Severity of Bronchopulmonary Dysplasia Among Very Preterm Infants in the United States

Hyperoxia exposure induces ferroptosis and apoptosis by downregulating PLAGL2 and repressing HIF-1α/VEGF signaling pathway in newborn alveolar typeII epithelial cell

BACKGROUD

Bronchopulmonary dysplasia (BPD) is one of the most important complications plaguing neonates and can lead to a variety of sequelae. the ability of the HIF-1α/VEGF signaling pathway to promote angiogenesis has an important role in neonatal lung development.

METHOD

Newborn rats were exposed to 85% oxygen. The effects of hyperoxia exposure on Pleomorphic Adenoma Gene like-2 (PLAGL2) and the HIF-1α/VEGF pathway in rats lung tissue were assessed through immunofluorescence and Western Blot analysis. In cell experiments, PLAGL2 was upregulated, and the effects of hyperoxia and PLAGL2 on cell viability were evaluated using scratch assays, CCK-8 assays, and EDU staining. The role of upregulated PLAGL2 in the HIF-1α/VEGF pathway was determined by Western Blot and RT-PCR. Apoptosis and ferroptosis effects were determined through flow cytometry and viability assays.

RESULTS

Compared with the control group, the expression levels of PLAGL2, HIF-1α, VEGF, and SPC in lung tissues after 3, 7, and 14 days of hyperoxia exposure were all decreased. Furthermore, hyperoxia also inhibited the proliferation and motility of type II alveolar epithelial cells (AECII) and induced apoptosis in AECII. Upregulation of PLAGL2 restored the proliferation and motility of AECII and suppressed cell apoptosis and ferroptosis, while the HIF-1α/VEGF signaling pathway was also revived.

CONCLUSIONS

We confirmed the positive role of PLAGL2 and HIF-1α/VEGF signaling pathway in promoting BPD in hyperoxia conditions, and provided a promising therapeutic targets.

Transcatheter and Surgical Ductus Arteriosus Closure in Very Low Birth Weight Infants: 2018-2022

BACKGROUND AND OBJECTIVE

The optimal patent ductus arteriosus (PDA) closure method in very low birth weight (VLBW) infants is uncertain. In 2019, the first transcatheter occlusion device was approved in the United States for infants ≥700 g. We described survival and short-term outcomes among VLBW infants who underwent transcatheter or surgical PDA closure (2018-2022).

METHODS

Vermont Oxford Network members submitted data on infants born from 401 to 1500 g or 22 to 29 weeks' gestational age. Adjusted risk ratios (aRR) for survival, length of stay (LOS), prematurity complications, and discharge support were used to compare transcatheter versus surgical closure. Subgroup analyses were conducted for infants with birth weight ≥700 g and born in 2020-2022.

RESULTS

Overall, 6410 of 216 267 infants at 726 hospitals received invasive PDA treatment. Transcatheter closure increased from 29.8% in 2018 to 71.7% in 2022. VLBW infants undergoing transcatheter closure had higher survival (adjusted rate ratio [aRR] 1.03; 1.02-1.04) with similar LOS (aRR 1.00; 0.97-1.03), neonatal complications (aRR 1.00; 0.98-1.01), and receipt of discharge support (aRR 0.94; 0.89-1.01). In subgroup analyses, survival (aRR 1.02; 1.00-1.04) and discharge support (aRR 0.90; 0.81-1.01) were similar between groups, whereas selected neonatal complications (aRR 0.95; 0.93-0.98) and LOS (aRR 0.95; 0.90-0.99) were lower after transcatheter closure.

CONCLUSIONS

Transcatheter PDA closure in VLBW infants was increasingly used after 2018. Selected short-term outcomes for infants receiving transcatheter closure may be more favorable, compared with surgical, and warrants further clinical investigation.

Surfactant treatment at birth in a contemporary cohort of preterm infants with bronchopulmonary dysplasia

OBJECTIVE

Initial surfactant studies demonstrated improvements in survival and need for respiratory support. However, as the use of non-invasive respiratory support has increased the use of surfactant has decreased. We examined in a contemporary cohort of BPD patients if surfactant use was associated with BPD severity.

STUDY DESIGN

An observational study using data from the BPD Collaborative Registry.

RESULTS

971 infants with BPD met entry criteria, 864 (89%) had received surfactant in the first 72 h of life (SURF) and the remainder had not (no surfactant). There was an association between SURF and BPD grade, with a greater likelihood of grade 3 BPD in infants who received surfactant in the DR or who had 2 or more doses.

CONCLUSIONS

We speculate that the use of surfactant in the DR and use of multiple doses reflect the impact of perinatal factors beyond immaturity alone that increase the risk for grade 3 BPD.

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.

Early Bubble CPAP Protocol Implementation and Rates of Death or Severe BPD

BACKGROUND

A multidisciplinary comprehensive protocol to use bubble continuous positive airway pressure (bCPAP) as the primary respiratory support in the delivery room (DR) and the NICU was introduced. With this study, we aimed to assess the association of this change with respiratory outcomes over time.

METHODS

Infants with gestational age <32 weeks and birth weight <1250 g admitted between January 2012 and June 2020 were included and categorized into 4 periods, including pre-implementation (P0: 2012-2014), and post-implementation (P1: 2014-2016, P2: 2016-2018, P3: 2018-2020). The primary outcome was the rates of death and severe bronchopulmonary dysplasia (BPD), and the secondary outcomes included the rates of DR and NICU intubation ≤7 days of age, need of surfactant, and pneumothorax. Multivariate logistic regression models accounting for relevant risk factors were used to calculate adjusted odds ratios (ORs).

RESULTS

The study included 440 infants (P0 = 90, P1 = 91, P2 = 128, P3 = 131). Over time, more infants were free of BPD (P < .001), and the rates of death and severe BPD decreased significantly: P1 = OR 1.21 (95% confidence interval [CI] 0.56-2.67), P2 = OR 0.45 (95% CI 0.20-0.99), and P3 = OR 0.37 (95% CI 0.15-0.84). DR intubation decreased from 66% (P0) to 24% (P3) in the entire cohort (P < .001) and from 96% (P0) to 40% (P3) in infants <26 weeks of age (P < .001). The need for NICU intubation was similar (P = .98), with a decreased need for surfactant (P = .001) occurring at higher FiO2 (P0 = 0.35 vs P3 = 0.55, P < .001). Pneumothorax rates were unchanged.

CONCLUSIONS

In very preterm infants, the implementation of a comprehensive bCPAP protocol led to a significant and consistent improvement in respiratory practices and the rates of death and severe BPD.

Bronchopulmonary Dysplasia-Associated Pulmonary Hypertension: Basing Care on Physiology

Bronchopulmonary dysplasia (BPD) is the heterogeneous chronic lung developmental disease of prematurity, which is often accompanied by multisystem comorbidities. Pulmonary vascular disease and pulmonary hypertension (PH) contribute significantly to the pathogenesis and pathophysiology of BPD and dramatically influence the outcomes of preterm infants with BPD. When caring for those patients, clinicians should consider the multitude of phenotypic presentations that fall under the "BPD-PH umbrella," reflecting the need for matching therapies to specific physiologies to improve short- and long-term outcomes. Individualized management based on the patient's prenatal and postnatal risk factors, clinical course, and cardiopulmonary phenotype needs to be identified and prioritized to provide optimal care for infants with BPD-PH.

Nissen Fundoplication in Infants With Severe Bronchopulmonary Dysplasia: A Propensity-Matched Analysis

INTRODUCTION

Bronchopulmonary dysplasia (BPD) is a common respiratory morbidity among premature infants. Nissen fundoplication may be performed on infants with BPD to protect the lungs from gastroesophageal reflux-related aspiration, but the indications and benefits associated with fundoplication are not well-defined. This study evaluated associations of Nissen with clinical outcomes in infants with severe BPD (sBPD), using propensity score matching to minimize bias and confounding.

METHODS

Infants ≤31 wk gestational age with sBPD (grade 2-3) admitted to a single neonatal intensive care unit (NICU) between January 2016 and October 2021 were included. Patients with sBPD who underwent Nissen fundoplication during initial NICU admission were propensity score-matched at a 1:2 ratio with control patients who did not undergo Nissen (no-Nissen). Outcomes were compared, including time to freedom from respiratory support (defined as ≤2 L nasal cannula), time to initial NICU discharge, and incidence of hospital readmission or death within 1 y postdischarge.

RESULTS

After propensity score matching, 18 Nissen infants were compared with 30 no-Nissen infants. The Nissen group trended toward longer time to freedom from respiratory support (median 105 versus 70 d, P = 0.09), and had longer initial hospital stays (188 versus 111 d, P = 0.002), more 1-y hospital readmissions (83% versus 50%, P = 0.04), and more tracheostomies (28% versus 0%, P = 0.005). Mortality during first-year postdischarge was similar (6% versus 10%, P = 1.0).

CONCLUSIONS

Despite adjustment for confounding variables, Nissen fundoplication was associated with prolonged support and greater resource utilization among infants with sBPD. Prospective studies are needed to clarify indications for fundoplication in this population.

