The emerging role of extracellular vesicles in bronchopulmonary dysplasia.

Extracellular vesicle (EV) biology in neonatal lung development and disease is a rapidly growing area of investigation. Although EV research in the neonatal population lags behind EV research in adult lung diseases, recent discoveries demonstrate promise in furthering our understanding of the pathophysiology of bronchopulmonary dysplasia and the potential use of EVs in the clinical setting, as both biomarkers and therapeutic agents. This review article explores some of the recent advances in this field and our evolving knowledge of the role of EVs in bronchopulmonary dysplasia.

Postnatal diuretics, weight gain and home oxygen requirement in extremely preterm infants.

OBJECTIVES: Diuretics are often given to infants with evolving/established bronchopulmonary dysplasia (BPD) with the hope of improving their pulmonary outcomes. We aimed to determine if diuretic use in preterm infants was associated with improved pulmonary outcomes, but poorer weight gain. METHODS: An observational study over a 5 year period was undertaken of all infants born at less than 29 weeks of gestation and alive at discharge in all neonatal units in England who received consecutive diuretic use for at least 7 days. Postnatal weight gain and home supplementary oxygen requirement were the outcomes. A literature review of randomised controlled trials (RCTs) and crossover studies was undertaken to determine if diuretic usage was associated with changes in lung mechanics and oxygenation, duration of supplementary oxygen and requirement for home supplementary oxygen. RESULTS: In the observational study, 9,457 infants survived to discharge, 44.6% received diuretics for at least 7 days. Diuretic use was associated with an increased probability of supplementary home oxygen of 0.14 and an increase in weight gain of 2.5 g/week. In the review, seven of the 10 studies reported improvements only in short term lung mechanics. There was conflicting evidence regarding whether diuretics resulted in short term improvements in oxygenation. CONCLUSIONS: Diuretic use was not associated with a reduction in requirement for supplemental oxygen on discharge. The literature review highlighted a lack of RCTs assessing meaningful long-term clinical outcomes. Randomised trials are needed to determine the long-term risk benefit ratio of chronic diuretic use.

Función pulmonar: función pulmonar en pacientes con displasia broncopulmonar / Pulmonary function: pulmonary function in patients with bronchopulmonary dysplasia

La displasia broncopulmonar (DBP) es una complicación frecuente en los prematuros extremos. La detención de la alveolarización determina menor volumen pulmonar total, el cual se recupera al menos parcialmente en el trayecto de la vida. La vía aérea se ve afectada en su crecimiento en mayor proporción que los alvéolos, y en los pacientes con displasia severa va a existir hasta la etapa adulta una limitación al flujo aéreo debido a su menor calibre. En este artículo, se describirá el origen, hallazgos característicos y evolución de las alteraciones en la función pulmonar, especialmente, en los pacientes con la nueva DBP.

Bronchopulmonary dysplasia (BPD) is a frequent complication in extremely premature infants. The arrest of alveolarization determines a lower total lung volume, which recovers at least partially during life. The airway is affected in its growth to a greater extent than the alveoli, and in patients with severe dysplasia there will be airflow limitation until adulthood due to its smaller caliber. In this article, the origin, characteristic findings, and evolution of changes in lung function will be described, especially in patients with the new BPD.

Definición de displasia broncopulmonar propuesta por la Comisión Neo SOCHINEP / Definition of bronchopulmonary dysplasia proposed by the Neo SOCHINEP Commission

