Perinatal risk factors for bronchopulmonary dysplasia in a national cohort of very-low-birthweight infants

Risk Calculator for Bronchopulmonary Dysplasia in Preterm Neonates: A Prospective Observational Study

OBJECTIVES

To determine the incidence, risk factors, and accuracy of a previously published risk estimator in predicting Bronchopulmonary dysplasia (BPD) in a very preterm cohort from India.

METHODS

A single-center prospective observational study was conducted in preterm neonates born at 23-30 wk of gestation with a birth weight of 501-1249 g. The incidence and risk factors of BPD were evaluated, and the accuracy of BPD prediction at six pre-specified time points using the National Institute of Child Health and Human Development (NICHD) BPD risk estimator was assessed by comparing the estimated risk with the observed rates.

RESULTS

A total of 310 neonates with mean gestation age of 28.7±1.5 wk and birth weight of 1023.6±171.4 g were enrolled in the study. The study cohort had 49.7% males and 32.3% neonates requiring resuscitation. Any BPD was observed in 54 (17.4%) neonates with severity being mild, moderate, and severe in 29 (53.7%), 17 (31.5%), and 8 (14.8%) neonates respectively. Hundred (32.3%) neonates died before discharge from the hospital. Sepsis, patent ductus arteriosus, retinopathy of prematurity, intraventricular hemorrhage, and blood transfusion were significant risk factors for the development of BPD. The calculator was accurate for the prediction of death or moderate-severe BPD on days 1 and 3 with the area under the curve of 0.82 and 0.77 respectively.

CONCLUSIONS

The NICHD BPD estimator helped to accurately predict moderate-severe BPD early in Indian preterm infants.

Late-Onset Sepsis among Extremely Preterm Infants of 24-28 Weeks Gestation: An International Comparison in 10 High-Income Countries

INTRODUCTION

Despite advances in neonatal care, late-onset sepsis remains an important cause of preventable morbidity and mortality. Neonatal late-onset sepsis rates have decreased in some countries, while in others they have not. Our objective was to compare trends in late-onset sepsis rates in 9 population-based networks from 10 countries and to assess the associated mortality within 7 days of late-onset sepsis.

METHODS

We performed a retrospective population-based cohort study. Infants born at 24-28 weeks' gestation between 2007 and 2019 were eligible for inclusion. Late-onset sepsis was defined as a positive blood or cerebrospinal fluid culture. Late-onset sepsis rates were calculated for 3 epochs (2007-11, 2012-15, and 2016-19). Adjusted risk ratios (aRRs) for late-onset sepsis were calculated for each network.

RESULTS

Of a total of 82,850 infants, 16,914 (20.4%) had late-onset sepsis, with Japan having the lowest rate (7.1%) and Spain the highest (44.6%). Late-onset sepsis rates decreased in most networks and remained unchanged in a few. Israel, Sweden, and Finland showed the largest decrease in late-onset sepsis rates. The aRRs for late-onset sepsis showed wide variations between networks. The rate of mortality temporally related to late-onset sepsis was 10.9%. The adjusted mean length of stay for infants with late-onset sepsis was increased by 5-18 days compared to infants with no late-onset sepsis.

CONCLUSIONS

One in 5 neonates of 24-28 weeks' gestation develops late-onset sepsis. Wide variability in late-onset sepsis rates exists between networks with most networks exhibiting improvement. Late-onset sepsis was associated with increased mortality and length of stay.

Improving early diagnosis of bronchopulmonary dysplasia

INTRODUCTION

Bronchopulmonary disease (BPD) is associated with long-term neurodevelopmental and cardiorespiratory complications, often requiring significant use of resources. To reduce this healthcare burden, it is essential that those at high risk of BPD are identified early so that strategies are introduced to prevent disease progression. Our aim was to discuss potential methods for improving early diagnosis in the first week after birth.

AREAS COVERED

A narrative review was undertaken. The search strategy involved searching PubMed, Embase and Cochrane databases from 1967 to 2024. The results of potential biomarkers and imaging modes are discussed. Furthermore, the value of scoring systems is explored.

EXPERT OPINION

BPD occurs as a result of disruption to pulmonary vascular and alveolar development, thus abnormal levels of factors regulating those processes are promising avenues to explore with regard to early detection of high-risk infants. Data from twin studies suggests genetic factors can be attributed to 82% of the observed difference in moderate to severe BPD, but large genome-wide studies have yielded conflicting results. Comparative studies are required to determine which biomarker or imaging mode may most accurately diagnose early BPD development. Models which include the most predictive factors should be evaluated going forward.

Outcomes after aortic coarctation repair in neonates weighing less than 2000 g

BACKGROUND

Preterm birth is common in children with congenital heart disease. However, data on how to manage low-birth-weight infants with aortic coarctation are scarce and outcomes are poorly reported. Surgery is often delayed in these infants because gaining weight is supposed to improve mortality and to reduce the risk for recoarctation.

METHODS

All infants weighing less than 2000 g who underwent repair for aortic coarctation at our institution between January 2017 and December 2020 were included in a retrospective study. Baseline characteristics, medical and surgical management, and outcomes, including recoarctation, death, and complications of preterm birth, were analyzed.

RESULTS

A total of 15 patients had coarctation repair at a median age of 15 days and at a median weight of 1585 g. Infants with a birth weight <1200 g were operated on later and did not have higher recoarctation rates compared to those with a birth weight >1200 g. The recoarctation rate was 26.6% and one infant died of an extracardiac cause. Concerning prematurity-related complications, we observed 40% of bronchopulmonary dysplasia, 40% of intraventricular hemorrhage, and 27% of retinopathy of prematurity. These complications were more prevalent in children with a birth weight of <1200 g.

CONCLUSION

Delaying surgery beyond 15 days to gain weight does not appear to decrease the risk of recoarctation and may be deleterious in low-birth-weight infants who are exposed for a longer period to risk factors of prematurity-related complications.

Mesenchymal stromal/stem cells and bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is a common complication in preterm infants, leading to chronic respiratory disease. There has been an improvement in perinatal care, but many infants still suffer from impaired branching morphogenesis, alveolarization, and pulmonary capillary formation, causing lung function impairments and BPD. There is an increased risk of respiratory infections, pulmonary hypertension, and neurodevelopmental delays in infants with BPD, all of which can lead to long-term morbidity and mortality. Unfortunately, treatment options for Bronchopulmonary dysplasia are limited. A growing body of evidence indicates that mesenchymal stromal/stem cells (MSCs) can treat various lung diseases in regenerative medicine. MSCs are multipotent cells that can differentiate into multiple cell types, including lung cells, and possess immunomodulatory, anti-inflammatory, antioxidative stress, and regenerative properties. MSCs are regulated by mitochondrial function, as well as oxidant stress responses. Maintaining mitochondrial homeostasis will likely be key for MSCs to stimulate proper lung development and regeneration in Bronchopulmonary dysplasia. In recent years, MSCs have demonstrated promising results in treating and preventing bronchopulmonary dysplasia. Studies have shown that MSC therapy can reduce inflammation, mitochondrial impairment, lung injury, and fibrosis. In light of this, MSCs have emerged as a potential therapeutic option for treating Bronchopulmonary dysplasia. The article explores the role of MSCs in lung development and disease, summarizes MSC therapy's effectiveness in treating Bronchopulmonary dysplasia, and delves into the mechanisms behind this treatment.

From nitrate to NO: potential effects of nitrate-reducing bacteria on systemic health and disease

Current research has described improving multisystem disease and organ function through dietary nitrate (DN) supplementation. They have provided some evidence that these floras with nitrate (NO3-) reductase are mediators of the underlying mechanism. Symbiotic bacteria with nitrate reductase activity (NRA) are found in the human digestive tract, including the mouth, esophagus and gastrointestinal tract (GT). Nitrate in food can be converted to nitrite under the tongue or in the stomach by these symbiotic bacteria. Then, nitrite is transformed to nitric oxide (NO) by non-enzymatic synthesis. NO is currently recognized as a potent bioactive agent with biological activities, such as vasodilation, regulation of cardiomyocyte function, neurotransmission, suppression of platelet agglutination, and prevention of vascular smooth muscle cell proliferation. NO also can be produced through the conventional L-arginine-NO synthase (L-NOS) pathway, whereas endogenous NO production by L-arginine is inhibited under hypoxia-ischemia or disease conditions. In contrast, exogenous NO3-/NO2-/NO activity is enhanced and becomes a practical supplemental pathway for NO in the body, playing an essential role in various physiological activities. Moreover, many diseases (such as metabolic or geriatric diseases) are primarily associated with disorders of endogenous NO synthesis, and NO generation from the exogenous NO3-/NO2-/NO route can partially alleviate the disease progression. The imbalance of NO in the body may be one of the potential mechanisms of disease development. Therefore, the impact of these floras with nitrate reductase on host systemic health through exogenous NO3-/NO2-/NO pathway production of NO or direct regulation of floras ecological balance is essential (e.g., regulation of body homeostasis, amelioration of diseases, etc.). This review summarizes the bacteria with nitrate reductase in humans, emphasizing the relationship between the metabolic processes of this microflora and host systemic health and disease. The potential effects of nitrate reduction bacteria on human health and disease were also highlighted in disease models from different human systems, including digestive, cardiovascular, endocrine, nervous, respiratory, and urinary systems, providing innovative ideas for future disease diagnosis and treatment based on nitrate reduction bacteria.

