Incidence and Predictors of Bronchopulmonary Dysplasia Development and Severity Among Preterm Infants Born at 32 Weeks of Gestation or Less

Background As the most common chronic lung disease (CLD) related to premature birth, bronchopulmonary dysplasia (BPD) is associated with long-term lung disease along with cardiovascular and neurodevelopmental disorders. However, data on the incidence and predictors of BPD in Qatar are lacking. Objectives In this study, we aimed to determine the incidence of BPD among infants born at ≤ 32 weeks gestational age (GA) at our neonatal unit, and identify risk factors for the development of BPD and moderate-severe BPD. Methods This was a retrospective observational cohort study conducted at a single site: a level-III neonatal intensive care unit (NICU) in Qatar. We included 1539 neonates born at ≤ 32 weeks of gestation with birth weights of ≤ 1500 grams who were admitted to the NICU between 2017 and 2020. Univariate and multivariate logistic regression analyses were performed to identify potential factors and predictors and their possible associations with the development of BPD and moderate-severe BPD. We also applied BPD classifications to determine the variability in the incidence of BPD in our cohort according to various definitions (2001 National Institute of Child Health and Human Development (NICHD) Diagnostic Criteria, 2016 Revisions of NICHD Criteria, and 2019 Neonatal Research Network Jensen Grading). Results A total of 451 infants (29.3%) had BPD (BPD group) while 1088 (70.7%) did not (non-BPD group), and the overall incidence of BPD was 29.3%. The most relevant risk factors associated with a higher risk of developing BPD identified in the multivariate logistic regression analysis were appropriate weight for gestational age (adjusted OR (aOR) 3.67, 95%CI 2.02-6.67, P < 0.001), presence of patent ductus arteriosus (PDA) (aOR 2.61, 95%CI 1.86-3.66, P < 0.001), late-onset sepsis (aOR 2.16; 95%CI 1.29-3.62; P = 0.003), and use of invasive ventilation (aOR 1.90; 95%CI 1.35-2.69; P < 0.001). The most relevant independent risk factors associated with a higher risk for developing moderate-severe BDP were postnatal steroids (aOR 7.12, 95%CI 3.77-13.44, P < 0.001), use of inhaled nitric oxide (aOR 3.65, 95%CI 1.48-9.01, P = 0.005), use of invasive ventilation (aOR 2.13, 95%CI 1.13-4.00, P = 0.019), late-onset sepsis (aOR 2.07, 95%CI 1.10-3.91, P = 0.025), and male sex (aOR 2.04, 95%CI 1.24-3.36, P = 0.005). The difference in the distribution of BPD severity across the three different definitions of NICHD was significant (P < 0.001). Conclusion The results of this study showed that the incidence of BPD remained high in infants born at ≤ 32 weeks of gestational age and birth weight <1500 g with appropriate weight for gestational age. The presence of PDA at birth or first echocardiography, late-onset sepsis, and use of invasive ventilation were significant risk factors for the incidence of BPD. The identification of risk factors will contribute to the implementation of lung-protective strategies for at-risk infants who may benefit from potential preventive therapy.

Risk Prediction of Severe Bronchopulmonary Dysplasia (BPD) Using the Respiratory Severity Score (RSS) in Extremely Preterm Infants: A Retrospective Study From Saudi Arabia

Background Bronchopulmonary dysplasia (BPD) is a significant complication in extremely preterm infants. Therefore, early diagnosis of BPD is important for planning treatment strategies. In this study, we aimed to assess the predictive efficacy of the Respiratory Severity Score (RSS) in determining severe BPD or death outcomes in very preterm infants. Methodology This retrospective study included preterm infants born with a gestational age of ≤30 weeks. The inclusion criteria comprised individuals who were mechanically ventilated (<1 week) during the first four weeks of life. Any patients who died during the first seven days of life were excluded. RSS values were recorded on days 3, 14, 21, and 28 of life. Multivariate logistic regression was used to identify a correlation between RSS and patient outcomes. Results A total of 154 infants were included in the analysis, of whom 82 (53.24%) developed severe BPD and 38 (24.67%) died. RSS was higher in patients who either died or developed severe BPD compared to those who survived. The multivariate logistic regression analysis revealed that RSSs at postnatal day 14 (odds ratio (OR) = 3.970; 95% confidence interval (CI) = 1.114-14.147; p < 0.05), day 21 (OR = 6.201; 95% CI = 1.937-19.851; p < 0.05), and day 28 (OR = 8.925; 95% CI = 3.331-28.383; p < 0.05) was significantly associated with a higher risk of death or severe BPD. Conclusions The findings of the present study revealed that RSS can help predict the risk of severe BPD in very preterm infants.