La displasia broncopulmonar (DBP) es la enfermedad crónica más frecuente del recién nacido prematuro. Los avances en su prevención y tratamiento han permitido una mayor sobrevida de prematuros más pequeños, pero su incidencia se ha mantenido estable en el tiempo, con una fisiopatología y presentación clínica que abarca un amplio espectro y que difiere de la DBP descrita originalmente hace más de 50 años. Aún existen controversias en su definición, la que se ha establecido en base al tratamiento, específicamente al requerimiento de soporte respiratorio. Las definiciones más utilizadas son el requerimiento de oxígeno por 28 días y a las 36 semanas de edad gestacional corregida (EGC). Recientemente se ha propuesto definirla en base al requerimiento de ventilación mecánica a las 36 semanas de EGC, lo que identificaría a los prematuros con DBP más grave y mayor probabilidad de complicaciones respiratorias y neurológicas en los 2 primeros años de vida. Nuestro objetivo en la comisión de Neo-SOCHINEP es el de recomendar la definición y clasificación que nos parece más adecuada para identificar a los prematuros portadores de DBP, considerando los aspectos fisiopatológicos, del compromiso de la función pulmonar y consecuencias prácticas de la definición en nuestro medio. También proponemos la definición del requerimiento de oxígeno en el prematuro cuando esta en neonatología, las condiciones e interpretación de la saturometría contínua cuando está pronto al alta y el seguimiento de la oxigenoterapia posterior al alta.

Bronchopulmonary dysplasia (BPD) is the most frequent chronic disease of the premature newborn. Advances in its prevention and treatment have allowed a greater survival of smaller preterm infants, but its incidence has remained stable over time, with a pathophysiology and clinical presentation that covers a wide spectrum and differs from the BPD originally described more than 50 years ago. There are still controversies in its definition, which has been established based on the treatment, specifically the requirement of respiratory support. The most used definitions are the oxygen requirement for 28 days and at 36 weeks of postmenstrual age (PMA). It has recently been proposed a definition based on the requirement of mechanical ventilation at 36 weeks of PMA, which would identify premature infants with more severe BPD and a greater probability of respiratory and neurological complications in the first 2 years of life. Our objective in the Neo-SOCHINEP commission is to recommend the definition and classification that we believe is most appropriate to identify premature infants with BPD, considering the pathophysiological aspects, the compromised lung function, and practical consequences of the definition in our medium. We also propose the definition of the oxygen requirement in premature infants when they are in neonatology, the conditions and interpretation of continuous saturation when they are soon discharged, and the follow-up of post-discharge oxygen therapy.

Impact of the definition of bronchopulmonary dysplasia on neurodevelopmental outcomes.

Understanding the short and long-term pulmonary and neurologic outcomes of neonates with bronchopulmonary dysplasia (BPD) is important in neonatal care for low-birth-weight infants. Different criteria for BPD may have different associations with long-term outcomes. Currently, two criteria for diagnosing BPD have been proposed by the NIH (2001) and NRN (2019) for preterm infants at a postmenstrual age (PMA) of 36 weeks. We investigated which BPD definition best predicts long-term outcomes. Korean nationwide data for preterm infants born between 24+0 and < 32+0 weeks gestation from January 2013 to December 2015 were collected. For long-term outcomes, severity based on the NRN criteria was significantly related to neurodevelopmental impairment (NDI) in a univariate analysis after other risk factors were controlled. For the admission rate for respiratory disorder, grade 3 BPD of the NRN criteria had the highest specificity (96%), negative predictive value (86%), and accuracy (83%). For predicting NDI at the 18-24 month follow-up, grade 3 BPD of the NRN criteria had the best specificity (98%), positive (64%) and negative (79%) predictive values, and accuracy (78%) while NIH severe BPD had the highest sensitivity (60%). The NRN definition was more strongly associated with poor 2-year developmental outcomes. BPD diagnosed by NRN definitions might better identify infants at high risk for NDI.

