Interstitial pneumonia pattern on day 7 chest radiograph predicts bronchopulmonary dysplasia in preterm infants

Deep Learning Model for Prediction of Bronchopulmonary Dysplasia in Preterm Infants Using Chest Radiographs

Bronchopulmonary dysplasia (BPD) is common in preterm infants and may result in pulmonary vascular disease, compromising lung function. This study aimed to employ artificial intelligence (AI) techniques to help physicians accurately diagnose BPD in preterm infants in a timely and efficient manner. This retrospective study involves two datasets: a lung region segmentation dataset comprising 1491 chest radiographs of infants, and a BPD prediction dataset comprising 1021 chest radiographs of preterm infants. Transfer learning of a pre-trained machine learning model was employed for lung region segmentation and image fusion for BPD prediction to enhance the performance of the AI model. The lung segmentation model uses transfer learning to achieve a dice score of 0.960 for preterm infants with ≤ 168 h postnatal age. The BPD prediction model exhibited superior diagnostic performance compared to that of experts and demonstrated consistent performance for chest radiographs obtained at ≤ 24 h postnatal age, and those obtained at 25 to 168 h postnatal age. This study is the first to use deep learning on preterm chest radiographs for lung segmentation to develop a BPD prediction model with an early detection time of less than 24 h. Additionally, this study compared the model's performance according to both NICHD and Jensen criteria for BPD. Results demonstrate that the AI model surpasses the diagnostic accuracy of experts in predicting lung development in preterm infants.

Noninvasive Monitoring Strategies for Bronchopulmonary Dysplasia or Post-Prematurity Respiratory Disease: Current Challenges and Future Prospects

Definitions of bronchopulmonary dysplasia (BPD) or post-prematurity respiratory disease (PPRD) aim to stratify the risk of mortality and morbidity, with an emphasis on long-term respiratory outcomes. There is no univocal classification of BPD due to its complex multifactorial nature and the substantial heterogeneity of clinical presentation. Currently, there is no definitive treatment available for extremely premature very-low-birth-weight infants with BPD, and challenges in finding targeted preventive therapies persist. However, innovative stem cell-based postnatal therapies targeting BPD-free survival are emerging, which are likely to be offered in the first few days of life to high-risk premature infants. Hence, we need easy-to-use noninvasive tools for a standardized, precise, and reliable BPD assessment at a very early stage, to support clinical decision-making and to predict the response to treatment. In this non-systematic review, we present an overview of strategies for monitoring preterm infants with early and evolving BPD-PPRD, and we make some remarks on future prospects, with a focus on near-infrared spectroscopy (NIRS).

Pulmonary phenotypes of bronchopulmonary dysplasia in the preterm infant

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

Defining and Promoting Pediatric Pulmonary Health: Assessing Lung Function and Structure

Lifelong respiratory health is rooted in the structural and functional development of the respiratory system in early life. Exposures and interventions antenatally through childhood can influence lung development into young adulthood, the life stage with the highest achievable lung function. Because early respiratory health sets the stage for adult lung function trajectories and risk of developing chronic obstructive pulmonary disease, understanding how to promote lung health in children will have far reaching personal and population benefits. To achieve this, it is critical to have accurate and precise measures of structural and functional lung development that track throughout life stages. From this foundation, evaluation of environmental, genetic, metabolic, and immune mechanisms involved in healthy lung development can be investigated. These goals require the involvement of general pediatricians, pediatric subspecialists, patients, and researchers to design and implement studies that are broadly generalizable and applicable to otherwise healthy and chronic disease populations. This National Institutes of Health workshop report details the key gaps and opportunities regarding lung function and structure.

The Most Valuable Predictive Factors for Bronchopulmonary Dysplasia in Very Preterm Infants

INTRODUCTION

It is urgent to make a rapid screening of infants at the highest risk for bronchopulmonary dysplasia (BPD) via some succinct postnatal biomarkers, such as Ureaplasma Urealyticum (UU) infection and chest radiograph images.