Optimising success of neonatal extubation: Respiratory support

In this review, we examine lung physiology before, during and after neonatal extubation and propose a three-phase model for the extubation procedure. We perform meta-analyses to compare different modes of non-invasive respiratory support after neonatal extubation and based on the findings, the following clinical recommendations are made.

Neurodevelopmental Outcome of Very Low Birth Weight Infants in the Northern District of Israel: A Cross-Sectional Study

BACKGROUND

Currently, no local database in Israel collects neurodevelopmental outcomes of very low birth weight (VLBW) preterm infants. We investigated neurodevelopmental outcomes in one district of the largest healthcare organization in Israel.

METHODS

A cross-sectional study including all VLBW (<1500 g) preterm infants born between 1 January 2006 and 31 December 2016 who were followed in any of seven child development centers in Israel's Northern District. Data were retrospectively collected from the computerized medical record database.

RESULTS

Out of 436 participants, 55.1% had normal developmental outcomes. A total of 8.9% had cerebral palsy (CP), 12.2% had a global developmental delay (GDD), and 33.4% had a language delay. Out of the extremely preterm infants (n = 109), 20.2% had CP, 22.0% had GDD, and 44.9% had language delay. We found a statistically significant higher rate of abnormal neurodevelopment outcomes in non-Jews compared to Jews (57% vs. 37.8%, respectively, p < 0.0001).

CONCLUSIONS

We found a relatively high overall rate of CP in our local population and a significant difference in neurodevelopmental outcomes between Jews and non-Jews. This study emphasizes the need for an expanded and detailed national database collecting post-discharge outcomes, as well as an assessment of national healthcare resource allocation and inequalities in preterm infants' post-discharge care.

Development and Validation of a Risk Scoring Tool for Bronchopulmonary Dysplasia in Preterm Infants Based on a Systematic Review and Meta-Analysis

Background: Bronchopulmonary dysplasia (BPD) is the most common serious pulmonary morbidity in preterm infants with high disability and mortality rates. Early identification and treatment of BPD is critical. Objective: This study aimed to develop and validate a risk scoring tool for early identification of preterm infants that are at high-risk for developing BPD. Methods: The derivation cohort was derived from a systematic review and meta-analysis of risk factors for BPD. The statistically significant risk factors with their corresponding odds ratios were utilized to construct a logistic regression risk prediction model. By scoring the weights of each risk factor, a risk scoring tool was established and the risk stratification was divided. External verification was carried out by a validation cohort from China. Results: Approximately 83,034 preterm infants with gestational age < 32 weeks and/or birth weight < 1500 g were screened in this meta-analysis, and the cumulative incidence of BPD was about 30.37%. The nine predictors of this model were Chorioamnionitis, Gestational age, Birth weight, Sex, Small for gestational age, 5 min Apgar score, Delivery room intubation, and Surfactant and Respiratory distress syndrome. Based on the weight of each risk factor, we translated it into a simple clinical scoring tool with a total score ranging from 0 to 64. External validation showed that the tool had good discrimination, the area under the curve was 0.907, and that the Hosmer-Lemeshow test showed a good fit (p = 0.3572). In addition, the results of the calibration curve and decision curve analysis suggested that the tool showed significant conformity and net benefit. When the optimal cut-off value was 25.5, the sensitivity and specificity were 0.897 and 0.873, respectively. The resulting risk scoring tool classified the population of preterm infants into low-risk, low-intermediate, high-intermediate, and high-risk groups. This BPD risk scoring tool is suitable for preterm infants with gestational age < 32 weeks and/or birth weight < 1500 g. Conclusions: An effective risk prediction scoring tool based on a systematic review and meta-analysis was developed and validated. This simple tool may play an important role in establishing a screening strategy for BPD in preterm infants and potentially guide early intervention.

Risk prediction of bronchopulmonary dysplasia in preterm infants by the nomogram model

Backgrounds and Aims

Bronchopulmonary dysplasia (BPD) has serious immediate and long-term sequelae as well as morbidity and mortality. The objective of this study is to develop a predictive model of BPD for premature infants using clinical maternal and neonatal parameters.

Methods

This single-center retrospective study enrolled 237 cases of premature infants with gestational age less than 32 weeks. The research collected demographic, clinical and laboratory parameters. Univariate logistic regression analysis was carried out to screen the potential risk factors of BPD. Multivariate and LASSO logistic regression analysis was performed to further select variables for the establishment of nomogram models. The discrimination of the model was assessed by C-index. The Hosmer-Lemeshow test was used to assess the calibration of the model.

Results

Multivariate analysis identified maternal age, delivery option, neonatal weight and age, invasive ventilation, and hemoglobin as risk predictors. LASSO analysis selected delivery option, neonatal weight and age, invasive ventilation, hemoglobin and albumin as the risk predictors. Both multivariate (AUC = 0.9051; HL P = 0.6920; C-index = 0.910) and LASSO (AUC = 0.8935; HL P = 0.7796; C-index = 0.899) - based nomograms exhibited ideal discrimination and calibration as confirmed by validation dataset.

Conclusions

The probability of BPD in a premature infant could be effectively predicted by the nomogram model based on the clinical maternal and neonatal parameters. However, the model required external validation using larger samples from multiple medical centers.

Effects of early aminophylline therapy on clinical outcomes in premature infants

BACKGROUND

Aminophylline use and the association between clinical outcomes and therapy timing have been less investigated. The objective of this study was to determine the efficacy of early aminophylline use (within the first two days of life) in premature infants.

METHOD

A retrospective observational cohort of infants weighing <1500 g and <30 weeks of gestational age at Kaohsiung Veterans General Hospital received aminophylline either within the first two days of life (EA, early aminophylline group), after the third day of life (LA, late aminophylline group), or without aminophylline during the first month of life (WA, without aminophylline group). Demographic data and neonatal clinical outcomes were compared among the three groups.

RESULTS

This study included 89 preterm infants (EA = 33, LA = 38, WA = 18). The EA group had a lower incidence of bronchopulmonary dysplasia (BPD) than the WA group (adjusted odds ratio [aOR] = 8.86(1.56-59.32); P = 0.024). Although there was no significant difference in BPD incidence between the EA and LA groups (aOR = 2.66(0.51-13.81), P = 0.244), a trend remained. Birth body weight less than 1000 g was also a significant risk factor for BPD (aOR = 8.86(1.32-47.41), P = 0.014). The duration of mechanical ventilation was shorter in the infants in the EA group compared to the WA group (estimated beta = -11.344(-19.57-3.12); P = 0.008).

CONCLUSION

Early aminophylline administration may be associated with a decreased incidence of BPD in preterm infants. However, the clinical benefits of aminophylline treatment require further investigation. In addition, a birth body weight of less than 1000 g was a crucial risk factor for BPD.

Impact of hypertensive disorders of pregnancy on respiratory outcomes in extremely and very preterm infants: A population-based study in Japan

OBJECTIVES

We aimed to evaluate the impact of hypertensive disorders of pregnancy (HDP) on short- and medium-term respiratory outcomes in extremely and very preterm infants using the Neonatal Research Network of Japan database.

STUDY DESIGN

This was a population-based retrospective study of preterm infants weighing ≤ 1500 g born between 22 and 31 weeks of gestation between 2003 and 2017. After 1:1 stratification matching by four factors (maternal age, gestational age, parity, and year of delivery), a total of 5137 infants in each group (HDP and non-HDP groups) were selected.

MAIN OUTCOME MEASURES

The association between HDP and various respiratory outcomes was evaluated using univariate and multivariate logistic regression analyses.

RESULTS

In the multivariate analyses, HDP was associated with higher odds for respiratory distress syndrome (RDS) (odds ratio 1.83, 95% confidence interval [1.65-2.03]), but reduced odds of persistent pulmonary hypertension of the newborn (PPHN) (0.34 [0.26-0.46]) and inhaled nitric oxide use (0.43 [0.33-0.55]). Although HDP was associated with an increased risk of chronic lung disease (CLD) in the univariate analysis, this association was not significant after adjustment for covariates (0.94 [0.83-1.07]). No significant association was found between HDP and home oxygen therapy (HOT) and medium-term oxygen use.

CONCLUSION

The impact of maternal HDP largely differed depending on respiratory disorders and respiratory support. HDP was associated with higher odds of RDS but reduced odds of PPHN. The risks for CLD, HOT, and medium-term respiratory outcomes in the HDP group were comparable to those in the non-HDP group.

