Early administration of inhaled corticosteroids for preventing chronic lung disease in ventilated very low birth weight preterm neonates

Early administration of inhaled corticosteroids for preventing chronic lung disease in very low birth weight preterm neonates

BACKGROUND

Chronic lung disease (CLD) remains a common complication among preterm infants. There is increasing evidence that inflammation plays an important role in the pathogenesis of CLD. Due to their strong anti-inflammatory properties, corticosteroids are an attractive intervention strategy. However, there are growing concerns regarding short- and long-term effects of systemic corticosteroids. Theoretically, administration of inhaled corticosteroids may allow for beneficial effects on the pulmonary system with a lower risk of undesirable systemic side effects.

OBJECTIVES

To determine the impact of inhaled corticosteroids administered to preterm infants with birth weight up to 1500 grams (VLBW) beginning in the first two weeks after birth for the prevention of CLD as reflected by the requirement for supplemental oxygen at 36 weeks' postmenstrual age (PMA).

SEARCH METHODS

Randomised and quasi-randomised trials were identified by searching the Cochrane Central Register of Controlled Trials (CENTRAL; 2015, Issue 12) in the Cochrane Library (searched 5 January 2016), MEDLINE (1966 to 5 January 2016), Embase (1980 to 5 January 2016), CINAHL (1982 to 5 January 2016), reference lists of published trials and abstracts published in Pediatric Research or electronically on the Pediatric Academic Societies web-site (1990 to May 2016).

SELECTION CRITERIA

We included in this review randomised controlled trials of inhaled corticosteroid therapy initiated within the first two weeks of life in VLBW preterm infants.

DATA COLLECTION AND ANALYSIS

We evaluated data regarding clinical outcomes, including: CLD at 28 days or 36 weeks' PMA; mortality; combined outcome of death or CLD at 28 days of age and at 36 weeks' PMA; the need for systemic corticosteroids; failure to extubate within 14 days; and adverse effects of corticosteroids. All data were analysed using Review Manager (RevMan) 5. Meta-analyses were performed using relative risk (RR) and risk difference (RD), along with their 95% confidence intervals (CI). If RD was significant, the number needed to treat for an additional beneficial outcome (NNTB) was calculated. We used the GRADE approach to assess the quality of evidence.

MAIN RESULTS

According to GRADE the quality of the studies was moderate. Three additional trials are included in this update. The present review includes data analyses based on 10 qualifying trials that enrolled 1644 neonates. There was no significant difference in the incidence of CLD at 36 weeks' PMA in the inhaled steroid versus the placebo group (5 trials, 429 neonates) among all randomised (typical RR 0.97, 95% CI 0.62 to 1.52; typical RD -0.00, 95% CI -0.07 to 0.06). There was no heterogeneity for this outcome (typical RR I² = 11%; typical RD I² = 0%). There was a significant reduction in the incidence of CLD at 36 weeks' PMA among survivors (6 trials, 1088 neonates) (typical RR 0.76, 95% CI 0.63 to 0.93; typical RD -0.07, 95% CI -0.13 to -0.02; NNTB 14, 95% CI 8 to 50). There was a significant reduction in the combined outcome of death or CLD at 36 weeks' PMA among all randomised neonates (6 trials, 1285 neonates) (typical RR 0.86, 95% CI 0.75 to 0.99; typical RD -0.06, 95% CI -0.11 to -0.00) (P = 0.04); NNTB 17, 95% CI 9 to infinity). There was no significant heterogeneity for any of these analyses (I² = 0%). A lower rate of reintubation was noted in the inhaled steroid group compared with the control group in one study. There were no statistically significant differences in short-term complications between groups and no differences in adverse events at long-term follow-up reported. Long-term follow-up of infants enrolled in the study by Bassler 2015 is ongoing.

AUTHORS' CONCLUSIONS

Based on this updated review, there is increasing evidence from the trials reviewed that early administration of inhaled steroids to VLBW neonates is effective in reducing the incidence of death or CLD at 36 weeks' PMA among either all randomised infants or among survivors. Even though there is statistical significance, the clinical relevance is of question as the upper CI limit for the outcome of death or CLD at 36 weeks' PMA is infinity. The long-term follow-up results of the Bassler 2015 study may affect the conclusions of this review. Further studies are needed to identify the risk/benefit ratio of different delivery techniques and dosing schedules for the administration of these medications. Studies need to address both the short- and long-term benefits and adverse effects of inhaled steroids with particular attention to neurodevelopmental outcome.

Early administration of inhaled corticosteroids for preventing chronic lung disease in ventilated very low birth weight preterm neonates

BACKGROUND

Chronic lung disease remains a common complication among preterm infants. There is increasing evidence that inflammation plays an important role in the pathogenesis of CLD. Due to their strong anti-inflammatory properties, corticosteroids are an attractive intervention strategy. However, there are growing concerns regarding short and long-term effects of systemic corticosteroids. Theoretically, administration of inhaled corticosteroids may allow for beneficial effects on the pulmonary system with a lower risk of undesirable systemic side effects.