The NICU tracheostomy team: multidisciplinary collaboration for improvement in survival of complex patients

OBJECTIVE

Evaluate feasibility and impact of "Tracheostomy Team" on survival and length of stay (LOS) at a level IV NICU.

METHODS

Plan-do-study-act cycles targeted five Global Tracheostomy Collaborative "key drivers". From January 2017 to December 2022 multidisciplinary, bimonthly bedside rounds were conducted.

RESULTS

After 3 cycles, in-hospital survival among 39 patients with tracheostomy improved and sustained from 67% to 100% (baseline 18/27; 66.7%; QI 35/39, 89.7%; p = 0.03). Median LOS (days [IQR]) did not significantly differ between baseline and QI (237 [57-308] vs. 217 [130-311]; p = 0.9). Among patients with BPD, median LOS was higher after QI interventions (baseline 248 [222-308] vs. QI 332.5 [283.5-392]; p = .02). Special cause variation resulted from peak increase in LOS during the COVID19 pandemic (2021). Tracheitis/pneumonia was treated significantly more frequently in QI BPD patients.

CONCLUSION

Multidisciplinary approach is feasible, resulting in improved survival without a sustained increase in LOS. Future QI efforts should address post-operative infectious complications.

Association between bronchopulmonary dysplasia severity and its risk factors and long-term outcomes in three definitions: a historical cohort study

OBJECTIVE

To compare the association of the severity categories of the 2001-National Institutes of Health (NIH), the 2018-NIH and the 2019-Jensen bronchopulmonary dysplasia (BPD) definitions with neurodevelopmental and respiratory outcomes at 2 and 5 years' corrected age (CA), and several BPD risk factors.

DESIGN

Single-centre historical cohort study with retrospective data collection.

SETTING

Infants born between 2009 and 2015 at the Amsterdam University Medical Centers, location Amsterdam Medical Center.

PATIENTS

Preterm infants born at gestational age (GA) <30 weeks and surviving up to 36 weeks' postmenstrual age.

INTERVENTIONS

Perinatal characteristics, (social) demographics and comorbidities were collected from the electronic patient records.

MAIN OUTCOME MEASURES

The primary outcomes were neurodevelopmental impairment (NDI) or late death, and respiratory morbidity at 2 and 5 years' CA. Using logistic regression and Brier scores, we investigated if the ordinal grade severity is associated with incremental increase of adverse long-term outcomes.

RESULTS

584 preterm infants (median GA: 28.1 weeks) were included and classified according to the three BPD definitions. None of the definitions showed a clear ordinal incremental increase of risk for any of the outcomes with increasing severity classification. No significant differences were found between the three BPD definitions (Brier scores 0.169-0.230). Respiratory interventions, but not GA, birth weight or small for GA, showed an ordinal relationship with BPD severity in all three BPD definitions.

CONCLUSION

The severity classification of three BPD definitions showed low accuracy of the probability forecast on NDI or late death and respiratory morbidity at 2 and 5 years' CA, with no differences between the definitions.

[The use of bronchial occlusion test in a preterm infant with severe bronchopulmonary dysplasia complicated by severe lobar emphysema]

In infants with severe bronchopulmonary dysplasia (sBPD), severe pulmonary lobar emphysema may occur as a complication, contributing to significant impairment in ventilation. Clinical management of these infants is extremely challenging and some may require lobectomy to improve ventilation. However, prior to the lobectomy, it is very difficult to assess whether the remaining lung parenchyma would be able to sustain adequate ventilation postoperatively. In addition, preoperative planning and perioperative management are also quite challenging in these patients. This paper reports the utility of selective bronchial occlusion in assessing the safety and efficacy of lobectomy in a case of sBPD complicated by severe right upper lobar emphysema. Since infants with sBPD already have poor lung development and significant lung injury, lobectomy should be viewed as a non-traditional therapy and be carried out with extreme caution. Selective bronchial occlusion test can be an effective tool in assessing the risks and benefits of lobectomy in cases with sBPD and lobar emphysema. However, given the technical difficulty, successful application of this technique requires close collaboration of an experienced interdisciplinary team.

Risk of Adverse Neonatal Events in Pregnancies Complicated by Severe Maternal Morbidity

OBJECTIVE

To investigate the risk of adverse neonatal events after a pregnancy complicated by severe maternal morbidity.

STUDY DESIGN

We analyzed a population-based cohort of deliveries in Quebec, Canada, between 2006 and 2021. The main exposure measure was severe maternal morbidity, comprising life-threatening conditions such as severe hemorrhage, cardiac complications, and eclampsia. The outcome included adverse neonatal events such as very preterm birth (gestational age <32 weeks), bronchopulmonary dysplasia, hypoxic ischemic encephalopathy, and neonatal death. Using log-binomial regression models, we estimated adjusted relative risks (RRs) and 95% confidence intervals (CIs) for the association between severe maternal morbidity and adverse neonatal events.

RESULTS

Among 1 199 112 deliveries, 29 992 (2.5%) were complicated by severe maternal morbidity and 83 367 (7.0%) had adverse neonatal events. Severe maternal morbidity was associated with 2.96 times the risk of adverse neonatal events compared with no morbidity (95% CI 2.90-3.03). Associations were greatest for mothers who required assisted ventilation (RR 5.86, 95% CI 5.34-6.44), experienced uterine rupture (RR 4.54, 95% CI 3.73-5.51), or had cardiac complications (RR 4.39, 95% CI 3.98-4.84). Severe maternal morbidity was associated with ≥3 times the risk of neonatal death and hypoxic-ischemic encephalopathy and ≥10 times the risk of very preterm birth and bronchopulmonary dysplasia.

CONCLUSIONS

Severe maternal morbidity is associated with an elevated risk of adverse neonatal events. Better prevention of severe maternal morbidity may help reduce burden of severe neonatal morbidity.

Factors affecting length of stay according to bronchopulmonary dysplasia severity: a nationwide cohort study in Korea

BACKGROUND

Longer hospitalizations for preterm infants with bronchopulmonary dysplasia (BPD) delay developmental outcomes, increase the risk for hospital-acquired complications, and exert a substantial socioeconomic burden. This study aimed to identify factors associated with an extended length of stay (LOS) at different levels of severity of BPD.

METHODS

A cohort study was conducted using the Korean Neonatal Network registry of very low birth weight infants with BPD between 2013 and 2017 through retrospective analysis.

RESULTS

A total of 4263 infants were diagnosed with BPD. For mild BPD, infants requiring surgical treatment for patent ductus arteriosus needed a longer LOS [eadjusted β coefficients (adj β) 1.041; 95% confidence interval (CI): 0.01-0.08] and hydrocephalus (eadj β 1.094; 95% CI 0.01-0.17). In moderate BPD, infants administered steroids or with intraventricular hemorrhage required a longer LOS (eadj β 1.041; 95% CI 0.00-0.07 and eadj β 1.271; 95% CI 0.11-0.38, respectively). In severe BPD, infants with comorbidities required a longer LOS: pulmonary hypertension (eadj β 1.174; 95% CI 0.09-0.23), administrated steroid for BPD (eadj β 1.116; 95% CI 0.07-0.14), sepsis (eadj β 1.062; 95% CI 0.01-0.11), patent ductus arteriosus requiring surgical ligation (eadj β 1.041; 95% CI 0.00-0.08), and intraventricular hemorrhage (eadj β 1.016; 95% CI 0.05-0.26). Additionally, the higher the clinical risk index score, the longer the LOS needed for infants in all groups.

CONCLUSIONS

The factors affecting LOS differed according to the severity of BPD. Individualized approaches to reducing LOS may be devised using knowledge of the various risk factors affecting LOS by BPD severity.

Use of Optical Redox Imaging to Quantify Alveolar Macrophage Redox State in Infants: Proof of Concept Experiments in a Murine Model and Human Tracheal Aspirates Samples

Emerging data indicate that lung macrophages (LM) may provide a novel biomarker to classify disease endotypes in bronchopulmonary dysplasia (BPD), a form of infant chronic lung disease, and that augmentation of the LM phenotype may be a potential therapeutic target. To contribute to this area of research, we first used Optical Redox Imaging (ORI) to characterize the responses to H2O2-induced oxidative stress and caffeine treatment in an in vitro model of mouse alveolar macrophages (AM). H2O2 caused a dose-dependent decrease in NADH and an increase in FAD-containing flavoproteins (Fp) and the redox ratio Fp/(NADH + Fp). Caffeine treatment did not affect Fp but significantly decreased NADH with doses of ≥50 µM, and 1000 µM caffeine treatment significantly increased the redox ratio and decreased the baseline level of mitochondrial ROS (reactive oxygen species). However, regardless of whether AM were pretreated with caffeine or not, the mitochondrial ROS levels increased to similar levels after H2O2 challenge. We then investigated the feasibility of utilizing ORI to examine macrophage redox status in tracheal aspirate (TA) samples obtained from premature infants receiving invasive ventilation. We observed significant heterogeneity in NADH, Fp, Fp/(NADH + Fp), and mitochondrial ROS of the TA macrophages. We found a possible positive correlation between gestational age and NADH and a negative correlation between mean airway pressure and NADH that provides hypotheses for future testing. Our study demonstrates that ORI is a feasible technique to characterize macrophage redox state in infant TA samples and supports further use of this method to investigate lung macrophage-mediated disease endotypes in BPD.