Types of home respiratory support in children with bronchopulmonary dysplasia and factors determining its duration: A scoping review

Bronchopulmonary dysplasia also known as chronic lung disease of prematurity has changed as a disease entity over the last five decades and children with "new bronchopulmonary dysplasia (BPD)" have better survival rates. This necessitates strategies to prevent severe BPD and provide organized home support. Home respiratory support in these children varies from home oxygen to noninvasive ventilation and tracheostomy ventilation. This review was conducted utilizing Joanna Briggs Institute publications on evidence synthesis and presentation of results for a scoping review. The Preferred Reporting Items for Systematic Review and Meta-Analyses were used to report the results. The risk of bias assessment was done using "The Cochrane Handbook for Systematic Reviews tool for interventional studies." After screening for the duplication of results and applying inclusion and exclusion criteria, twenty-seven studies were assessed by reading the full texts. Out of these, eleven were finally included in this systematic review. The total sample size from all studies was 4794, including 2705 males. The 4/11 studies home oxygen, one study reported continuous positive airway pressure/bilevel positive airway pressure and seven studies used tracheostomy or tracheostomy ventilation. The median duration of post-natal invasive ventilation was higher in those discharged on home oxygen compared to those who did not need oxygen at discharge. There is a significant proportion of children who are tracheostomy ventilated (8.65%) at home. In the absence of established guidelines, these children are vulnerable when it comes to care at home and the timing of decannulation. For home oxygen alone, guidelines by ERS, ATS and BTS have streamlined weaning protocols and the need for having a multi-disciplinary team to care for these children.

Comparing low-dose (DART) and enhanced low-dose dexamethasone regimens in preterm infants with bronchopulmonary dysplasia

Introduction

Determining the optimal dexamethasone dosage for facilitating extubation in extremely low birth weight (ELBW) infants with bronchopulmonary dysplasia (BPD) remains uncertain. This study aims to compare the effectiveness of low-dose (DART) and enhanced low-dose dexamethasone regimens in achieving successful extubation in these infants.

Methods

We conducted a retrospective cohort study at the Women's Wellness and Research Center (WWRC) involving ELBW infants who received dexamethasone for BPD prevention or treatment, or for extubation between January 1st, 2015, and December 31st, 2019. Our goal was to assess successful extubation within various time points of treatement.

Results

A total of 77 patients, matched in gestational age and BW, were enrolled in the study, receiving a total of 121 dexamethasone courses. Low-dose dexamethasone courses were administered 75 times to 49 infants, while 46 courses of enhanced low-dose were given to 28 infants. Treatment commenced at 30.8 ± 3.4 weeks post-menstrual age, compared to 32.1 ± 2.5 weeks in the enhanced low-dose group (p = 0.014). The median (IQR) course duration was seven (3-10) days in the low-dose group, while it was 10 (8-14) days in the enhanced low-dose group (p < 0.001). The median (IQR) course dose was 0.73 (0.53-0.86) mg/kg in the low-dose group and 1.27 (0.97-2.05) mg/kg in the enhanced low-dose group (p < 0.001). There were no differences in extubation success at any time point between the two groups at 72 h and seven days after treatment initiation, by course completion, and within seven days after treatment completion. However, regression analysis identified several predictors of successful extubation; baseline FiO2, course duration, and duration of invasive mechanical ventilation were negatively associated with successful extubation at various time points, while received dose per kg and cumulative dose positively correlated with successful extubation at different time points. No significant differences were observed in secondary outcomes, including death or BPD.

Conclusion

The choice between low-dose and enhanced low-dose dexamethasone regimens may not significantly impact extubation success. However, careful consideration of dosing, ventilation status, and treatment duration remains crucial in achieving successful extubation. This study highlights the need for personalized dexamethasone therapy in ELBW infants.

Health-Related Qualities of Life in School-Aged Children with Bronchopulmonary Dysplasia

OBJECTIVE

To determine health-related quality of life (HRQOL) of school-aged children with bronchopulmonary dysplasia (BPD) using the standardized Patient-Reported Outcomes Measurement Information System (PROMIS) assessment tools.

STUDY DESIGN

The Indoor Air Quality and Respiratory Morbidity in Children with BPD Study is an ongoing observational study of school-aged children with BPD. HRQOL is assessed at enrollment by 3 PROMIS questionnaires, Parent Proxy Scale-Global Health 7, Parent Proxy Psychological Stress Experiences-Short Form, and the Parent Proxy Profile-Profile-25. PROMIS data were tested for significant deviation from the standardized T-Score references for normative populations of children.

RESULTS

Eighty-nine subjects enrolled in the AERO-BPD study had complete outcome data for HRQOL. The mean age was 9 (±2) years and 43% were female. Mean days on respiratory support totaled 96 (±40). Across all domains, school-aged children with BPD reported similar or slightly better outcomes than the reference sample. Statistically significant findings of lower depression (P < .0001), fatigue (P < .0001), and pain (P < .0001) scores were found; there was no difference in psychological stress experiences (P = .87), global health (P = .06), anxiety (P = .08), relationships (P = .80), and mobility (P = .59) domains.