OBJECTIVES

To determine the impact of inhaled corticosteroids administered to ventilated very low birth weight preterm neonates in the first two weeks of life for the prevention of chronic lung disease (CLD).

SEARCH METHODS

Randomised and quasi-randomised trials were identified by searching the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 3, 2007), MEDLINE (1966 to July 2007), EMBASE (1980 to July 2007), CINAHL (1982 to July 2007), reference lists of published trials and abstracts published in Pediatric Research or electronically on the Pediatric Academic Societies web-site (1990 to April 2007).This search was updated in 2011.

SELECTION CRITERIA

Randomised controlled trials of inhaled corticosteroid therapy initiated within the first two weeks of life in ventilated preterm infants with birth weight <1500 grams were included in this review.

DATA COLLECTION AND ANALYSIS

Data regarding clinical outcomes including chronic lung disease at 28 days or 36 weeks postmenstrual age (PMA), mortality, combined outcome of death or CLD at 28 days of age and at 36 weeks PMA, the need for systemic corticosteroids, failure to extubate within 14 days and adverse effects of corticosteroids were evaluated. All data were analysed using RevMan 4.2.10. When possible, meta-analysis was performed using relative risk (RR), risk difference (RD), along with their 95% confidence intervals (CI). If RD was significant, the number needed to treat (NNT) was calculated.

MAIN RESULTS

One ongoing trial was identified for inclusion in this update. Eleven trials assessing the impact of inhaled corticosteroid for the prevention of CLD were identified. Four trials were excluded. The present review includes data analyses based on seven qualifying trials. There was no statistically significant effect of inhaled steroids on CLD either at 28 days [typical RR 1.05 (95% CI 0.84 to 1.32); typical RD 0.02 (95% CO -0.07 to 0.11)] or at 36 weeks PMA [typical RR 0.97 (95% CI 0.62 to 1.52); typical RD 0.00 (95% CI -0.07, 0.06)], when analysed either for all randomised infants or among survivors. No statistically significant differences were noted for mortality or for the combined outcome of mortality and CLD either at 28 days of age or at 36 weeks PMA. There were no statistically significant differences in adverse events between groups.

AUTHORS' CONCLUSIONS

Based on this updated review, there is no evidence from the trials reviewed that early administration (in the first two weeks of life) of inhaled steroids to ventilated preterm neonates was effective in reducing the incidence of CLD. Currently, use of inhaled steroids in this population cannot be recommended. Studies are needed to identify the risk/benefit ratio of different delivery techniques and dosing schedules for the administration of these medications. Studies need to address both the short-term and long-term benefits and adverse effects of inhaled steroids with particular attention to neurodevelopmental outcome.

Drug studies in newborns: a therapeutic imperative

Although some drugs have been developed for the neonate, drug development for the least mature and most vulnerable pediatric patients is lacking. Most of the drugs are off-label or off-patent and are empirically administered to newborns once efficacy has been demonstrated in adults and usefulness is suspected or demonstrated in the older pediatric population. Few drugs are approved by the Food and Drug Administration for use in this population. The factors that prevent the demonstration of efficacy and safety in the newborn are discussed and a change in the current approach for neonatal drug studies is suggested.

Postnatal corticosteroids to treat or prevent chronic lung disease in preterm infants

This statement is intended for health care professionals caring for neonates and young infants. The objectives of this statement are to review the short and long term effects of systemic and inhaled postnatal corticosteroids for the prevention or treatment of evolving or established chronic lung disease, and to make recommendations for the use of corticosteroids in infants with very low birth weight. The routine use of systemic dexamethasone for the prevention or treatment of chronic lung disease in infants with very low birth weight is not recommended.

Early prophylactic inhaled beclomethasone in infants less than 1250 g for the prevention of chronic lung disease

OBJECTIVE

Inflammation plays an important role in the development of chronic lung disease (CLD), which has become a major cause of morbidity in surviving infants less than 1250 g at birth. The authors hypothesized that the progression of this inflammation and, therefore, the establishment of CLD would be decreased with the use of early prophylactic inhaled corticosteroids. Short, and long term respiratory and neurodevelopmental outcomes were also examined.

DESIGN

A double-blind, randomized placebo controlled trial.

SETTING

Level-III neonatal intensive care unit.

POPULATION STUDIED

Sixty infants less than 1250 g at birth, diagnosed with respiratory distress syndrome and requiring ventilatory support at 72 h of age were enrolled in the study.

INTERVENTION

Infants enrolled received either placebo or beclomethasone diproprionate by a metered dose inhaler, which was used in-line with the ventilator circuit while the infant was ventilated and then via a spacer until 28 days of age.