Eficacia y seguridad de palivizumab en la prevención de la enfermedad grave causada por el virus sincitial respiratorio en niños con displasia broncopulmonar y antecedente de prematuridad / Efficacy and safety of palivizumab in the prevention of severe respiratory syncytial virus disease in children with bronchopulmonary dysplasia and a history of prematurity

INTRODUCCIÓN: El presente dictamen expone la evaluación de la eficacia y seguridad de palivizumab para prevenir la enfermedad grave causada por el VSR en niños con DBP que hayan recibido tratamiento para la DBP en los últimos seis meses y tengan antecedente de haber nacido a las 29 semanas o menos de gestación. A nivel mundial, el virus sincitial respiratorio (VSR) es una de las principales causas de infección del tracto respiratorio inferior en niños. En Perú, el VSR ha sido detectado en el 86 % de niños menores de un año y en el 76 % de niños de uno a cuatro años, con infecciones respiratorias agudas. La displasia broncopulmonar (DBP) y la prematuridad son factores de riesgo para el desarrollo de enfermedad grave por VSR y están asociadas con mayores tasas de hospitalización, 388/1000 en niños con DBP y 57/1000 en niños prematuros, y muerte, tasas de casos fatales que van del 3.5 % al 23 % en niños con DBP y del 1.2 % al 6.1 % en niños prematuros. Un aspecto importante de la epidemiología del VSR es que difiere de acuerdo con las condiciones meteorológicas de las regiones. Por ejemplo, en las regiones tropicales y subtropicales, como es el caso de Perú, las infecciones por VSR se distribuyen de manera uniforme a lo largo de todo el año, con algunos aumentos variables. Actualmente, no se cuenta con un tratamiento antiviral efectivo para las infecciones por VSR, por lo que las medidas profilácticas toman gran importancia. Palivizumab, un anticuerpo monoclonal, es usado como una medida para prevenir el desarrollo de la enfermedad grave causada por el VSR, que requiera hospitalización, en niños susceptibles a desarrollar enfermedad. En el contexto de EsSalud, no se cuenta con una medida profiláctica frente a la enfermedad grave causada por el VSR. Los especialistas de EsSalud consideran que palivizumab ayudaría a prevenir la hospitalización, mortalidad y morbilidad causadas por la infección por VSR, en pacientes con alto riesgo de desarrollar enfermedad grave. En ese sentido, el presente dictamen expone la evaluación de la eficacia y seguridad de palivizumab, comparado con placebo, en la prevención de la enfermedad grave causada por el VSR en niños con DBP, que hayan recibido tratamiento para la DBP en los últimos seis meses, y con antecedente de haber nacido a las 29 semanas, o menos, de gestación. METODOLOGÍA: La búsqueda de la literatura se realizó con el objetivo de identificar evidencia sobre la eficacia y seguridad de palivizumab, en comparación con placebo, para prevenir la enfermedad grave causada por el VSR en niños con DBP que hayan recibido tratamiento para la DBP en los últimos seis meses, con antecedente de haber nacido a las 29 semanas o menos de gestación. La búsqueda de la evidencia se realizó en las bases de datos bibliográficas: PubMed, LILACS y The Cochrane Library. Adicionalmente, se amplió la búsqueda revisando la evidencia generada por grupos internacionales que realizan revisiones sistemáticas, evaluaciones de tecnologías sanitarias y guías de práctica clínica, tales como The National Institute for Health and Care Excellence (NICE), The Canadian Agency for Drugs and Technologies in Health (CADTH), Centro Nacional de Excelencia Tecnológica en Salud (CENETEC), Scottish Intercollegiate Guidelines Network (SIGN), Institute for Quality and Efficiency in Health Care (IQWiG), Scottish Medicines Consortium (SMC), Agency for Healthcare Research and Quality's (AHRQ), National Health and Medical Research Council (NHMRC), New Zealand Guidelines Group (NZGG), Canadian Medical Association (CMA), American College of Physicians Clinical Practice Guidelines y Registered Nurses Association of Ontario (RNAO). Adicionalmente, se realizó una búsqueda manual en las bases The Guidelines International Network (G-I-N), eGuidelines, y el portal de la Base Regional de Informes de Evaluación de Tecnologías en Salud de las Américas (BRISA). Finalmente, se realizó una búsqueda manual en el portal ClinicalTrials.gov del National Institutes of Health (NIH) para identificar ensayos clínicos en desarrollo o cuyos resultados aún no hayan sido publicados en una revista científica. RESULTADOS: Se describe la evidencia disponible según el tipo de publicación, siguiendo lo indicado en los criterios de elegibilidad. CONCLUSIONES: En el presente documento, se evaluó la mejor evidencia científica disponible hasta agosto del 2021, en relación con la eficacia y seguridad de palivizumab en la prevención de la enfermedad grave causada por el VSR, que requiere hospitalización, en niños con DBP que hayan recibido tratamiento para la DBP en los últimos seis meses, con antecedente de haber nacido a las 29 semanas o menos de gestación. En EsSalud no se cuenta con una medida profiláctica frente al desarrollo de enfermedad grave causada por el VSR, que requiera hospitalización, para niños con alto riesgo; enmarcándose en un contexto de vacío terapéutico. La búsqueda sistemática de la evidencia culminó con la selección de dos GPC (Castaños y Rodríguez 2019; Ralston et al. 2014), dos ETS (Ministerio de Salud de Chile 2017; DIGEMID 2016), y el ECA de fase III IMPACT (The IMpact-RSV Study Group 1998). Las guías de Castaños y Rodríguez, y de Ralston et al., coinciden en recomendar la profilaxis con palivizumab en niños con DBP y prematuridad; aunque difieren en el rango de EG del paciente prematuro y el grado de DBP. Ambas guías tomaron en consideración los resultados del ECA IMPACT para emitir sus recomendaciones. Las dos ETS, del Ministerio de Salud de Chile y la DIGEMID de Perú, brindan recomendaciones opuestas sobre el uso profiláctico de palivizumab en niños con DBP y prematuridad. El Ministerio de Salud de Chile aprobó la ampliación de uso de palivizumab en pacientes prematuros menores a 36 semanas con patologías o condiciones de riesgo asociadas. En cambio, la DIGEMID de Perú decide no incluir a palivizumab en el PNUME para su uso en neonatos con EG de 29 a 32 semanas con DBP y edad corregida menor o igual a 3 meses al inicio de la profilaxis. Ambas ETS tomaron en cuenta los resultados del ECA IMPACT. El ECA IMPACT, evaluó el uso de palivizumab versus placebo en niños prematuros con edad menor o igual a seis meses, y niños con DBP y edad menor o igual a dos años. El ECA reportó la reducción de la incidencia de hospitalizaciones por VSR en los niños que recibieron palivizumab en comparación con placebo; un menor número de ingresos a UCI a favor de palivizumab. No se observaron diferencias en la incidencia de ventilación mecánica, duración de ventilación mecánica, mortalidad y el reporte de EA, entre el uso de placebo y palivizumab. El ECA IMPACT (estudio de fase III, doble ciego y pivotal de palivizumab) es el único ECA disponible que evalúa la eficacia comparativa de palivizumab. Las limitaciones del ECA IMPACT afectan la validez y precisión de sus resultados. Tomando en cuenta estas limitaciones, el uso de palivizumab sería eficaz en reducir la incidencia de hospitalización solo en el subgrupo de pacientes de 6 meses de edad o menos y prematuridad (EG menor o igual a 35 semanas). El contexto de vacío terapéutico y la evidencia disponible sugieren que el uso de palivizumab podría tener un impacto significativo en la incidencia de hospitalizaciones por VSR en la población objetivo del presente dictamen (pacientes con DBP y antecedente de prematuridad). Por lo expuesto, el IETSI aprueba el uso de palivizumab para la prevención de la enfermedad grave causada por el VSR en niños con DBP que hayan recibido tratamiento para la DBP en los últimos seis meses, con antecedente de haber nacido a las 29 semanas o menos de gestación, según lo establecido en el Anexo N°1. La vigencia del presente dictamen preliminar es de un año a partir de la fecha de publicación. Así, la continuación de dicha aprobación estará sujeta a la evaluación de los resultados obtenidos y de mayor evidencia que pueda surgir en el tiempo.

