Preschool healthcare utilisation related to home oxygen status

Early metabolic markers as predictors of respiratory complications in preterm infants with bronchopulmonary dysplasia

BACKGROUND

Bronchopulmonary dysplasia (BPD), a common complication of premature birth, exerts considerable impact on the respiratory health of infants. This study aimed to identify the role of plasma metabolites in predicting respiratory outcomes in BPD-afflicted infants.

METHODS

This was a case-control study including 15 BPD premature infants and 15 gestational age and birth weight matched no-BPD preterm infants. Plasma samples, obtained at 36 weeks postmenstrual age (PMA), were subjected to a comprehensive analysis of over 300 metabolites using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The respiratory outcomes of the infants were collected with the first 2 years of corrected postnatal age.

RESULTS

The analysis revealed a significant upregulation of urea and downregulation of nine metabolites in BPD infants, including oxalacetic acid, cis-aconitic acid, itaconic acid, betaine, L-asparagine, L-alanine, picolinic acid, inositol, and purine (p < 0.05). These metabolites primarily pertained to the citrate cycle (TCA cycle), glyoxylate and dicarboxylate metabolism, and alanine, aspartate, and glutamate metabolism. Furthermore, seven metabolites demonstrated substantial predictive capacity for respiratory readmissions within the first two years of corrected postnatal age, achieving an area under curve (AUC) exceeding or equal to 0.8. These included chenodeoxycholic acid, dehydrolithocholic acid, glucaric acid, D-glucuronic acid, gamma-glutamylvaline, mevalonic acid, and 3-ureidopropionic acid.

CONCLUSIONS

This study identified ten distinct plasma metabolites at 36 weeks PMA that differentiate BPD infants from their non-BPD counterparts, implicating three major metabolic pathways. Additionally, seven metabolites showed strong predictive value for heightened risk of respiratory readmission within two years, underscoring their potential utility in clinical prognostication and management strategies for BPD.

Outpatient management of established bronchopulmonary dysplasia: An update

As the incidence of infants with bronchopulmonary dyspasia (BPD) has continued to rise, so has their rate of survival. Their medical management is often complex and requires the use of numerous therapies such as steroids, bronchodilators, diuretics and modalities to deliver supplemental oxygen and positive pressure. It also requires multi-disciplinary care to ensure adequate growth and to optimize neurodevelopmental outcomes. This review aims to discuss the most widely used therapies in the treatment of patients with established BPD. The focus will be on ongoing outpatient (post-neonatal intensive care) management of children with BPD. Since many of the mentioned therapies lack solid evidence to support their use, more high quality research, such as randomized controlled trials, is needed to assess their effectiveness using defined outcomes.

Outpatient respiratory outcomes in children with BPD on supplemental oxygen

INTRODUCTION

Preterm children with bronchopulmonary dysplasia (BPD) frequently require supplemental oxygen in the outpatient setting. In this study, we sought to determine patient characteristics and demographics associated with need for supplemental oxygen at initial hospital discharge, timing to supplemental oxygen liberation, and associations between level of supplemental oxygen and likelihood of respiratory symptoms and acute care usage in the outpatient setting.

METHODS

A retrospective analysis of subjects with BPD on supplemental oxygen (O2 ) was performed. Subjects were recruited from outpatient clinics at Johns Hopkins University and the Children's Hospital of Philadelphia between 2008 and 2021. Data were obtained by chart review and caregiver questionnaires.

RESULTS

Children with BPD receiving ≥1 L of O2 were more likely to have severe BPD, pulmonary hypertension, and be older at initial hospital discharge. Children discharged on higher levels of supplemental O2 were slower to wean to room air compared to lower O2 groups (p < 0.001). Additionally, weaning off supplemental O2 in the outpatient setting was delayed in children with gastrostomy tubes and those prescribed inhaled corticosteroids, on public insurance or with lower household incomes. Level of supplemental O2 at discharge did not influence outpatient acute care usage or respiratory symptoms.

CONCLUSION

BPD severity and level of supplemental oxygen use at discharge did not correlate with subsequent acute care usage or respiratory symptoms in children with BPD. Weaning of O2 however was significantly associated with socioeconomic status and respiratory medication use, contributing to the variability in O2 weaning in the outpatient setting.

Early-life hyperoxia-induced Flt3L drives neonatal lung dendritic cell expansion and proinflammatory responses

Premature infants with chronic lung disease, bronchopulmonary dysplasia (BPD), develop recurrent cough and wheezing following respiratory viral infections. The mechanisms driving the chronic respiratory symptoms are ill-defined. We have shown that hyperoxic exposure of neonatal mice (a model of BPD) increases the activated lung CD103+ dendritic cells (DCs) and these DCs are required for exaggerated proinflammatory responses to rhinovirus (RV) infection. Since CD103+ DC are essential for specific antiviral responses and their development depends on the growth factor Flt3L, we hypothesized that early-life hyperoxia stimulates Flt3L expression leading to expansion and activation of lung CD103+ DCs and this mediates inflammation. We found that hyperoxia numerically increased and induced proinflammatory transcriptional signatures in neonatal lung CD103+ DCs, as well as CD11bhi DCs. Hyperoxia also increased Flt3L expression. Anti-Flt3L antibody blocked CD103+ DC development in normoxic and hyperoxic conditions, and while it did not affect the baseline number of CD11bhi DCs, it neutralized the effect of hyperoxia on these cells. Anti-Flt3L also inhibited hyperoxia-induced proinflammatory responses to RV. In tracheal aspirates from preterm infants mechanically-ventilated for respiratory distress in the first week of life levels of FLT3L, IL-12p40, IL-12p70 and IFN-γ were higher in infants who went on to develop BPD and FLT3L levels positively correlated with proinflammatory cytokines levels. This work highlights the priming effect of early-life hyperoxia on lung DC development and function and the contribution of Flt3L in driving these effects.

Cost-effectiveness analysis of extended extracorporeal membrane oxygenation duration in newborns with congenital diaphragmatic hernia in the United States

BACKGROUND

The duration of extracorporeal membrane oxygenation (ECMO) has been historically confined in many centers to two weeks. We evaluated the cost-effectiveness of additional weeks on ECMO beyond two weeks for newborns with congenital diaphragmatic hernia (CDH) who may require longer stays to maximize survival potential.