Caffeine and bronchopulmonary dysplasia: Clinical benefits and the mechanisms involved

Bronchopulmonary dysplasia (BPD) is a chronic respiratory disease that occurs during the neonatal period and is commonly associated with prematurity. This condition results in a severe economic burden on society and the families involved. Caffeine is used not only for the treatment of apnea in prematurity, but also for the prevention of BPD. There are multiple clinical benefits of caffeine treatment, including improved extubation success, a reduced duration of mechanical ventilation, improved lung function, and a reduction of patent ductus arteriosus requiring treatment. These clinical benefits of caffeine for the treatment of BPD are supported by both clinical trials and evidence from animal models. However, the mechanism by which caffeine protects against BPD remains unclear. Here, we review the clinical value of caffeine in the prevention of BPD and its potential mechanisms of action, including anti-inflammatory, antioxidant, antifibrotic, and antiapoptotic properties, the regulation of angiogenesis, and diuretic effects. Our aim is to provide a new theoretical basis for the clinical treatment of BPD.

Association of Maternal Hypertensive Disorders During Pregnancy With Severe Bronchopulmonary Dysplasia: A Systematic Review and Meta-Analysis

BACKGROUND

This meta-analysis was performed to examine the association between maternal hypertension during pregnancy (HDP) and neonatal bronchopulmonary dysplasia (BPD).

METHODS

We systematically searched PubMed, EMBASE, the Cochrane Library, and the KoreaMed database for relevant studies. We used the Newcastle-Ottawa Scale for quality assessment of all included studies. The meta-analysis was performed using Comprehensive Meta-Analysis software (version 3.3).

RESULTS

We included 35 studies that fulfilled the inclusion criteria; the total number of infants evaluated came to 97,399 through review process. Maternal HDP was not significantly associated with any definition of BPD, i.e., oxygen dependency at 36 weeks of gestation (odds ratio [OR], 1.162; 95% confidence interval [CI], 0.991-1.362; P = 0.064) in pooled analysis of 29 studies or oxygen dependency at 28 days of age (OR, 1.084; 95% CI, 0.660-1.780; P = 0.751) in pooled analysis of 8 studies. Maternal HDP was significantly associated only with severe BPD (OR, 2.341; 95% CI, 1.726-3.174; P < 0.001). BPD was not associated with HDP in the overall analysis (OR, 1.131; 95% CI, 0.977-1.309; P = 0.100) or subgroup analysis according to the definition of HDP.

CONCLUSION

Maternal HDP was not associated with neonatal BPD defined by the duration of oxygen dependency (at either 36 weeks of gestation or 28 days of life) but was associated with severe BPD.

The Relationship Between Cord Blood Cytokine Levels and Perinatal Characteristics and Bronchopulmonary Dysplasia: A Case-Control Study

Objective

To establish the association between serial levels of inflammatory cytokines in cord blood and perinatal characteristics and bronchopulmonary dysplasia (BPD) in preterm infants.

Methods

147 premature infants with gestational age ≤32 weeks who were born and hospitalized in the First Affiliated Hospital of Zhengzhou University between July 2019 and August 2021 were enrolled in this retrospective case-control study. Multiple microsphere flow immunofluorescence was used to detect seven cytokines in cord blood collected within 24 h of birth. Demographics, delivery characteristics, maternal factors, neonatal characteristics, and clinical outcomes were collected for the two groups. An unconditional logistic regression model was used in this study to assess the clinical variables.

Results

IL-6 cord blood levels at birth were significantly higher in the BPD group than in the non-BPD group, but the odds ratio (OR) was very small (OR = 1). No differences in other cytokine concentrations were observed between the two groups. Multivariable logistic regression analysis demonstrated that increased maternal white blood cell (WBC) count on admission and lower birth weight increased the risk of BPD progression.

Conclusions

Increased IL-6 cord blood levels at birth in preterm infants may have trivial significance for predicting BPD. Furthermore, higher maternal WBC count on admission and lower birth weight increased the risk of BPD.

Novel Ventilation Strategies to Reduce Adverse Pulmonary Outcomes

Extremely preterm infants who must suddenly support their own gas exchange with lungs that are incompletely developed and lacking adequate amount of surfactant and antioxidant defenses are susceptible to lung injury. The decades-long quest to prevent bronchopulmonary dysplasia has had limited success, in part because of increasing survival of more immature infants. The process must begin in the delivery room with gentle assistance in establishing and maintaining adequate lung aeration, followed by noninvasive support and less invasive surfactant administration. Various modalities of invasive and noninvasive support have been used with varying degree of effect and are reviewed in this article.

Risk factors and bronchopulmonary dysplasia severity: data from the Spanish Bronchopulmonary Dysplasia Research Network

GEIDIS is a national-based research-net registry of patients with bronchopulmonary dysplasia (BPD) from public and private Spanish hospitals. It was created to provide data on the clinical characterization and follow-up of infants with BPD until adulthood. The purpose of this observational study was to analyze the characteristics and the impact of perinatal risk factors on BPD severity. The study included 1755 preterm patients diagnosed with BPD. Of the total sample, 90.6% (n = 1591) were less than 30 weeks of gestation. The median gestational age was 27.1 weeks (25.8-28.5) and median birth weight 885 g (740-1,070 g). A total of 52.5% (n = 922) were classified as mild (type 1), 25.3% (n = 444) were moderate (type 2), and 22.2% (n = 389) were severe BPD (type 3). In patients born at under 30 weeks' gestation, most pre-and postnatal risk factors for type 2/3 BPD were associated with the length of exposure to mechanical ventilation (MV). Independent prenatal risk factors were male gender, oligohydramnios, and intrauterine growth restriction. Postnatal risk factors included the need for FiO2 of > 0.30 in the delivery room, nosocomial pneumonia, and the length of exposure to MV. Conclusion: In this national-based research-net registry of BPD patients, the length of MV is the most important risk factor associated with type 2/3 BPD. Among type 3 BPD patients, those who required an FiO2 > .30 at 36 weeks' postmenstrual age had a higher morbidity, during hospitalization and at discharge, compared to those with nasal positive pressure but FiO2 < .30. What is Known: • BPD is a highly complex multifactorial disease associated with preterm birth. What is New: • The length of exposure to mechanical ventilation is the most important postnatal risk factor associated to bronchopulmonary severity which modulate the effect of most pre and postnatal risk factors. • Among patients with BPD, the requirement for FiO2 >.30% at 36 weeks of postmenstrual age is associated with greater morbidity during hospitalization and at discharge.

The DELUX study: development of lung volumes during extubation of preterm infants

OBJECTIVE

To measure changes in end-expiratory lung impedance (EELI) as a marker of functional residual capacity (FRC) during the entire extubation procedure of very preterm infants.

METHODS

Prospective observational study in preterm infants born at 26-32 weeks gestation being extubated to non-invasive respiratory support. Changes in EELI and cardiorespiratory parameters (heart rate, oxygen saturation) were recorded at pre-specified events during the extubation procedure compared to baseline (before first handling of the infant).

RESULTS

Overall, 2912 breaths were analysed in 12 infants. There was a global change in EELI during the extubation procedure (p = 0.029). EELI was lowest at the time of extubation [median (IQR) difference to baseline: -0.30 AU/kg (-0.46; -0.14), corresponding to an FRC loss of 10.2 ml/kg (4.8; 15.9), p_adj = 0.004]. The biggest EELI loss occurred during adhesive tape removal [median change (IQR): -0.18 AU/kg (-0.22; -0.07), p_adj = 0.004]. EELI changes were highly correlated with changes in the SpO₂/FiO₂ ratio (r = 0.48, p < 0.001). Forty per cent of FRC was re-recruited at the tenth breath after the initiation of non-invasive ventilation (p < 0.001).

CONCLUSIONS

The extubation procedure is associated with significant changes in FRC. This study provides novel information for determining the optimal way of extubating a preterm infant.

IMPACT

This study is the first to examine the development of lung volumes during the entire extubation procedure including the impact of associated events. The extubation procedure significantly affects functional residual capacity with a loss of approximately 10 ml/kg at the time of extubation. Removal of adhesive tape is the major contributing factor to FRC loss during the extubation procedure. Functional residual capacity is regained within the first breaths after initiation of non-invasive ventilation and is further increased after turning the infant into the prone position.