Breast-feeding as protective factor against bronchopulmonary dysplasia in preterm infants

Breast-feeding is associated with fewer comorbidities in very-low-birth-weight (VLBW) preterm infants. Bronchopulmonary dysplasia (BPD) of VLBW infants is a multifactorial pathology in which nutritional aspects may be of special importance. The aim of this study is to determine, in a cohort of VLBW infants, whether breast milk nutrition is associated with a reduced prevalence and severity of BPD. A retrospective study was conducted to record the intake of mother's own milk (MOM), pasteurised donor human milk or preterm formula milk in the first 2 weeks of postnatal life of 566 VLBW newborns at our hospital during the period January 2008-December 2021. After applying the relevant exclusion criteria, data for 489 VLBW infants were analysed; 195 developed some degree of BPD. Moderate or severe BPD is associated with less weight gain. Moreover, the preferential ingestion of breast milk in the first and second postnatal weeks had effects associated with lower OR for BPD, which were statistically demonstrable for mild (OR 0·16; 95 % CI 0·03, 0·71) and severe (OR 0·08; 95 % CI 0·009, 0·91) BPD. Breast-feeding during the first weeks of postnatal life is associated with a reduced prevalence of BPD, which is frequently associated with less weight gain as a result of greater respiratory effort with greater energy expenditure.

[Impact of different angles of pulmonary surfactant administration on bronchopulmonaryplasia and intracranial hemorrhage in preterm infants: a prospective randomized controlled study]

OBJECTIVES

To investigate the effects of different angles of pulmonary surfactant (PS) administration on the incidence of bronchopulmonary dysplasia and intracranial hemorrhage in preterm infants.

METHODS

A prospective study was conducted on 146 preterm infants (gestational age <32 weeks) admitted to the Department of Neonatology, Provincial Hospital Affiliated to Anhui Medical University from January 2019 to May 2023. The infants were randomly assigned to different angles for injection of pulmonary surfactant groups: 0° group (34 cases), 30° group (36 cases), 45° group (38 cases), and 60° group (38 cases). Clinical indicators and outcomes were compared among the groups.

RESULTS

The oxygenation index was lower in the 60° group compared with the other three groups, with shorter invasive ventilation time and oxygen use time, and a lower incidence of bronchopulmonary dysplasia than the other three groups (P<0.05). The incidence of intracranial hemorrhage was lower in the 60° group compared to the 0° group (P<0.05). The cure rate in the 60° group was higher than that in the 0° group and the 30° group (P<0.05).

CONCLUSIONS

The clinical efficacy of injection of pulmonary surfactant at a 60° angle is higher than other angles, reducing the incidence of intracranial hemorrhage and bronchopulmonary dysplasia in preterm infants.

Inhaled bronchodilators for the prevention and treatment of chronic lung disease in preterm infants

BACKGROUND

Chronic lung disease (CLD) occurs frequently in preterm infants and is associated with respiratory morbidity. Bronchodilators have the potential effect of dilating small airways with muscle hypertrophy. Increased compliance and tidal volume, and decreased airway resistance, have been documented with the use of bronchodilators in infants with CLD. Therefore, bronchodilators are widely considered to have a role in the prevention and treatment of CLD, but there remains uncertainty as to whether they improve clinical outcomes. This is an update of the 2016 Cochrane review.

OBJECTIVES

To determine the effect of inhaled bronchodilators given as prophylaxis or as treatment for chronic lung disease (CLD) on mortality and other complications of preterm birth in infants at risk for or identified as having CLD.

SEARCH METHODS

An Information Specialist searched CENTRAL, MEDLINE, Embase, CINAHL and three trials registers from 2016 to May 2023. In addition, the review authors undertook reference checking, citation searching and contact with trial authors to identify additional studies.

SELECTION CRITERIA

We included randomised and quasi-randomised controlled trials involving preterm infants less than 32 weeks old that compared bronchodilators to no intervention or placebo. CLD was defined as oxygen dependency at 28 days of life or at 36 weeks' postmenstrual age. Initiation of bronchodilator therapy for the prevention of CLD had to occur within two weeks of birth. Treatment of infants with CLD had to be initiated before discharge from the neonatal unit. The intervention had to include administration of a bronchodilator by nebulisation or metered dose inhaler. The comparator was no intervention or placebo.

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures expected by Cochrane. Critical outcomes included: mortality within the trial period; CLD (defined as oxygen dependency at 28 days of life or at 36 weeks' postmenstrual age); adverse effects of bronchodilators, including hypokalaemia (low potassium levels in the blood), tachycardia, cardiac arrhythmia, tremor, hypertension and hyperglycaemia (high blood sugar); and pneumothorax. We used the GRADE approach to assess the certainty of the evidence for each outcome.

MAIN RESULTS

We included two randomised controlled trials in this review update. Only one trial provided useable outcome data. This trial was conducted in six neonatal intensive care units in France and Portugal, and involved 173 participants with a gestational age of less than 31 weeks. The infants in the intervention group received salbutamol for the prevention of CLD. The evidence suggests that salbutamol may result in little to no difference in mortality (risk ratio (RR) 1.08, 95% confidence interval (CI) 0.50 to 2.31; risk difference (RD) 0.01, 95% CI -0.09 to 0.11; low-certainty evidence) or CLD at 28 days (RR 1.03, 95% CI 0.78 to 1.37; RD 0.02, 95% CI -0.13 to 0.17; low-certainty evidence), when compared to placebo. The evidence is very uncertain about the effect of salbutamol on pneumothorax. The one trial with usable data reported that there were no relevant differences between groups, without providing the number of events (very low-certainty evidence). Investigators in this study did not report if side effects occurred. We found no eligible trials that evaluated the use of bronchodilator therapy for the treatment of infants with CLD. We identified no ongoing studies.

AUTHORS' CONCLUSIONS

Low-certainty evidence from one trial showed that inhaled bronchodilator prophylaxis may result in little or no difference in the incidence of mortality or CLD in preterm infants, when compared to placebo. The evidence is very uncertain about the effect of salbutamol on pneumothorax, and neither included study reported on the incidence of serious adverse effects. We identified no trials that studied the use of bronchodilator therapy for the treatment of CLD. Additional clinical trials are necessary to assess the role of bronchodilator agents in the prophylaxis or treatment of CLD. Researchers studying the effects of inhaled bronchodilators in preterm infants should include relevant clinical outcomes in addition to pulmonary mechanical outcomes.

Long-term pulmonary outcomes in BPD throughout the life-course

Respiratory disease is one of the most common complications of preterm birth. Survivors of prematurity have increased risks of morbidities and mortalities independent of prematurity, and frequently require multiple medications, home respiratory support, and subspecialty care to maintain health. Although advances in neonatal and pulmonary care have improved overall survival, earlier gestational age, lower birth weight, chorioamnionitis and late onset sepsis continue to be major factors in the development of bronchopulmonary dysplasia. These early life events associated with prematurity can have respiratory consequences that persist into adulthood. Furthermore, after initial hospital discharge, air pollution, respiratory tract infections and socioeconomic status may modify lung growth trajectories and influence respiratory outcomes in later life. Given that the incidence of respiratory disease associated with prematurity remains stable or increased, there is a need for pediatric and adult providers to be familiar with the natural history, manifestations, and common complications of disease.

Synergistic effects of achieving perinatal interventions on bronchopulmonary dysplasia in preterm infants

To investigate the effect of perinatal interventions on the risk of severe BPD (sBPD) and death in extremely preterm infants (EPIs) and their synergistic effects. This was a secondary analysis of the prospective cohort Chinese Neonatal Network (CHNN). Infants with a birth weight of 500 to 1250 g or 24-28 weeks completed gestational age were recruited. The impacts and the synergistic effects of six evidence-based perinatal interventions on the primary outcomes of sBPD and death were assessed by univariate and multivariable logistic regression modeling. Totally, 6568 EPIs were finally enrolled. Antenatal corticosteroid (adjusted OR, aOR, 0.74; 95%CI, 0.65-083), birth in centers with tertiary NICU (aOR, 0.64; 95%CI, 0.57-0.72), preventing intubation in the delivery room (aOR, 0.65; 95%CI, 0.58-0.73), early caffeine therapy (aOR, 0.59; 95%CI, 0.52-0.66), and early extubating (aOR, 0.42; 95%CI 0.37-0.47), were strongly associated with a lower risk of sBPD and death while early surfactant administration was associated with a lower risk of death (aOR, 0.84; 95%CI, 0.72, 0.98). Compared with achieving 0/1 perinatal interventions, achieving more than one intervention was associated with decreased rates (46.6% in 0/1 groups while 38.5%, 29.6%, 22.2%, 16.2%, and 11.7% in 2/3/4/5/6-intervention groups respectively) and reduced risks of sBPD/death with aORs of 0.76(0.60, 0.96), 0.55(0.43, 0.69), 0.38(0.30, 0.48), 0.28(0.22, 0.36), and 0.20(0.15, 0.27) in 2, 3, 4, 5, and 6 intervention groups respectively. Subgroup analyses showed consistent results.