CONCLUSIONS

This study demonstrated that children with BPD may have less depression, fatigue, and pain HRQL than the general population. Once validated, these findings may offer reassurance to parents and providers caring for children with BPD.

Patterns of early life somatic growth in infants and children with a history of chronic lung disease of prematurity

OBJECTIVE

Preterm infants, and especially those with additional comorbidities, are at risk of early life growth failure, which may impact postnatal lung growth and attainment of peak lung function. However, little is known about the early life growth patterns of those with chronic lung disease. The goal of this study was to describe the patterns appreciated in this population and their association with certain clinical characteristics.

STUDY DESIGN

Demographic, clinical characteristics, and somatic growth parameters between birth and 3 years were retrospectively reviewed for a cohort of children (n = 616) recruited from an outpatient pulmonary clinic. Group-based trajectory modeling was used to identify unique longitudinal trajectories for each growth parameter. Demographic and clinical characteristics were compared using nonparametric analysis.

RESULTS

Four distinct trajectories were appreciated in all three somatic growth domains (weight, length, and weight-for-length), which demonstrated a sizable proportion of subjects with a z-score below zero at 36 months of age, suggesting that the traditional preterm paradigm of "catch-up" growth may not be accurate for this population.

CONCLUSIONS

Children with a history of chronic lung disease begin life with somatic growth measurements well below their term peers and display heterogeneous patterns of weight and length growth through the first 3 years of life. Future studies should focus on further understanding the relationship between somatic growth and respiratory outcomes in this population, which will ideally allow for the use of somatic growth measures as surrogate markers to identify individuals at the highest risk of postnatal growth failure and poor respiratory outcomes.

Association between the development of bronchopulmonary dysplasia and platelet transfusion: a protocol for a systematic review and meta-analysis

Background

There is a lack of consensus on the management of thrombocytopenia in preterm infants, and the threshold for prophylactic platelet transfusion varies widely among clinicians and institutions. Reports in animal models suggested that platelets may play a relevant role in lung alveolarization and regeneration. Bronchopulmonary dysplasia (BPD) is a severe respiratory condition with a multifactorial origin that affects infants born at the early stages of lung development. Recent randomized controlled trials on the platelets count threshold for prophylactic transfusions in preterm infants with thrombocytopenia suggest that a higher exposition to platelet transfusion may increase the risk of BPD. Here, we report a protocol for a systematic review, which aims to assist evidence-based clinical practice and clarify if the administration of platelet products may be associated with the incidence of BPD and/or death in preterm infants.

Methods

MEDLINE, Embase, Cochrane databases, and sources of gray literature for conference abstracts and trial registrations will be searched with no time or language restrictions. Case-control studies, cohort studies, and nonrandomized or randomized trials that evaluated the risk for BPD and/or death in preterm infants exposed to platelet transfusion will be included. Data from studies that are sufficiently similar will be pooled as appropriate. Data extraction forms will be developed a priori. Observational studies and nonrandomized and randomized clinical trials will be analyzed separately. Odds ratio with 95% confidence interval (CI) for dichotomous outcomes and the mean difference (95% CI) for continuous outcomes will be combined. The expected heterogeneity will be accounted for using a random-effects model. Subgroup analysis will be performed based on a priori-determined covariate of interest. In case of sufficient homogeneity of interventions and outcomes evaluated, results from subgroups of studies will be pooled together in a meta-analysis.

Discussion

This systematic review will investigate the association of BPD/death with platelet components administration in preterm infants, and, consequently, it will provide reliable indications for the evidence-based management of premature patients with thrombocytopenia.

Pharmacotherapy for Pulmonary Hypertension in Infants with Bronchopulmonary Dysplasia: Past, Present, and Future

Approximately 8-42% of premature infants with chronic lung disease of prematurity, bronchopulmonary dysplasia (BPD), develop pulmonary hypertension (PH). Infants with BPD-PH carry alarmingly high mortality rates of up to 47%. Effective PH-targeted pharmacotherapies are desperately needed for these infants. Although many PH-targeted pharmacotherapies are commonly used to treat BPD-PH, all current use is off-label. Moreover, all current recommendations for the use of any PH-targeted therapy in infants with BPD-PH are based on expert opinion and consensus statements. Randomized Control Trials (RCTs) are needed to determine the efficacy of PH-targeted treatments in premature infants with or at risk of BPD-PH. Prior to performing efficacy RCTs, studies need to be conducted to obtain pharmacokinetic, pharmacodynamic, and safety data for any pharmacotherapy used in this understudied and fragile patient population. This review will discuss current and needed treatment strategies, identify knowledge deficits, and delineate both challenges to be overcome and approaches to be taken to develop effective PH-targeted pharmacotherapies that will improve outcomes for premature infants with or at risk of developing BPD-PH.

Discharge Practices for Infants with Bronchopulmonary Dysplasia: A Survey of National Experts

OBJECTIVE

To establish consensus practices among a panel of national experts for the discharge of premature infants with bronchopulmonary dysplasia (BPD) from the hospital to home.