RESULTS

Thirty infants were given beclomethasone and 30 were given placebo. There were two deaths in each group. Among the surviving infants, the frequency of moderate-to-severe CLD was 17% in each study group. Mean time to extubation was not different for beclomethasone compared with placebo at 16.4 and 12.5 days (P=0.12), respectively. The requirement for intravenous corticosteroids was lower in the beclomethasone-treated group (RR 0.67, 95% CI 0.43 to 1.04), although this difference was not statistically significant. The incidence of growth failure, infection and intraventricular hemmorhage did not differ between the two groups. Long term outcomes were not different with respect to the incidence of respiratory re-admissions, cerebral palsy, developmental delay, blindness or deafness.

CONCLUSIONS

Early treatment with inhaled beclomethasone diproprionate did not reduce the incidence of CLD or decrease the duration of mechanical ventilation. The decrease in intravenous corticosteroid use was not statistically significant. Long term outcome was not affected.

Pathogenesis and treatment of bronchopulmonary dysplasia

PURPOSE OF REVIEW

Bronchopulmonary dysplasia (BPD) is a chronic lung disease of infancy affecting mostly premature infants with significant morbidity and mortality. Improved survival of very immature infants has led to increased numbers of infants with this disorder. Acute and chronic lung injury and impaired postnatal lung growth are thought to be responsible for the development of BPD. Whereas changes in clinical practice have improved the clinical course and outcomes for infants with BPD, over the past decade, the overall incidence of BPD has not changed. This review will describe the prenatal and postnatal factors that contribute to the pathogenesis of BPD as well as current and experimental therapies for treatment of BPD.

RECENT FINDINGS

The factors that contribute to the pathogenesis of BPD are well described; however, recent studies have better defined how these factors modulate lung growth. Inflammation, proinflammatory cytokines and altered angiogenic gene signaling contribute to lung injury and impair prenatal and postnatal lung growth resulting in BPD; however, to date no therapy has been identified that potently and consistently prevents or reverses their effects on lung growth. We will discuss the cell signaling pathways affected in BPD and current therapies available for modulating these pathways.

SUMMARY

Despite current advances in neonatal care, BPD remains a heavy burden on healthcare resources. New treatments directed at either reducing lung injury or improving lung growth are under study.

Early (< 8 days) postnatal corticosteroids for preventing chronic lung disease in preterm infants

BACKGROUND

Chronic lung disease (CLD) remains a major problem in neonatal intensive care units. Persistent inflammation in the lungs is the most likely underlying pathogenesis. Corticosteroids have been used to either prevent or treat CLD because of their potent anti-inflammatory effects.

OBJECTIVES

To determine if postnatal corticosteroid treatment is of benefit in the prevention of chronic lung disease (CLD) in preterm infants. This review examines the outcome of trials where preterm infants at risk of CLD were given postnatal corticosteroids within the first seven days of life.

SEARCH STRATEGY

Randomised controlled trials (RCTs) of postnatal corticosteroid therapy were sought from the Cochrane Controlled Trials Register, MEDLINE (1966 - May 2008), hand searching paediatric and perinatal journals, examining previous review articles and information received from practising neonatologists. Authors of all studies were contacted, where possible, to confirm details of reported follow-up studies, or to obtain any information about long-term follow-up where none had been reported.

SELECTION CRITERIA

Randomised controlled trials of postnatal corticosteroid treatment within the first 7 days of life (early) in high risk preterm infants were selected for this review. Most studies evaluated the use of dexamethasone but we also included studies that assessed hydrocortisone, even if it was used to manage hypotension.

DATA COLLECTION AND ANALYSIS

Data regarding clinical outcomes including mortality, CLD (including late rescue with corticosteroids, and need for home oxygen therapy), death or CLD, failure to extubate, complications during the primary hospitalisation (including infection, hyperglycaemia, hypertension, pulmonary air leak, patent ductus arteriosus (PDA), severe intraventricular haemorrhage (IVH), periventricular leucomalacia (PVL), necrotising enterocolitis (NEC), gastrointestinal bleeding, intestinal perforation, severe retinopathy of prematurity (ROP), and long-term outcome (including blindness, deafness, cerebral palsy and major neurosensory disability) were abstracted and analysed using RevMan 5.