METHODS

A retrospective study was performed. Moderate to severe BPD or death was set as the main outcome. The association between putative variables and the main outcome were assessed by bivariate analyses and logistic regression.

RESULTS

A total of 134 infants were enrolled. Bivariate analyses showed the gestational age, birth weight, appearances of diffuse opacities or grid shadows/interstitial opacities or mass opacities or cystic lucencies on chest radiographic images, a ductal diameter ≥1.5 mm and whether UU infection was associated with BPD. After adjustment by logistic regression, the risk of BPD with gestational age, sex and specific chest-radiographic manifestations remained significant.

CONCLUSIONS

Chest radiograph images (appearance of diffuse opacities or grid shadows/interstitial opacities or mass opacities or cystic lucencies) could provide a quick prediction of developing BPD in clinical practice, in addition to gestational age and sex. UU infection was not an independent risk factor for BPD.

Early severity prediction of BPD for premature infants from chest X-ray images using deep learning: A study at the 28th day of oxygen inhalation

BACKGROUND AND OBJECTIVE

Bronchopulmonary dysplasia is a common respiratory disease in premature infants. The severity is diagnosed at the 56th day after birth or discharge by analyzing the clinical indicators, which may cause the delay of the best treatment opportunity. Thus, we proposed a deep learning-based method using chest X-ray images of the 28th day of oxygen inhalation for the early severity prediction of bronchopulmonary dysplasia in clinic.

METHODS

We first adopted a two-step lung field extraction method by combining digital image processing and human-computer interaction to form the one-to-one corresponding image and label. The designed XSEG-Net model was then trained for segmenting the chest X-ray images, with the results being used for the analysis of heart development and clinical severity. Therein, Six-Point cardiothoracic ratio measurement algorithm based on corner detection was designed for the analysis of heart development; and the transfer learning of deep convolutional neural network models were used for the early prediction of clinical severities.

RESULTS

The dice and cross-entropy loss value of the training of XSEG-Net network reached 0.9794 and 0.0146. The dice, volumetric overlap error, relative volume difference, precision, and recall were used to evaluate the trained model in testing set with the result being 98.43 ± 0.39%, 0.49 ± 0.35%, 0.49 ± 0.35%, 98.67 ± 0.40%, and 98.20 ± 0.47%, respectively. The errors between the Six-Point cardiothoracic ratio measurement method and the gold standard were 0.0122 ± 0.0084. The deep convolutional neural network model based on VGGNet had the promising prediction performance, with the accuracy, precision, sensitivity, specificity, and F1 score reaching 95.58 ± 0.48%, 95.61 ± 0.55%, 95.67 ± 0.44%, 96.98 ± 0.42%, and 95.61±0.48%, respectively.

CONCLUSIONS

These experimental results of the proposed methods in lung field segmentation, cardiothoracic ratio measurement and clinic severity prediction were better than previous methods, which proved that this method had great potential for clinical application.

Factors associated with successful extubation following the first course of systemic dexamethasone in ventilator-dependent preterm infants with or at risk of developing bronchopulmonary dysplasia

OBJECTIVES

We aimed to identify factors present at the start of an initial course of systemic dexamethasone that would be associated with successful extubation in mechanically ventilated neonates <30 weeks gestational age (GA) with or at risk of developing bronchopulmonary dysplasia (BPD).

METHODS

We studied a retrospective cohort of neonates (23⁺⁰ -29⁺⁶ weeks GA), with or at risk of developing BPD, prescribed their first course of systemic dexamethasone to aid in extubation from mechanical ventilation. The data collected only pertained to the first course of dexamethasone. Neonates given dexamethasone for airway edema were not included. The primary outcome of interest was successful extubation (i.e., extubated within 14 days of starting dexamethasone and remaining extubated for at least 7 days). Binary logistic regression was employed.