Right ventricular function and vasoactive peptides for early prediction of bronchopulmonary dysplasia.

BACKGROUND: To assess the prognostic value of early echocardiographic indices of right ventricular function and vasoactive peptides for prediction of bronchopulmonary dysplasia (BPD) or death in very preterm infants. METHODS: Prospective study involving 294 very preterm infants (median [IQR] gestational age 28.4 [26.4-30.4] weeks, birth weight 1065 [800-1380] g), of whom 57 developed BPD (oxygen supplementation at 36 weeks postmenstrual age) and 10 died. Tricuspid annular plane systolic excursion (TAPSE), right ventricular index of myocardial performance (RIMP), plasma concentrations of mid-regional pro-atrial natriuretic peptide (MR-proANP) and C-terminal pro-endothelin-1 (CT-proET1) were measured on day 7 of life. RESULTS: RIMP was significantly increased (median [IQR] 0.3 [0.23-0.38] vs 0.22 [0.15-0.29]), TAPSE decreased (median [IQR] 5.0 [5.0-6.0] vs 6.0 [5.4-7.0] mm), MR-proANP increased (median [IQR] 784 [540-936] vs 353 [247-625] pmol/L), and CT-proET1 increased (median [IQR] 249 [190-345] vs 199 [158-284] pmol/L) in infants who developed BPD or died, as compared to controls. All variables showed significant but weak correlations with each other (rS -0.182 to 0.359) and predicted BPD/death with similar accuracy (areas under receiver operator characteristic curves 0.62 to 0.77). Multiple regression revealed only RIMP and birth weight as independent predictors of BPD or death. CONCLUSIONS: Vasoactive peptide concentrations and echocardiographic assessment employing standardized measures, notably RIMP, on day 7 of life are useful to identify preterm infants at increased risk for BPD or death.

Association between Intermittent Hypoxemia and Severe Bronchopulmonary Dysplasia in Preterm Infants.

Rationale: Bronchopulmonary dysplasia increases the risk of disability in extremely preterm infants. Although the pathophysiology remains uncertain, prior exposure to intermittent hypoxemia may play a role in this relationship. Objectives: To determine the association between prolonged episodes of intermittent hypoxemia and severe bronchopulmonary dysplasia. Methods: A post hoc analysis of extremely preterm infants in the Canadian Oxygen Trial who survived to 36 weeks' postmenstrual age was performed. Oxygen saturations <80% for ⩾1 minute and the proportion of time per day with hypoxemia were quantified using continuous pulse oximetry data that had been sampled every 10 seconds from within 24 hours of birth until 36 weeks' postmenstrual age. The study outcome was severe bronchopulmonary dysplasia as defined in the 2001 NIH Workshop Summary. Measurements and Main Results: Of 1,018 infants, 332 (32.6%) developed severe bronchopulmonary dysplasia. The median number of hypoxemic episodes ranged from 0.8/day (interquartile range, 0.2-1.1) to 60.2/day (interquartile range, 51.4-70.3) among the least and most affected 10% of infants. Compared with the lowest decile of exposure to hypoxemic episodes, the adjusted relative risk of severe bronchopulmonary dysplasia increased progressively from 1.72 (95% confidence interval, 1.55-1.90) at the 2nd decile to 20.40 (95% confidence interval, 12.88-32.32) at the 10th decile. Similar risk gradients were observed for time in hypoxemia. Significant differences in the rates of hypoxemia between infants with and without severe bronchopulmonary dysplasia emerged within the first week after birth. Conclusions: Prolonged intermittent hypoxemia beginning in the first week after birth was associated with an increased risk of developing severe bronchopulmonary dysplasia among extremely preterm infants. Clinical trial registered with www.isrctn.com (ISRCTN62491227) and www.clinicaltrials.gov (NCT00637169).

Air quality, Environment and Respiratory Outcomes in Bronchopulmonary Dysplasia, the AERO-BPD cohort study: design and adaptation during the SARS-CoV-2 pandemic.