CONCLUSION

Six perinatal interventions can effectively reduce the risk of sBPD and death in a synergistic form.

WHAT IS KNOWN

• Bronchopulmonary dysplasia (BPD) is a multifactorial chronic lung disease associated with prematurity. The effective management of BPD requires a comprehensive set of interventions. However, the extent to which these interventions can mitigate the risk of severe outcomes, such as severe BPD or mortality, or if they possess synergistic effects remains unknown.

WHAT IS NEW

• The implementation of various perinatal interventions, such as prenatal steroids, birth in centers with tertiary NICU, early non-Invasive respiratory support, surfactant administration within 2 hours after birth, early caffeine initiation within 3 days, and early extubation within 7 days after birth has shown promising results in the prevention of severe bronchopulmonary dysplasia (BPD) or mortality in extremely preterm infants. Moreover, these interventions have demonstrated synergistic effects when implemented in combination.

Lung ultrasound scores within the first 3 days of life to predict respiratory outcomes

BACKROUND

Lung ultrasound (LUS) is a rapid and simple method to evaluate preterm babies with respiratory distress. Lately, LUS has also been reported as an accurate predictor for bronchopulmonary dysplasia (BPD).

OBJECTIVES

The aim of the study was to investigate the relationship between the LUS scores within the first 3 days of life and respiratory outcomes including the need and the duration of invasive mechanical ventilation, and development of BPD.

METHODS

It was a retrospective observational study. Preterm infants younger than 32 weeks were included at an academic tertiary Neonatal Intensive Care Unit between 2018 and 2023. LUS was performed within the first 3 days. Each lung was divided into three regions and defined as a score of 0 to 3 points; the total score was obtained by adding the six regional scores. LUS scores were noted in two groups as the highest and lowest scores. Statistical analyses were done to predict respiratory outcomes.

RESULTS

Total 218 patients were enrolled; 40, 17, and 18 infants had mild, moderate, and severe BPD, respectively. BPD did not develop in 143 patients. Within the first 3 days, the highest and lowest LUS scores significantly predicted moderate-to-severe BPD (p < .001) (area under receiver operating characteristic [ROC] curve, 0.684-0.913; area under ROC curve 0.647-0.902; respectively). High LUS scores were also related with the need of mechanical ventilation (p < .001). There was not a significant correlation between the duration of mechanical ventilation and the LUS scores. Regression analysis revealed that the highest LUS scores within the first 3 days of life, sepsis, and the presence of hemodynamically significant patent ductus arteriosus (hsPDA) were significantly associated with the severity of BPD.

CONCLUSIONS

In preterm babies, the LUS scores were useful to predict BPD and the need of invasive ventilation in long term. However, it was not related with the length of invasive ventilation.

Successful Atrial Septal Defect Closure Subsequent to Medical Pulmonary Preconditioning in an Infant With Severe Pulmonary Hypertension Associated With Bronchopulmonary Dysplasia

While atrial septal defect (ASD) may contribute to right ventricular decompression in patients with severe pulmonary hypertension (PH), the pulmonary vasculature might be compromised by increased pulmonary blood flow, even though pulmonary vasodilators successfully reduce resistance. ASD closure is a treatment option that may ameliorate PH symptoms associated with bronchopulmonary dysplasia (BPD) in infants. However, the feasibility of ASD closure is obscure in patients with BPD-PH causing right-to-left shunting. Here, we present an eight-month-old girl with ASD complicated by BPD-PH, in which the pulmonary pressure exceeded the systemic pressure; the ASD was successfully closed after pulmonary preconditioning with dexamethasone and high-dose diuretics. Our patient was delivered as the third baby in triplets at a gestational age of 25 weeks, with a birth weight of 344 g. She was diagnosed with BPD at three months of age (37 weeks of postmenstrual age) with a body weight of 1.4 kg. Mild pulmonary hypertension was identified at the age of five months, and oral sildenafil was initiated. While her atrial septal defect was small at the time of PH diagnosis, it became hemodynamically significant when she grew up to 3.4 kg of body weight, at seven months after birth. Her estimated right ventricular pressure was apparently more than the systemic pressure, and oxygen saturation fluctuated between 82% and 97% under oxygen supplementation due to bidirectional interatrial shunt with predominant right-to-left shunting. Pulmonary preconditioning lowered the estimated right ventricular pressure to almost equal the systemic pressure and elevated arterial oxygen saturation while also suppressing right-to-left shunting. Cardiac catheterization after preconditioning revealed a ratio of pulmonary blood pressure to systemic blood pressure ratio (Pp/Ps) of 0.9, pulmonary resistance of 7.3 WU-m2, and a pulmonary to systemic blood flow ratio (Qp/Qs) of 1.3 (approximately 1.0 in the normal circulation without significant shunt), with the cardiac index of 2.8 L/min/m2. The acute pulmonary vasoreactivity test against the combination of 20 ppm nitric oxide and 100% oxygen was negative, although the patient had consistently high pulmonary flow with makeshift improvements after preconditioning. Despite the high pulmonary resistance even after preconditioning, aggressive ASD closure was performed so that pulmonary flow could be consistently suppressed regardless of the pulmonary condition. Her Pp/Ps under 100% oxygen with 20 ppm nitric oxide was 0.7 immediately after closure. After two years of follow-up, her estimated right ventricular pressure was less than half of the systemic pressure with the use of three pulmonary vasodilators, including sildenafil, macitentan, and beraprost. A strategy to temporarily improve PH and respiratory status aimed at ASD closure could be a treatment option for the effective use of multiple pulmonary vasodilators, by which intensive treatment of BPD can be achieved.

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.

Exploring the Association of Male Sex With Adverse Outcomes in Severe Bronchopulmonary Dysplasia: A Retrospective, Multicenter Cohort Study

BACKGROUND

Bronchopulmonary dysplasia (BPD) is a significant contributor to morbidity and death in infants who are born premature. Male sex is an independent risk factor for the development of BPD. However, whether male sex is associated with adverse outcomes that occur after formal diagnosis of severe BPD prior to hospital discharge remains unclear.

RESEARCH QUESTION

Is male sex associated with a higher risk of adverse outcomes in infants with established severe BPD?

STUDY DESIGN AND METHODS

A retrospective, multicenter cohort study of infants enrolled in the BPD Collaborative Registry from January 1, 2015, to June 29, 2022, was performed. Demographics, clinical characteristics, and outcomes were stratified by sex (ie, male vs female). Regression modeling was used to estimate the association of sex with the primary composite outcome of death or tracheostomy at hospital discharge.

RESULTS

We identified 1,156 infants with severe BPD, defined at 36 weeks postmenstrual age by the National Institutes of Health 2001 consensus definition. The cohort was predominantly male (59% male infants, 41% female infants). However, rates of mechanical ventilation at 36 weeks postmenstrual age (ie, type 2 severe BPD) did not differ by sex. Overall mortality rates within the cohort were low (male infants, 5.3%; female infants, 3.6%). The OR of death or tracheostomy for male-to-female infants was 1.0 (95% CI, 0.7-1.5).

INTERPRETATION

Our results lead us to speculate that, although sex is an important variable that contributes to the development and pathogenesis of severe BPD, it does not appear to be associated with adverse outcomes in this cohort of infants with established disease. The surprising results raise important questions surrounding the temporal role of biological sex in the development of severe BPD and its progression during the neonatal ICU stay. As we explore the phenotypes and endotypes of BPD, it is imperative to consider how sex modulates the disease from birth through hospital discharge.

Prediction of bronchopulmonary dysplasia in very preterm infants: competitive risk model nomogram

Objective

To develop predictive clinical models of bronchopulmonary dysplasia (BPD) through competing risk analysis.

Methods

Retrospective observational cohort study, including preterm newborns ≤32 weeks gestational age, conducted between January 1, 2013 and September 30, 2022 in a third-level Neonatal Intensive Care Unit in Spain. A prediction study was carried out using competing risk models, where the event of interest was BPD and the competing event was death. A multivariate competing risk model was developed separately for each postnatal day (days 1, 3, 7 and 14). Nomograms to predict BPD risk were developed from the coefficients of the final models and internally validated.

Results

A total of 306 patients were included in the study, of which 73 (23.9%) developed BPD and 29 (9.5%) died. On day 1, the model with the greatest predictive capacity was that including birth weight, days since rupture of membranes, and surfactant requirement (area under the receiver operating characteristic (ROC) curve (AUC), 0.896; 95% CI, 0.792-0.999). On day 3, the final predictive model was based on the variables birth weight, surfactant requirement, and Fraction of Inspired Oxygen (FiO2) (AUC, 0.891; 95% CI, 0.792-0.989).