RESULTS

A total of 287 neonates were included. Each additional week of GA at birth led to a 1.53 increase in the odds of successful extubation (95% CI: 1.122-2.096, p < 0.01). Higher average fraction of inspired oxygen (FiO₂ ) requirements in the preceding 24 h resulted in a 0.94 decrease in the odds of successful extubation (p < 0.05) and higher mean airway pressure (MAP) resulted in 0.76 decrease in odds of successful extubation (p < 0.01).

CONCLUSIONS

Mechanically ventilated neonates with or at risk of developing BPD, born at <30 week GA and initiated on dexamethasone to facilitate extubation, had a lower likelihood of successful extubation by Day 14 if they had younger GA at birth, and at the time of commencing steroids had higher MAPs and had higher oxygen requirements.

Bronchopulmonary dysplasia from chest radiographs to magnetic resonance imaging and computed tomography: adding value

Bronchopulmonary dysplasia (BPD) is a common long-term complication of preterm birth. The chest radiograph appearance and survivability have evolved since the first description of BPD in 1967 because of improved ventilation and clinical strategies and the introduction of surfactant in the early 1990s. Contemporary imaging care is evolving with the recognition that comorbidities of tracheobronchomalacia and pulmonary hypertension have a great influence on outcomes and can be noninvasively evaluated with CT and MRI techniques, which provide a detailed evaluation of the lungs, trachea and to a lesser degree the heart. However, echocardiography remains the primary modality to evaluate and screen for pulmonary hypertension. This review is intended to highlight the important findings that chest radiograph, CT and MRI can contribute to precision diagnosis, phenotyping and prognosis resulting in optimal management and therapeutics.

The Value of Lung Ultrasound Score in Neonatology

Point-of-care lung ultrasound (LUS) is increasingly applied in the neonatal intensive care unit (NICU). Diagnostic applications for LUS in the NICU contain the diagnosis of many common neonatal pulmonary diseases (such as Respiratory distress syndrome, Transient tachypnea of the newborn, Meconium aspiration syndrome, Pneumonia, Pneumothorax, and Pleural effusion) which have been validated. In addition to being employed as a diagnostic tool in the classical sense of the term, recent studies have shown that the number and type of artifacts are associated with lung aeration. Based on this theory, over the last few years, LUS has also been used as a semi-quantitative method or as a "functional" tool. Scores have been proposed to monitor the progress of neonatal lung diseases and to decide whether or not to perform a specific treatment. The semi-quantitative LUS scores (LUSs) have been developed to predict the demand for surfactant therapy, the need of respiratory support and the progress of bronchopulmonary dysplasia. Given their ease of use, accuracy and lack of invasiveness, the use of LUSs is increasing in clinical practice. Therefore, this manuscript will review the application of LUSs in neonatal lung diseases.

Application of ultrasonography in neonatal lung disease: An updated review

Lung disease is often life-threatening for both preterm and term newborns. Therefore, an accurate and rapid diagnosis of lung diseases in newborns is crucial, as management strategies differ with different etiologies. To reduce the risk of radiation exposure derived from the conventionally used chest x-ray as well as computed tomography scans, lung ultrasonography (LUS) has been introduced in clinical practice to identify and differentiate neonatal lung diseases because of its radiation-free characteristic, convenience, high accuracy, and low cost. In recent years, it has been proved that LUS exhibits high sensitivity and specificity for identifying various neonatal lung diseases. Here, we offer an updated review of the applications of LUS in neonatal lung diseases based on the reports published in recent years (2017 to present).

Lung growth and pulmonary function after prematurity and bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) still carries a heavy burden of morbidity and mortality in survivors of extreme prematurity. The disease is characterized by simplification of the alveolar structure, involving a smaller number of enlarged alveoli due to decreased septation and a dysmorphic pulmonary microvessel growth. These changes lead to persistent abnormalities mainly affecting the smaller airways, lung parenchyma, and pulmonary vasculature, which can be assessed with lung function tests and imaging techniques. Several longitudinal lung function studies have demonstrated that most preterm-born subjects with BPD embark on a low lung function trajectory, never achieving their full airway growth potential. They are consequently at higher risk of developing a chronic obstructive pulmonary disease-like phenotype later in life. Studies based on computer tomography and magnetic resonance imaging, have also shown that in these patients there is a persistence of lung abnormalities like emphysematous areas, bronchial wall thickening, interstitial opacities, and mosaic lung attenuation also in adult age. This review aims to outline the current knowledge of pulmonary and vascular growth in survivors of BPD and the evidence of their lung function and imaging up to adulthood.