METHODS

We modeled lifetime outcomes using a decision tree from the US societal perspective. Survival at discharge, probability of long-term sequelae, direct medical costs, indirect costs, and quality-adjusted life years (QALY) for long-term disability were considered. Considering the nature of severity of CDH, we used $200,000 per QALY as the willingness-to-pay threshold in the base case.

RESULTS

The lifetime costs per CDH infant generated from staying on ECMO for ≤2 weeks, 2-3 weeks, and >3 weeks are $473,334, $654,771, $1,007,476, respectively (2018 USD), and the total QALYs gained from each treatment arm are 1.83, 3.6, and 5.05. In the base case, the net monetary benefits are -$108,034 for ECMO ≤2 weeks, $64,258 for 2-3 weeks, and $2955 for >3 weeks. In probabilistic simulations, a duration of ≤2 weeks is dominated by a duration of 2-3 weeks in 65.3% of cases and dominated by > 3 weeks in 60.2% of cases. A duration of 2-3 weeks is more cost-effective than >3 weeks in 68.6% of simulations.

CONCLUSION

Our findings suggest that 2-3 weeks of ECMO may be the most cost-effective for CDH infants that are unable to wean off at 2 weeks from the US societal perspective. Regardless of ECMO duration, ECMO use generates positive incremental NMB at WTP of $200,000 if the survival probability is greater than 0.3. Future research must be conducted to evaluate the long-term outcomes and sequelae of CDH patients post-discharge to better inform the clinical decision-making in neonatal intensive care unit.

Gelsolin Attenuates Neonatal Hyperoxia-Induced Inflammatory Responses to Rhinovirus Infection and Preserves Alveolarization

Prematurity and bronchopulmonary dysplasia (BPD) increase the risk of asthma later in life. Supplemental oxygen therapy is a risk factor for chronic respiratory symptoms in infants with BPD. Hyperoxia induces cell injury and release of damage-associated molecular patterns (DAMPs). Cytoskeletal filamentous actin (F-actin) is a DAMP which binds Clec9a, a C-type lectin selectively expressed on CD103+ dendritic cells (DCs). Co-stimulation of Clec9a and TLR3 induces maximal proinflammatory responses. We have shown that neonatal hyperoxia (a model of BPD) increases lung IL-12+Clec9a+CD103+ DCs, pro-inflammatory responses and airway hyperreactivity following rhinovirus (RV) infection. CD103+ DCs and Clec9a are required for these responses. Hyperoxia increases F-actin levels in bronchoalveolar lavage fluid (BALF). We hypothesized that the F-actin severing protein gelsolin attenuates neonatal hyperoxia-induced Clec9a+CD103+ DC-dependent pro-inflammatory responses to RV and preserves alveolarization. We exposed neonatal mice to hyperoxia and treated them with gelsolin intranasally. Subsequently we inoculated the mice with RV intranasally. Alternatively, we inoculated normoxic neonatal mice with BALF from hyperoxia-exposed mice (hyperoxic BALF), RV and gelsolin. We analyzed lung gene expression two days after RV infection. For in vitro studies, lung CD11c+ cells were isolated from C57BL/6J or Clec9a^gfp-/- mice and incubated with hyperoxic BALF and RV. Cells were analyzed by flow cytometry. In neonatal mice, gelsolin blocked hyperoxia-induced Il12p40, TNF-α and IFN-γ mRNA and protein expression in response to RV infection. Similar effects were observed when gelsolin was co-administered with hyperoxic BALF and RV. Gelsolin decreased F-actin levels in hyperoxic BALF in vitro and inhibited hyperoxia-induced D103lo DC expansion and inflammation in vivo. Gelsolin also attenuated hyperoxia-induced hypoalveolarization. Further, incubation of lung CD11c+ cells from WT and Clec9a^gfp-/- mice with hyperoxic BALF and RV, showed Clec9a is required for maximal hyperoxic BALF and RV induced IL-12 expression in CD103+ DCs. Finally, in tracheal aspirates from mechanically ventilated human preterm infants the F-actin to gelsolin ratio positively correlates with FiO2, and gelsolin levels decrease during the first two weeks of mechanical ventilation. Collectively, our findings demonstrate a promising role for gelsolin, administered by inhalation into the airway to treat RV-induced exacerbations of BPD and prevent chronic lung disease.

Home oxygen use and 1-year outcome among preterm infants with bronchopulmonary dysplasia discharged from a Chinese regional NICU

OBJECTIVE

This study aims to compare the clinical characteristics and 1-year outcomes of preterm infants with bronchopulmonary dysplasia (BPD) who were discharged on supplemental oxygen or room air.

MATERIALS AND METHODS

The preterm infants (born <32 weeks' gestation, birth weight ≤1,250 g) diagnosed with BPD and admitted between January 2020 and December 2020 were enrolled. The clinical data during hospitalization were collected through the hospital's electronic record system. The outcomes after discharge were acquired from the outpatient system and through telephonic interviews.

RESULTS

Of the 87 preterm infants diagnosed with BPD, 81 infants survived until discharge. The 81 infants were divided into the home oxygen group (n = 29) and room air group (n = 52) according to supplemental oxygen or not at discharge. Infants in the home oxygen group were more likely to receive postnatal systemic steroids and higher ventilation settings at 36 weeks' PMA. There was one patient in each group who died before 1 year corrected age, respectively. All the infants had successfully weaned off oxygen eventually during the first year. The median duration of home oxygen therapy was 25 (7,42) days. Readmission occurred in 49 (64.5%) infants. Readmissions for infants with home oxygen were more often related to respiratory disease. In addition, wheezing disorders and home inhalation occurred more frequently in the home oxygen group (p = 0.022, p = 0.004). Although the incidence of underweight at 1 year corrected age was higher in the room air group (10.0 vs. 3.8%), there was no significant difference (p = 0.620). The rate of neurodevelopmental impairment was similar between these two groups (26.0 vs. 30.8%, p = 0.659).

CONCLUSIONS

It was the first study focused on preterm infants with BPD receiving home oxygen in China. Infants with home oxygen were more likely to have respiratory problems after discharge from NICU. Home oxygen use was not associated with more readmission for infants with BPD, and no difference was found in neurodevelopmental impairment and growth outcome.

