Delayed (>3 weeks) postnatal corticosteroids for chronic lung disease in preterm infants

Systemic corticosteroid regimens for prevention of bronchopulmonary dysplasia in preterm infants

BACKGROUND

Systematic reviews showed that systemic postnatal corticosteroids reduce the risk of bronchopulmonary dysplasia (BPD) in preterm infants. However, corticosteroids have also been associated with an increased risk of neurodevelopmental impairment. It is unknown whether these beneficial and adverse effects are modulated by differences in corticosteroid treatment regimens related to type of steroid, timing of treatment initiation, duration, pulse versus continuous delivery, and cumulative dose.

OBJECTIVES

To assess the effects of different corticosteroid treatment regimens on mortality, pulmonary morbidity, and neurodevelopmental outcome in very low birth weight infants.

SEARCH METHODS

We conducted searches in September 2022 of MEDLINE, the Cochrane Library, Embase, and two trial registries, without date, language or publication- type limits. Other search methods included checking the reference lists of included studies for randomized controlled trials (RCTs) and quasi-randomized trials.

SELECTION CRITERIA

We included RCTs comparing two or more different treatment regimens of systemic postnatal corticosteroids in preterm infants at risk for BPD, as defined by the original trialists. The following comparisons of intervention were eligible: alternative corticosteroid (e.g. hydrocortisone) versus another corticosteroid (e.g. dexamethasone); lower (experimental arm) versus higher dosage (control arm); later (experimental arm) versus earlier (control arm) initiation of therapy; a pulse-dosage (experimental arm) versus continuous-dosage regimen (control arm); and individually-tailored regimens (experimental arm) based on the pulmonary response versus a standardized (predetermined administered to every infant) regimen (control arm). We excluded placebo-controlled and inhalation corticosteroid studies.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed eligibility and risk of bias of trials, and extracted data on study design, participant characteristics and the relevant outcomes. We asked the original investigators to verify if data extraction was correct and, if possible, to provide any missing data. We assessed the following primary outcome: the composite outcome mortality or BPD at 36 weeks' postmenstrual age (PMA). Secondary outcomes were: the components of the composite outcome; in-hospital morbidities and pulmonary outcomes, and long-term neurodevelopmental sequelae. We analyzed data using Review Manager 5 and used the GRADE approach to assess the certainty of the evidence.

MAIN RESULTS

We included 16 studies in this review; of these, 15 were included in the quantitative synthesis. Two trials investigated multiple regimens, and were therefore included in more than one comparison. Only RCTs investigating dexamethasone were identified. Eight studies enrolling a total of 306 participants investigated the cumulative dosage administered; these trials were categorized according to the cumulative dosage investigated, 'low' being < 2 mg/kg, 'moderate' being between 2 and 4 mg/kg, and 'high' > 4 mg/kg; three studies contrasted a high versus a moderate cumulative dose, and five studies a moderate versus a low cumulative dexamethasone dose. We graded the certainty of the evidence low to very low because of the small number of events, and the risk of selection, attrition and reporting bias. Overall analysis of the studies investigating a higher dose versus a lower dosage regimen showed no differences in the outcomes BPD, the composite outcome death or BPD at 36 weeks' PMA, or abnormal neurodevelopmental outcome in survivors assessed. Although there was no evidence of a subgroup difference for the higher versus lower dosage regimens comparisons (Chi2 = 2.91, df = 1 (P = 0.09), I2 = 65.7%), a larger effect was seen in the subgroup analysis of moderate-dosage regimens versus high-dosage regimens for the outcome cerebral palsy in survivors. In this subgroup analysis, there was an increased risk of cerebral palsy (RR 6.85, 95% CI 1.29 to 36.36; RD 0.23, 95% CI 0.08 to 0.37; P = 0.02; I² = 0%; NNTH 5, 95% CI 2.6 to 12.7; 2 studies, 74 infants). There was evidence of subgroup differences for higher versus lower dosage regimens comparisons for the combined outcomes death or cerebral palsy, and death and abnormal neurodevelopmental outcomes (Chi2 = 4.25, df = 1 (P = 0.04), I2 = 76.5%; and Chi2 = 7.11, df = 1 (P = 0.008), I2 = 85.9%, respectively). In the subgroup analysis comparing a high dosage regimen of dexamethasone versus a moderate cumulative-dosage regimen, there was an increased risk of death or cerebral palsy (RR 3.20, 95% CI 1.35 to 7.58; RD 0.25, 95% CI 0.09 to 0.41; P = 0.002; I² = 0%; NNTH 5, 95% CI 2.4 to 13.6; 2 studies, 84 infants; moderate-certainty evidence), and death or abnormal neurodevelopmental outcome (RR 3.41, 95% CI 1.44 to 8.07; RD 0.28, 95% CI 0.11 to 0.44; P = 0.0009; I² = 0%; NNTH 4, 95% CI 2.2 to 10.4; 2 studies, 84 infants; moderate-certainty evidence). There were no differences in outcomes between a moderate- and a low-dosage regimen. Five studies enrolling 797 infants investigated early initiation of dexamethasone therapy versus a moderately early or delayed initiation, and showed no significant differences in the overall analyses for the primary outcomes. The two RCTs investigating a continuous versus a pulse dexamethasone regimen showed an increased risk of the combined outcome death or BPD when using the pulse therapy. Finally, three trials investigating a standard regimen versus a participant-individualized course of dexamethasone showed no difference in the primary outcome and long-term neurodevelopmental outcomes. We assessed the GRADE certainty of evidence for all comparisons discussed above as moderate to very low, because the validity of all comparisons is hampered by unclear or high risk of bias, small samples of randomized infants, heterogeneity in study population and design, non-protocolized use of 'rescue' corticosteroids and lack of long-term neurodevelopmental data in most studies.