Diagnosis and management of bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is the most common chronic lung disease in infants and is associated with increased mortality, respiratory morbidity, neurodevelopmental impairment, and increased healthcare costs. In parallel with advances made in the field of neonatal intensive care, the phenotype of BPD has evolved from a fibrocystic disease affecting late preterm infants to one of impaired parenchymal development and dysregulated vascular growth predominantly affecting infants born before 29 weeks' gestational age. BPD has been shown to have significant lifelong consequences. Adults with BPD have been found to have abnormal lung function tests, reduced exercise tolerance, and may be at increased risk for developing chronic obstructive pulmonary disease. Evidence shows that BPD occurs secondary to genetic-environmental interactions in an immature lung. In this review, we evaluate the various clinical definitions, imaging modalities, and biomarker data that are helpful in making an early diagnosis of BPD. In addition, we evaluate recent evidence about the prevention and treatment of BPD. We discuss the invasive and non-invasive ventilation strategies and pharmacological agents used in the early, evolving, and established phases of BPD.

Construction of early risk prediction models for bronchopulmonary dysplasia in preterm infants

OBJECTIVES

To construct risk prediction models for bronchopulmonary dysplasia (BPD) in preterm infants on postnatal days 3, 7, and 14.

METHODS

A retrospective analysis was performed on the medical data of 414 preterm infants, with a gestational age of <32 weeks and a birth weight (BW) of <1 500 g, who were admitted to the neonatal intensive care unit from July 2019 to April 2021. According to the diagnostic criteria for BPD revised in 2018, they were divided into a BPD group with 98 infants and a non-BPD group with 316 infants. The two groups were compared in terms of general status, laboratory examination results, treatment, and complications. The logistic regression model was used to identify the variables associated with BPD. The receiver operating characteristic (ROC) curve was used to evaluate the predictive value of models.

RESULTS

The logistic regression analysis showed that BW, asphyxia, grade III-IV respiratory distress syndrome (RDS), acute chorioamnionitis, interstitial pneumonia, fraction of inspired oxygen (FiO2), and respiratory support mode were the main risk factors for BPD (P<0.05). The prediction models on postnatal days 7 and 14 were established as logit (P7) =-2.049-0.004×BW (g) +0.686×asphyxia (no=0, yes=1) +1.842×grade III-IV RDS (no=0, yes=1) +0.906×acute chorioamnionitis (no=0, yes=1) +0.506×interstitial pneumonia (no=0, yes=1) +0.116×FiO2 (%) +0.816×respiratory support mode (no=0, nasal tube=1, nasal continuous positive airway pressure=2, conventional mechanical ventilation=3, high-frequency mechanical ventilation=4) and logit (P14) =-1.200-0.004×BW (g) +0.723×asphyxia+2.081×grade III-IV RDS+0.799×acute chorioamnionitis+0.601×interstitial pneumonia+0.074×FiO2 (%) +0.800×respiratory support mode, with an area under the ROC curve (AUC) of 0.876 and 0.880, respectively, which was significantly larger than the AUC of the prediction model on postnatal day 3 (P<0.05).

CONCLUSIONS

BW, asphyxia, grade III-IV RDS, acute chorioamnionitis, interstitial pneumonia, FiO2, and respiratory support mode are the main risk factors for BPD and can be used to construct risk prediction models. The prediction models on postnatal days 7 and 14 can effectively predict BPD.