Short- and Long-Term Complications of Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is a chronic lung disease most commonly seen in preterm infants of low birthweight who required postnatal respiratory support. Although overall incidence rates have not changed, recent advancements in medical care have resulted in lower mortality rates, and those affected are beginning to live longer. As a result, the long-term repercussions of BPD are becoming more apparent. Whereas BPD has been thought of as a disease of just the lungs, resulting in abnormalities such as increased susceptibility to pulmonary infections, impaired exercise tolerance, and pulmonary hypertension, the enduring complications of BPD have been found to extend much further. This includes an increased risk for cerebral palsy and developmental delays, lower intelligence quotient (IQ) scores, impaired executive functioning, behavioral challenges, delays in expressive and receptive language development, and an increased risk of growth failure. In addition, the deficits of BPD have been found to influence much more than just physical health; BPD survivors have been noted to have higher rates of health care use, starting with the initial hospitalization and continuing with therapy and specialist follow-up, as well as impairments in quality of life, both physical and psychological, that continue into adulthood. The long-term consequences of BPD may best be addressed through future research, including better understanding of the pathophysiologic mechanisms leading to BPD, further comparisons between newborns with BPD and those without, and long-term assessment and management of BPD patients as adults.

Systematic review of the healthcare cost of bronchopulmonary dysplasia

OBJECTIVES

To determine the costs directly or indirectly related to bronchopulmonary dysplasia (BPD) in preterm infants. The secondary objective was to stratify the costs based on gestational age and/or birth weight.

DESIGN

Systematic literature review.

SETTING

PubMed and Scopus were searched on 3 February 2020. Studies were selected based on eligibility criteria by two independent reviewers. Included studies were further searched to identify eligible references and citations.Two independent reviewers extracted data with a prespecified data extraction sheet, including items from a published checklist for quality assessment. The costs in the included studies are reported descriptively.

PRIMARY OUTCOME MEASURE

Costs of BPD.

RESULTS

The 13 included studies reported the total costs or marginal costs of BPD. Most studies reported costs during birth hospitalisation (cost range: Int$21 392-Int$1 094 509 per child, equivalent to €19 103-€977 397, in 2019) and/or during the first year of life. One study reported costs during the first 2 years; two other studies reported costs later, during the preschool period and one study included a long-term follow-up. The highest mean costs were associated with infants born at extremely low gestational ages. The quality assessment indicated a low risk of bias in the reported findings of included studies.

CONCLUSIONS

This study was the first systematic review of costs associated with BPD. We confirmed previous reports of high costs and described the long-term follow-up necessary for preterm infants with BPD, particularly infants of very low gestational age. Moreover, we identified a need for studies that estimate costs outside hospitals and after the first year of life.

PROSPERO REGISTRATION NUMBER

CRD42020173234.

Predicting the duration of supplemental home oxygen in prematurely-born infants at discharge from neonatal care

BACKGROUND

Discharge home of preterm infants on supplemental oxygen has significant healthcare, parental psychological and financial implications, but the potential ability of clinical parameters at discharge to predict the duration of home oxygen has not been previously examined.

AIMS

To use clinical and epidemiological parameters available at discharge to predict the duration of home oxygen therapy.

STUDY DESIGN

Retrospective observational cohort study with a primary and a validation cohort.

SUBJECTS

Seventy one infants born <32 completed weeks of gestational age, born between 1/1/2013-1/1/2020 at King's College Hospital NHS Foundation trust and discharged home on supplemental oxygen were studied.

OUTCOME MEASURE

Duration of home oxygen therapy.

RESULTS

In a primary cohort of 52 infants with a median (IQR) gestational age of 26.4 (25.0-28.1) weeks and birth weight of 0.81 (0.69-0.96) kg, the duration of home oxygen was four (3-7) months (range: 1-22 months). The postmenstrual age (adjusted p = 0.001) and oxygen flow at discharge (adjusted p = 0.046) were independently associated with the duration of home oxygen therapy. In a validation cohort of 19 infants, the correlation coefficient between the calculated and the observed duration of home oxygen was 0.62, p = 0.005 and the coefficient of determination was 0.38.

CONCLUSIONS

Infants discharged home on higher oxygen flows and at a greater postmenstrual age require a longer duration of home oxygen therapy and these parameters can be used to predict the duration of home oxygen therapy.

Early Changes and Indicators Characterizing Lung Aging in Neonatal Chronic Lung Disease

Infants suffering from neonatal chronic lung disease, i.e., bronchopulmonary dysplasia, are facing long-term consequences determined by individual genetic background, presence of infections, and postnatal treatment strategies such as mechanical ventilation and oxygen toxicity. The adverse effects provoked by these measures include inflammatory processes, oxidative stress, altered growth factor signaling, and remodeling of the extracellular matrix. Both, acute and long-term consequences are determined by the capacity of the immature lung to respond to the challenges outlined above. The subsequent impairment of lung growth translates into an altered trajectory of lung function later in life. Here, knowledge about second and third hit events provoked through environmental insults are of specific importance when advocating lifestyle recommendations to this patient population. A profound exchange between the different health care professionals involved is urgently needed and needs to consider disease origin while future monitoring and treatment strategies are developed.

Lung CD103+dendritic cells and Clec9a signaling are required for neonatal hyperoxia-induced inflammatory responses to rhinovirus infection

Premature infants, especially those with bronchopulmonary dysplasia (BPD), develop recurrent severe respiratory viral illnesses. We have shown that hyperoxic exposure of immature mice, a model of BPD, increases lung IL-12-producing Clec9a+ CD103+ dendritic cells (DCs), pro-inflammatory responses, and airway hyperreactivity following rhinovirus (RV) infection. However, the requirement for CD103+ DCs and Clec9a, a DAMP receptor that binds necrotic cell cytoskeletal filamentous actin (F-actin), for RV-induced inflammatory responses has not been demonstrated. To test this, 2-day-old C57BL/6J, CD103+ DC-deficient Batf3-/- or Clec9agfp-/- mice were exposed to normoxia or hyperoxia for 14 days. Also, selected mice were treated with neutralizing antibody against CD103. Immediately after hyperoxia, the mice were inoculated with RV intranasally. We found that compared with wild-type mice, hyperoxia-exposed Batf3-/- mice showed reduced levels of IL-12p40, IFN-γ, and TNF-α, fewer IFN-γ-producing CD4+ T cells, and decreased airway responsiveness following RV infection. Similar effects were observed in anti-CD103-treated and Clec9agfp-/- mice. Furthermore, hyperoxia increased airway dead cell number and extracellular F-actin levels. Finally, studies in preterm infants with respiratory distress syndrome showed that tracheal aspirate CLEC9A expression positively correlated with IL12B expression, consistent with the notion that CLEC9A+ cells are responsible for IL-12 production in humans as well as mice. We conclude that CD103+ DCs and Clec9a are required for hyperoxia-induced pro-inflammatory responses to RV infection. In premature infants, Clec9a-mediated activation of CD103+ DCs may promote pro-inflammatory responses to viral infection, thereby driving respiratory morbidity.