STUDY DESIGN

We conducted a Delphi study that included US neonatologists and pediatric pulmonologists from the Bronchopulmonary Dysplasia Collaborative to establish consensus practices-defined as recommendations with at least 80% agreement-for infants with BPD being discharged from the hospital. Specifically, we evaluated recommendations for diagnostic tests to be completed around discharge, follow-up respiratory care, and family education.

RESULTS

Thirty-one expert participants completed 3 rounds of surveys, with a 99% response rate (92 of 93). Consensus was established that infants with moderate-severe BPD (ie, those who remain on respiratory support at 36 weeks) and those discharged on oxygen should be targeted for in-person pulmonary follow-up within 1 month of hospital discharge. Specialized neonatal follow-up is an alternative for infants with mild BPD. Infants with moderate or severe BPD should have an echocardiogram performed after 36 weeks to screen for pulmonary hypertension. Infants with BPD warrant additional evaluations if they have growth restriction or poor growth, pulmonary hypertension, or tachypnea and if they are discharged to home on oxygen, diuretics, or nonoral feeds.

CONCLUSIONS

This Delphi survey establishes expert consensus around best practices for follow-up respiratory management and routine evaluation for infants with BPD surrounding neonatal discharge. Areas of disagreement for which consensus was not established are discussed.

Safety and Efficacy of Mesenchymal Stem Cells for the Treatment of Evolving and Established Bronchopulmonary Dysplasia: A Systematic Literature Review

Bronchopulmonary dysplasia (BPD) is a frequent sequela of modern medicine when infants are born prematurely. Currently, there is no single treatment or combination of treatments to prevent or fully treat BPD. Mesenchymal stem cells (MSCs) have promising properties that could aid in the reversal of lung injury, as seen in patients with BPD. This study reviews the available evidence regarding the safety and efficacy of the use of MSCs for the treatment of evolving and established BPD. This systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). We found eight studies that fulfilled the inclusion and exclusion criteria. While all studies proved the safety and efficacy of MSCs administered intravenously and intratracheally, the only available randomized controlled trial (RCT) failed to demonstrate the benefit of MSC administration in the early treatment of BPD. The remaining studies varied between phase I clinical trials and case reports, but all seemed to show some evidence that MSCs may be of benefit in the late treatment of established BPD. Considering some of the studies have less evidence, early treatment to prevent lung fibrosis may be more successful, particularly in the younger gestational ages where lung development is more immature, and research should focus on this.

Symptomatic preterm infants suffer from lung function deficits, regardless of bronchopulmonary dysplasia

BACKGROUND

The long-term respiratory consequences for children with bronchopulmonary dysplasia (BPD) are well known. However, there is little emphasis on monitoring preterm infants without BPD. Few studies have explored the lung function status of infants with the symptoms of chronic lung disease of prematurity (CLD).

OBJECTIVE

To evaluate functional lung deficits in preterm infants with CLD, and to assess the perinatal determinants of diminished lung function.

METHODS

In our cross-sectional study, 132 preterm infants with symptomatic CLD underwent infant pulmonary function testing (iPFT) at a median post-term age of 0.9 years. The iPFT included bodypletysmography, compliance measurement, tidal breath analysis, and rapid thoracoabdominal compression. The relationships between the respective z scores of the iPFT parameters and perinatal characteristics, postnatal treatment, and BPD status were investigated.

RESULTS

Seventy-three patients (55.3%) were born before the 28^th week of gestation, and 92 (69.7%) met the BPD criteria. Functional deficits were detected in 85.8%. The obstructive ventilatory pattern was more prevalent than restrictive (36.3 vs. 12.4%, p < 0.001). Infants with restriction had lower birth weight (BW) and required a longer duration of oxygenotherapy. In a univariate model, the lung function correlated with the duration of invasive mechanical ventilation, gestational week, and BW. In a general linear model, BPD status was not an additional determinant of the iPFT results.

CONCLUSION

IPFT may reveal significant functional deficits in preterm infants with CLD even without BPD. The current symptoms and perinatal factors may be more important determinants of functional deficits than the BPD status itself.

Cost Savings Without Increased Risk of Respiratory Hospitalization for Preterm Children after the 2014 Palivizumab Policy Update

OBJECTIVE

 Our objective was to compare rates of hospitalizations for respiratory illnesses in preterm and full-term (FT) children for 4 years before and after the 2014 update to the American Academy of Pediatrics (AAP) respiratory syncytial virus (RSV) immunoprophylaxis guidance, which restricted eligibility among infants born at 29 to 34 weeks in the first winter and all preterm infants in the second winter after neonatal discharge.

STUDY DESIGN

 We conducted pre-post and interrupted time series analyses on claims data from a commercial national managed care plan. We compared the number of RSV and all respiratory hospital admissions in the first and second RSV seasons after neonatal discharge among a cohort of preterm children, regardless of palivizumab status, in the 4 years before and after the implementation of the 2014 palivizumab eligibility change. A FT group was included for reference.