Prediction Model for Bronchopulmonary Dysplasia in Preterm Newborns

OBJECTIVE: To develop a multifactorial model that allows the prediction of bronchopulmonary dysplasia (BPD) in preterm newborns. MATERIALS AND METHODS: A single-center retrospective study of infants born below 32 + 0 weeks gestational age. We created a receiver operating characteristic curve to assess the multifactorial BPD risk and calculate the BPD risk accuracy using the area under the curve (AUC). BPD risk was categorized using a multifactorial predictive model based on the weight of the evidence. RESULTS: Of the 278 analyzed preterm newborns, 127 (46%) developed BPD. The significant risk factors for BPD in the multivariate analysis were gestational age, number of red blood cell concentrate transfusions, number of surfactant administrations, and hemodynamically significant patent ductus arteriosus. The combination of these factors determined the risk of developing BPD, with an AUC value of 0.932. A multifactorial predictive model based on these factors, weighted by their odds ratios, identified four categories of newborns with mean BPD risks of 9%, 59%, 82%, and 100%. CONCLUSION: A multifactorial model based on easily available clinical factors can predict BPD risk in preterm newborns and inform potential preventive measures.

Lung ultrasound predicts the development of bronchopulmonary dysplasia: a prospective observational diagnostic accuracy study

This study aimed to evaluate the predictive ability of lung ultrasound (LU) in the development of bronchopulmonary dysplasia (BPD) in very low birth weight (VLBW) infants. A total of 130 VLBW infants with gestational age < 32 weeks were included; LU was performed at days 1, 2, 3, 6, 9, 12, and 15 postnatally. We calculated the LU score by 12-region, 10-region, and 6-region protocols. The incidence of BPD according to the National Institutes of Health (NIH) 2001 definition and 2019 criteria was 38.5% and 64.6%, respectively. By 12-region and 10-region protocols, LU predicted BPD from the 9^th to 15^th days of life (DOLs) regardless of the criteria used, with an area under the curve (AUC) ranging from 0.826 (95% confidence interval (CI): 0.750-0.887) to 0.877 (95% CI: 0.807-0.928). According to the 2019 BPD definition, the LU score incorporated gestational age, and invasive mechanical ventilation >6 days predicted BPD on the 6^th DOL with an AUC of 0.862 (95% CI: 0.790-0.916). The 6-region protocol had significantly smaller AUC values on the 6^th and 9^th DOLs than the other two protocols.Conclusion: The 12-region and 10-region LU scoring protocols are superior to the 6-region protocol in the prediction of BPD. LU can predict the development of BPD from the 9^th to 15^th DOLs. With the addition of clinical variables, the earliest prediction time was the 6^th DOL. What is Known: • Bronchopulmonary dysplasia is the most common and adverse complication of prematurity. Recent four studies found that lung ultrasound score or findings predicted the development of bronchopulmonary dysplasia. What is New: • We present analysis by classical 6-region and the other two lung ultrasound score (10-region and 12-region) which include an assessment of the posterior lung to allow to understand what is the best score to be used. In addition, we explore whether LU-incorporated clinical variables could improve the predictive value for BPD.

Characterization of the innate immune response in a novel murine model mimicking bronchopulmonary dysplasia

BACKGROUND

Bronchopulmonary dysplasia (BPD), the most common complication of prematurity, arises from various factors that compromise lung development, including oxygen and inflammation. Hyperoxia has been used to mimic the disease in newborn rodents. The use of a second hit to induce systemic inflammation has been suggested as an added strategy to better mimic the inflammatory aspect of BPD. Here we report a novel 2 hit (2HIT) BPD model with in-depth characterization of the innate immune response, enabling mechanistic studies of therapies with an immunomodulatory component.

METHODS

C57BL/6N mice were exposed to 85% O₂ from postnatal day (P)1 to P7, and received postnatally (P3) Escherichia coli LPS. At various timepoints, immune activation in the lung and at the systemic level was analyzed by fluorescence-activated cell sorting (FACS), and gene and protein expressions.