MAIN RESULTS

Twenty-eight RCTs enrolling a total of 3740 participants were eligible for inclusion in this review. A meta-analysis of these trials demonstrated significant benefits as regards earlier extubation and decreased risks of CLD at both 28 days and 36 weeks' postmenstrual age (PMA), death or CLD at 28 days and 36 weeks' PMA, PDA and ROP, including severe ROP. There were no significant differences in the rates of neonatal or subsequent mortality, infection, severe IVH, PVL, NEC or pulmonary haemorrhage. Gastrointestinal bleeding and intestinal perforation were important adverse effects and the risks of hyperglycaemia, hypertension, hypertrophic cardiomyopathy and growth failure were also increased. In the twelve trials that reported late outcomes, several adverse neurological effects were found at follow-up examinations including developmental delay (not defined), cerebral palsy and abnormal neurological examination. However, major neurosensory disability was not significantly increased, either overall in the seven studies where this outcome could be determined, or in the two individual studies where the rates of cerebral palsy or abnormal neurological examination were significantly increased. Moreover, the rates of the combined outcomes of death or cerebral palsy, or of death or major neurosensory disability were not significantly increased. Dexamethasone was the drug used in most studies (n = 20); only eight studies used hydrocortisone. In subgroup analyses by type of corticosteroid, most of the beneficial and harmful effects were attributable to dexamethasone; hydrocortisone had little effect on any outcomes except for an increase in intestinal perforation and a borderline reduction in PDA.

AUTHORS' CONCLUSIONS

The benefits of early postnatal corticosteroid treatment (</= 7 days), particularly dexamethasone, may not outweigh the known or potential adverse effects of this treatment. Although early corticosteroid treatment facilitates extubation and reduces the risk of chronic lung disease and patent ductus arteriosus, it causes short-term adverse effects including gastrointestinal bleeding, intestinal perforation, hyperglycaemia, hypertension, hypertrophic cardiomyopathy and growth failure. Long-term follow-up studies report an increased risk of abnormal neurological examination and cerebral palsy. However, the methodological quality of the studies determining long-term outcomes is limited in some cases; the surviving children have been assessed predominantly before school age, and no study has been sufficiently powered to detect important adverse long-term neurosensory outcomes. There is a compelling need for the long-term follow-up and reporting of late outcomes, especially neurological and developmental outcomes, among surviving infants who participated in all randomised trials of early postnatal corticosteroid treatment. Hydrocortisone in the doses and regimens used in the reported RCTs has few beneficial or harmful effects and cannot be recommended for prevention of CLD.

Early (< 8 days) postnatal corticosteroids for preventing chronic lung disease in preterm infants

BACKGROUND

Chronic lung disease (CLD) remains a major problem in neonatal intensive care units. Persistent inflammation in the lungs is the most likely underlying pathogenesis. Corticosteroids have been used to either prevent or treat CLD because of their potent anti-inflammatory effects.

OBJECTIVES

To determine if postnatal corticosteroid treatment is of benefit in the prevention of chronic lung disease (CLD) in preterm infants. This review examines the outcome of trials where preterm infants at risk of CLD were given postnatal corticosteroids within the first seven days of life.

SEARCH STRATEGY

Randomised controlled trials (RCTs) of postnatal corticosteroid therapy were sought from the Cochrane Controlled Trials Register, MEDLINE (1966 - May 2008), hand searching paediatric and perinatal journals, examining previous review articles and information received from practising neonatologists. Authors of all studies were contacted, where possible, to confirm details of reported follow-up studies, or to obtain any information about long-term follow-up where none had been reported.

SELECTION CRITERIA

Randomised controlled trials of postnatal corticosteroid treatment within the first 7 days of life (early) in high risk preterm infants were selected for this review. Most studies evaluated the use of dexamethasone but we also included studies that assessed hydrocortisone, even if it was used to manage hypotension.

DATA COLLECTION AND ANALYSIS

Data regarding clinical outcomes including mortality, CLD (including late rescue with corticosteroids, and need for home oxygen therapy), death or CLD, failure to extubate, complications during the primary hospitalisation (including infection, hyperglycaemia, hypertension, pulmonary air leak, patent ductus arteriosus (PDA), severe intraventricular haemorrhage (IVH), periventricular leucomalacia (PVL), necrotising enterocolitis (NEC), gastrointestinal bleeding, intestinal perforation, severe retinopathy of prematurity (ROP), and long-term outcome (including blindness, deafness, cerebral palsy and major neurosensory disability) were abstracted and analysed using RevMan 5.

MAIN RESULTS

Twenty-eight RCTs enrolling a total of 3740 participants were eligible for inclusion in this review. A meta-analysis of these trials demonstrated significant benefits as regards earlier extubation and decreased risks of CLD at both 28 days and 36 weeks' postmenstrual age (PMA), death or CLD at 28 days and 36 weeks' PMA, PDA and ROP, including severe ROP. There were no significant differences in the rates of neonatal or subsequent mortality, infection, severe IVH, PVL, NEC or pulmonary haemorrhage. Gastrointestinal bleeding and intestinal perforation were important adverse effects and the risks of hyperglycaemia, hypertension, hypertrophic cardiomyopathy and growth failure were also increased. In the twelve trials that reported late outcomes, several adverse neurological effects were found at follow-up examinations including developmental delay (not defined), cerebral palsy and abnormal neurological examination. However, major neurosensory disability was not significantly increased, either overall in the seven studies where this outcome could be determined, or in the two individual studies where the rates of cerebral palsy or abnormal neurological examination were significantly increased. Moreover, the rates of the combined outcomes of death or cerebral palsy, or of death or major neurosensory disability were not significantly increased. Dexamethasone was the drug used in most studies (n = 20); only eight studies used hydrocortisone. In subgroup analyses by type of corticosteroid, most of the beneficial and harmful effects were attributable to dexamethasone; hydrocortisone had little effect on any outcomes except for an increase in intestinal perforation and a borderline reduction in PDA.