Hyperoxia/Hypoxia Exposure Primes a Sustained Pro-Inflammatory Profile of Preterm Infant Macrophages Upon LPS Stimulation

Preterm infants are highly susceptible to sustained lung inflammation, which may be triggered by exposure to multiple environmental cues such as supplemental oxygen (O₂) and infections. We hypothesized that dysregulated macrophage (MФ) activation is a key feature leading to inflammation-mediated development of bronchopulmonary dysplasia (BPD) in preterm infants. Therefore, we aimed to determine age-dependent differences in immune responses of monocyte-derived MФ comparing cord blood samples derived from preterm (n=14) and term (n=19) infants as well as peripheral blood samples from healthy adults (n=17) after lipopolysaccharide (LPS) exposure. Compared to term and adult MФ, LPS-stimulated preterm MФ showed an enhanced and sustained pro-inflammatory immune response determined by transcriptome analysis, cytokine release inducing a RORC upregulation due to T cell polarization of neonatal T cells, and TLR4 surface expression. In addition, a double-hit model was developed to study pulmonary relevant exposure factors by priming MФ with hyperoxia (O₂ = 65%) or hypoxia (O₂ = 3%) followed by lipopolysaccharide (LPS, 100ng/ml). When primed by 65% O₂, subsequent LPS stimulation in preterm MФ led to an exaggerated pro-inflammatory response (e.g. increased HLA-DR expression and cytokine release) compared to LPS stimulation alone. Both, exposure to 65% or 3% O₂ together with subsequent LPS stimulation, resulted in an exaggerated pro-inflammatory response of preterm MФ determined by transcriptome analysis. Downregulation of two major transcriptional factors, early growth response gene (Egr)-2 and growth factor independence 1 (Gfi1), were identified to play a role in the exaggerated pro-inflammatory response of preterm MФ to LPS insult after priming with 65% or 3% O₂. Preterm MФ responses to LPS and hyperoxia/hypoxia suggest their involvement in excessive inflammation due to age-dependent differences, potentially mediated by downregulation of Egr2 and Gfi1 in the developing lung.

Development and verification of a risk prediction model for bronchopulmonary dysplasia in very low birth weight infants

BACKGROUND

To analyze the risk factors of bronchopulmonary dysplasia (BPD) of very low birth weight infants (VLBWIs), and to develop and verify a risk prediction model of BPD.

METHODS

The data of 611 VLBWIs from the neonatal intensive care unit (NICU) of a tertiary grade A hospital in Suzhou from January 2017 to September 2019 were collected. The data was randomly divided into the modeling set (451 cases) and the validation set (160 cases). Binary logistic regression was used to analyze the data, and the model was examined by a receiver operating characteristic (ROC) curve. The grouped data was used to verify the sensitivity and specificity of the model.

RESULTS

The study found that neonatal asphyxia, the positive rate of sputum culture, neonatal sepsis, neonatal respiratory distress syndrome (NRDS), blood transfusions (≥3), patent ductus arteriosus (PDA), the time of invasive mechanical ventilation, the duration of oxygen therapy, and the time of parenteral nutrition were the independent risk factors of BPD, while 1 min Apgar score was a protective factor. The model formula was Z=neonatal asphyxia * 1.229 + the positive rate of sputum culture * 1.265 + neonatal sepsis * 1.677 + NRDS * 1.848 + blood transfusions (≥3) * 1.455 + PDA * 1.835 - 1 min Apgar score * 0.25 + the time of invasive mechanical ventilation * 0.123 + the duration of oxygen therapy * 0.09 + the time of parenteral nutrition * 0.057 - 8.077. The area under the ROC curve of this model was 0.965 (95% CI: 0.946-0.983), with a sensitivity of 93.7% and a specificity of 91.3%. Verification of this prediction model showed a sensitivity of 92.9% and a specificity of 76%, demonstrating that the effects of this model were satisfactory.

CONCLUSIONS

The risk prediction model had a good predictive effect for the risk of BPD in VLBWIs, and can provide a reference for preventive treatment and nursing intervention.

Antepartum Hemorrhage and Outcome of Very Low Birth Weight, Very Preterm Infants: A Population-Based Study

OBJECTIVE

We aimed to determine the independent effect of maternal antepartum hemorrhage (APH) on mortality and major neonatal morbidities among very low birth weight (VLBW), very preterm infants.

STUDY DESIGN

A population-based cohort study of VLBW singleton infants born at 24 to 31 weeks of gestation between 1995 and 2016 was performed. Infants born with the following pregnancy associated complications were excluded: maternal hypertensive disorders, prolonged rupture of membranes, amnionitis, maternal diabetes, and small for gestational age. APH included hemorrhage due to either placenta previa or placental abruption. Univariate and multivariable logistic regression analyses were performed to assess the effect of maternal APH on mortality and major neonatal morbidities.

RESULTS

The initial cohort included 33,627 VLBW infants. Following exclusions, the final study population comprised 6,235 infants of whom 2,006 (32.2%) were born following APH and 4,229 (67.8%) without APH. In the APH versus no APH group, there were higher rates of extreme prematurity (24-27 weeks of gestation; 51.6% vs. 45.3%, p < 0.0001), mortality (20.2 vs. 18.5%, p = 0.011), bronchopulmonary dysplasia (BPD, 16.1 vs. 13.0%, p = 0.004) and death or adverse neurologic outcome (37.4 vs. 34.5%, p = 0.03). In the multivariable analyses, APH was associated with significantly increased odds ratio (OR) for BPD in the extremely preterm infants (OR: 1.31, 95% confidence interval: 1.05-1.65). The OR's for mortality, adverse neurological outcomes, and death or adverse neurological outcome were not significantly increased in the APH group.

CONCLUSION

Among singleton, very preterm VLBW infants, maternal APH was associated with increased odds for BPD only in extremely premature infants, but was not associated with excess mortality or adverse neonatal neurological outcomes.

KEY POINTS

· Outcome of very low birth weight infants born after antepartum hemorrhage (APH) was assessed.. · APH was not associated with higher infant mortality.. · APH was not associated with adverse neurological outcome.. · APH was associated with increased bronchopulmonary dysplasia in extremely preterm infants..

The Role of Nutrition in the Prevention and Management of Bronchopulmonary Dysplasia: A Literature Review and Clinical Approach

Bronchopulmonary dysplasia (BPD) remains the most common severe complication of preterm birth, and nutrition plays a crucial role in lung growth and repair. A practical nutritional approach for infants at risk of BPD or with established BPD is provided based on a comprehensive literature review. Ideally, infants with BPD should receive a fluid intake of not more than 135-150 mL/kg/day and an energy intake of 120-150 kcal/kg/day. Providing high energy in low volume remains a challenge and is the main cause of growth restriction in these infants. They need a nutritional strategy that encompasses early aggressive parenteral nutrition and the initiation of concentrated feedings of energy and nutrients. The order of priority is fortified mother's own milk, followed by fortified donor milk and preterm enriched formulas. Functional nutrient supplements with a potential protective role against BPD are revisited, despite the limited evidence of their efficacy. Specialized nutritional strategies may be necessary to overcome difficulties common in BPD infants, such as gastroesophageal reflux and poorly coordinated feeding. Planning nutrition support after discharge requires a multidisciplinary approach to deal with multiple potential problems. Regular monitoring based on anthropometry and biochemical markers is needed to guide the nutritional intervention.

New BPD-prevalence and risk factors for bronchopulmonary dysplasia/mortality in extremely low gestational age infants ≤28 weeks

OBJECTIVE

To evaluate prevalence and risk factors of moderate-severe Bronchopulmonary dysplasia (BPD)/Death in extremely low gestation age neonates (ELGANs).

STUDY DESIGN

Study of 266 ELGANs born at gestational age (GA) ≤ 28 weeks (w). Primary Outcome measure-composite outcome of moderate-severe BPD/Death using the National Institute of Child Health and Human Development NICHD's (2001) BPD definition.

RESULT

Cohort's mean GA and birth-weight (BW) were 25.3 ± 1.4w and 724 ± 14 g respectively with an overall mortality of 19% and moderate-severe BPD of 67%. Prevalence of moderate-severe BPD/death decreased significantly with increasing GA (86-93%) at 23-24 w; to <60% at 27-28w (OR 0.63; 95% CI; 0.52-0.77). On univariate analysis, other risk factors included BW(OR 1.005; 95% CI; 1.003-1.007), Sepsis (OR 2.9; 95% CI, 1.3-6.4), PDA needing treatment (OR 2.2; 95% CI, 1.3-3.9); air leaks (OR 2.7; 95% CI; 1.02-7.3) FiO₂ requirement >25%(OR 1.06; 95% CI; 1.01-1.11); and mechanical ventilation(MV) on Day7 (OR5.5; 95% CI; 2.8-10.8). Only need for Day7 MV was independently predictive of composite outcome (OR1.97; 95% CI; 1.3-3.1).

CONCLUSION

Risk factor identification will enable initiatives to implement lung protective strategies and develop prospective models for BPD prediction and prognostication.

Neurodevelopmental outcomes in very preterm infants: The role of severity of Bronchopulmonary Dysplasia

OBJECTIVE

Bronchopulmonary dysplasia is a chronic respiratory disease that still affects preterm neonates; its association with neurodevelopmental (ND) impairment is already known. Different studies investigated neurodevelopmental outcomes in infants with BPD, often using the old dichotomous definition (BPD vs Non-BPD). This retrospective study aims to evaluate the role of different BPD severity grades on ND outcomes at 24 months of corrected age (CA).