RESULTS

 The cohort included 821 early preterm (EP, <29 weeks), 4,790 moderate preterm (MP, 29-34 weeks), and 130,782 FT children. Palivizumab use after the policy update decreased among MP children in the first and second RSV seasons after neonatal discharge, without any change in the odds of hospitalization with RSV or respiratory illness. For the EP group, there was no change in the rate of palivizumab or the odds of hospitalization with RSV or respiratory illness after the policy update. For the FT group, there was a slight decrease in odds of hospitalization post-2014 after the policy update. The interrupted time series did not reveal any secular trends over time in hospitalization rates among preterm children. Following the policy change, there were cost savings for MP children in the first and second RSV seasons, when accounting for the cost of hospitalizations and the cost of palivizumab.

CONCLUSION

 Hospitalizations for RSV or respiratory illness did not increase, and cost savings were obtained after the implementation of the 2014 AAP palivizumab prophylaxis policy.

KEY POINTS

· Palivizumab use decreased among children born moderate preterm (29 to34 weeks) after the 2014 palivizuamb policy update.. · There was no change in odds of hospitalization with respiratory syncitial virus or respiratory illness among preterm infants after the policy update when compared to before.. · There were cost savings, when accounting for the cost of hospitalizations and the cost of palivizumab, after the policy update among children born moderate preterm..

Childhood interstitial lung disease: A case-based review of the imaging findings

Childhood interstitial lung disease (chILD) consists of a large, heterogeneous group of individually rare disorders. chILD demonstrates major differences in disease etiology, natural history, and management when compared with the adult group. It occurs primarily secondary to an underlying developmental or genetic abnormality affecting the growth and maturity of the pediatric lung. They present with different clinical, radiologic, and pathologic features. In this pictorial review article, we will divide chILD into those more prevalent in infancy and those not specific to infancy. We will use a case based approach to discuss relevant imaging findings including modalities such as radiograph and computed tomography in a wide variety of pathologies.

Inhaled vitamin A is more effective than intramuscular dosing in mitigating hyperoxia-induced lung injury in a neonatal rat model of bronchopulmonary dysplasia

Prevention of bronchopulmonary dysplasia (BPD) in premature-birth babies continues to be an unmet medical need. Intramuscular vitamin A is currently employed in preterm neonates to prevent BPD but requires intramuscular injections in fragile neonates. We hypothesized that noninvasive inhaled delivery of vitamin A, targeted to lung, would be a more effective and tolerable strategy. We employed our well-established hyperoxia-injury neonatal rat model, exposing newborn rats to 7 days of constant extreme (95% O₂) hyperoxia, comparing vitamin A dosed every 48 h via either aerosol inhalation or intramuscular injection with normoxic untreated healthy animals and vehicle-inhalation hyperoxia groups as positive and negative controls, respectively. Separately, similar vitamin A dosing of normoxia-dwelling animals was performed. Analyses after day 7 included characterization of alveolar histomorphology and protein biomarkers of alveolar maturation [surfactant protein C (SP-C), peroxisome proliferator-activated receptor (PPAR) γ, cholinephosphate cytidylyl transferase, vascular endothelial growth factor and its receptor, FLK-1, and retinoid X receptors (RXR-α, -β, and -γ], apoptosis (Bcl2 and Bax) key injury repair pathway data including protein markers (ALK-5 and β-catenin) and neutrophil infiltration, and serum vitamin A levels. Compared with intramuscular dosing, inhaled vitamin A significantly enhanced biomarkers of alveolar maturation, mitigated hyperoxia-induced lung damage, and enhanced surfactant protein levels, suggesting that it may be more efficacious in preventing BPD in extremely premature infants than the traditionally used IM dosing regimen. We speculate lung-targeted inhaled vitamin A may also be an effective therapy against other lung damaging conditions leading to BPD or, more generally, to acute lung injury.

Indoor Air Pollution Sources and Respiratory Symptoms in Bronchopulmonary Dysplasia

OBJECTIVE

To evaluate the impact of exposure to indoor air pollution on respiratory health outcomes (healthcare utilization, symptoms, medication use) in infants and children with bronchopulmonary dysplasia (BPD).

STUDY DESIGN

A total of 244 subjects were included from the Johns Hopkins Bronchopulmonary Dysplasia registry. Parents completed an environmental exposure questionnaire including secondhand smoke and indoor combustion (gas/propane heat, gas or wood stove, gas/wood burning fireplace) exposures in the home. Respiratory symptoms, both acute (healthcare utilization, steroid/antibiotic use) and chronic (cough/wheeze, nocturnal cough, use of beta-agonists, tolerance of physical activity), were also collected.