AUTHORS' CONCLUSIONS

The evidence is very uncertain about the effects of different corticosteroid regimens on the outcomes mortality, pulmonary morbidity, and long term neurodevelopmental impairment. Despite the fact that the studies investigating higher versus lower dosage regimens showed that higher-dosage regimens may reduce the incidence of death or neurodevelopmental impairment, we cannot conclude what the optimal type, dosage, or timing of initiation is for the prevention of BPD in preterm infants, based on current level of evidence. Further high quality trials would be needed to establish the optimal systemic postnatal corticosteroid dosage regimen.

Late (≥ 7 days) systemic postnatal corticosteroids for prevention of bronchopulmonary dysplasia in preterm infants

BACKGROUND

Many infants born preterm develop bronchopulmonary dysplasia (BPD), with lung inflammation playing a role. Corticosteroids have powerful anti-inflammatory effects and have been used to treat individuals with established BPD. However, it is unclear whether any beneficial effects outweigh the adverse effects of these drugs.

OBJECTIVES

To examine the relative benefits and adverse effects of late (starting at seven or more days after birth) systemic postnatal corticosteroid treatment for preterm infants with evolving or established BPD.

SEARCH METHODS

We ran an updated search on 25 September 2020 of the following databases: CENTRAL via CRS Web and MEDLINE via OVID. We also searched clinical trials databases and reference lists of retrieved articles for randomised controlled trials (RCTs). We did not include quasi-RCTs.

SELECTION CRITERIA

We selected for inclusion in this review RCTs comparing systemic (intravenous or oral) postnatal corticosteroid treatment versus placebo or no treatment started at seven or more days after birth for preterm infants with evolving or established BPD. We did not include trials of inhaled corticosteroids.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. We extracted and analysed data regarding clinical outcomes that included mortality, BPD, and cerebral palsy. We used the GRADE approach to assess the certainty of evidence.

