Intratracheal Administration of Budesonide-Surfactant in Prevention of Bronchopulmonary Dysplasia in Very Low Birth Weight Infants: A Systematic Review and Meta-Analysis

An update on the post-NICU discharge management of bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is a chronic lung disease which develops as a result of neonatal/perinatal lung injury. It is the commonest cause of chronic lung disease in infancy and the most frequent morbidity associated with prematurity. The incidence of BPD has continued to rise despite many advances in neonatal care and this increase has been attributed to the increased survival of younger and more premature babies. There have been many advances in the care of patients with early and evolving BPD, yet there is a paucity of data regarding outpatient management of patients with established BPD. There are limited adequately-powered high-quality studies/randomized controlled trials which assess commonly used therapies such as supplemental oxygen, bronchodilators, steroids and diuretics in patients with BPD, beyond short-term effects. Further research is needed to improve our understanding of the role of currently used treatments on the long-term outcomes of patients with established BPD, post-discharge from the neonatal intensive care unit.

Surfactant, steroids and non-invasive ventilation in the prevention of BPD

Bronchopulmonary dysplasia (BPD) is a complex disorder with multiple factors implicated in its etiopathogenesis. Despite the scientific advances in the field of neonatology, the incidence of BPD has remained somewhat constant due to increased survival of extremely premature infants. Surfactant deficiency in the immature lung, exposure to invasive mechanical ventilation leading to volutrauma, barotrauma and lung inflammation are some of the critical contributing factors to the pathogenesis of BPD. Hence, strategies to prevent BPD in the postnatal period revolve around mitigation of this injury and inflammation. This article reviews the progress made in the last 5 years in the development of new preparations of surfactant, use of corticosteroids and non-invasive ventilation in the prevention of BPD. Emerging techniques of surfactant delivery through minimally invasive and non-invasive routes are also discussed.

Review shows that using surfactant a number of times or as a vehicle for budesonide may reduce the risk of bronchopulmonary dysplasia

AIM

Bronchopulmonary dysplasia (BPD) remains the most common respiratory morbidity in immature infants. This review describes the diagnosis of BPD has evolved and summarises the therapeutic approaches that have made it possible to limit the incidence of BPD.

METHOD

We reviewed the literature from the first definition of BPD by Northway in 1967 to the surfactant treatment policies that are currently in use, drawing on more than 50 papers up to 2017.

RESULTS

Our review showed that improvements in neonatal survival have been associated with an increased risk of severe BPD, significant levels of long-term morbidity and the increased use of healthcare resources. These issues have encouraged researchers to explore potential new treatments that limit the incidence of BPD. Repeated surfactant instillation and the use of surfactant as a vehicle for budesonide are promising strategies for alleviating the burden of chronic lung disease. Ongoing research on surfactant or stem cell therapy may further improve the respiratory prognosis for prematurely born children.

CONCLUSION

Considerable research has been carried out into the increase in BPD, which has resulted from improvements in neonatal survival. Key areas of research include repeated surfactant administration, using surfactant as a vehicle for budesonide and stem cell therapy.

Novel therapeutics for bronchopulmonary dysplasia

PURPOSE OF REVIEW

This review provides a concise summary of recent literature pertaining to emerging therapies for bronchopulmonary dysplasia (BPD). To provide context for the presented therapies, a brief overview of recently proposed changes to the definition of BPD and the concept of expanded respiratory outcomes is included.

RECENT FINDINGS

New or redefined respiratory outcomes are required to improve accuracy in evaluating new therapies and correlating results with long-term clinical outcomes of importance. Dexamethasone is no longer the only steroid-based therapy showing promise for impacting BPD. Early trials indicate hydrocortisone, inhaled budesonide, and a budesonide-surfactant combination may be of benefit to preterm infants. Additionally, simple approaches like increasing utilization of mother's own milk may deserve more emphasis. Of significant interest is the traction stem cell therapies are acquiring as one of the more anticipated treatments for BPD. A new preclinical meta-analysis demonstrates the benefits of mesenchymal stromal cell therapy in animal models while the results of early clinical trials remain eagerly awaited.

SUMMARY

BPD continues to be the most frequently occurring significant morbidity for extremely preterm infants, yet highly effective therapies remain elusive. Promising new treatments are on the horizon, but only continued efforts to complete well-designed clinical trials will determine the true impact of these emerging therapies.

Effects of budesonide and surfactant in preterm fetal sheep

Mechanical ventilation causes lung injury and systemic inflammatory responses in preterm sheep and is associated with bronchopulmonary dysplasia (BPD) in preterm infants. Budesonide added to surfactant decreased BPD by 20% in infants. We wanted to determine the effects of budesonide and surfactant on injury from high tidal volume (V_T) ventilation in preterm lambs. Ewes at 125 ± 1 days gestational age had fetal surgery to expose fetal head and chest with placental circulation intact. Lambs were randomized to 1) mechanical ventilation with escalating V_T to target 15 ml/kg by 15 min or 2) continuous positive airway pressure (CPAP) of 5 cmH₂O. After the 15-min intervention, lambs were given surfactant 100 mg/kg with saline, budesonide 0.25 mg/kg, or budesonide 1 mg/kg. The fetuses were returned to the uterus for 24 h and then delivered and ventilated for 30 min to assess lung function. Budesonide levels were low in lung and plasma. CPAP groups had improved oxygenation, ventilation, and decreased injury markers compared with fetal V_T lambs. Budesonide improved ventilation in CPAP lambs. Budesonide decreased lung weights and lung liquid and increased lung compliance and surfactant protein mRNA. Budesonide decreased proinflammatory and acute-phase responses in lung. Airway thickness increased in animals not receiving budesonide. Systemically, budesonide decreased monocyte chemoattractant protein-1 mRNA and preserved glycogen in liver. Results with 0.25 and 1 mg/kg budesonide were similar. We concluded that budesonide with surfactant matured the preterm lung and decreased the liver responses but did not improve lung function after high V_T injury in fetal sheep.

Recent Advances in Bronchopulmonary Dysplasia: Pathophysiology, Prevention, and Treatment

Bronchopulmonary dysplasia (BPD) is potentially one of the most devastating conditions in premature infants with longstanding consequences involving multiple organ systems including adverse effects on pulmonary function and neurodevelopmental outcome. Here we review recent studies in the field to summarize the progress made in understanding in the pathophysiology, prognosis, prevention, and treatment of BPD in the last decade. The work reviewed includes the progress in understanding its pathobiology, genomic studies, ventilatory strategies, outcomes, and therapeutic interventions. We expect that this review will help guide clinicians to treat premature infants at risk for BPD better and lead researchers to initiate further studies in the field.