AUTHORS' CONCLUSIONS

The benefits of early postnatal corticosteroid treatment (</= 7 days), particularly dexamethasone, may not outweigh the known or potential adverse effects of this treatment. Although early corticosteroid treatment facilitates extubation and reduces the risk of chronic lung disease and patent ductus arteriosus, it causes short-term adverse effects including gastrointestinal bleeding, intestinal perforation, hyperglycaemia, hypertension, hypertrophic cardiomyopathy and growth failure. Long-term follow-up studies report an increased risk of abnormal neurological examination and cerebral palsy. However, the methodological quality of the studies determining long-term outcomes is limited in some cases; the surviving children have been assessed predominantly before school age, and no study has been sufficiently powered to detect important adverse long-term neurosensory outcomes. There is a compelling need for the long-term follow-up and reporting of late outcomes, especially neurological and developmental outcomes, among surviving infants who participated in all randomised trials of early postnatal corticosteroid treatment. Hydrocortisone in the doses and regimens used in the reported RCTs has few beneficial or harmful effects and cannot be recommended for prevention of CLD.

Late (>7 days) postnatal corticosteroids for chronic lung disease in preterm infants

BACKGROUND

Many preterm infants who survive go on to develop chronic lung disease (CLD). This is true in infants who have had respiratory distress syndrome (RDS) and in infants without RDS. This is probably due to persistence of inflammation in the lung. Corticosteroids have powerful anti-inflammatory effects and have been used to treat established CLD. However, it is unclear whether any beneficial effects outweigh the adverse effects of these drugs.

OBJECTIVES

To determine the effect of late (> 7 days) postnatal corticosteroid treatment compared to control (placebo or nothing) in the preterm infant with CLD.

SEARCH STRATEGY

Randomised controlled trials of postnatal corticosteroid therapy were sought from the Cochrane Central Register of Controlled Trials (The Cochrane Library), MEDLINE 1966 through May 2008, hand searching paediatric and perinatal journals, examining previous review articles and information received from practising neonatologists. When possible, authors of all studies were contacted to confirm details of reported follow-up studies or to obtain any information about long-term follow-up where none had been reported.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of postnatal corticosteroid treatment initiated after seven days after birth in preterm infants with or developing CLD were selected for this review.

DATA COLLECTION AND ANALYSIS

Data regarding clinical outcomes including mortality, CLD (including need for home oxygen, or need for late rescue with corticosteroids), death or CLD, failure to extubate, complications in the primary hospitalisation (including infection, hyperglycaemia, glycosuria, hypertension, echodensities on ultrasound scan of brain, necrotising enterocolitis (NEC), gastrointestinal (GI) bleeding, GI perforation, intraventricular hemorrhage (IVH), severe retinopathy of prematurity (ROP), and long-term outcomes (including blindness, deafness, cerebral palsy and major neurosensory disability), were abstracted and analysed using RevMan 5

MAIN RESULTS

Nineteen RCTs enrolling a total of 1345 participants were eligible for this review. Late steroid treatment was associated with a reduction in neonatal mortality (at 28 days) but not mortality at discharge or latest reported age. Beneficial effects of delayed steroid treatment included reductions in failure to extubate by 3, 7 or 28 days, CLD at both 28 days and 36 weeks' postmenstrual age (overall and in survivors), need for late rescue treatment with dexamethasone, discharge to home on oxygen therapy, and death or CLD at both 28 days and 36 weeks' postmenstrual age (PMA). There was a trend towards an increase in risk of infection and GI bleeding but not NEC. Short-term adverse affects included hyperglycaemia, glycosuria and hypertension. There was an increase in severe ROP (overall and a trend in survivors) but no significant increase in blindness. There was trend towards a reduction in severe IVH but only 247 infants were enrolled in five studies reporting this outcome. The trends to an increase in cerebral palsy or abnormal neurological examination were partly offset by a trend in the opposite direction in death before late follow-up. The combined rate of death or cerebral palsy was not significantly different between steroid and control groups. Major neurosensory disability, and the combined rate of death or major neurosensory disability, were not significantly different between steroid and control groups. There were no substantial differences between groups for other outcomes in later childhood, including respiratory health or function, blood pressure, or growth.

