with evidence-based recommendations.

An Update on the Prevention and Management of Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is a common morbidity affecting preterm infants and is associated with substantial long-term disabilities. There has been no change in the incidence of BPD over the past 20 years, despite improvements in survival and other outcomes. The preterm lung is vulnerable to injuries occurring as a result of invasive ventilation, hyperoxia, and infections that contribute to the development of BPD. Clinicians caring for infants in the neonatal intensive care unit use multiple therapies for the prevention and management of BPD. Non-invasive ventilation strategies and surfactant administration via thin catheters are treatment approaches that aim to avoid volutrauma and barotrauma to the preterm developing lung. Identifying high-risk infants to receive postnatal corticosteroids and undergo patent ductus arteriosus closure may help to individualize care and promote improved lung outcomes. In infants with established BPD, outpatient management is complex and requires coordination from several specialists and therapists. However, most current therapies used to prevent and manage BPD lack solid evidence to support their effectiveness. Further research is needed with appropriately defined outcomes to develop effective therapies and impact the incidence of BPD.

A systematic review of reports of quality improvement for bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is the most common morbidity of preterm infants, and its incidence has not responded to research and intervention efforts to the same degree as other major morbidities associated with prematurity. The complexity of neonatal respiratory care as well as persistent inter-institutional variability in BPD rates suggest that BPD may be amenable to quality improvement (QI) efforts. We present a systematic review of QI for BPD in preterm infants. We identified 22 reports from single centers and seven from collaborative efforts published over the past two decades. In almost all of the reports, respiratory QI interventions successfully reduced BPD or other key respiratory measures, particularly for infants with birth weight over 1000 g. Several themes and lessons from existing reports may help inform future efforts in both research and QI to impact the burden of BPD.

Effect of Bias Gas Flow on Tracheal Cytokine Concentrations in Ventilated Extremely Preterm Infants: A Randomized Controlled Trial

BACKGROUND

The objective of this study was to determine whether ventilator bias gas flow affects tracheal aspirate (TA) cytokine concentrations in ventilated extremely preterm infants.

METHODS

This is a randomized controlled trial in a tertiary neonatal unit in New Zealand. Preterm infants (<28 weeks' gestation/<1,000 g) requiring intubation in the first 7 days after birth were randomized to bias gas flows of 4 or 10 L/min. Cytokine concentrations in TA and plasma were measured at 24, 72, and 120 h after the onset of ventilation. The primary outcome measure was concentration of interleukin (IL)-8 in TA 24 h after the onset of mechanical ventilation.

RESULTS

Baseline demographics were similar in babies randomized to 4 (n = 50) and 10 (n = 45) L/min bias gas flow. TA IL-8 concentrations were not different between groups. Plasma IL-8 concentrations decreased over time (p < 0.05). Respiratory support and incidence of bronchopulmonary dysplasia at 36 weeks' corrected gestational age were similar between groups. Fewer babies ventilated at 4 L/min developed necrotizing enterocolitis (NEC) ≥ stage 2 (n = 0 vs. n = 5; p = 0.02) and fewer died (n = 1 vs. n = 5, p = 0.06).

CONCLUSIONS

Lower bias gas flow in ventilated extremely preterm infants did not alter TA cytokine concentrations but the lower incidence of NEC and mortality warrants further investigation.

Bronchopulmonary Dysplasia: Then, Now, and Next

Bronchopulmonary dysplasia (BPD) has evolved considerably since its first description over 50 years ago. This review aims to provide a historical framework for conceptualizing BPD and a current understanding of the changing definition, epidemiology, pathophysiology, treatment, and outcomes of BPD. The transdisciplinary approach that led to the initial phenotypic description of BPD continues to hold promise today. Investigators are refining the definition of BPD in light of changes in clinical care and increasing survival rates of very preterm infants. Despite improvements in perinatal care the incidence of BPD continues to increase. There is growing recognition that antenatal risk factors play a key role in the development of BPD. Strategies designed to prevent or limit neonatal lung injury continue to evolve. Defining the phenotype of infants with BPD can meaningfully direct treatment. Infants with BPD benefit from an interdisciplinary approach to longitudinal care with a focus on growth and neurocognitive development. While the ultimate impact of BPD on long-term pulmonary morbidity remains an active area of investigation, current data indicate that most children and adolescents with a history of BPD have a quality of life comparable to that of other preterm infants.

Hospitalization costs associated with bronchopulmonary dysplasia in the first year of life

OBJECTIVE

To determine costs of hospitalization associated with bronchopulmonary dysplasia (BPD) during the first year in very low birth weight infants.

STUDY DESIGN

Retrospective cohort study of California births from 2008 to 2011 linking birth certificate, discharge records, and clinical data from California Perinatal Quality Care Collaborative. Inclusion: birth weight 401-1500 g, gestational age < 30 weeks, inborn or transferred within 2 days, alive at 36 weeks corrected, and without major congenital anomalies. Outcomes included cost and length of stay of initial hospitalization and rehospitalizations.

RESULT

Out of 7998 eligible infants, 2696 (33.7%) developed BPD. Median hospitalization cost in the first year was $377,871 per infant with BPD compared with $175,836 per infant without BPD (adjusted cost ratio 1.54, 95% confidence interval (CI) 1.49-1.59). Infants with BPD also had longer length of stay and a higher likelihood of rehospitalization.

CONCLUSION

BPD is associated with substantial resource utilization. Prevention strategies could help conserve healthcare resources.