RESULTS

Three-quarters of the infants were exposed to at least 1 combustible source of air pollution in the home, and this exposure was associated with an increased risk of hospitalization in infants and children on home respiratory support. Only 14% of the study population reported secondhand smoke exposure, but we found that this was associated with chronic respiratory symptoms, including activity limitation and nocturnal cough. Infants on respiratory support also had increased daytime cough and wheezing. Approximately one-third reported having an air purifier in the home, and its presence attenuated the effect of secondhand smoke exposure on reported activity limitation.

CONCLUSIONS

Exposure to combustible sources of indoor air pollution was associated with increased respiratory morbidity in a group of high risk of infants with BPD. Our results support that indoor air pollution is a modifiable risk factor for respiratory health in infants with BPD.

Fractional exhaled nitric oxide in preterm-born subjects: A systematic review and meta-analysis

BACKGROUND

Decreased lung function is common in preterm-born survivors. Increased fractional exhaled nitric oxide (FeNO) appears to be a reliable test for eosinophillic airway inflammation especially in asthma. We, systematically, reviewed the literature to compare FeNO levels in preterm-born children and adults who did or did not have chronic lung disease of prematurity (CLD) in infancy with term-born controls.

METHODS

We searched eight databases up to February 2018. Studies comparing FeNO levels in preterm-born subjects (<37 weeks' gestation) in childhood and adulthood with and without (CLD) with term-born subjects were identified and extracted by two reviewers. Data were analysed using Review Manager v5.3.

RESULTS

From 6042 article titles, 183 full articles were screened for inclusion. Nineteen studies met the inclusion criteria. Seventeen studies compared FeNO levels in preterm- and term-born children and adults; 11 studies (preterm n = 640 and term n = 4005) were included in a meta-analysis. The mean FeNO concentration difference between the preterm-born and term-born group was -0.74 (95% CI -1.88 to 0.41) ppb. For the six studies reporting data on CLD (preterm n = 204 and term n = 211) the mean difference for FeNO levels was -2.82 (95% CI -5.87 to 0.22) ppb between the preterm-born CLD and term-born groups.

CONCLUSIONS

Our data suggest that preterm born children with and without CLD have similar FeNO levels to term-born children suggesting an alternative mechanism to eosinophilic inflammation for symptoms of wheezing and airway obstruction observed in preterm-born subjects.

Bronchial hyper-responsiveness in preterm-born subjects: A systematic review and meta-analysis

BACKGROUND

Preterm-born survivors have increased respiratory symptoms and decreased lung function, but the nature of bronchial hyper-responsiveness (BHR) is unclear. We conducted a systematic review and meta-analysis for BHR in preterm-born survivors including those with and without chronic lung disease in infancy (CLD) comparing results to term-born subjects.

METHODS

We searched eight databases up to December 2016. Included articles compared BHR in preterm-born and term-born subjects. Studies reporting BHR as decreases in forced expiratory volume in 1 second (FEV₁ ) after provocation stimuli were included. The analysis used Review Manager V5.3.

RESULTS

From 10 638 titles, 265 full articles were screened, and 28 included in a descriptive analysis. Eighteen articles were included in a meta-analysis as they reported the proportion of subjects who had BHR. Pooled odds ratio (OR) estimates (95% confidence interval) for BHR comparing the preterm and term-born groups was 1.88 (1.32, 2.66). The majority of the studies reported BHR after a methacholine challenge or an exercise test. Odds ratio was 1.89 (1.12, 3.19) after methacholine challenge and 2.59 (1.50, 4.50) after an exercise test. Nine of fifteen articles reporting BHR in CLD subjects were included in a meta-analysis. Differences for BHR including for methacholine (OR 4.35; 2.36, 8.03) and exercise (OR 5.13; 1.82, 14.47) were greater in the CLD group compared to the term group.

CONCLUSIONS

Preterm-born subjects especially those who had CLD had increased rates of BHR to direct (methacholine) and indirect (exercise) stimuli compared to term-born subjects suggesting subgroups might benefit from anti-inflammatory or bronchodilator therapies.

Effectiveness of Palivizumab in High-risk Infants and Children: A Propensity Score Weighted Regression Analysis

BACKGROUND

Infants with premature birth ≤35 weeks gestational age, chronic lung disease of prematurity and congenital heart disease are at an increased risk for lower respiratory tract infections and hospitalization from respiratory syncytial virus (RSV), which has been shown in randomized trials to be prevented by palivizumab. However, palivizumab effectiveness (PE) has not been studied in a large clinical setting.

METHODS

A multicenter study among high-risk US and Canadian children younger than 24 months hospitalized with lower respiratory tract infection and whose nasopharyngeal aspirates were tested for human metapneumovirus (HMPV) and RSV were the subjects of the trial. We conducted a test-negative case-control study in these subjects to determine PE. We used an inverse propensity score weighted (IPSW) multiple logistic regression model to adjust PE.