INTRODUCTION: Almost half of all school-age children with bronchopulmonary dysplasia (BPD) have asthma-like symptoms and more suffer from lung function deficits. While air pollution and indoor respiratory irritants are known to affect high-risk populations of children, few studies have objectively evaluated environmental contributions to long-term respiratory morbidity in this population. This study aimed to examine the role of indoor environmental exposures on respiratory morbidity in children with BPD. METHODS AND ANALYSIS: The Air quality, Environment and Respiratory Ouctomes in BPD (AERO-BPD) study is a prospective, single-centre observational study that will enrol a unique cohort of 240 children with BPD and carefully characterise participants and their indoor home environmental exposures. Measures of indoor air quality constituents will assess the relationship of nitrogen dioxide (NO2), particulate matter (PM2.5), nitric oxide (NO), temperature and humidity, as well as dust concentrations of allergens, with concurrently measured respiratory symptoms and lung function.Adaptations to the research protocol due to the SARS-CoV-2 pandemic included remote home environment and participant assessments. ETHICS AND DISSEMINATION: Study protocol was approved by the Boston Children's Hospital Committee on Clinical Investigation. Dissemination will be in the form of peer-reviewed publications and participant information products. TRIAL REGISTRATION NUMBER: NCT04107701.

VIP/PACAP signaling as an alternative target during hyperoxic exposure in preterm newborns.

The use of oxygen therapy (high doses of oxygen - hyperoxia) in the treatment of premature infants results in their survival. However, it also results in a high incidence of chronic lung disease known as bronchopulmonary dysplasia, a disease in which airway hyper-responsiveness and pulmonary hypertension are well known as consequences. In our previous studies, we have shown that hyperoxia causes airway hyper-reactivity, characterized by an increased constrictive and impaired airway smooth muscle relaxation due to a reduced release of relaxant molecules such as nitric oxide, measured under in vivo and in vitro conditions (extra- and intrapulmonary) airways. In addition, the relaxation pathway of the vasoactive intestinal peptide (VIP) and/or pituitary adenylate cyclase activating peptide (PACAP) is another part of this system that plays an important role in the airway caliber. Peptide, which activates VIP cyclase and pituitary adenylate cyclase, has prolonged airway smooth muscle activity. It has long been known that VIP inhibits airway smooth muscle cell proliferation in a mouse model of asthma, but there is no data about its role in the regulation of airway and tracheal smooth muscle contractility during hyperoxic exposure of preterm newborns.

Surfactant protein D and bronchopulmonary dysplasia: a new way to approach an old problem.

Surfactant protein D (SP-D) is a collectin protein synthesized by alveolar type II cells in the lungs. SP-D participates in the innate immune defense of the lungs by helping to clear infectious pathogens and modulating the immune response. SP-D has shown an anti-inflammatory role by down-regulating the release of pro-inflammatory mediators in different signaling pathways such as the TLR4, decreasing the recruitment of inflammatory cells to the lung, and modulating the oxidative metabolism in the lungs. Recombinant human SP-D (rhSP-D) has been successfully produced mimicking the structure and functions of native SP-D. Several in vitro and in vivo experiments using different animal models have shown that treatment with rhSP-D reduces the lung inflammation originated by different insults, and that rhSP-D could be a potential treatment for bronchopulmonary dysplasia (BPD), a rare disease for which there is no effective therapy up to date. BPD is a complex disease in preterm infants whose incidence increases with decreasing gestational age at birth. Lung inflammation, which is caused by different prenatal and postnatal factors like infections, lung hyperoxia and mechanical ventilation, among others, is the key player in BPD. Exacerbated inflammation causes lung tissue injury that results in a deficient gas exchange in the lungs of preterm infants and frequently leads to long-term chronic lung dysfunction during childhood and adulthood. In addition, low SP-D levels and activity in the first days of life in preterm infants have been correlated with a worse pulmonary outcome in BPD. Thus, SP-D mediated functions in the innate immune response could be critical aspects of the pathogenesis in BPD and SP-D could inhibit lung tissue injury in this preterm population. Therefore, administration of rhSP-D has been proposed as promising therapy that could prevent BPD.