RESULTS

2HIT mice showed fewer alveoli, increased lung compliance, and right ventricular hypertrophy. A transient proinflammatory cytokine response was observed locally and systemically. Type 2 anti-inflammatory cytokine expression was decreased in the lung together with the number of mature alveolar macrophages. Simultaneously, a Siglec-F intermediate macrophage population emerged.

CONCLUSION

This study provides long-term analysis of the 2HIT model, suggesting impairment of type 2 cytokine environment and altered alveolar macrophage profile in the lung.

IMPACT

We have developed a novel 2HIT mouse BPD model with postnatal LPS and hyperoxia exposure, which enables mechanistic studies of potential therapeutic strategies with an immunomodulatory component. This is the first report of in-depth characterization of the lung injury and recovery describing the evolution of the innate immune response in a standardized mouse model for experimental BPD with postnatal LPS and hyperoxia exposure. The 2HIT model has the potential to help understand the link between inflammation and impaired lung development, and will enable testing of new therapies in a short and more robust manner.

Clinical Characteristics and Outcomes Until 2 Years of Age in Preterm Infants With Typical Chest Imaging Findings of Bronchopulmonary Dysplasia: A Propensity Score Analysis

Objective: The goal of the current study was to assess the associations of typical chest imaging findings of bronchopulmonary dysplasia (BPD) in preterm infants with clinical characteristics and outcomes until 2 years of age. Method: This retrospective cohort study enrolled 256 preterm infants with BPD who were admitted between 2014 and 2018. A propensity score analysis was used to adjust for confounding factors. The primary outcomes were the severity of BPD, home oxygen therapy (HOT) at discharge and mortality between 28 days after birth and 2 years of age. A multivariate logistic regression analysis was performed to identify related variables of mortality. Results: Seventy-eight patients with typical chest imaging findings were enrolled, of which 50 (64.1%) were first found by CXR, while 28 (35.9%) were first found by CT. In addition, 85.9% (67/78) were discovered before 36 weeks postmenstrual age (PMA) (gestational age [GA] < 32 weeks) or before 56 days after birth (GA > 32 weeks). After propensity score matching, the matched groups consisted of 58 pairs of patients. Those with typical imaging findings had a remarkably higher mortality rate (29.3 vs. 12.1%, p = 0.022, OR 3.021), higher proportion of severe BPD (32.8 vs. 12.1%, p = 0.003, OR 4.669) and higher rate of HOT at discharge (74.1 vs. 46.6%, p = 0.002, OR 3.291) than those without typical imaging findings. The multivariate logistic regression analysis showed that typical imaging findings ≤ 7 days and typical typical imaging findings >7 days were independent risk factors for mortality in preterm infants with BPD (OR 7.794, p = 0.004; OR 4.533, p = 0.001). Conclusions: More attention should be given to chest imaging findings of BPD, especially in the early stage (within 7 days). Early recognition of the development of BPD helps early individualized treatment of BPD. Clinical Trial Registration:www.ClinicalTrials.gov, identifier: NCT04163822.

Lung ultrasound score as early predictor of bronchopulmonary dysplasia in very low birth weight infants

BACKGROUND

Lung ultrasound (LU) has been widely used to diagnose and monitor acute lung diseases in neonates, but its role in chronic diseases has not been elucidated.

OBJECTIVE

We aim to describe the evolution of a lung ultrasound score (LU score) in very low birth weight infants (VLBWI) with and without bronchopulmonary dysplasia (BPD).

METHODS

We prospectively included 59 VLBWI and performed LU in the first 24 and 72 hours of life, and then weekly until 36 weeks´ postmenstrual age (PMA). We calculated the LU score as a semiquantitative score representing the aeration (0-3) in three different areas of each lung.