AUTHORS' CONCLUSIONS

The benefits of late corticosteroid therapy may not outweigh actual or potential adverse effects. Although there continues to be concern about an increased incidence of adverse neurological outcomes in infants treated with postnatal steroids (see also review of "Early postnatal corticosteroids for preventing chronic lung disease in preterm infants"), this review of postnatal corticosteroid treatment for CLD initiated after seven days of age suggests that late therapy may reduce neonatal mortality without significantly increasing the risk of adverse long-term neurodevelopmental outcomes. However, the methodological quality of the studies determining the long-term outcome is limited in some cases; in some studies the surviving children have only been assessed before school age when some important neurological outcomes cannot be determined with certainty, and no study was sufficiently powered to detect increased rates of important adverse long-term neurosensory outcomes. Given the evidence of both benefits and harms of treatment, and the limitations of the evidence at present, it appears prudent to reserve the use of late corticosteroids to infants who cannot be weaned from mechanical ventilation and to minimise the dose and duration of any course of treatment.

Chronic lung disease in newborns

Chronic lung disease (CLD) or bronchopulmonary dysplasia (BPD) occurs in preterm infants who require respiratory support in the first few days of birth. Apart from prematurity, oxygen therapy and assisted ventilation, factors like intrauterine/postnatal infections, patent ductus arteriosus, and genetic polymorphisms also contribute to its pathogenesis. The severe form of BPD with extensive inflammatory changes is rarely seen nowadays; instead, a milder form characterized by decreased alveolar septation due to arrest in lung development is more common. A multitude of strategies, mainly pharmacological and ventilatory, have been employed for prevention and treatment of BPD. Unfortunately, most of them have not been proved to be beneficial. A comprehensive protocol for management of BPD based on the current evidence is discussed here.

Early administration of inhaled corticosteroids for preventing chronic lung disease in ventilated very low birth weight preterm neonates

BACKGROUND

Chronic lung disease remains a common complication among preterm infants. There is increasing evidence that inflammation plays an important role in the pathogenesis of CLD. Due to their strong anti-inflammatory properties, corticosteroids are an attractive intervention strategy. However, there are growing concerns regarding short and long-term effects of systemic corticosteroids. Theoretically, administration of inhaled corticosteroids may allow for beneficial effects on the pulmonary system with a lower risk of undesirable systemic side effects.

OBJECTIVES

To determine the impact of inhaled corticosteroids administered to ventilated very low birth weight preterm neonates in the first two weeks of life for the prevention of chronic lung disease (CLD).

SEARCH STRATEGY

Randomized and quasi-randomized trials were identified by searching the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 3, 2007), MEDLINE (1966 - July 2007), EMBASE (1980 - July 2007), CINAHL (1982 - July 2007), reference lists of published trials and abstracts published in Pediatric Research or electronically on the Pediatric Academic Societies web-site (1990 - April 2007).

SELECTION CRITERIA

Randomized controlled trials of inhaled corticosteroid therapy initiated within the first 2 weeks of life in ventilated preterm infants with birth weight <1500 grams were included in this review.

DATA COLLECTION AND ANALYSIS

Data regarding clinical outcomes including chronic lung disease at 28 days or 36 weeks postmenstrual age (PMA), mortality, combined outcome of death or CLD at 28 days of age and at 36 weeks PMA, the need for systemic corticosteroids, failure to extubate within 14 days and adverse effects of corticosteroids were evaluated. All data were analyzed using RevMan 4.2.10. When possible, meta-analysis was performed using relative risk (RR), risk difference (RD), along with their 95% confidence intervals (CI). If RD was significant, the number needed to treat (NNT) was calculated.

MAIN RESULTS

Three additional trials were identified for inclusion in this update. Eleven trials assessing the impact of inhaled corticosteroid for the prevention of CLD were identified. Four trials were excluded. The present review includes data analyses based on seven qualifying trials. There was no statistically significant effect of inhaled steroids on CLD either at 28 days [typical RR 1.05 (95% CI 0.84, 1.32); typical RD 0.02 (95% CO -0.07, 0.11)] or at 36 weeks PMA [typical RR 0.97 (95% CI 0.62, 1.52); typical RD 0.00 (95% CI -0.07, 0.06)], when analyzed either for all randomized infants or among survivors. No statistically significant differences were noted for mortality or for the combined outcome of mortality and CLD either at 28 days of age or at 36 weeks PMA. There were no statistically significant differences in adverse events between groups.

AUTHORS' CONCLUSIONS

Based on this updated review, there is no evidence from the trials reviewed that early administration (in the first two weeks of life) of inhaled steroids to ventilated preterm neonates was effective in reducing the incidence of CLD. Currently, use of inhaled steroids in this population cannot be recommended. Studies are needed to identify the risk/benefit ratio of different delivery techniques and dosing schedules for the administration of these medications. Studies need to address both the short-term and long-term benefits and adverse effects of inhaled steroids with particular attention to neurodevelopmental outcome.