Prematurity as an Independent Risk Factor for the Development of Pulmonary Disease

OBJECTIVES

To determine if premature infants without bronchopulmonary dysplasia (BPD) are at similar risk for developing pulmonary morbidity as compared with those with BPD and if there are differences in management of care.

STUDY DESIGN

We retrospectively abstracted information from our electronic medical record from January 1, 2006, to December 31, 2015, for primary care patients born at <30 weeks of gestation (n = 811). Multivariate models determined the impact of BPD on a diagnosis of respiratory disease, respiratory medications, subspecialty visits, and emergency department use or hospitalizations after adjusting for gestational age, sex, insurance type, and race.

RESULTS

Infants with BPD were more likely to be diagnosed with asthma than those without BPD (75% vs 60%; OR, 1.8; 95% CI, 1.27-2.54), but not all respiratory conditions (OR, 1.56; 95% CI, 0.7-3.51), and were more likely to be referred to a pulmonologist (relative risk, 5.98; 95% CI, 4.1-8.74). Infants with BPD were more likely to be hospitalized for respiratory conditions than those without BPD (50% vs 30%; relative risk, 2.44; 95% CI, 1.73-3.45).

CONCLUSIONS

Although infants with BPD were more likely to have a diagnosis of asthma and be readmitted for respiratory conditions, 60% of infants without BPD were also diagnosed with asthma and 30% were readmitted. There were significant differences in the management of patients, including time to pulmonary referral and prescription rates for inhaled corticosteroids. Practitioners should consider all patients born prematurely at high risk for respiratory morbidity.

Impact of a protocol-driven unified service for neonates with bronchopulmonary dysplasia

Aim

A new specialised service for preterm infants with bronchopulmonary dysplasia requiring long-term oxygen therapy (LTOT) was established in 2007, led by the paediatric respiratory team, transitioning from neonatal-led follow-up. The new service included the utilisation of a clear protocol. Our objective was to review whether this service initiation led to a reduction of time in LTOT and hospital readmissions.

Methods

We performed a retrospective cohort study of infants born at <32 weeks’ gestation requiring LTOT in a single tertiary neonatal service. Cases were identified from hospital records, BadgerNet and a local database for two cohorts, 2004–2006 and 2008–2010. Data collected for infants requiring LTOT included demographic details, length of neonatal stay, time in oxygen and hospital attendance rates.

Results

The initiation of the service led to an increase in the number of discharges in LTOT: 13.1% of infants born alive before 32 weeks’ gestation in comparison to 3.5% (p<0.001). However, the length of time in LTOT reduced from 15 to 5 months (p=0.01). There was no difference in hospital readmission rates (p=0.365).

Conclusions

In our experience the increase in neonates requiring LTOT is likely to be due to enhanced provision of overnight oximetry studies prior to discharge. Structured monitoring and weaning led to a shorter duration of home oxygen therapy.

The implementation of a clear protocol for assessment and management of neonates with bronchopulmonary dysplasia may lead to more infants being discharged in home oxygen, but has potential to reduce overall healthcare costs and improve long-term outcomeshttp://ow.ly/fYcv30nIc2c

Predictors of hospitalization for acute lower respiratory infections during the first two years of life in a population of preterm infants with bronchopulmonary dysplasia

BACKGROUND

There have been few research studies aimed at obtaining a better understanding of the prediction of subsequent respiratory morbidity at follow-up in infants with a previous history of bronchopulmonary dysplasia (BPD) living in low- and middle-income countries (LMIC). The aim of the present study was to identify predictors of hospitalization for acute lower respiratory infections (ALRIs) in a population of infants with a history of BPD living in a LMIC.

METHODS

In a prospective cohort study, we determined independent predictors of the number of hospitalizations for ALRIs during the first two years of life in a population of infants with a history of BPD living in Bogota, Colombia. In multivariate analyses, we included both clinico-demographic variables and underlying disease characteristics as predictor variables of hospitalization for ALRIs.

RESULTS

Of a total of 138 patients included in the study, 83 (60.1%) had at least one hospitalization for ALRI during the follow-up period. Independent predictors of the number of hospitalizations for ALRIs included duration of neonatal ventilatory support (IRR 1.02; CI 95% 1.00-1.03; p = 0.010), duration of subsequent ambulatory oxygen therapy (IRR 2.06; CI 95% 1.16-3.64; p = 0.013), and breastfeeding in females (IRR 0.35; CI 95% 0.14-0.84; p = 0.019).

CONCLUSIONS

Duration of mechanical ventilation, duration of subsequent ambulatory oxygen therapy, and breastfeeding in females were independently associated with the number of hospitalizations for ALRIs in our population of infants with a history of BPD.

Gene Expression Signatures Point to a Male Sex-Specific Lung Mesenchymal Cell PDGF Receptor Signaling Defect in Infants Developing Bronchopulmonary Dysplasia

Male sex is a risk factor for development of bronchopulmonary dysplasia (BPD), a common chronic lung disease following preterm birth. We previously found that tracheal aspirate mesenchymal stromal cells (MSCs) from premature infants developing BPD show reduced expression of PDGFRα, which is required for normal lung development. We hypothesized that MSCs from male infants developing BPD exhibit a pathologic gene expression profile deficient in PDGFR and its downstream effectors, thereby favoring delayed lung development. In a discovery cohort of 6 male and 7 female premature infants, we analyzed the tracheal aspirate MSCs transcriptome. A unique gene signature distinguished MSCs from male infants developing BPD from all other MSCs. Genes involved in lung development, PDGF signaling and extracellular matrix remodeling were differentially expressed. We sought to confirm these findings in a second cohort of 13 male and 12 female premature infants. mRNA expression of PDGFRA, FGF7, WNT2, SPRY1, MMP3 and FOXF2 were significantly lower in MSCs from male infants developing BPD. In female infants developing BPD, tracheal aspirate levels of proinflammatory CCL2 and profibrotic Galectin-1 were higher compared to male infants developing BPD and female not developing BPD. Our findings support a notion for sex-specific differences in the mechanisms of BPD development.