METHODS

All preterm infants born between 2011 and 2015 in the study hospital with a gestational age (GA) ≤ 30 weeks and discharged from our NICU were included and were divided in infants with and without BPD. Infants with BPD were divided into three severity groups as defined by NICHD/NHLBI Workshop in 2001, and were compared to their Non-BPD peers, matching them according to the same GA and year of birth. At 24 months postmenstrual age, we assessed general outcomes (growth and hospital readmissions) and neurodevelopmental outcomes (motor, developmental and sensory outcomes) with a standardized assessment.

RESULTS

We enrolled 89 patients affected by BPD of different grades of severity and a control group of 89 preterm infants without BPD. Infants with Moderate and Severe BPD showed a significantly higher corrected odds ratio (OR) for cognitive impairment compared to controls. Within the group of infants without severe disability (regarding Griffiths' scales), infants with Moderate and Severe BPD as well as infants with Mild BPD showed a significantly higher risk of a lower total Developmental Quotient (DQ) score, even after correction for confounding factors.

CONCLUSIONS

Our study evidenced that not only Severe BPD infants, but also Moderate ones showed a higher risk of overall cognitive impairment at 24 months CA. Within the group of infants without severe disability, also those with Mild BPD had lower Griffiths DQ scores than those without. This would suggest that infants with BPD, regardless of severity, warrant neurodevelopmental follow-up.

Respiratory Tract Microecology and Bronchopulmonary Dysplasia in Preterm Infants

Bronchopulmonary dysplasia (BPD) is a severe respiratory complication in preterm infants. Although the etiology and pathogenesis of BPD are complex and remain to be clarified, recent studies have reported a certain correlation between the microecological environment of the respiratory tract and BPD. Changes in respiratory tract microecology, such as abnormal microbial diversity and altered evolutional patterns, are observed prior to the development of BPD in premature infants. Therefore, research on the colonization and evolution of neonatal respiratory tract microecology and its relationship with BPD is expected to provide new ideas for its prevention and treatment. In this paper, we review microecological changes in the respiratory tract and the mechanisms by which they can lead to BPD in preterm infants.

Survival without Bronchopulmonary Dysplasia of Extremely Preterm Infants: A Predictive Model at Birth

INTRODUCTION

Early prediction of survival without bronchopulmonary dysplasia (BPD) at 36 weeks of postmenstrual age remains challenging for infants born extremely preterm. We aimed to provide a new predictive model including variables available only at or soon after birth based on the literature and existing models.

METHODS

We conducted a systematic review to identify all variables considered to be significant predictors of BPD and survival at birth in extremely preterm infants. We then assessed the external validity of the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) Neonatal Research Network BPD estimator on the PREMILOC cohort, a recent French study with a large sample of extremely preterm infants and a vast number of variables at baseline. Finally, we attempted to improve this model by testing the added value of other early predictors reported in previous studies.

RESULTS

Restricted to baseline predictors, the NICHD Neonatal Research Network BPD estimator confirmed its calibration and fair discrimination (area under the receiver operating characteristic [auROC] [95% CI] = 0.73 [0.68-0.77] when used with a published model and auROC [95% CI] = 0.77 [0.73-0.81] when fitted to the PREMILOC dataset). We were able to improve the discriminatory power by adding candidate variables at birth associated with BPD in previous studies. The modified best predicting model included gestational age at birth, birthweight, respiratory support at baseline, gender, center effect, and multiple pregnancy as baseline predictors. This model showed significantly better discrimination (auROC [95% CI] = 0.85 [0.82-0.88]) and better confirmed calibration (Hosmer-Lemeshow test, p = 0.45).

CONCLUSION

This new model, based on 6 early predictors, appears to improve the prediction soon after birth of BPD-free survival in extremely preterm infants.

What is bronchopulmonary dysplasia and does caffeine prevent it?

Bronchopulmonary dysplasia (BPD) is among the most severe complications of very premature birth. Clinical and laboratory studies indicate that lung immaturity, inflammatory lung injury, and disordered lung repair are the primary mechanisms responsible for the development of BPD. Caffeine, initiated within the first 10 days after birth, is one of few drug therapies shown to significantly decrease the risk of BPD in very low birth weight infants. This benefit is likely derived, at least in part, from reduced exposure to positive airway pressure and supplemental oxygen with caffeine therapy. Additional cardiorespiratory benefits of caffeine that may contribute to the lower risk of BPD include less frequent treatment for a PDA, improved pulmonary mechanics, and direct effects on pulmonary inflammation, alveolarization, and angiogenesis. Routine administration of caffeine is indicated in the vast majority of very low birth weight infants. However, current preventative strategies including widespread use of caffeine do not avert BPD in all cases. As such, there is continued need for novel methods to further reduce the risk of BPD in very low birth weight infants.

Endothelial to mesenchymal transition during neonatal hyperoxia-induced pulmonary hypertension

Bronchopulmonary dysplasia (BPD), a chronic lung disease in premature infants, results from mechanical ventilation and hyperoxia, amongst other factors. Although most BPD survivors can be weaned from supplemental oxygen, many show evidence of cardiovascular sequelae in adulthood, including pulmonary hypertension and pulmonary vascular remodeling. Endothelial-mesenchymal transition (EndoMT) plays an important role in mediating vascular remodeling in idiopathic pulmonary arterial hypertension. Whether hyperoxic exposure, a known mediator of BPD in rodent models, causes EndoMT resulting in vascular remodeling and pulmonary hypertension remains unclear. We hypothesized that neonatal hyperoxic exposure causes EndoMT, leading to the development of pulmonary hypertension in adulthood. To test this hypothesis, newborn mice were exposed to hyperoxia and then allowed to recover in room air until adulthood. Neonatal hyperoxic exposure gradually caused pulmonary vascular and right ventricle remodeling as well as pulmonary hypertension. Male mice were more susceptible to developing pulmonary hypertension compared to female mice, when exposed to hyperoxia as newborns. Hyperoxic exposure induced EndoMT in mouse lungs as well as in cultured lung microvascular endothelial cells (LMVECs) isolated from neonatal mice and human fetal donors. This was augmented in cultured LMVECs from male donors compared to those from female donors. Using primary mouse LMVECs, hyperoxic exposure increased phosphorylation of both Smad2 and Smad3, but reduced Smad7 protein levels. Treatment with a selective TGF-β inhibitor SB431542 blocked hyperoxia-induced EndoMT in vitro. Altogether, we show that neonatal hyperoxic exposure caused vascular remodeling and pulmonary hypertension in adulthood. This was associated with increased EndoMT. These novel observations provide mechanisms underlying hyperoxia-induced vascular remodeling and potential approaches to prevent BPD-associated pulmonary hypertension by targeting EndoMT. © 2020 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Present and Future of Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is the most common respiratory disorder among infants born extremely preterm. The pathogenesis of BPD involves multiple prenatal and postnatal mechanisms affecting the development of a very immature lung. Their combined effects alter the lung's morphogenesis, disrupt capillary gas exchange in the alveoli, and lead to the pathological and clinical features of BPD. The disorder is ultimately the result of an aberrant repair response to antenatal and postnatal injuries to the developing lungs. Neonatology has made huge advances in dealing with conditions related to prematurity, but efforts to prevent and treat BPD have so far been only partially effective. Seeing that BPD appears to have a role in the early origin of chronic obstructive pulmonary disease, its prevention is pivotal also in long-term respiratory outcome of these patients. There is currently some evidence to support the use of antenatal glucocorticoids, surfactant therapy, protective noninvasive ventilation, targeted saturations, early caffeine treatment, vitamin A, and fluid restriction, but none of the existing strategies have had any significant impact in reducing the burden of BPD. New areas of research are raising novel therapeutic prospects, however. For instance, early topical (intratracheal or nebulized) steroids seem promising: they might help to limit BPD development without the side effects of systemic steroids. Evidence in favor of stem cell therapy has emerged from several preclinical trials, and from a couple of studies in humans. Mesenchymal stromal/stem cells (MSCs) have revealed a reparatory capability, preventing the progression of BPD in animal models. Administering MSC-conditioned media containing extracellular vesicles (EVs) have also demonstrated a preventive action, without the potential risks associated with unwanted engraftment or the adverse effects of administering cells. In this paper, we explore these emerging treatments and take a look at the revolutionary changes in BPD and neonatology on the horizon.