How has research in the past 5 years changed my clinical practice

This article discusses how research in the past 5 years into management strategies influencing respiratory outcomes has changed (or not changed) the author's clinical practice. Changes include using inhaled nitric oxide but no longer systemic pulmonary vasodilators in term born infants with pulmonary hypertension. Use of postnatal steroids is now restricted to systemic administration in infants with severe respiratory failure and who are ventilator dependent beyond 2 weeks of age. Infants with bronchopulmonary dysplasia, unless they have pulmonary hypertension, are maintained at oxygen saturation levels of 90-92% rather than >/=95%. Supine sleeping is instituted in prematurely born infants without contraindications several weeks prior to neonatal discharge to reinforce to parents the importance of supine sleeping their baby at home. Further research is required to identify the optimal respiratory support strategy, particularly for very immature infants.

Calcineurin/Nfat signaling is required for perinatal lung maturation and function

Pulmonary surfactant proteins and lipids are required for lung function after birth. Lung immaturity and resultant surfactant deficiency cause respiratory distress syndrome, a common disorder contributing to morbidity and mortality in preterm infants. Surfactant synthesis increases prior to birth in association with formation of the alveoli that mediate efficient gas exchange. To identify mechanisms controlling perinatal lung maturation, the Calcineurin b1 (Cnb1) gene was deleted in the respiratory epithelium of the fetal mouse. Deletion of Cnb1 caused respiratory failure after birth and inhibited the structural maturation of the peripheral lung. Synthesis of surfactant and a lamellar body-associated protein, ABC transporter A3 (ABCA3), was decreased prior to birth. Nuclear factor of activated T cells (Nfat) calcineurin-dependent 3 (Nfatc3), a transcription factor modulated by calcineurin, was identified as a direct activator of Sftpa, Sftpb, Sftpc, Abca3, Foxa1, and Foxa2 genes. The calcineurin/Nfat pathway controls the morphologic maturation of lungs prior to birth and regulates expression of genes involved in surfactant homeostasis that are critical for adaptation to air breathing.

Progress in Discovery and Evaluation of Treatments to Prevent Bronchopulmonary Dysplasia

BACKGROUND

Recent improvements in the survival of extremely preterm infants have been accompanied by evolution in the pathogenesis and histopathology of bronchopulmonary dysplasia (BPD). Although oxygen and barotrauma-induced injury remain important contributing factors, pulmonary developmental arrest appears to play an equally important causal role in prolonged respiratory illness, especially among the most immature surviving preterm newborns. To date, clinical trials have failed to demonstrate a substantial benefit of a single treatment or preventive strategy for BPD.

OBJECTIVES

To evaluate the current evidence in favor of treatments that might prevent BPD.

METHODS

Review of clinical studies of preventive treatment strategies for BPD.

RESULTS

High frequency oscillatory ventilation, permissive hypercapnea, and inhaled nitric oxide might offer benefit to infants at risk of BPD. These and other potential preventive therapies for BPD, such as superoxide dismutase, inositol, and alpha(1)-proteinase inhibitor, deserve further study.

CONCLUSIONS

Although some current treatments offer promise, no preventive therapy for BPD has proven safe and effective, except for intramuscular vitamin A. Additional studies of respiratory technologies, management strategies, and protective molecules are needed.

Bronchopulmonary dysplasia

Bronchopulmonary dysplasia is a chronic lung disease that affects premature babies and contributes to their morbidity and mortality. Improved survival of very immature infants has led to increased numbers of infants with this disorder. This increase puts a heavy burden on health resources since these infants need frequent re-admission to hospital in the first 2 years after birth and, even as adolescents, have lung-function abnormalities and persistent respiratory symptoms. Unlike the original description of the disease in 1967, premature infants can develop chronic oxygen dependency without severe, acute respiratory distress; this "new bronchopulmonary dysplasia" could be the result of impaired postnatal lung growth. Whether such infants subsequently have catch-up lung growth, especially if given corticosteroids postnatally, is unknown. No safe and effective preventive therapy has been identified, but promising new treatments directed either at reducing lung injury or improving lung growth are under study.

Bronchopulmonary dysplasia in preterm infants: pathophysiology and management strategies