Conclusions

Competing risk analysis allowed accurate prediction of BPD, avoiding the potential bias resulting from the exclusion of deceased newborns or the use of combined outcomes. The resulting models are based on clinical variables measured at bedside during the first 3 days of life, can be easily implemented in clinical practice, and can enable earlier identification of patients at high risk of BPD.

Transpyloric feeding is associated with adverse in-hospital outcomes in infants with severe bronchopulmonary dysplasia

OBJECTIVE

To estimate the association of transpyloric feeding (TPF) with the composite outcome of tracheostomy or death for patients with severe bronchopulmonary dysplasia (sBPD).

STUDY DESIGN

Retrospective multi-center cohort study of preterm infants <32 weeks with sBPD receiving enteral feedings. We compared infants who received TPF at 36, 44, or 50 weeks post-menstrual age to those who did not receive TPF at any of those timepoints. Odds ratios were adjusted for gestational age, small for gestational age, male sex, and invasive ventilation and FiO2 at 36 weeks.

RESULTS

Among 1039 patients, 129 (12%) received TPF. TPF was associated with an increased odds of tracheostomy or death (aOR 3.5, 95% CI 2.0-6.1) and prolonged length of stay or death (aOR 3.1, 95% CI 1.9-5.2).

CONCLUSIONS

Use of TPF in sBPD after 36 weeks was infrequent and associated with worse in-hospital outcomes, even after adjusting for respiratory severity at 36 weeks.

Trends in bronchopulmonary dysplasia and respiratory support among extremely preterm infants in China over a decade

OBJECTIVE

Bronchopulmonary dysplasia (BPD) is one of the most serious complications affecting extremely preterm infants. We aimed to evaluate temporal trends in BPD and administration of respiratory support among extremely preterm infants in China over a decade.

METHODS

This was a retrospective study using data from a multicenter database, which included infants born less than 28 weeks' gestation discharged from 68 tertiary neonatal care centers in China between 2010 and 2019. Changes in rates and severity of BPD, as well as modalities and duration of respiratory support, were evaluated.

RESULTS

Among 4808 eligible infants with gestational age (GA) of 21+6/7  to 27+6/7 weeks and a mean (SD) birth weight of 980 (177) g, no significant change of median GA was found over time. Overall, 780 (16.2%) infants died before 36 weeks' postmenstrual age, 2415 (50.2%) were classified as having no BPD, 917 (19.1%) developed Grade 1 BPD, 578 (12.0%) developed Grade 2 BPD, and 118 (2.5%) developed Grade 3 BPD. The rate of BPD increased from 20.8% in 2010 to 40.7% in 2019 (aRR for trend, 1.081; 95% confidence interval, 1.062-1.099), especially for Grade 1 and Grade 2. Although survival to discharge improved over the decade, the overall survival without BPD did not change during the study period. The use of invasive mechanical ventilation (IMV) remained unchanged. However, the use of noninvasive ventilation (NIV) increased from 71.5% in 2010 to 89.8% in 2019. Moreover, the median duration of NIV increased over time, from 17.0 (4.8, 34.0) days in 2010 to 33.0 (21.0, 44.0) days in 2019, without significant change in the duration of IMV.

CONCLUSIONS

Although survival increased over the decade and respiratory support practices changed significantly between 2010 and 2019 in China, with increased use and duration of NIV, there was an increased rate of BPD and survival without BPD has not improved.

Association between Weight for Length and the Severity of Respiratory Morbidity in Preterm Infants

Association Between Weight for Length and the Severity of Respiratory Morbidity in Preterm Infants.

OBJECTIVE

To determine whether higher weight-to-length z-scores after 32 weeks of gestation are associated with higher pulmonary scores (PSs) in preterm infants requiring respiratory support using a prospective observational study.

METHODS

Infants born at <30 weeks, with a post-menstrual age (PMA) of 30-33 weeks, were enrolled. The infant's weight, length, and head circumference were measured weekly. Data on calories/kg/d, protein g/kg/d, weight-for-length percentiles, z-scores, and BMI at 33 through 40 weeks PMA were collected. The PS was calculated.

RESULTS

We analyzed 91 infants. The mean gestational age was 26.9 ± 1.7 weeks. The mean birthweight was 0.898 ± 0.238 kgs. They were predominantly African American (81.3%) and girls (56%). Postnatal steroids were administered in 26.4% of the infants. The mean duration of invasive ventilation was 19.23 days ± 28.30 days. There was a significant association between the PS and W/L z-score (p < 0.0001). For every one-unit increase in W/L z-score, the PS increased by 0.063. There was a significant association between the PS and W/L percentile (p = 0.0017), as well as BMI (p ≤ 0.0001). For every unit increase in W/L percentile, the PS increased by 0.002, and for a unit increase in BMI, the PS increased by 0.04. The association remained significant after postnatal steroid use, sex, and corrected and birth gestational ages were included in the regression analysis. Nutrition did not affect the anthropometric measurements.

CONCLUSIONS

Our study is the first to demonstrate that a higher BMI and W/L may adversely affect the respiratory severity in preterm infants. Studies with larger sample sizes are needed to confirm our findings.

The association between bronchopulmonary dysplasia grade and risks of adverse neurodevelopmental outcomes among preterm infants born at less than 30 weeks of gestation

BACKGROUND

Bronchopulmonary dysplasia (BPD) is a multifactorial disease with neurodevelopmental implications. This study aims to quantify the risks of adverse neurodevelopmental outcomes for each BPD grade among preterm infants born at less than 30 weeks' gestation.

METHODS

We retrospectively studied infants who received care in our institution until at least 36 weeks postmenstrual age and had a formal neurodevelopmental assessment in our infant follow-up clinic using the Bayley Scales for Infant and Toddler Development (BSID). We assessed the association between BPD grade and adverse neurodevelopmental outcomes using descriptive statistics and regression models.

RESULTS

Two hundred and fifty infants, including 89 (35.6%), 87 (34.8%), 65 (20.6%), and 9 (3.6%) with No BPD, Grade 1, Grade 2, and Grade 3 BPD, were included in the study. Small for gestational age, late pulmonary hypertension, dexamethasone administration, and adverse neurodevelopmental outcomes were more common as BPD grade increased. In a logistic regression analysis, Grades 2 and 3, but not Grade 1, BPD were associated with increased odds of a composite adverse neurodevelopmental outcome by 2.7 and 7.2 folds, respectively. A BSID domain-specific analysis showed that higher grades were associated with lower scores in the cognitive, gross motor, and fine motor domains.

CONCLUSIONS

Grades 2 and 3 BPD, but not Grade 1, correlate with risks of adverse neurodevelopmental outcomes at a grade-dependent manner in our single-center cohort retrospective study. Further validation using a multi-center large cohort is warranted.

Regulating NLRP3 Inflammasome-Induced Pyroptosis via Nrf2: TBHQ Limits Hyperoxia-Induced Lung Injury in a Mouse Model of Bronchopulmonary Dysplasia

Nuclear factor e2-related factor 2 (Nrf2) plays a key role in cellular resistance to oxidative stress injury. Oxidative stress injury, caused by Nrf2 imbalance, results in increased pyroptosis, DNA damage, and inflammatory activation, which may lead to the arrest of alveolar development and bronchopulmonary dysplasia (BPD) in premature infants under hyperoxic conditions. We established a BPD mouse model to investigate the effects of tert-butylhydroquinone (TBHQ), an Nrf2 activator, on oxidative stress injury, pyroptosis, NLRP3 inflammasome activation, and alveolar development. TBHQ reduced abnormal cell death in the lung tissue of BPD mice and restored the number and normal structure of the alveoli. TBHQ administration activated the Nrf2/heme oxygenase-1 (HO-1) signaling pathway, resulting in the decrease in the following: reactive oxygen species (ROS), activation of the NOD-like receptor pyrin domain containing 3 (NLRP3) inflammasome, and IL-18 and IL-1β expression and activation, as well as inhibition of pyroptosis. In contrast, after Nrf2 gene knockout in BPD mice, there was more severe oxidative stress injury and cell death in the lungs, there were TUNEL + and NLRP3 + co-positive cells in the alveoli, the pyroptosis was significantly increased, and the development of alveoli was significantly blocked. We demonstrated that TBHQ may promote alveolar development by enhancing Nrf2-induced antioxidation in the lung tissue of BPD mice and that the decrease in the NLRP3 inflammasome and pyroptosis caused by Nrf2 activation may be the underlying mechanism. These results suggest that TBHQ is a promising treatment for lung injury in premature infants with hyperoxia.

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.