Health Care and Societal Costs of Bronchopulmonary Dysplasia

Despite significant technological advances and increasing survival of premature infants, bronchopulmonary dysplasia (BPD) continues to be the most prevalent major morbidity in surviving very low-birthweight infants. Infants with BPD are often sicker, require longer stays in the NICU, and accumulate greater hospital costs. However, care of the infant with BPD extends beyond the time spent in the NICU. This article reviews the costs of BPD in the health-care setting, during the initial hospitalization and beyond, and the long-term neurodevelopmental impact of BPD, as well as the impact on a family caring for a child with BPD.

Predictors of prolonged length of hospital stay or readmissions for acute viral lower respiratory tract infections among infants with a history of bronchopulmonary dysplasia

Length of hospital stay and readmissions are outcome measures that have been largely overlooked in many studies that have evaluated the clinical evolution of pediatric patients with bronchopulmonary dysplasia (BPD). The aim of the present study was to identify predictors of prolonged hospitalizations or readmissions for acute lower respiratory infections (ALRIs) in infants with BPD. In a prospective cohort study, we determined independent predictors of prolonged hospitalizations or readmissions for ALRIs during the first 2 years of life in a population of infants with BPD living in Bogota, Colombia. Of a total of 138 patients included in the study, 83 (60.1%) had at least one hospitalization for ALRI during the follow-up period. After controlling for potential confounders, we found that independent predictors of prolonged hospitalizations or readmissions for ALRIs included male gender (OR = 3.09; CI 95% 1.27-7.52; P = 0.013), ambulatory oxygen therapy between 90 and 119 days (OR = 3.21; CI 95% 1.00-10.24; P = 0.049), ambulatory oxygen therapy equal to or greater than 120 days (OR = 5.73; CI 95% 2.01-16.32; P = 0.001), gestational age at birth (OR = 1.35; CI 95% 1.03-1.76; P = 0.026), birth weight (OR = 0.997; CI 95% 0.996-0.999; P = 0.010), and duration of breastfeeding equal to or greater than 6 months (OR = 0.39; CI 95% 0.16-0.96; P = 0.039). The factors identified can be taken into account when planning policies to reduce duration of hospital stay and readmissions in infants with BPD.

Comparison of Follow-up Courses after Discharge from Neonatal Intensive Care Unit between Very Low Birth Weight Infants with and without Home Oxygen

In order to investigate the clinical impact of home oxygen use for care of premature infants, we compared the follow-up courses after neonatal intensive care unit (NICU) discharge between very low birth weight infants (VLBWIs) with and without home oxygen. We retrospectively identified 1,232 VLBWIs born at 22 to 32 weeks of gestation, discharged from the NICU of 43 hospitals in Korea between April 2009 and March 2010, and followed them up until April 2011. Clinical outcomes, medical service uses, and readmission and death rates during follow-up after the NICU discharge were compared between VLBWIs with (HO, n = 167) and those without (CON, n = 1,056) home oxygen at discharge. The HO infants comprised 13.7% of the total VLBWIs with significant institutional variations and showed a lower gestational age (GA) and birth weight than the CON infants. The HO infants had more frequent regular pediatric outpatient clinic visits (12.7 ± 7.5 vs. 9.5 ± 6.6; P < 0.010) and emergency center visits related to respiratory problems (2.5 ± 2.2 vs. 1.8 ± 1.4; P < 0.010) than the CON infants. The HO infants also had significantly increased readmission (adjusted hazard ratio [HR], 1.60; 95% confidence interval [CI], 1.25-2.04) and death risks (adjusted HR, 7.40; 95% CI, 2.06-26.50) during up to 2 years following the NICU discharge. These increased readmission and death risks in the HO infants were not related to their prematurity degree. In conclusion, home oxygen use after discharge increases the risks for healthcare utilization, readmission, and death after NICU discharge in VLBWIs, regardless of GA, requiring more careful health care monitoring during their follow-up.

Hyperoxic Exposure of Immature Mice Increases the Inflammatory Response to Subsequent Rhinovirus Infection: Association with Danger Signals

Infants with a history of prematurity and bronchopulmonary dysplasia have a high risk of asthma and viral-induced exacerbations later in life. We hypothesized that hyperoxic exposure, a predisposing factor to bronchopulmonary dysplasia, modulates the innate immune response, producing an exaggerated proinflammatory reaction to viral infection. Two- to 3-d-old C57BL/6J mice were exposed to air or 75% oxygen for 14 d. Mice were infected intranasally with rhinovirus (RV) immediately after O2 exposure. Lung mRNA and protein expression, histology, dendritic cells (DCs), and airway responsiveness were assessed 1-12 d postinfection. Tracheal aspirates from premature human infants were collected for mRNA detection. Hyperoxia increased lung IL-12 expression, which persisted up to 12 d postexposure. Hyperoxia-exposed RV-infected mice showed further increases in IL-12 and increased expression of IFN-γ, TNF-α, CCL2, CCL3, and CCL4, as well as increased airway inflammation and responsiveness. In RV-infected, air-exposed mice, the response was not significant. Induced IL-12 expression in hyperoxia-exposed, RV-infected mice was associated with increased IL-12-producing CD103(+) lung DCs. Hyperoxia also increased expression of Clec9a, a CD103(+) DC-specific damaged cell-recognition molecule. Hyperoxia increased levels of ATP metabolites and expression of adenosine receptor A1, further evidence of cell damage and related signaling. In human preterm infants, tracheal aspirate Clec9a expression positively correlated with the level of prematurity. Hyperoxic exposure increases the activation of CD103(+), Clec9a(+) DCs, leading to increased inflammation and airway hyperresponsiveness upon RV infection. In premature infants, danger signal-induced DC activation may promote proinflammatory airway responses, thereby increasing respiratory morbidity.