RESULTS

Palivizumab was used in 434 (51%) of 849 eligible children. RSV was identified in 403 (47%) children. The unadjusted PE was 43% [95% confidence interval (CI), 34%-51%)]. After IPSW adjustment, the adjusted PE was 58% (95% CI, 43%-69%). Palivizumab prevented intensive care unit admissions (PE, 62%; 95% CI, 35%-78%). PE for 29-35 weeks gestational age and ≤6 months of chronologic age without chronic lung disease of prematurity or congenital heart disease was 74% (95% CI, 56%-85%).

CONCLUSIONS

Using a test-negative case-control design with RSV molecular detection, palivizumab is shown to prevent RSV hospitalizations and intensive care unit admissions in high-risk infants.

The Future of Bronchopulmonary Dysplasia: Emerging Pathophysiological Concepts and Potential New Avenues of Treatment

Yearly more than 15 million babies are born premature (<37 weeks gestational age), accounting for more than 1 in 10 births worldwide. Lung injury caused by maternal chorioamnionitis or preeclampsia, postnatal ventilation, hyperoxia, or inflammation can lead to the development of bronchopulmonary dysplasia (BPD), one of the most common adverse outcomes in these preterm neonates. BPD patients have an arrest in alveolar and microvascular development and more frequently develop asthma and early-onset emphysema as they age. Understanding how the alveoli develop, and repair, and regenerate after injury is critical for the development of therapies, as unfortunately there is still no cure for BPD. In this review, we aim to provide an overview of emerging new concepts in the understanding of perinatal lung development and injury from a molecular and cellular point of view and how this is paving the way for new therapeutic options to prevent or treat BPD, as well as a reflection on current treatment procedures.

Physical activity outcomes following preterm birth

Physical activity (PA) is an important mediator of health and disease. Many correlates may play an important role in explaining differences in PA between populations; however, the role of birth outcomes such as prematurity on levels of PA is relatively poorly represented in the literature. Children born preterm may be at risk for reduced levels of PA as they have increased respiratory symptoms as well as decrements in lung function and exercise capacity. Emerging evidence suggests that the effects are prevalent across the whole range of gestational age. This review summarises the current literature in regards to levels of PA in preterm-born children and also explores PA in cohorts of young adults in order to contextualise the possible impact on long term risks to respiratory health.

Bronchopulmonary Dysplasia: Chronic Lung Disease of Infancy and Long-Term Pulmonary Outcomes. J Clin Med. 2017;6:4. [PMID: 28067830 PMCID: PMC5294957 DOI: 10.3390/jcm6010004]

Bronchopulmonary dysplasia (BPD) is a chronic lung disease most commonly seen in premature infants who required mechanical ventilation and oxygen therapy for acute respiratory distress. While advances in neonatal care have resulted in improved survival rates of premature infants, limited progress has been made in reducing rates of BPD. Lack of progress may in part be attributed to the limited therapeutic options available for prevention and treatment of BPD. Several lung-protective strategies have been shown to reduce risks, including use of non-invasive support, as well as early extubation and volume ventilation when intubation is required. These approaches, along with optimal nutrition and medical therapy, decrease risk of BPD; however, impacts on long-term outcomes are poorly defined. Characterization of late outcomes remain a challenge as rapid advances in medical management result in current adult BPD survivors representing outdated neonatal care. While pulmonary disease improves with growth, long-term follow-up studies raise concerns for persistent pulmonary dysfunction; asthma-like symptoms and exercise intolerance in young adults after BPD. Abnormal ventilatory responses and pulmonary hypertension can further complicate disease. These pulmonary morbidities, combined with environmental and infectious exposures, may result in significant long-term pulmonary sequalae and represent a growing burden on health systems. Additional longitudinal studies are needed to determine outcomes beyond the second decade, and define risk factors and optimal treatment for late sequalae of disease.

Point Prevalence, Clinical Characteristics, and Treatment Variation for Infants with Severe Bronchopulmonary Dysplasia

OBJECTIVES

Despite improvements in survival of preterm infants, bronchopulmonary dysplasia (BPD) remains a persistent morbidity. The incidence, clinical course, and current management of severe BPD (sBPD) remain to be defined. To address these knowledge gaps, a multicenter collaborative was formed to improve outcomes in this population.

STUDY DESIGN

We performed a "snapshot" in eight neonatal intensive care units (NICUs) on December 17, 2013. A standardized clinical data form for each inpatient born at < 32 weeks was completed and collated centrally for analysis. sBPD was defined as receiving ≥ 30% supplemental oxygen and/or receiving positive pressure ventilation at 36 weeks postmenstrual age (PMA).

RESULTS

Of a total census of 710 inpatients, 351 infants were born at < 32 weeks and 128 of those (36.5%) met criteria for sBPD. The point prevalence of sBPD varied between centers (11-58%; p < 0.001). Among infants with sBPD there was a variation among centers in the use of mechanical ventilation at 28 days of life (p < 0.001) and at 36 weeks PMA (p = 0.001). We observed differences in the use of diuretics (p = 0.018), inhaled corticosteroids (p < 0.001), and inhaled β-agonists (p < 0.001).