The Association of Pregnancy-induced Hypertension with Bronchopulmonary Dysplasia - A Retrospective Study Based on the Korean Neonatal Network database

The prevalence of pregnancy-induced hypertension (PIH) and preeclampsia (PE) are 5-10% and 2-4%, respectively. PIH might affect angiogenesis in preterm neonates, but its association with bronchopulmonary dysplasia (BPD) remains controversial. This study evaluated the association between PIH and BPD in very low-birth weight infants. We retrospectively analysed the maternal, perinatal, and neonatal data of preterm infants born before 30 weeks of gestation, selected from the nationwide registry of very low-birth weight infants, between January 2013 and December 2014. As a result, 1,624 infants without maternal PIH (gestational age: 27.3 ± 1.8 weeks) and 203 infants with maternal PIH (28.0 ± 1.4 weeks, p < 0.001) were included. Birth weight was higher in the non-PIH group, compared with the PIH group (1027.4 ± 250.2 vs. 876.4 ± 261.5 g, p < 0.001). Multivariate logistic regression showed that PIH was associated with BPD (adjusted OR 1.474, 95% confidence interval 1.025-2.121), after adjusting for confounders, including small-for-gestation age (SGA). The result of present study is consistent with the current concept of BPD as an early form of pulmonary vascular disease, for both PIH and BPD are attributed by abnormal vascular formation.

The effects of gasotransmitters on bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD), which remains a major clinical problem for preterm infants, is caused mainly by hyperoxia, mechanical ventilation and inflammation. Many approaches have been developed with the aim of decreasing the incidence of or alleviating BPD, but effective methods are still lacking. Gasotransmitters, a type of small gas molecule that can be generated endogenously, exert a protective effect against BPD-associated lung injury; nitric oxide (NO), carbon monoxide (CO) and hydrogen sulfide (H₂S) are three such gasotransmitters. The protective effects of NO have been extensively studied in animal models of BPD, but the results of these studies are inconsistent with those of clinical trials. NO inhalation seems to have no effect on BPD, although side effects have been reported. NO inhalation is not recommended for BPD treatment in preterm infants, except those with severe pulmonary hypertension. Both CO and H₂S decreased lung injury in BPD rodent models in preclinical studies. Another small gas molecule, hydrogen, exerts a protective effect against BPD. The nuclear factor erythroid-derived 2 (Nrf2)/heme oxygenase-1 (HO-1) axis seems to play a central role in the protective effect of these gasotransmitters on BPD. Gasotransmitters play important roles in mammals, but further clinical trials are needed to explore their effects on BPD.

Association of Chorioamnionitis With Bronchopulmonary Dysplasia Among Preterm Infants: A Systematic Review, Meta-analysis, and Metaregression

Importance

Bronchopulmonary dysplasia (BPD), a chronic lung disease of prematurity, remains one of the major and most common complications of very preterm birth. Insight into factors associated with the pathogenesis of BPD is key to improving its prevention and treatment.

Objective

To perform a systematic review, meta-analysis, and metaregression of clinical studies exploring the association between chorioamnionitis (CA) and BPD in preterm infants.

Data Sources

PubMed and Embase were searched without language restriction (last search, October 1, 2018). Key search terms included bronchopulmonary dysplasia, chorioamnionitis, and risk factors.

Study Selection

Included studies were peer-reviewed studies examining preterm (<37 weeks' gestation) or very low-birth-weight (<1500 g) infants and reporting primary data that could be used to measure the association between exposure to CA and the development of BPD.

Data Extraction and Synthesis

The Meta-analysis of Observational Studies in Epidemiology (MOOSE) guideline was followed. Data were independently extracted by 2 researchers. A random-effects model was used to calculate odds ratios (ORs) and 95% CIs. Heterogeneity in effect size across studies was studied using multivariate, random-effects metaregression analysis.

Main Outcomes and Measures

The primary outcome was BPD, defined as supplemental oxygen requirement on postnatal day 28 (BPD28) or at the postmenstrual age of 36 weeks (BPD36). Covariates considered as potential confounders included differences between CA-exposed and CA-unexposed infants in gestational age, rates of respiratory distress syndrome (RDS), exposure to antenatal corticosteroids, and rates of early- and late-onset sepsis.

Results

A total of 3170 potentially relevant studies were found, of which 158 met the inclusion criteria (244 096 preterm infants, 20 971 CA cases, and 24 335 BPD cases). Meta-analysis showed that CA exposure was significantly associated with BPD28 (65 studies; OR, 2.32; 95% CI, 1.88-2.86; P < .001; heterogeneity: I2 = 84%; P < .001) and BPD36 (108 studies; OR, 1.29; 95% CI, 1.17-1.42; P < .001; heterogeneity: I2 = 63%; P < .001). The association between CA and BPD remained significant for both clinical and histologic CA. In addition, significant differences were found between CA-exposed and CA-unexposed infants in gestational age, birth weight, odds of being small for gestational age, exposure to antenatal corticosteroids, and early- and late-onset sepsis. Chorioamnionitis was not significantly associated with RDS (48 studies; OR, 1.10; 95% CI, 0.92-1.34; P = .24; heterogeneity: I2 = 90%; P < .001), but multivariate metaregression analysis with backward elimination revealed that a model combining the difference in gestational age and the odds of RDS was associated with 64% of the variance in the association between CA and BPD36 across studies.

Conclusions and Relevance

The results of this study confirm that among preterm infants, exposure to CA is associated with a higher risk of developing BPD, but this association may be modulated by gestational age and risk of RDS.

Bronchopulmonary dysplasia: risk prediction models for very-low- birth-weight infants

OBJECTIVE

Our objective is to develop risk prediction models for moderate/severe bronchopulmonary dysplasia (BPD) and BPD and/or death in very-low-birth-weight infants (VLBWI) at birth, 3, 7, and 14 postnatal days.

STUDY DESIGN

It is a multicenter study including 16,407 infants weighing 500-1500 g (2001-2015) from the Neocosur Network. BPD was defined as oxygen dependency at 36 weeks. Variables were selected using forward logistic regression models. Predictive values were evaluated using the ROC curve.

RESULTS

In total, 2580 (15.7%) presented BPD and 6121 (37.3%) BPD/death. The AUC values for the BPD models were 0.788, 0.818, 0.827, and 0.894 respectively. For BPD/death, the AUC values were 0.860, 0.869, 0.867, and 0.906. BW and gestational age had higher contribution at birth; at later ages, the length of oxygen therapy and ventilation had the highest contribution. All AUC values were statistically significant when compared with a neutral value of 0.5 (p-value < 0.001).

CONCLUSIONS

We developed high predictive power models for moderate/severe BPD and BPD/death at four postnatal ages.

Adverse early-life environment impairs postnatal lung development in mice

BACKGROUND

Fetal growth restriction (FGR) is a major risk factor for bronchopulmonary dysplasia (BPD). Maternal stress and poor diet are linked to FGR. Effect of perinatal stress on lung development remains unknown.

OBJECTIVE

Using a murine model of adverse early life environment (AELE), we hypothesized that maternal exposure to perinatal environmental stress and high-fat diet (Western diet) lead to impaired lung development in the offspring.

METHODS

Female mice were placed on either control diet or Western diet before conception. Those exposed to Western diet were also exposed to perinatal environmental stress, the combination referred to as AELE. Pups were either euthanized at postnatal day 21 (P21) or weaned to control diet and environment until adulthood (8-14 wk old). Lungs were harvested for histology, gene expression by quantitative RT-PCR, microRNA profiling, and immunoblotting.

RESULTS

AELE increased the mean linear intercept and decreased the radial alveolar count and secondary septation in P21 and adult mice. Capillary count was also decreased in P21 and adult mice. AELE lungs had decreased vascular endothelial growth factor A (VEGFA), VEGF receptor 2, endothelial nitric oxide synthase, and hypoxia inducible factor-1α protein levels and increased expression of genes that regulate DNA methylation and upregulation of microRNAs that target genes involved in lung development at P21.

CONCLUSION

AELE leads to impaired lung alveolar and vascular growth, which persists into adult age despite normalizing the diet and environment at P21. AELE also alters the expression of genes involved in lung remodeling.

Perinatal Ureaplasma Exposure Is Associated With Increased Risk of Late Onset Sepsis and Imbalanced Inflammation in Preterm Infants and May Add to Lung Injury

Background: Controversy remains concerning the impact of Ureaplasma on preterm neonatal morbidity.

Methods: Prospective single-center study in very low birth weight infants <30 weeks' gestation. Cord blood and initial nasopharyngeal swabs were screened for Ureaplasma parvum and U. urealyticum using culture technique and polymerase chain reaction. Neonatal outcomes were followed until death or discharge. Multi-analyte immunoassay provided cord blood levels of inflammatory markers. Using multivariate regression analyses, perinatal Ureaplasma exposure was evaluated as risk factor for the development of bronchopulmonary dysplasia (BPD), other neonatal morbidities until discharge and systemic inflammation at admission.

Results: 40/103 (39%) infants were positive for Ureaplasma in one or both specimens, with U. parvum being the predominant species. While exposure to Ureaplasma alone was not associated with BPD, we found an increased risk of BPD in Ureaplasma-positive infants ventilated ≥5 days (OR 1.64; 95% CI 0.12–22.98; p = 0.009). Presence of Ureaplasma was associated with a 7-fold risk of late onset sepsis (LOS) (95% CI 1.80–27.39; p = 0.014). Moreover, Ureaplasma-positive infants had higher I/T ratios (b 0.39; 95% CI 0.08–0.71; p = 0.014), increased levels of interleukin (IL)-17 (b 0.16; 95% CI 0.02–0.30; p = 0.025) and matrix metalloproteinase 8 (b 0.77; 95% CI 0.10–1.44; p = 0.020), decreased levels of IL-10 (b −0.77; 95% CI −1.58 to −0.01; p = 0.043) and increased ratios of Tumor necrosis factor-α, IL-8, and IL-17 to anti-inflammatory IL-10 (p = 0.003, p = 0.012, p < 0.001).