Bronchopulmonary dysplasia early changes leading to long-term consequences

Neonatal chronic lung disease, i.e., bronchopulmonary dysplasia, is characterized by impaired pulmonary development resulting from the impact of different risk factors including infections, hyperoxia, and mechanical ventilation on the immature lung. Remodeling of the extracellular matrix, apoptosis as well as altered growth factor signaling characterize the disease. The immediate consequences of these early insults have been studied in different animal models supported by results from in vitro approaches leading to the successful application of some findings to the clinical setting in the past. Nonetheless, existing information about long-term consequences of the identified early and most likely sustained changes to the developing lung is limited. Interesting results point towards a tremendous impact of these early injuries on the pulmonary repair capacity as well as aging related processes in the adult lung.

Advances in paediatric pulmonary vascular disease associated with bronchopulmonary dysplasia

Pulmonary hypertension (PH) is a common finding in infants with bronchopulmonary dysplasia (BPD). The aim of this review is to describe recent advances in the diagnosis and treatment of PH and discuss whether they will benefit infants and children with BPD related PH. Echocardiography remains the mainstay of diagnosis but has limitations, further developments in diagnostic techniques and identification of biomarkers are required. There are many potential therapies for PH associated with BPD. Inhaled nitric oxide has been shown to improve short term outcomes only. Sidenafil in resource limited settings was shown in three randomized trials to significantly reduce mortality. The efficacy of other therapies including prostacyclin, PDE3 inhibitors and endothelin receptor blockers has only been reported in case reports or case series. Randomized controlled trials with long term follow up are required to appropriately assess the efficacy of therapies aimed at improving the outcome of children with PH.

Chronic lung disease in the preterm infant. Lessons learned from animal models

Neonatal chronic lung disease, also known as bronchopulmonary dysplasia (BPD), is the most common complication of premature birth, affecting up to 30% of very low birth weight infants. Improved medical care has allowed for the survival of the most premature infants and has significantly changed the pathology of BPD from a disease marked by severe lung injury to the "new" form characterized by alveolar hypoplasia and impaired vascular development. However, increased patient survival has led to a paucity of pathologic specimens available from infants with BPD. This, combined with the lack of a system to model alveolarization in vitro, has resulted in a great need for animal models that mimic key features of the disease. To this end, a number of animal models have been created by exposing the immature lung to injuries induced by hyperoxia, mechanical stretch, and inflammation and most recently by the genetic modification of mice. These animal studies have 1) allowed insight into the mechanisms that determine alveolar growth, 2) delineated factors central to the pathogenesis of neonatal chronic lung disease, and 3) informed the development of new therapies. In this review, we summarize the key findings and limitations of the most common animal models of BPD and discuss how knowledge obtained from these studies has informed clinical care. Future studies should aim to provide a more complete understanding of the pathways that preserve and repair alveolar growth during injury, which might be translated into novel strategies to treat lung diseases in infants and adults.

Epidemiology of bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is among the most common and serious sequelae of preterm birth. BPD affects at least one-quarter of infants born with birth weights less than 1500 g. The incidence of BPD increases with decreasing gestational age and birth weight. Additional important risk factors include intrauterine growth restriction, sepsis, and prolonged exposure to mechanical ventilation and supplemental oxygen. The diagnosis of BPD predicts multiple adverse outcomes including chronic respiratory impairment and neurodevelopmental delay. This review summarizes the diagnostic criteria, incidence, risk factors, and long-term outcomes of BPD.

Long-term respiratory consequences of premature birth at less than 32 weeks of gestation

Chronic respiratory morbidity is a common adverse outcome of very premature birth, particularly in infants who had developed bronchopulmonary dysplasia (BPD). Prematurely born infants who had BPD may require supplementary oxygen at home for many months and affected infants have increased healthcare utilisation until school age. Chest radiograph abnormalities are common; computed tomography of the chest gives predictive information in children with ongoing respiratory problems. Readmission to hospital is common, particularly for those who have BPD and suffer respiratory syncytial virus lower respiratory infections (RSV LRTIs). Recurrent respiratory symptoms requiring treatment are common and are associated with evidence of airways obstruction and gas trapping. Pulmonary function improves with increasing age, but children with BPD may have ongoing airflow limitation. Lung function abnormalities may be more severe in those who had RSV LRTIs, although this may partly be explained by worse premorbid lung function. Worryingly, lung function may deteriorate during the first year. Longitudinal studies are required to determine if there is catch up growth.

The impact of bronchopulmonary dysplasia on caregiver health related quality of life during the first 2 years of life

OBJECTIVES

Preterm children with bronchopulmonary dysplasia (BPD) frequently require complex home medical regimens and re-hospitalization during the first 2 years of life. The burden of caring for these medically complex children may negatively affect caregiver health related quality of life (HRQoL). The objectives of this study were to measure caregiver HRQoL of children with BPD and to identify factors that impact caregiver HRQoL during the first 2 years of life.

METHODS

Children (n = 186) were recruited from the Johns Hopkins BPD Outpatient Clinic between January 2008 and July 2011. Caregiver HRQoL was measured using The PedsQL(TM) Family Impact Module. Respiratory symptoms and morbidities were assessed using questionnaires.

RESULTS

Among caregivers of BPD children, significant improvement in physical, worry, and daily domains improved longitudinally as children aged. An association was found between lower total HRQoL scores and caregivers of BPD children who reported more respiratory symptoms and acute care usage. No difference in total HRQoL scores was found between caregivers of BPD children requiring respiratory/enteral support and caregivers of children who did not. Caregiver income and educational level did not predict total HRQoL score, but Non-White race and public insurance was associated with a higher total HRQoL score at the first outpatient visit.

CONCLUSION

An association was found between lower HRQoL scores and caregivers of BPD children with frequent respiratory symptoms and acute care usage. Screening for low HRQoL in caregivers of BPD children with frequent respiratory illnesses should be considered to identify those who may benefit from additional support and intervention.

Recommendations for long-term home oxygen therapy in children and adolescents

OBJECTIVE

To advise pediatricians, neonatologists, pulmonologists, pediatric pulmonologists, and other professionals in the area on the main indications and characteristics of long-term home oxygen therapy in children and adolescents.