Furin Regulates the Alveolarization of Neonatal Lungs in a Mouse Model of Hyperoxic Lung Injury

Despite advances in treatment options, such as corticosteroid administration and less invasive respiratory support, bronchopulmonary dysplasia (BPD) remains an important prognostic factor in preterm infants. We previously reported that furin regulates changes in lung smooth muscle cell phenotypes, suggesting that it plays a critical role in BPD pathogenesis. Therefore, in this study, we aimed to evaluate whether it regulates the alveolarization of immature lungs through activating alveolarization-driving proteins. We first examined furin expression levels, and its functions, using an established hyperoxia-induced BPD mouse model. Thereafter, we treated mice pups, as well as primary myofibroblast cell cultures, with furin inhibitors. Finally, we administered the hyperoxia-exposed mice pups with recombinant furin. Immunofluorescence revealed the co-expression of furin with alpha-smooth muscle actin. Hyperoxia exposure for 10 d decreased alveolar formation, as well as the expression of furin and its target, IGF-1R. Hexa-D-arginine administration also significantly inhibited alveolar formation. Another furin inhibitor, decanoyl-RVKR-chloromethylketone, accumulated pro-IGF-1R, and decreased IGF-1R phosphorylation in myofibroblast primary cultures. Finally, recombinant furin treatment significantly improved alveolarization in hyperoxia-exposed mice pups. Furin regulates alveolarization in immature lungs. Therefore, this study provides novel insights regarding the involvement of furin in BPD pathogenesis, and highlights a potential treatment target for ameliorating the impact of BPD.

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.

Impact of bronchopulmonary dysplasia on brain GABA concentrations in preterm infants: Prospective cohort study

BACKGROUND

Bronchopulmonary dysplasia (BPD) is associated with cognitive-behavioral deficits in very preterm (VPT) infants, often in the absence of structural brain injury. Advanced GABA-editing techniques like Mescher-Garwood point resolved spectroscopy (MEGA-PRESS) can quantify in-vivo gamma-aminobutyric acid (GABA+, with macromolecules) and glutamate (Glx, with glutamine) concentrations to investigate for neurophysiologic perturbations in the developing brain of VPT infants.

OBJECTIVE

To investigate the relationship between the severity of BPD and basal-ganglia GABA+ and Glx concentrations in VPT infants.

METHODS

MRI studies were performed on a 3 T scanner in a cohort of VPT infants [born ≤32 weeks gestational age (GA)] without major structural brain injury and healthy-term infants (>37 weeks GA) at term-equivalent age. MEGA-PRESS (TE68ms, TR2000ms, 256averages) sequence was acquired from the right basal-ganglia voxel (∼3cm3) and metabolite concentrations were quantified in institutional units (i.u.). We stratified VPT infants into no/mild (grade 0/1) and moderate-severe (grade 2/3) BPD.

RESULTS

Reliable MEGA-PRESS data was available from 63 subjects: 29 healthy-term and 34 VPT infants without major structural brain injury. VPT infants with moderate-severe BPD (n = 20) had the lowest right basal-ganglia GABA+ (median 1.88 vs. 2.28 vs. 2.12 i.u., p = 0.025) and GABA+/choline (0.73 vs. 0.99 vs. 0.88, p = 0.004) in comparison to infants with no/mild BPD and healthy-term infants. The GABA+/Glx ratio was lower (0.34 vs. 0.44, p = 0.034) in VPT infants with moderate-severe BPD than in infants with no/mild BPD.

CONCLUSIONS

Reduced GABA+ and GABA+/Glx in VPT infants with moderate-severe BPD indicate neurophysiologic perturbations which could serve as early biomarkers of future cognitive deficits.

Preterm lung and brain responses to mechanical ventilation and corticosteroids

Mechanical ventilation is necessary to maintain oxygenation and ventilation in many preterm infants. Unfortunately, even short periods of mechanical ventilation can cause lung and airway injury, and initiate the lung inflammation that contributes to the development of bronchopulmonary dysplasia (BPD). The mechanical stretch leads to airway cell differentiation and simplification of the alveoli, and releases cytokines that cause systemic response in other organs. Mechanical ventilation also leads to brain injury (IVH, white and gray matter) and neuronal inflammation that can affect the neurodevelopment of preterm infants. In efforts to decrease BPD, corticosteroids have been used for both prevention and treatment of lung inflammation. Corticosteroids have also been demonstrated to cause neuronal injury, so the clinician must balance the negative effects of both mechanical ventilation and steroids on the brain and lungs. Predictive models for BPD can help assess the infants who will benefit most from corticosteroid exposure. This review describes the lung and brain injury from mechanical ventilation in the delivery room and chronic mechanical ventilation in animal models. It provides updates on the current guidelines for use of postnatal corticosteroids (dexamethasone, hydrocortisone, budesonide, budesonide with surfactant) for the prevention and treatment of BPD, and the effects the timing of each steroid regimen has on neurodevelopment.

Towards a harmonized bronchopulmonary dysplasia definition: a study protocol for an international Delphi procedure

INTRODUCTION

Bronchopulmonary dysplasia (BPD) remains the most common complication of preterm birth with lifelong consequences. Multiple BPD definitions are currently used in daily practice. Uniformity in defining BPD is important for clinical care, research and benchmarking. The aim of this Delphi procedure is to determine what clinicians and researchers consider the key features for defining BPD. With the results of this study, we hope to advance the process of reaching consensus on the diagnosis of BPD.

METHODS AND ANALYSIS

A Delphi procedure will be used to establish why, when and how clinicians propose BPD should be diagnosed. This semi-anonymous iterative technique ensures an objective approach towards gaining these insights. An international multidisciplinary panel of clinicians and researchers working with preterm infants and/or patients diagnosed with BPD will participate. Steering committee members will recruit potential participants in their own region or network following eligibility guidelines to complete a first round survey online. This round will collect demographic information and opinions on key features of BPD definitions. Subsequent rounds will provide participants with the results from the previous round, for final acceptance or rejection of key features. Statements will be rated using a 5-point Likert scale. After completing the Delphi procedure, an (online) consensus meeting will be organised to discuss the results.

ETHICS AND DISSEMINATION

For this study, ethical approval a waiver has been provided. However, all participants will be asked to provide consent for the use of personal data. After the Delphi procedure is completed, it will be published in a peer-reviewed journal and disseminated at international conferences.

Respiratory management of established severe bronchopulmonary dysplasia

Respiratory management of infants with established severe BPD is difficult and there is little evidence upon which to base decisions. Nonetheless, the physiology of severe BPD is well described with a predominantly obstructive pattern. This pulmonary dysfunction results in prolonged exhalatory time constants and thus ventilator management must be focused on maintaining adequate oxygenation and ventilation through achieving full exhalation. This approach is often difficult to maintain in acute care settings and a culture of chronic care focused on slow change and steady progress is imperative. Once respiratory stability is achieved, the focus should shift to growth and development and avoidance of care practices and medications that impair neurodevelopment.

Imaging of bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is a multifactorial disease with many associated co-morbidities, responsible for most cases of chronic lung disease in childhood. The use of imaging exams is pivotal for the clinical care of BPD and the identification of candidates for experimental therapies and a closer follow-up. Imaging is also useful to improve communication with the family and objectively evaluate the clinical evolution of the patient's disease. BPD imaging has been classically performed using only chest X-rays, but several modern techniques are currently available, such as lung ultrasound, thoracic tomography, magnetic resonance imaging and electrical impedance tomography. These techniques are more accurate and provide clinically meaningful information. We reviewed the most recent evidence published in the last five years regarding these techniques and analyzed their advantages and disadvantages.

Comparison of two novel diagnostic criteria for bronchopulmonary dysplasia in predicting adverse outcomes of preterm infants: a retrospective cohort study

BACKGROUND

This study aimed to compare the predictive value of two diagnostic criteria for bronchopulmonary dysplasia (BPD) in preterm infants with gestational age (GA) < 32 weeks for death or severe respiratory morbidity at corrected age of 18-24 months.

METHODS

In this retrospective cohort study, clinical data from July 2019 to September 2021 were classified by 2018 National Institute of Child Health and Human Development (NICHD) and 2019 Jensen definitions of BPD. Based on the follow-up results, the enrolled population was divided into adverse outcome group and normal outcome group. Logistic regression and receiver operating characteristic (ROC) curve analyses were conducted to explore the risk factors of adverse outcomes and evaluate the predictive value of both diagnostic criteria.

RESULTS

Of 451 infants, 141 (31.3%) had adverse outcomes, which increased with increasing severity of BPD. Logistic regression analysis showed only BPD was an independent risk factor for adverse outcomes in preterm infants. ROC analysis revealed that both diagnostic criteria showed similar predictive values (2018 NICHD definition AUC = 0.771 vs. 2019 Jensen definition AUC = 0.770), with specificities of 93.5% and 96.8%, respectively; however, combining them separately with GA or birth weight did not improve their predictive values.

CONCLUSIONS

The two novel definitions of BPD demonstrate similar predictive values in predicting death or severe respiratory morbidity at corrected age of 18-24 months, with higher specificity observed in both.