RESULTS

The non-BPD group (n = 38) had lower LU score at 1, 2, 3, 4, and 36 weeks' PMA than the BPD group: median score of 1 (0-4) vs 7 (3-10), P < .001; 0 (0-1) vs 7 (4-9), P < .001; 0 (0-1) vs 8 (7-11), P < .001; 0 (0-2) vs 9 (4-12), P < .001; 0 (0-0) vs 3 (0-6), P < .001. A LU score of 5 or above at 1 week of life predicted BPD with a sensitivity (Se) of 71%, specificity (Sp) 80%, area under the ROC curve (AUC) 0.8, and at 2 weeks of life with Se 74%, Sp 100%, and AUC 0.93. An LU score of 4 or above at 4 weeks predicted moderate-severe BPD (Se 100%, Sp 80%, and AUC 0.89).

CONCLUSION

In VLBWI without BPD, LU score increases during the first week of life and decreases thereafter, whereas among subjects with BPD, the LU score remains high until 36 weeks´ PMA. LU score can predict the diagnosis of BPD at 1 week and 2 weeks of life, and may predict moderate-severe BPD at 4 weeks of life.

Perinatal factors associated with bubbly/cystic appearance in bronchopulmonary dysplasia: a nationwide, population-based cohort study in Japan

BACKGROUND

Bronchopulmonary dysplasia (BPD) remains one of the most serious morbidities associated with preterm birth. Previous study reported that bubbly/cystic appearance on chest X-rays in the neonatal period is the strongest determinant of impaired lung function at school age in BPD patients.

AIMS

To determine perinatal risk factors for bubbly/cystic appearance on chest X-rays in extremely premature infants with BPD exposed to histological chorioamnionitis histological chorioamnionitis (hCAM).

STUDY DESIGN

Multicenter retrospective cohort study.

SUBJECTS

We analyzed 1369 extremely premature infants with severe hCAM who were admitted to the neonatal intensive care units participating in the Neonatal Research Network, Japan (NRNJ) Neonatal research network Japan.

OUTCOME MEASURES

Perinatal characteristics were compared and logistic regression analysis was performed for multivariate risk factor assessment.

RESULT

Infants with bubbly/cystic appearance on chest X-rays underwent longer duration of invasive mechanical ventilation and required inhaled nitric oxide and home oxygen therapy more frequently. Low gestational age (odds ratio 1.244; 95% confidence interval 1.139-1.359) and preterm premature rupture of membranes (odds ratio 1.507; 95% confidence interval 1.200-1.893) were significant risk factors.

CONCLUSION

Low gestational age and preterm premature rupture of membranes were independent risk factors for bubbly/cystic appearance in extremely premature infants with BPD following exposure to severe hCAM.

Impact of chest radiography-based definition of bronchopulmonary dysplasia

BACKGROUND

Bubbly/cystic appearance on chest radiograph is an important factor in severe-type bronchopulmonary dysplasia (BPD) in Japan. The aim of this study was to determine the perinatal characteristics and neonatal complications of the bubbly/cystic(+) group in extremely preterm infants with BPD, that is, oxygen dependency at day 28 after birth (BPD28).

METHODS

This was a multicenter retrospective cohort study of population data from infants (birthweight, <1,500 g) enrolled in the Neonatal Research Network of Japan. Of the 15 480 infants born at <28 weeks' gestational age (GA) between 2003 and 2012, 8,979 met the BPD28 criteria. The BPD28 infants were classified according to bubbly/cystic appearance on radiograph (±) at >28 postnatal days.

RESULTS

The bubbly/cystic(+) group had lower GA and birthweight and required longer mechanical ventilation and oxygen dependency than the bubbly/cystic(-) group. After adjustment for confounding factors, bubbly/cystic appearance was an independent risk factor for home oxygen therapy at discharge.

CONCLUSION

Bubbly/cystic appearance on chest radiograph was a predictor of short-term respiratory outcomes in infants with BPD28, which is diagnosed much earlier (≥28 postnatal days), and has a potentially different etiology to BPD36 (oxygen and/or positive pressure respiratory support dependency at 36 weeks' postmenstrual age).