Established severe BPD: is there a way out? Change of ventilatory paradigms.

Improved survival of extremely preterm newborn infants has increased the number of infants at risk for developing bronchopulmonary dysplasia (BPD). Despite efforts to prevent BPD, many of these infants still develop severe BPD (sBPD) and require long-term invasive mechanical ventilation. The focus of research and clinical management has been on the prevention of BPD, which has had only modest success. On the other hand, research on the management of the established sBPD patient has received minimal attention even though this condition poses large economic and health problems with extensive morbidities and late mortality. Patients with sBPD, however, have been shown to respond to treatments focused not only on ventilatory strategies but also on multidisciplinary approaches where neurodevelopmental support, growth promoting strategies, and aggressive treatment of pulmonary hypertension improve their long-term outcomes. In this review we will try to present a physiology-based ventilatory strategy for established sBPD, emphasizing a possible paradigm shift from acute efforts to wean infants at all costs to a more chronic approach of stabilizing the infant. This chronic approach, herein referred to as chronic phase ventilation, aims at allowing active patient engagement, reducing air trapping, and improving ventilation-perfusion matching, while providing sufficient support to optimize late outcomes. IMPACT: Based on pathophysiological aspects of evolving and established severe BPD in premature infants, this review presents some lung mechanical properties of the most severe phenotype and proposes a chronic phase ventilatory strategy that aims at reducing air trapping, improving ventilation-perfusion matching and optimizing late outcomes.

Lung function trajectories in children with post-prematurity respiratory disease: identifying risk factors for abnormal growth.

BACKGROUND: Survivors of prematurity are at risk for abnormal childhood lung function. Few studies have addressed trajectories of lung function and risk factors for abnormal growth in childhood. This study aims to describe changes in lung function in a contemporary cohort of children born preterm followed longitudinally in pulmonary clinic for post-prematurity respiratory disease and to assess maternal and neonatal risk factors associated with decreased lung function trajectories. METHODS: Observational cohort of 164 children born preterm ≤ 32 weeks gestation followed in pulmonary clinic at Boston Children's Hospital with pulmonary function testing. We collected demographics and neonatal history. We used multivariable linear regression to identify the impact of neonatal and maternal risk factors on lung function trajectories in childhood. RESULTS: We identified 264 studies from 82 subjects with acceptable longitudinal FEV1 data and 138 studies from 47 subjects with acceptable longitudinal FVC and FEV1/FVC data. FEV1% predicted and FEV1/FVC were reduced compared to childhood norms. Growth in FVC outpaced FEV1, resulting in an FEV1/FVC that declined over time. In multivariable analyses, longer duration of mechanical ventilation was associated with a lower rate of rise in FEV1% predicted and greater decline in FEV1/FVC, and postnatal steroid exposure in the NICU was associated with a lower rate of rise in FEV1 and FVC % predicted. Maternal atopy and asthma were associated with a lower rate of rise in FEV1% predicted. CONCLUSIONS: Children with post-prematurity respiratory disease demonstrate worsening obstruction in lung function throughout childhood. Neonatal risk factors including exposure to mechanical ventilation and postnatal steroids, as well as maternal atopy and asthma, were associated with diminished rate of rise in lung function. These results may have implications for lung function trajectories into adulthood.

Cerebral Oxygenation and Perfusion when Positioning Preterm Infants: Clinical Implications.