The Pandemic Allocation of Ventilators Model Penalizes Infants with Bronchopulmonary Dysplasia

During the COVID-19 pandemic, institutions developed ventilator allocation models. In one proposed model, neonates compete with adults for ventilators using a scoring system. Points are given for conditions that increase one- and five-year (y) mortality. For example, comparable points were added for adult conditions with mortality of 71.3% and for neonates with moderate or severe bronchopulmonary dysplasia (mod/sBPD). We hypothesized that this model overestimates mortality in neonates with BPD and would penalize these infants unfairly. There was little information available on 1 y and 5 y mortality risk for mod/sBPD. To evaluate this allocation protocol, a retrospective chart review was performed on infants born ≥22 weeks and weighing <1500 g admitted to Rainbow Babies and Children's Hospital in 2015 to identify babies with BPD. The main outcomes were 1 and 5 y mortality. In 2015, 28 infants were diagnosed with mod/s BPD based on NIH 2001 definition; 4 infants had modBPD and 24 had sBPD. All infants (100%) with modBPD survived to 5 y; 2 infants with sBPD died by 1 y (8%) and 22 survived (92%) to 1 y; 3 died (12.5%) by 5 y; and at least 13 survived (54%) to 5 y. Infants with mod/s BPD had lower-than-predicted 1 and 5 y mortality, suggesting the points assigned in the model are too high for these conditions. We believe this model would unfairly penalize these babies.

Classifying multicenter approaches to invasive mechanical ventilation for infants with bronchopulmonary dysplasia using hierarchical clustering analysis

INTRODUCTION

Evidence-based ventilation strategies for infants with severe bronchopulmonary dysplasia (BPD) remain unknown. Determining whether contemporary ventilation approaches cluster as specific BPD strategies may better characterize care and enhance the design of clinical trials. The objective of this study was to test the hypothesis that unsupervised, multifactorial clustering analysis of point prevalence ventilator setting data would classify a discrete number of physiology-based approaches to mechanical ventilation in a multicenter cohort of infants with severe BPD.

METHODS

We performed a secondary analysis of a multicenter point prevalence study of infants with severe BPD treated with invasive mechanical ventilation. We clustered the cohort by mean airway pressure (MAP), positive end expiratory pressure (PEEP), set respiratory rate, and inspiratory time (Ti) using Ward's hierarchical clustering analysis (HCA).

RESULTS

Seventy-eight patients with severe BPD were included from 14 centers. HCA classified three discrete clusters as determined by an agglomerative coefficient of 0.97. Cluster stability was relatively strong as determined by Jaccard coefficient means of 0.79, 0.85, and 0.77 for clusters 1, 2, and 3, respectively. The median PEEP, MAP, rate, Ti, and PIP differed significantly between clusters for each comparison by Kruskall-Wallis testing (p < 0.0001).

CONCLUSIONS

In this study, unsupervised clustering analysis of ventilator setting data identified three discrete approaches to mechanical ventilation in a multicenter cohort of infants with severe BPD. Prospective trials are needed to determine whether these approaches to mechanical ventilation are associated with specific severe BPD clinical phenotypes and differentially modify respiratory outcomes.

Bronchopulmonary Dysplasia: A Five-Year Retrospective Cohort Study on Differences in Clinical Characteristics and Morbidities According to Severity Grading

INTRODUCTION

Bronchopulmonary dysplasia (BPD) is the most common complication associated with extreme prematurity. Although several criteria defining severity were developed over time, there are a few studies describing the differences in BPD phenotype and neonatal morbidities and complications between severity groups. We aimed to describe these differences in BPD patients of a neonatal intensive care unit (NICU).

METHODS

We conducted an observational retrospective cohort study through a medical record review over a five-year period. Participants were newborns admitted to an NICU who were diagnosed with BPD. We performed a descriptive statistical analysis of gestational complications and the use of antenatal corticosteroid therapy, birth-related data, and complications throughout the NICU stay, as well as the respiratory support used. We also compared different severity groups across these variables. The patients were divided into severe and non-severe BPD using the severity criteria of the 2001 NICHD/NHLBI/ORD consensus workshop.

RESULTS

A total of 101 newborns with BPD participated in the study and 73 had data on BPD severity. The median gestational age was 27 weeks, ranging from 23 to 32 weeks. Of these 73 newborns, 36 had mild BPD (49.3%), 10 had moderate BPD (13.7%), and 27 had severe BPD (37.0%). When comparing severe and non-severe BPD, we found that extreme prematurity, extremely low birth weight, and small size for gestational age were more frequent in the severe BPD group (p-value=0.012, p-value<0.001, and p-value=0.012, respectively). Infants with severe BPD had a longer duration of invasive ventilation than those with mild or moderate BPD (p-value<0.001). Late sepsis, necrotizing enterocolitis, severe brain injury, and retinopathy of prematurity were more frequent in severe BPD (p-value=0.017, p-value=0.045, p-value=0.033, p-value=0.003, respectively).

DISCUSSION

Previously published evidence describing causal links between BPD development and comorbidities exists but data on their impact on BPD severity are scarce. In our study, severe BPD seemed to be associated with a higher frequency of comorbidities and complications. Further studies are needed to ascertain the impact of each morbidity on the severity of BPD and if measures to prevent them could lead to potentially milder BPD disease.

The role of rhIGF-1/BP3 in the prevention of pulmonary hypertension in bronchopulmonary dysplasia and its underlying mechanism

BACKGROUND

This study aimed to determine whether postnatal treatment with recombinant human IGF-1 (rhIGF-1)/binding peptide 3 (BP3) ameliorates lung injury and prevents pulmonary hypertension (PH) in bronchopulmonary dysplasia (BPD) models.

METHODS

We used two models of BPD in this study: one model that was associated with chorioamnionitis (CA), stimulated by intra-amniotic fluid and exposure to lipopolysaccharide (LPS), whereas the other was exposed to postnatal hyperoxia. Newborn rats were treated with rhIGF-1/BP3 (0.2 mg/Kg/d) or saline via intraperitoneal injection. The study endpoints included the wet/dry weight (W/D) ratio of lung tissues, radial alveolar counts (RACs), vessel density, right ventricular hypertrophy (RVH), lung resistance, and lung compliance. Hematoxylin and eosin (H&E) and Masson staining were used to evaluate the degree of lung injury and pulmonary fibrosis. IGF-1 and eNOS expression were detected using western blotting or quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). The levels of SP-C, E-cadherin, N-cadherin, FSP1, and Vimentin in the lung tissues were detected by immunofluorescence.

RESULTS

LPS and hyperoxia treatment increased lung injury and pulmonary fibrosis, enhanced RVH and total respiratory resistance, and decreased RAC, pulmonary vascular density and pulmonary compliance in young mice (all p < 0.01). Simultaneously, LPS and hyperoxia induced an increase in epithelial-mesenchymal transition (EMT) in airway epithelial cells. However, rhIGF-1/BP3 treatment reduced lung injury and pulmonary fibrosis, decreased RVH and total respiratory resistance, and enhanced RAC, pulmonary vascular density and pulmonary compliance, as well as inhibited EMT in airway epithelial cells in LPS and hyperoxia treated mice.

CONCLUSION

Postnatal rhIGF-1/BP3 treatment relieved the effects of LPS or hyperoxia on lung injury and prevented RVH, providing a promising strategy for the treatment of BPD.

Bronchopulmonary Dysplasia: Ongoing Challenges from Definitions to Clinical Care

Bronchopulmonary dysplasia (BPD) is the most common complication of extreme prematurity. Its etiology is multifactorial and is attributed to genetic susceptibility to prenatal and postnatal factors. As advancements in neonatology have led to the increased survival of premature infants, a parallel increase in the incidence of BPD has occurred. Over time, the definition and diagnostic criteria for BPD have evolved, as have management strategies. However, challenges continue to exist in the management of these infants, which is not surprising given the complexity of the disease. We summarize the key diagnostic criteria and provide insight into the challenges related to various aspects of BPD definitions, data comparisons, and clinical care implementation.

Longer duration of initial invasive mechanical ventilation is still a crucial risk factor for moderate-to-severe bronchopulmonary dysplasia in very preterm infants: a multicentrer prospective study

OBJECTIVES

We aimed to evaluate the risk factors for moderate-to-severe bronchopulmonary dysplasia (BPD) and focus on discussing its relationship with the duration of initial invasive mechanical ventilation (IMV) in very preterm neonates less than 32 weeks of gestational age (GA).

METHODS

We performed a prospective cohort study involving infants born at 23-31 weeks of GA who were admitted to 47 different neonatal intensive care unit (NICU) hospitals in China from January 2018 to December 2021. Patient data were obtained from the Sina-northern Neonatal Network (SNN) Database.

RESULTS

We identified 6538 very preterm infants, of whom 49.5% (3236/6538) received initial IMV support, and 12.6% (823/6538) were diagnosed with moderate-to-severe BPD symptoms. The median duration of initial IMV in the moderate-to-severe BPD group was 26 (17-41) days, while in the no or mild BPD group, it was 6 (3-10) days. The incidence rate of moderate-to-severe BPD and the median duration of initial IMV were quite different across different GAs. Multivariable logistic regression analysis showed that the onset of moderate-to-severe BPD was significantly associated with the duration of initial IMV [adjusted odds ratio (AOR): 1.97; 95% confidence interval (CI): 1.10-2.67], late-onset neonatal sepsis (LONS), and patent ductus arteriosus (PDA).