CONCLUSION

The high point prevalence of sBPD and variable management among NICUs emphasizes the lack of evidence in guiding optimal care to improve long-term outcomes of this high-risk, understudied population.

Transcriptional responses of neonatal mouse lung to hyperoxia by Nrf2 status

Hyperoxia exposure can inhibit alveolar growth in the neonatal lung through induction of p21/p53 pathways and is a risk factor for the development of bronchopulmonary dysplasia (BPD) in preterm infants. We previously found that activation of nuclear factor erythroid 2 p45-related factor (Nrf2) improved survival in neonatal mice exposed to hyperoxia likely due to increased expression of anti-oxidant response genes. It is not known however, whether hyperoxic induced Nrf2 activation attenuates the growth impairment caused by hyperoxia in neonatal lung. To determine if Nrf2 activation modulates cell cycle regulatory pathway genes associated with growth arrest we examined the gene expression in the lungs of Nrf2(-/-) and Nrf2(+/+) neonatal mice at one and 3days of hyperoxia exposure.

METHODS

Microarray analysis was performed in neonatal Nrf2(+/+) and Nrf2(-/-) lungs exposed to one and 3days of hyperoxia. Sulforaphane, an inducer of Nrf2 was given to timed pregnant mice to determine if in utero exposure attenuated p21 and IL-6 gene expression in wildtype neonatal mice exposed to hyperoxia.

RESULTS

Cell cycle regulatory genes were induced in Nrf2(-/-) lung at 1day of hyperoxia. At 3days of hyperoxia, induction of cell cycle regulatory genes was similar in Nrf2(+/+) and Nrf2(-/-) lungs, despite higher inflammatory gene expression in Nrf2(-/-) lung.

CONCLUSION

p21/p53 pathways gene expression was not attenuated by Nrf2 activation in neonatal lung. In utero SUL did not attenuate p21 expression in wildtype neonatal lung exposed to hyperoxia. These findings suggest that although Nrf2 activation induces expression of anti-oxidant genes, it does not attenuate alveolar growth arrest caused by exposure to hyperoxia.

Relationship of proteinases and proteinase inhibitors with microbial presence in chronic lung disease of prematurity

BACKGROUND

A proteolytic imbalance has been implicated in the development of "classical" chronic lung disease of prematurity (CLD). However, in "new" CLD this pattern has changed. This study examines the longitudinal relationship between neutrophil proteinases and their inhibitors in ventilated preterm infants and their relationship to microbial colonisation.

METHODS

Serial bronchoalveolar lavage fluid was obtained from ventilated newborn preterm infants. Neutrophil elastase (NE) activity, cell counts, metalloproteinase (MMP)-9, MMP-9/TIMP-1 complex, SerpinB1 concentration and percentage of SerpinB1 and alpha(1)-antitrypsin (AAT) in complex with elastase were measured. The presence of microbial genes was examined using PCR for 16S rRNA genes.

RESULTS

Statistically more infants who developed CLD had NE activity in at least one sample (10/20) compared with infants with resolved respiratory distress syndrome (RDS) (2/17). However, NE activity was present in a minority of samples, occurring as episodic peaks. Peak levels of MMP-9, MMP-9/TIMP-1 complex, percentage of AAT and SerpinB1 in complex and cell counts were all statistically greater in infants developing CLD than in infants with resolved RDS. Peak values frequently occurred as episodic spikes and strong temporal relationships were noted between all markers. The peak values for all variables were significantly correlated to each other. The presence of bacterial 16S rRNA genes was associated with the development of CLD and with elevated elastase and MMP-9.

CONCLUSION

NE activity and MMP-9 appear to be important in the development of "new" CLD with both proteinase and inhibitor concentrations increasing episodically, possibly in response to postnatal infection.

cause chronic lung disease of prematurity: ask the audience?

Ureaplasma has long been implicated in the pathogenesis of both preterm labour and neonatal morbidity, particularly chronic lung disease of prematurity (CLD), but despite numerous studies, reviews and meta-analyses, its exact role remains unclear. Many papers call for a definitive randomised control trial to determine if eradication of pulmonary Ureaplasma decreases the rates of CLD but few address in detail the obstacles to an adequately powered clinical trial. We review the evidence for Ureaplasma as a causative agent in CLD, asking why a randomised control trial has not been performed. We surveyed the opinions of senior neonatologists in the UK on whether they felt that there was sufficient evidence for Ureaplasma either causing or not causing CLD and whether a definitive trial was needed, as well as their views on the design of such a trial. Additionally, we ascertained current practice with respect to Ureaplasma detection in preterm neonates in the UK. There is clear support for an adequately powered randomised controlled clinical trial by senior neonatologists in the UK. There are no reasons why a definitive trial cannot be conducted especially as the appropriate samples, and methods to culture or identify the organism by PCR are already available.