Conclusions: Positive Ureaplasma screening was not associated with BPD. However, exposure contributed to BPD in infants ventilated ≥5 days and conferred an increased risk of LOS and imbalanced inflammatory cytokine responses.

Impact of family integrated care on infants' clinical outcomes in two children's hospitals in China: a pre-post intervention study

Background

Most Neonatal Intensive Care Units (NICUs) in China have restricted visiting policies for parents. This also implicates that parents are not involved in the care of their infant. Family Integrated Care (FIC), empowering parents in direct care delivery and decisions, is becoming the standard in NICUs in many countries and can improve quality-of-life and health outcomes of preterm infants. The aim of this study was to evaluate the impact of a FIC intervention on the clinical outcomes of preterm infants with Bronchopulmonary Dysplasia (BPD).

Methods

A pre-post intervention study was conducted at NICUs in two Chinese children’s hospitals. Infants with BPD were included: pre-intervention group (n = 134) from December 2015 to September 2016, post-intervention (FIC) group (n = 115) and their parents from October 2016 to June 2017. NICU nurses were trained between July and September 2016 to deliver the FIC intervention, including parent education and support. Parents had to be present and care for their infant minimal three hours a day. The infants’ outcome measures were length-of-stay, breastfeeding, weight gain, respiratory and oxygen support, and parent hospital expenses.

Results

Compared with control group (n = 134), the FIC group (n = 115) had significantly increased breastfeeding rates (83% versus 71%, p = 0.030), breastfeeding time (31 days versus 19 days, p < 0.001), enteral nutrition time (50 days versus 34 days, p < 0.001), weight gain (29 g/day versus 23 g/day, p = 0.002), and significantly lower respiratory support time (16 days versus 25 days, p < 0.001). Oxygen Exposure Time decreased but not significant (39 days versus 41 days p = 0.393). Parents hospital expenses in local Chinese RMB currency was not significant (84 K versus 88 K, p = 0.391).

Conclusion

The results of our study suggests that FIC is feasible in two Chinese NICUs and might improve clinical outcomes of preterm infants with BPD. Further research is needed to include all infants admitted to NICUs and should include parent reported outcome measures. Our study may help other NICUs with limited parental access to implement FIC to enhance parental empowerment and involvement in the care of their infant.

Bronchopulmonary dysplasia: clinical aspects and preventive and therapeutic strategies

BACKGROUND

Bronchopulmonary dysplasia (BPD) is the result of a complex process in which several prenatal and/or postnatal factors interfere with lower respiratory tract development, leading to a severe, lifelong disease. In this review, what is presently known regarding BPD pathogenesis, its impact on long-term pulmonary morbidity and mortality and the available preventive and therapeutic strategies are discussed.

MAIN BODY

Bronchopulmonary dysplasia is associated with persistent lung impairment later in life, significantly impacting health services because subjects with BPD have, in most cases, frequent respiratory diseases and reductions in quality of life and life expectancy. Prematurity per se is associated with an increased risk of long-term lung problems. However, in children with BPD, impairment of pulmonary structures and function is even greater, although the characterization of long-term outcomes of BPD is difficult because the adults presently available to study have received outdated treatment. Prenatal and postnatal preventive measures are extremely important to reduce the risk of BPD.

CONCLUSION

Bronchopulmonary dysplasia is a respiratory condition that presently occurs in preterm neonates and can lead to chronic respiratory problems. Although knowledge about BPD pathogenesis has significantly increased in recent years, not all of the mechanisms that lead to lung damage are completely understood, which explains why therapeutic approaches that are theoretically effective have been only partly satisfactory or useless and, in some cases, potentially negative. However, prevention of prematurity, systematic use of nonaggressive ventilator measures, avoiding supraphysiologic oxygen exposure and administration of surfactant, caffeine and vitamin A can significantly reduce the risk of BPD development. Cell therapy is the most fascinating new measure to address the lung damage due to BPD. It is desirable that ongoing studies yield positive results to definitively solve a major clinical, social and economic problem.

Delivery room interventions to prevent bronchopulmonary dysplasia in extremely preterm infants

Bronchopulmonary dysplasia (BPD) is the most common chronic respiratory complication of preterm birth. Preterm infants are at risk for acute lung injury immediately after birth, which predisposes to BPD. In this article, we review the current evidence for interventions applied during neonatal transition (delivery room and first postnatal hours of life) to prevent BPD in extremely preterm infants: continuous positive airway pressure (CPAP), sustained lung inflation, supplemental oxygen use during neonatal resuscitation, and surfactant therapy including less-invasive surfactant administration. Preterm infants should be stabilized with CPAP in the delivery room, reserving invasive mechanical ventilation for infants who fail non-invasive respiratory support. For infants who require endotracheal intubation and mechanical ventilation soon after birth, surfactant should be given early (<2 h of life). We recommend prudent titration of supplemental oxygen in the delivery room to achieve targeted oxygen saturations. Promising interventions that may further reduce BPD, such as sustained inflation and non-invasive surfactant administration, are currently under investigation.

Bronchopulmonary dysplasia: A review of pathogenesis and pathophysiology

Bronchopulmonary dysplasia (BPD) is a chronic lung disease of primarily premature infants that results from an imbalance between lung injury and repair in the developing lung. BPD is the most common respiratory morbidity in preterm infants, which affects nearly 10, 000 neonates each year in the United States. Over the last two decades, the incidence of BPD has largely been unchanged; however, the pathophysiology has changed with the substantial improvement in the respiratory management of extremely low birth weight (ELBW) infants. Here we have attempted to comprehensively review and summarize the current literature on the pathogenesis and pathophysiology of BPD. Our goal is to provide insight to help further progress in preventing and managing severe BPD in the ELBW infants.

Genome-wide association study of bronchopulmonary dysplasia: a potential role for variants near the CRP gene

Bronchopulmonary dysplasia (BPD), the main consequence of prematurity, has a significant heritability, but little is known about predisposing genes. The aim of this study was to identify gene loci predisposing infants to BPD. The initial genome-wide association study (GWAS) included 174 Finnish preterm infants of gestational age 24–30 weeks. Thereafter, the most promising single-nucleotide polymorphisms (SNPs) associated with BPD were genotyped in both Finnish (n = 555) and non-Finnish (n = 388) replication cohorts. Finally, plasma CRP levels from the first week of life and the risk of BPD were assessed. SNP rs11265269, flanking the CRP gene, showed the strongest signal in GWAS (odds ratio [OR] 3.2, p = 3.4 × 10⁻⁶). This association was nominally replicated in Finnish and French African populations. A number of other SNPs in the CRP region, including rs3093059, had nominal associations with BPD. During the first week of life the elevated plasma levels of CRP predicted the risk of BPD (OR 3.4, p = 2.9 × 10^–4) and the SNP rs3093059 associated nominally with plasma CRP levels. Finally, SNP rs11265269 was identified as a risk factor of BPD (OR 1.8, p = 5.3 × 10⁻⁵), independently of the robust antenatal risk factors. As such, in BPD, a potential role for variants near CRP gene is proposed.

The significance of IL-1β +3953C>T, IL-6 -174G>C and -596G>A, TNF-α -308G>A gene polymorphisms and 86 bp variable number tandem repeat polymorphism of IL-1RN in bronchopulmonary dysplasia in infants born before 32 weeks of gestation

Introduction

Bronchopulmonary dysplasia (BPD) is a chronic lung disease that affects primarily preterm infants. Genetic factors are also taken into consideration in the pathogenesis of BPD. Genetic predispositions to higher production of inflammation mediators seem to be crucial.

Material and methods

The aim of this study was to evaluate the possible relationship between polymorphisms: interleukin-1β +3953 C>T, interleukin-6 -174 G>C and -596 G>A, tumour necrosis factor -308 G>A and interleukin-1RN VNTR 86bp and the occurrence of BPD in a population of 100 preterm infants born from singleton pregnancy, before 32+0 weeks of gestation, exposed to antenatal steroids therapy, and without congenital abnormalities.

Results

In the study population BPD was diagnosed in 36 (36%) newborns. Among the studied polymorphisms we found the higher prevalence for BPD developing of the following genotypes: 1/2 (OR 1.842 [0.673-5.025] and 2/2 IL-1RN (OR 1.75 [0.418-6.908] 86bpVNTR; GC (2.222 [0.658-8.706]) and CC IL-6 -174G>C (1.6 [0.315-8.314]) and GA (2.753 [0.828-10.64]) and AA (1.5 [0.275-8.067] IL-6 -596G>A), GA 1.509 (0.515-4.301) TNF-α -308G>A. However, these finding were not statistically significant.