CONCLUSION

In this multicenter cohort study, the duration of initial IMV was still relatively long in very premature infants, and the longer duration of initial IMV accounts for the increased risk of moderate-to-severe BPD.

Early prediction of pulmonary outcomes in preterm infants using electrical impedance tomography

Introduction

Electrical impedance tomography (EIT) allows assessment of ventilation and aeration homogeneity which may be associated with respiratory outcomes in preterm infants.

Methods

This was a secondary analysis to a recent randomized controlled trial in very preterm infants in the delivery room (DR). The predictive value of various EIT parameters assessed 30 min after birth on important respiratory outcomes (early intubation <24 h after birth, oxygen dependency at 28 days after birth, and moderate/severe bronchopulmonary dysplasia; BPD) was assessed.

Results

Thirty-two infants were analyzed. A lower percentage of aerated lung volume [OR (95% CI) = 0.8 (0.66-0.98), p = 0.027] as well as a higher aeration homogeneity ratio (i.e., more aeration in the non-gravity-dependent lung) predicted the need for supplemental oxygen at 28 days after birth [9.58 (5.16-17.78), p = 0.0028]. Both variables together had a similar predictive value to a model using known clinical contributors. There was no association with intubation or BPD, where numbers were small.

Discussion

In very preterm infants, EIT markers of aeration at 30 min after birth accurately predicted the need for supplemental oxygen at 28 days after birth but not BPD. EIT-guided individualized optimization of respiratory support in the DR may be possible.

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.

Respiratory outcomes after delivery room stabilisation with a new respiratory support system using nasal prongs

AIM

To study if stabilisation using a new respiratory support system with nasal prongs compared to T-piece with a face mask is associated with less need for mechanical ventilation and bronchopulmonary dysplasia.

METHODS

A single-centre follow-up study of neonates born <28 weeks gestation at Karolinska University Hospital, Stockholm included in the multicentre Comparison of Respiratory Support after Delivery (CORSAD) trial and randomised to initial respiratory support with the new system versus T-piece. Data on respiratory support, neonatal morbidities and mortality were collected up to 36 weeks post-menstrual age.

RESULTS

Ninety-four infants, 51 female, with a median (range) gestational age of 25 + 2 (23 + 0, 27 + 6) weeks and days, were included. Significantly fewer infants in the new system group received mechanical ventilation during the first 72 h, 24 (52.2%) compared with 35 (72.9%) (p = 0.034) and during the first 7 days, 29 (63.0%) compared with 39 (81.3%) (p = 0.045) in the T-piece group. At 36 weeks post-menstrual age, 13 (28.3%) in the new system and 13 (27.1%) in the T-piece group were diagnosed with bronchopulmonary dysplasia.

CONCLUSION

Stabilisation with the new system was associated with less need for mechanical ventilation during the first week of life. No significant difference was seen in the outcome of bronchopulmonary dysplasia.

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.

Impact of early screening echocardiography and targeted PDA treatment on neonatal outcomes in "22-23" week and "24-26" infants

The hemodynamically significant patent ductus arteriosus (hsPDA) is a controversial topic in neonatology, particularly among neonates at the earliest gestational ages of 22+0-23+6 weeks. There is little, to no data on the natural history or impact of the PDA in extremely preterm babies. In addition, these high-risk patients have typically been excluded from randomized clinical trials of PDA treatment. In this work, we present the impact of early hemodynamic screening (HS) of a cohort of patients born 22+0-23+6 weeks gestation who either were diagnosed with hsPDA or died in the first postnatal week as compared to a historical control (HC) cohort. We also report a comparator population of 24+0-26+6 weeks gestation. All patients in the HS epoch were evaluated between 12-18h postnatal age and treated based on disease physiology whereas the HC patients underwent echocardiography at the discretion of the clinical team. We demonstrate a two-fold reduction in the composite primary outcome of death prior to 36 weeks or severe BPD and report a lower incidence of severe intraventricular hemorrhage (n=5, 7% vs n=27, 27%), necrotizing enterocolitis (n=1, 1% vs n=11, 11%) and first-week vasopressor use (n=7, 11% vs n=40, 39%) in the HS cohort. HS was also associated with an increase in survival free of severe morbidity from the already high rate of 50% to 73% among neonates <24 weeks gestation. We present a biophysiological rationale behind the potential modulator role of hsPDA on these outcomes and review the physiology relevant to neonates born at these extremely preterm gestations. These data highlight the need for further interrogation of the biological impact of hsPDA and impact of early echocardiography directed therapy in infants born less than 24 weeks gestation.

Prevention for moderate or severe BPD with intravenous infusion of autologous cord blood mononuclear cells in very preterm infants-a prospective non-randomized placebo-controlled trial and two-year follow up outcomes

BACKGROUND

Bronchopulmonary dysplasia (BPD) is the primary severe complication of preterm birth. Severe BPD was associated with higher risks of mortality, more postnatal growth failure, long term respiratory and neurological developmental retardation. Inflammation plays a central role in alveolar simplification and dysregulated vascularization of BPD. There is no effective treatment to improve BPD severity in clinical practice. Our previous clinical study showed autologous cord blood mononuclear cells (ACBMNCs) infusion could reduce the respiratory support duration safely and potential improved BPD severity. Abundant preclinical studies have reported the immunomodulation effect as an important mechanism underlying the beneficial results of stem cell therapies in preventing and treating BPD. However, clinical studies assessing the immunomodulatory effect after stem cells therapy were rare. This study was to investigate the effect of ACBMNCs infusion soon after birth on prevention for severe BPD and long term outcomes in very preterm neonates. The immune cells and inflammatory biomarkers were detected to investigate the underlying immunomodulatory mechanisms.

METHODS

This single-center, prospective, investigator-initiated, non-randomized trial with blinded outcome assessment aimed to assess the effect of a single intravenous infusion of ACBMNCs in preventing severe BPD (moderate or severe BPD at 36 weeks of gestational age or discharge home) in surviving very preterm neonates less than 32 gestational weeks. Patients admitted to the Neonatal Intensive Care Unit (NICU) of Guangdong Women and Children Hospital from July 01, 2018 to January 1, 2020 were assigned to receiving a targeted dosage of 5 × 10⁷ cells/kg ACBMNC or normal saline intravenously within 24 h after enrollment. Incidence of moderate or severe BPD in survivors were investigated as the primary short term outcome. Growth, respiratory and neurological development were assessed as long term outcomes at corrected age of 18-24 month-old. Immune cells and inflammatory biomarkers were detected for potential mechanism investigation. The trial was registered at ClinicalTrials.gov (NCT02999373).

FINDINGS

Six-two infants were enrolled, of which 29 were enrolled to intervention group, 33 to control group. Moderate or severe BPD in survivors significantly decreased in intervention group (adjusted p = 0.021). The number of patients needed to treat to gain one moderate or severe BPD-free survival was 5 (95% confidence interval: 3-20). Survivors in the intervention group had a significantly higher chance to be extubated than infants in the control group (adjusted p = 0.018). There was no statistical significant difference in total BPD incidence (adjusted p = 0.106) or mortality (p = 1.000). Incidence of developmental delay reduced in intervention group in long term follow-up (adjusted p = 0.047). Specific immune cells including proportion of T cells (p = 0.04) and CD4⁺ T cells in lymphocytes (p = 0.03), and CD4+ CD25+ forkhead box protein 3 (FoxP3)+ regulatory T cells in CD4+ T cells increased significantly after ACBMNCs intervention (p ＜ 0.001). Anti-inflammatory factor IL-10 was higher (p = 0.03), while pro-inflammatory factor such as TNF-a (p = 0.03) and C reactive protein (p ＜ 0.001) level was lower in intervention group than in control group after intervention.

INTERPRETATION

ACBMNCs could prevent moderate or severe BPD in surviving very premature neonates and might improve neurodevelopmental outcomes in long term. An immunomodulatory effect of MNCs contributed to the improvement of BPD severity.

FUNDING

This work was supported by National Key R&D Program of China (2021YFC2701700), National Natural Science Foundation of China (82101817, 82171714, 8187060625), Guangzhou science and technology program (202102080104).

A review and guide to nutritional care of the infant with established bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) remains the most common long-term morbidity of premature birth, and the incidence of BPD is not declining despite medical advancements. Infants with BPD are at high risk for postnatal growth failure and are often treated with therapies that suppress growth. Additionally, these infants may display excess weight gain relative to linear growth. Optimal growth and nutrition are needed to promote lung growth and repair, improve long-term pulmonary function, and improve neurodevelopmental outcomes. Linear growth in particular has been associated with favorable outcomes yet can be difficult to achieve in these patients. While there has been a significant clinical and research focus regarding BPD prevention and early preterm nutrition, there is a lack of literature regarding nutritional care of the infant with established BPD. There is even less information regarding how nutritional needs change as BPD evolves from an acute to chronic disease. This article reviews the current literature regarding nutritional challenges, enteral nutrition management, and monitoring for patients with established BPD. Additionally, this article provides a practical framework for interdisciplinary nutritional care based on our clinical experience at the Comprehensive Center for Bronchopulmonary Dysplasia.