DATA SOURCE

A literature search was carried out in the MEDLINE/PubMed database (1990 to 2011). Additionally, references from selected studies were included. As consistent scientific evidence does not exist for many aspects, some of the recommendations were based on clinical experience.

DATA SYNTHESIS

Long-term home oxygen therapy has been a growing practice in pediatric patients and is indicated in bronchopulmonary dysplasia, cystic fibrosis, bronchiolitis obliterans, interstitial lung diseases, and pulmonary hypertension, among others. The benefits are: decrease in hospitalizations, optimization of physical growth and neurological development, improvement of exercise tolerance and quality of sleep, and prevention of pulmonary hypertension/cor pulmonale. The levels of oxygen saturation indicative for oxygen therapy differ from those established for adults with chronic obstructive pulmonary disease, and vary according to age and disease. Pulse oximetry is used to evaluate oxygen saturation; arterial blood gas is unnecessary. There are three available sources of oxygen: gas cylinders, liquid oxygen, and oxygen concentrators. The flows used are usually smaller, as are the number of hours/day needed when compared to the use in adults. Some diseases show improvement and oxygen therapy discontinuation is possible.

CONCLUSIONS

Long-term home oxygen therapy is increasingly common in pediatrics and has many indications. There are relevant particularities when compared to its use in adults, regarding indications, directions for use, and monitoring.

Definition and outpatient management of the very low-birth-weight infant with bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD), also known as chronic lung disease of prematurity, is the major cause of pulmonary disease in infants. The pathophysiology and management of BPD have evolved over the past four decades as improved neonatal intensive care unit (NICU) modalities have increased survival rates. The likelihood for developing BPD increases with the degree of prematurity and reaches 25-35% in very low-birth-weight and extremely low-birth-weight infants. BPD affects many organ systems, and infants with BPD are at increased risk for rehospitalization and numerous complications following NICU discharge. The management of BPD and medically related problems, particularly during the first 2 years of life, remains a continuing challenge for parents and healthcare providers. It is important that a multidisciplinary team consisting of the neonatologist/attending physician, primary care physician, and other specialized support staff work in concert and meet regularly to provide continuity of care and accurate patient assessments.

Long term respiratory outcomes of very premature birth (<32 weeks)

Many very prematurely born infants develop bronchopulmonary dysplasia (BPD), remaining oxygen dependent for many months and requiring frequent rehospitalisations. Troublesome, recurrent respiratory symptoms requiring treatment and lung function abnormalities at follow-up are common. The most severely affected may remain symptomatic with evidence of airways obstruction even as adults. Data from adolescents and adults on the respiratory outcome of extreme prematurity, however, are usually from patients who have had 'classical' BPD with severe respiratory failure in the neonatal period. Nowadays, infants have 'new' BPD developing chronic oxygen dependence despite initially minimal or even no respiratory distress. Affected patients do suffer chronic respiratory morbidity and their lung function may deteriorate during the first year after birth. Infants who suffer respiratory syncytial virus lower respiratory tract infections are most likely to require rehospitalisation and suffer chronic respiratory morbidity, but this may reflect greater abnormal premorbid lung function.

Long-term respiratory outcome of babies born prematurely

Chronic respiratory morbidity is a common adverse outcome of premature birth, particularly in infants who develop bronchopulmonary dysplasia (BPD). Prematurely born infants who had BPD may require supplementary oxygen at home for many months, but few remain oxygen dependent beyond 2 years of age. Readmission to hospital is common, particularly for those who had BPD, but only in the first 2 years after birth. The readmissions are usually for respiratory problems, particularly respiratory syncytial virus lower respiratory infections. Recurrent respiratory symptoms requiring treatment are common, particularly in those who had BPD, even at school age and in adolescence. Affected children have evidence of airways obstruction. Pulmonary function does improve with age, but children with BPD may have ongoing airflow limitation. Computed tomography of the chest gives helpful information at follow up of patients with ongoing respiratory problems who had BPD.

Polysomnography in preterm infants and children with chronic lung disease

OBJECTIVE

To determine the utility of overnight polysomnography (PSG) in assessing pulmonary reserve in stable preterm children with chronic lung disease (CLD).

STUDY DESIGN

A retrospective review and descriptive study of overnight PSGs and clinic visits of preterm infants/children less than 3 years of age who were diagnosed with bronchopulmonary dysplasia at discharge from the hospital and enrolled in the Johns Hopkins CLD patient registry between 2008 and 2010.

RESULTS

Sixty-two clinically stable patients underwent at least one overnight polysomnogram for clinical indications. The majority of patients were referred for oxygen titration (71%). PSGs from first studies revealed a mean respiratory disturbance index (RDI) of 8.2 ± 10.1 events/hr and a mean O(2) saturation (SaO(2) ) nadir of 86.2 ± 5.7%. In patients who underwent more than one PSG (n = 23), a significant decrease in RDI (P < 0.001) was found between the first study (mean age: 8.0 ± 3.3 months) and second study (mean age: 13.4 ± 5.2 months). Outpatient clinical measures of mean room air SaO(2) and respiratory rate were not predictive of PSG measures of RDI and SaO(2) nadir.

CONCLUSION

Mean RDI was higher in stable preterm infants/children with CLD compared to previously published controls. RDI decreased with age in stable preterm infants/children with CLD suggesting improved pulmonary reserve with age. Outpatient clinical measures (respiratory rate and room air SaO(2) ) did not correlate with RDI and SaO(2) nadir indicating that overnight PSG is more sensitive in assessing pulmonary reserve than outpatient clinical measures.

Respiratory morbidity, healthcare utilisation and cost of care at school age related to home oxygen status

The aim of the study was to determine whether respiratory morbidity, lung function, healthcare utilisation and cost of care at school age in prematurely born children who had bronchopulmonary dysplasia (BPD) were influenced by use of supplementary oxygen at home after neonatal intensive care unit discharge. Healthcare utilisation and cost of care in years 5 to 7 and respiratory morbidity (parent-completed respiratory questionnaire) and lung function measurements at least at age 8 years were assessed in 160 children. Their median gestational age was 27 (range 22-31) weeks and 65 of them had received supplementary oxygen when discharged home (home oxygen group). The home oxygen group had more outpatient attendances (p = 0.0168) and respiratory-related outpatient attendances (p = 0.0032) with greater related cost of care (p = 0.0186 and p = 0.0030, respectively), their cost of care for prescriptions (p = 0.0409) and total respiratory related cost of care (p = 0.0354) were significantly greater. There were, however, no significant differences in cough, wheeze or lung function results between the two groups.