Conclusions

Genetic factors are undeniably involved in the pathogenesis of BPD. In the times of individualised therapy finding genes responsible for BPD might allow the development of new treatment strategies. A new way of specific therapy could ensure the reduction of complications connected with BPD and treatment costs.

The influence of gender on respiratory outcomes in children with bronchopulmonary dysplasia during the first 3 years of life

INTRODUCTION

Since premature males are more likely to be diagnosed with bronchopulmonary dysplasia we hypothesized that differences in respiratory outcomes after initial hospital discharge and during the first 3 years of life would exist between females and males diagnosed with BPD.

METHODS

Subjects with the diagnosis of BPD were recruited from the Johns Hopkins Bronchopulmonary Dysplasia Clinic between 2008 and 2014. Clinical features were assessed through chart review (n = 482). Respiratory morbidities were assessed by caregiver questionnaires at clinic visits (n = 429), including emergency department visits, hospital admissions, systemic steroid use, and antibiotic use for respiratory reasons since the last BPD clinic visit or after initial hospital discharge if assessed at the first visit.

RESULTS

Male infants weighed significantly more at birth, had higher birth weight percentiles and were more likely to be non-white compared to female infants. The frequency of ever acute care use was 36.9% for emergency department visits, 27.4% for hospital admissions, 36.9% for systemic steroid use, and 40.5% for antibiotic use for a respiratory illness. No differences in respiratory morbidities were found between males and females. Females however, tended to be weaned from supplemental oxygen over 3 months later than males.

CONCLUSIONS

Compared to females with BPD, males were more likely to weigh more, have higher birth weight percentiles and be non-white. After initial hospital discharge, there were no difference in respiratory morbidities between males and females with BPD. Female infants however were more likely to be weaned from supplemental oxygen at a later age than male infants. Pediatr Pulmonol. 2017;52:217-224. © 2016 Wiley Periodicals, Inc.

Activation of the IL-1β/CXCL1/MMP-10 axis in chorioamnionitis induced by inactivated Group B Streptococcus

Infection or inflammation during pregnancy is known to lead to maternal immune activation triggering a fetal inflammatory response syndrome associated with deleterious effects, such as brain injury and neurodevelopmental disabilities. Group B Streptococcus (GBS) - one of the most common bacterium colonizing pregnant women - can be responsible for chorioamnionitis. Given that interleukin (IL)-1β has a major role in anti-GBS host defense, we hypothesized that IL-1β-driven innate immune response is implicated in GBS-induced chorioamnionitis. Using a rat model of GBS-induced chorioamnionitis, this study showed that inflammatory response to this pathogen was associated with maternal and placental IL-1β hyper expression. Following placental chemokine (C-X-C motif) ligand 1 (CXCL1) production, polymorphonuclear leukocytes (PMN) placental infiltration started at 24 h post-GBS exposure, and MMP-10 was released within these placentas. At 72 h, PMN infiltration extended to membranes and to membranes' arteries. This was associated with IL-1β release within the fetus blood at 72 h. Such a GBS-associated inflammatory cascade might be deleterious for fetal organs. These results pave the way toward targeted placento-protective anti-inflammatory strategies against GBS-induced chorioamnionitis.

Placental Complications and Bronchopulmonary Dysplasia: EPIPAGE-2 Cohort Study

OBJECTIVE

To investigate the relationship between placenta-mediated pregnancy complications and bronchopulmonary dysplasia (BPD) in very preterm infants.

METHODS

National prospective population-based cohort study including 2697 singletons born before 32 weeks' gestation. The main outcome measure was moderate to severe BPD. Three groups of placenta-mediated pregnancy complications were compared with no placenta-mediated complications: maternal disorders only (gestational hypertension or preeclampsia), fetal disorders only (antenatal growth restriction), and both maternal and fetal disorders.

RESULTS

Moderate to severe BPD rates were 8% in infants from pregnancies with maternal disorders, 15% from both maternal and fetal disorders, 23% from fetal disorders only, and 9% in the control group (P < .001). When we adjusted for gestational age, the risk of moderate to severe BPD was greater in the groups with fetal disorders only (odds ratio [OR] = 6.6; 95% confidence interval [CI], 4.1-10.7), with maternal and fetal disorders (OR = 3.7; 95% CI, 2.5-5.5), and with maternal disorders only (OR = 1.7; 95% CI, 1.0-2.7) than in the control group. When we also controlled for birth weight, the relationship remained in groups with fetal disorders only (OR = 4.2; 95% CI, 2.1-8.6) and with maternal and fetal disorders (OR = 2.1; 95% CI, 1.1-3.9).

CONCLUSIONS

Placenta-mediated pregnancy complications with fetal consequences are associated with moderate to severe BPD in very preterm infants independently of gestational age and birth weight, but isolated maternal hypertensive disorders are not. Fetal growth restriction, more than birth weight, could predispose to impaired lung development.

Trends in Survival and Incidence of Bronchopulmonary Dysplasia in Extremely Preterm Infants at 23-26 Weeks Gestation

The aim of this study was to investigate the relationship between survival and incidence of bronchopulmonary dysplasia (BPD) in extremely premature infants, and identify clinical factors responsible for this association. Medical records of 350 infants at 23-26 weeks gestation from 2000 to 2005 (period I, n = 137) and 2006 to 2010 (period II, n = 213) were retrospectively reviewed. The infants were stratified into 23-24 and 25-26 weeks gestation, and the survival, BPD incidence, and clinical characteristics were analyzed. BPD was defined as oxygen dependency at 36 weeks postmenstrual age. The overall survival rate was significantly improved in period II compared to period I (80.3% vs. 70.0%, respectively; P = 0.028), especially in infants at 23-24 weeks gestation (73.9% vs. 47.4%, respectively; P = 0.001). The BPD incidence in survivors during period II (55.0%) was significantly decreased compared to period I (67.7%; P = 0.042), especially at 25-26 weeks gestation (41.7% vs. 62.3%, respectively; P = 0.008). Significantly improved survival at 23-24 weeks gestation was associated with a higher antenatal steroid use and an improved 5-minute Apgar score. A significant decrease in BPD incidence at 25-26 weeks gestation was associated with early extubation, prolonged use of less invasive continuous positive airway pressure, and reduced supplemental oxygen. Improved perinatal and neonatal care can simultaneously lead to improved survival and decreased BPD incidence in extremely premature infants.

BPD Following Preterm Birth: A Model for Chronic Lung Disease and a Substrate for ARDS in Childhood

It has been suggested that pediatric acute respiratory distress syndrome (PARDS) may be a different entity, vis-à-vis adult acute respiratory distress syndrome (ARDS), based on its epidemiology and outcomes. A more pediatric-specific definition of PARDS to include the subgroup of patients with underlying lung (and heart) disease has been proposed. Epidemiological data suggest that up to 13% of the children with ARDS have a history of prematurity and/or underlying chronic lung disease. However, the specific contribution of bronchopulmonary dysplasia (BPD), the most common chronic lung disease in infants, to the development of PARDS is not known. BPD leads to damaged lungs with long-term consequences secondary to disordered growth and immune function. These damaged lungs could potentially act as a substrate, which given the appropriate noxious stimuli, can predispose a child to PARDS. Interestingly, similar biomarkers [KL-6, interleukin (IL)-6, IL-8, sICAM-1, angiopoietin-2, and matrix metalloproteinase-8 and -9] of pulmonary injury have been associated both with BPD and ARDS. Recognition of a unique pattern of clinical symptomatology and/or outcomes of PARDS, if present, could potentially be useful for investigating targeted therapeutic interventions.

Utility of large-animal models of BPD: chronically ventilated preterm lambs

This paper is focused on unique insights provided by the preterm lamb physiological model of bronchopulmonary dysplasia (BPD). Connections are also made to insights provided by the former preterm baboon model of BPD, as well as to rodent models of lung injury to the immature, postnatal lung. The preterm lamb and baboon models recapitulate the clinical setting of preterm birth and respiratory failure that require prolonged ventilation support for days or weeks with oxygen-rich gas. An advantage of the preterm lamb model is the large size of preterm lambs, which facilitates physiological studies for days or weeks during the evolution of neonatal chronic lung disease (CLD). To this advantage is linked an integrated array of morphological, biochemical, and molecular analyses that are identifying the role of individual genes in the pathogenesis of neonatal CLD. Results indicate that the mode of ventilation, invasive mechanical ventilation vs. less invasive high-frequency nasal ventilation, is related to outcomes. Our approach also includes pharmacological interventions that test causality of specific molecular players, such as vitamin A supplementation in the pathogenesis of neonatal CLD. The new insights that are being gained from our preterm lamb model may have important translational implications about the pathogenesis and treatment of BPD in preterm human infants.