OBJECTIVES: To evaluate cerebral tissue oxygenation (cTOI) and cerebral perfusion in preterm infants in supine vs prone positions. STUDY DESIGN: Sixty preterm infants, born before 32 weeks of gestation, were enrolled; 30 had bronchopulmonary dysplasia (BPD, defined as the need for respiratory support and/or supplemental oxygen at 36 weeks of postmenstrual age). Cerebral perfusion, cTOI, and polysomnography were measured in both the supine and prone position with the initial position being randomized. Infants with a major intraventricular hemorrhage or major congenital abnormality were excluded. RESULTS: Cerebral perfusion was unaffected by position or BPD status. In the BPD group, the mean cTOI was higher in the prone position compared with the supine position by a difference of 3.27% (P = .03; 95% CI 6.28-0.25) with no difference seen in the no-BPD group. For the BPD group, the burden of cerebral hypoxemia (cumulative time spent with cTOI <55%) was significantly lower in the prone position (23%) compared with the supine position (29%) (P < .001). In those without BPD, position had no effect on cTOI. CONCLUSIONS: In preterm infants with BPD, the prone position improved cerebral oxygenation and reduced cerebral hypoxemia. These findings may have implications for positioning practices. Further research will establish the impact of position on short- and long-term developmental outcomes.

Fluid status in the first 10 days of life and death/bronchopulmonary dysplasia among preterm infants.

OBJECTIVE: To investigate the association between fluid and sodium status in the first 10 postnatal days and death/bronchopulmonary dysplasia (BPD) among infants born <29 weeks' gestation. STUDY DESIGN: Single center retrospective cohort study (2015-2018) of infants born 23-28 weeks'. Three exposure variables were evaluated over the first 10 postnatal days: cumulative fluid balance (CFB), median serum sodium concentration, and maximum percentage weight loss. Primary outcome was death and/or BPD. Multivariable logistic regression adjusting for patient covariates was used to assess the association between exposure variables and outcomes. RESULTS: Of 191 infants included, 98 (51%) had death/BPD. Only CFB differed significantly between BPD-free survivors and infants with death/BPD: 4.71 dL/kg (IQR 4.10-5.12) vs 5.11 dL/kg (IQR 4.47-6.07; p < 0.001). In adjusted analyses, we found an association between higher CFB and higher odds of death/BPD (AOR 1.56, 95% CI 1.11-2.25). This was mainly due to the association of CFB with BPD (AOR 1.60, 95% CI 1.12-2.35), rather than with death (AOR 1.08, 95% CI 0.54-2.30). CONCLUSION: Among preterm infants, a higher CFB in the first 10 days after delivery is associated with higher odds of death/BPD. IMPACT: Previous studies suggest that postnatal fluid status influences survival and respiratory function in neonates. Fluid balance, serum sodium concentration, and daily weight changes are commonly used as fluid status indicators in neonates. We found that higher cumulative fluid balance in the first 10 days of life was associated with higher odds of death/bronchopulmonary dysplasia in neonates born <29 weeks. Monitoring of postnatal fluid balance may be an appropriate non-invasive strategy to favor survival without bronchopulmonary dysplasia. We developed a cumulative fluid balance chart with corresponding thresholds on each day to help design future trials and guide clinicians in fluid management.

miR34a: a novel small molecule regulator with a big role in bronchopulmonary dysplasia.

Preterm infants with bronchopulmonary dysplasia (BPD), characterized by pulmonary inflammation leading to impaired alveolarization and vascular dysregulation, have an increased risk of abnormal lung function in infancy, childhood, and adulthood. These include a heightened risk of pulmonary hypertension, and respiratory illnesses. MicroRNAs (miRNAs) are known to disrupt normal lung development and function by interrupting alveolarization and vascularization resulting in the development of BPD. Among the various miRs involved in BPD, miR34a has been shown to have a significant role in BPD pathogenesis. Targeting miR34a or its downstream targets may be a promising therapeutic intervention for BPD. In this review, we summarize the data on cellular arrest, proliferation, differentiation, epithelial-mesenchymal transition, mitochondrial dysfunction, and apoptosis impacted by miR34a in the development of BPD pulmonary phenotypes while predicting the future perspective of miR34a in BPD.