CONCLUSION

Prematurely born children who had BPD and supplementary oxygen at home after discharge had increased healthcare utilisation at school age. Whether such children require greater follow, in the absence of excess respiratory morbidity, merits investigation.

The experience of mothers whose very low-birth-weight infant requires the delivery of supplemental oxygen in the neonatal intensive care unit

PURPOSE

This study examines the experience of mothers whose very low-birth-weight infants require the delivery of supplemental oxygen during their hospitalization in the neonatal intensive care unit (NICU).

SUBJECTS

Eleven mothers of very low-birth-weight infants who have received various supplemental oxygen delivery methods in the NICU for a minimum of 7 days were selected for interview.

DESIGN

Qualitative descriptive.

METHODS

One semistructured interview exploring mothers' experiences surrounding oxygen delivery methods was conducted. Qualitative content analysis was undertaken to describe mothers' experience.

PRINCIPLE RESULTS

Four themes emerged related to the oxygen therapy and the various methods of delivery: Oxygen therapy is a positive, worries about the adverse effects for my baby now and in the future, a learning experience, and the delivery of supplemental oxygen is a barrier to mothering.

CONCLUSION

Mothers balanced the positive aspects of oxygen therapy with their fears of the negative consequences. They were able to adapt to the equipment and trajectory of having their infant on supplemental oxygen delivery methods. Mothers were particularly distressed by the physical barriers created by oxygen delivery methods (ie, unable to hold, hear, or see their baby). Nurses in the NICU should support mothers' positive reframing as a way of coping, provide education about the consequences of this therapy, encourage mothers to touch and hold their infants, and provide opportunities for them to see their infants' faces.

Preterm birth and respiratory disease in later life

Chronic respiratory diseases are a common complication of preterm birth, particularly among very immature infants or those suffering from bronchopulmonary dysplasia. Major progress in the treatment of preterm newborns has changed the pattern of late respiratory complications. The major respiratory problem in infancy and early childhood is respiratory exacerbations caused by infections (particularly viral ones), which need hospitalization. The symptoms become mild in school-age children; however, a group of children still present with chronic airway obstruction defined by recurrent episodes of wheezing and decreased lung function tests (decreased forced expiratory volume). For some preterm infants, particularly those with bronchopulmonary dysplasia, obstructive lung disease persists into adulthood. They are very likely to develop chronic obstructive pulmonary disease or similar disease later in life. In these patients, a program of lung function monitoring and pulmonary prophylaxis by means of elimination of specific risk factors in adulthood is advisable.

[Bronchopulmonary dysplasia and prematurity. Short-and long-term respiratory changes]

Bronchopulmonary dysplasia (BPD) is the most frequent chronic lung disease in premature children. With the inclusion of antenatal steroid therapy, surfactant use and novel mechanical ventilation strategies, survival of premature newborns has increased, whereupon the incidence of BPD has not only decreased but has also risen in extremely premature newborns. This has led to a high respiratory morbidity in the first 2-3 years of life, with numerous admissions to hospital and respiratory exacerbations mostly due to viral infections. Although there is a trend towards improvement, during school age and adolescence, respiratory symptoms may persist, due to changes in pulmonary function often showing a lower exercise capacity. Although BPD symptoms are similar to those of asthma, as there is limitation in airflow and bronchial hyperresponsiveness (BHR), pathophysiological mechanisms could be different in both diseases. On the other hand, isolated prematurity plays an important role in the child's respiratory pathology, proving that pulmonary function alterations in preterm children are present since the first months of life. A higher respiratory morbidity has also been observed in these children when compared to full-term newborns, not only during the first years of life but also subsequently. In this study, different aspects of chronic respiratory disease associated with prematurity will be analysed, drawing special attention to clinical symptoms, respiratory function changes, BHR and exercise capacity. All these aspects will be reviewed from early childhood until adolescence and young adult age. Similarities and differences between BPD and asthma will also be discussed.

Ventilatory strategies for the extremely premature infant

Bronchopulmonary dysplasia (BPD), which has long-term adverse outcomes, is common following extremely premature birth. BPD has a multifactorial etiology, including a high level or prolonged use of mechanical ventilation. Numerous research studies, therefore, have attempted to identify ventilatory techniques which reduce the likelihood of baro/volutrauma and hence BPD; these have been critically examined in this review, particularly with regard to their relevance to the extremely prematurely born infant. This has highlighted that few randomized studies of ventilatory strategies have concentrated exclusively on those high-risk infants. Overall, in prematurely born infants, advantages have been suggested by the results of studies examining pressure support, proportional assist and volume-targeted ventilation. In addition, High-Frequency Oscillatory Ventilation (HFOV) may reduce the deterioration seen in lung function of prematurely born infants over the first year after birth. In conclusion, more randomized studies are required which concentrate exclusively on the extremely prematurely born population who are at highest risk of BPD. It is essential in such studies that long-term follow-up assessment is inbuilt so that the benefits/adverse effects can be appropriately identified.

Late respiratory outcomes after preterm birth

Chronic respiratory morbidity is common following premature birth, particularly if complicated by bronchopulmonary dysplasia (BPD) development. Affected patients can remain oxygen dependent for many months, but unusually beyond two years. Those requiring supplementary oxygen at home have increased healthcare utilisation, even during the preschool years when no longer oxygen dependent. More than 50% of "BPD" patients require readmission in the first two years, particularly for respiratory infections. Prematurely born children, especially those who had BPD, are more likely to suffer frequent troublesome symptoms at school age and in adolescence than term born controls. This is associated with evidence of airways obstruction. Although lung function improves as the clinical condition improves, abnormalities can be detected even in young adults who had severe BPD. Nowadays, severe BPD is uncommon, but those with "new" BPD may have abnormal antenatal lung growth, whether they achieve appropriate catch up lung growth needs careful investigation.