Bronchopulmonary dysplasia (BPD) has classically been described as including inflammation, architectural disruption, fibrosis, and disordered/delayed development of the infant lung. As infants born at progressively earlier gestations have begun to survive the neonatal period, a 'new' BPD, consisting primarily of disordered/delayed development, has emerged. BPD causes not only significant complications in the newborn period, but is associated with continuing mortality, cardiopulmonary dysfunction, re-hospitalization, growth failure, and poor neurodevelopmental outcome after hospital discharge. Four major risk factors for BPD include premature birth, respiratory failure, oxygen supplementation, and mechanical ventilation, although it is unclear whether any of these factors is absolutely necessary for development of the condition. Genetic susceptibility, infection, and patent ductus arteriosus have also been implicated in the pathogenesis of the disease. The strategies with the strongest evidence for effectiveness in preventing or lessening the severity of BPD include prevention of prematurity and closure of a clinically significant patent ductus arteriosus. Some evidence of effectiveness also exists for single-course therapy with antenatal glucocorticoids in women at risk for delivering premature infants, surfactant replacement therapy in intubated infants with respiratory distress syndrome, retinol (vitamin A) therapy, and modes of respiratory support designed to minimize 'volutrauma' and oxygen toxicity. The most effective treatments for ameliorating symptoms or preventing exacerbation in established BPD include oxygen therapy, inhaled glucocorticoid therapy, and vaccination against respiratory pathogens.Many other strategies for the prevention or treatment of BPD have been proposed, but have weaker or conflicting evidence of effectiveness. In addition, many therapies have significant side effects, including the possibility of worsening the disease despite symptom improvement. For instance, supraphysiologic systemic doses of glucocorticoids lessen the incidence of BPD in infants at risk for the disease, and promote weaning of oxygen and mechanical ventilation in infants with established BPD. However, the side effects of systemic glucocorticoid therapy, most notably the recently recognized adverse effects on neurodevelopment, preclude their routine use for the prevention or treatment of BPD. Future research in BPD will most probably focus on continued incremental improvements in outcome, which are likely to be achieved through the combined effects of many therapeutic modalities.

Current perspectives on the prevention and management of chronic lung disease in preterm infants

Chronic lung disease (CLD) or bronchopulmonary dysplasia is a recognized sequel of preterm birth. With improving survival of infants at lower gestational ages, the incidence is on the rise. Pathological features of CLD include alveolar maldevelopment, with or without areas of pulmonary fibrosis. Assisted ventilation, infection/inflammation, oxygen administration, and fluid overload are the major risk factors in the evolution of CLD.Interventions, including the treatment of maternal infection, administration of prenatal glucocorticoids, and postnatal surfactant replacement therapy, improve the survival of preterm infants; however, their effect on CLD is difficult to determine. Strategies that have been effective in reducing CLD are the administration of retinol (vitamin A), high frequency oscillatory ventilation, and administration of glucocorticoids. Previous concerns regarding neurological problems associated with high frequency ventilation have not been substantiated in recent studies. Current recommendations do not advise the routine use of glucocorticoids due to concerns regarding long-term neurodevelopment. Therapies that were found to be ineffective in reducing the incidence of CLD include prenatal thyrotropin, cromolyn sodium (sodium cromoglycate), alpha-1 antitrypsin, superoxide dismutase, tocopherol (vitamin E), ascorbic acid (vitamin C), allopurinol, ambroxol, inositol, inhaled bronchodilators, and fluid restriction. Strategies that may be effective in reducing lung injury and subsequent CLD include avoiding assisted ventilation, lung protective ventilatory maneuvers, permissive hypercapnia, prevention of infection, early aggressive nutrition, and the treatment of a patent ductus arteriosus. The use of inhaled glucocorticoids improves pulmonary dynamics but long-term effects are unknown. The management of infants with established CLD has not been studied adequately, and the role of various ventilatory strategies for infants with established CLD is not clear. Adequate oxygenation should be maintained to prevent hypoxic episodes. Diuretics are helpful during acute decompensation; however, their long-term impact has not been well studied. Provision of adequate nutrition, immunization (routine and against respiratory syncytial virus), follow-up, and monitoring are the key elements in the long-term management of infants with CLD. Future research priorities should be to identify strategies to prevent/treat inflammation and promote the healing processes in the injured lung. The long-term effects of lung-protective ventilation strategies need to be studied.

Postnatal corticosteroids to treat or prevent chronic lung disease in preterm infants

This statement is intended for health care professionals caring for neonates and young infants. The objectives of this statement are to review the short- and long-term effects of systemic and inhaled postnatal corticosteroids for the prevention or treatment of evolving or established chronic lung disease and to make recommendations for the use of corticosteroids in infants with very low birth weight. The routine use of systemic dexamethasone for the prevention or treatment of chronic lung disease in infants with very low birth weight is not recommended.

Postnatal glucocorticoid therapy for prevention of bronchopulmonary dysplasia: routes of administration compared

Postnatal systemic and inhaled glucocorticoid therapies continue to be used in the management of bronchopulmonary dysplasia (BPD). Systemic dexamethasone therapy has been studied longer than aerosolized glucocorticoid therapy. Several prophylactic trials of systemic dexamethasone therapy demonstrated a reduction in the incidence of BPD and neonatal mortality. However, evidence of potentially serious acute and long-term adverse effects has reduced enthusiasm for use of systemic dexamethasone therapy. Although no trial to date of inhaled glucocorticoid therapy showed a reduction in the incidence of BPD, some studies demonstrated secondary pulmonary benefits with few short-term adverse effects. This article compares the clinical efficacy and safety of these two routes of administration of glucocorticoid therapy.