MAIN RESULTS

Use of the GRADE approach revealed that the certainty of evidence was high for most of the major outcomes considered, except for BPD at 36 weeks for all studies combined and for the dexamethasone subgroup, which were downgraded one level to moderate because of evidence of publication bias, and for the combined outcome of mortality or BPD at 36 weeks for all studies combined and for the dexamethasone subgroup, which were downgraded one level to moderate because of evidence of substantial heterogeneity. We included 23 RCTs (1817 infants); 21 RCTS (1382 infants) involved dexamethasone (one also included hydrocortisone) and two RCTs (435 infants) involved hydrocortisone only. The overall risk of bias of included studies was low; all were RCTs and most trials used rigorous methods. Late systemic corticosteroids overall reduce mortality to the latest reported age (risk ratio (RR) 0.81, 95% confidence interval (CI) 0.66 to 0.99; 21 studies, 1428 infants; high-certainty evidence). Within the subgroups by drug, neither dexamethasone (RR 0.85, 95% CI 0.66 to 1.11; 19 studies, 993 infants; high-certainty evidence) nor hydrocortisone (RR 0.74, 95% CI 0.54 to 1.02; 2 studies, 435 infants; high-certainty evidence) alone clearly reduce mortality to the latest reported age. We found little evidence for statistical heterogeneity between the dexamethasone and hydrocortisone subgroups (P = 0.51 for subgroup interaction). Late systemic corticosteroids overall probably reduce BPD at 36 weeks' postmenstrual age (PMA) (RR 0.89, 95% CI 0.80 to 0.99; 14 studies, 988 infants; moderate-certainty evidence). Dexamethasone probably reduces BPD at 36 weeks' PMA (RR 0.76, 95% CI 0.66 to 0.87; 12 studies, 553 infants; moderate-certainty evidence), but hydrocortisone does not (RR 1.10, 95% CI 0.92 to 1.31; 2 studies, 435 infants; high-certainty evidence) (P < 0.001 for subgroup interaction). Late systemic corticosteroids overall probably reduce the combined outcome of mortality or BPD at 36 weeks' PMA (RR 0.85, 95% CI 0.79 to 0.92; 14 studies, 988 infants; moderate-certainty evidence). Dexamethasone probably reduces the combined outcome of mortality or BPD at 36 weeks' PMA (RR 0.75, 95% CI 0.67 to 0.84; 12 studies, 553 infants; moderate-certainty evidence), but hydrocortisone does not (RR 0.98, 95% CI 0.88 to 1.09; 2 studies, 435 infants; high-certainty evidence) (P < 0.001 for subgroup interaction). Late systemic corticosteroids overall have little to no effect on cerebral palsy (RR 1.17, 95% CI 0.84 to 1.61; 17 studies, 1290 infants; high-certainty evidence). We found little evidence for statistical heterogeneity between the dexamethasone and hydrocortisone subgroups (P = 0.63 for subgroup interaction). Late systemic corticosteroids overall have little to no effect on the combined outcome of mortality or cerebral palsy (RR 0.90, 95% CI 0.76 to 1.06; 17 studies, 1290 infants; high-certainty evidence). We found little evidence for statistical heterogeneity between the dexamethasone and hydrocortisone subgroups (P = 0.42 for subgroup interaction). Studies had few participants who were not intubated at enrolment; hence, it is not possible to make any meaningful comments on the effectiveness of late corticosteroids in preventing BPD in non-intubated infants, including those who might in the present day be supported by non-invasive techniques such as nasal continuous positive airway pressure or high-flow nasal cannula oxygen/air mixture, but who might still be at high risk of later BPD. Results of two ongoing studies are awaited.

AUTHORS' CONCLUSIONS

Late systemic postnatal corticosteroid treatment (started at seven days or more after birth) reduces the risks of mortality and BPD, and the combined outcome of mortality or BPD, without evidence of increased cerebral palsy. However, the methodological quality of studies determining long-term outcomes is limited, and no studies were powered to detect increased rates of important adverse long-term neurodevelopmental outcomes. This review supports the use of late systemic corticosteroids for infants who cannot be weaned from mechanical ventilation. The role of late systemic corticosteroids for infants who are not intubated is unclear and needs further investigation. Longer-term follow-up into late childhood is vital for assessment of important outcomes that cannot be assessed in early childhood, such as effects of late systemic corticosteroid treatment on higher-order neurological functions, including cognitive function, executive function, academic performance, behaviour, mental health, motor function, and lung function. Further RCTs of late systemic corticosteroids should include longer-term survival free of neurodevelopmental disability as the primary outcome.

Late (> 7 days) systemic postnatal corticosteroids for prevention of bronchopulmonary dysplasia in preterm infants

BACKGROUND

Many preterm infants who survive go on to develop bronchopulmonary dysplasia, probably as the result of persistent inflammation in the lungs. Corticosteroids have powerful anti-inflammatory effects and have been used to treat individuals with established bronchopulmonary dysplasia. However, it is unclear whether any beneficial effects outweigh the adverse effects of these drugs.

OBJECTIVES

To examine the relative benefits and adverse effects of late systemic postnatal corticosteroid treatment (> 7 days) for preterm infants with evolving or established bronchopulmonary dysplasia.

SEARCH METHODS

For the 2017 update, we used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 1); MEDLINE via PubMed (January 2013 to 21 February 2017); Embase (January 2013 to 21 February 2017); and the Cumulative Index to Nursing and Allied Health Literature (CINAHL; January 2013 to 21 February 2017). We also searched clinical trials databases, conference proceedings, and reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials.

SELECTION CRITERIA

We selected for inclusion in this review randomised controlled trials (RCTs) comparing systemic postnatal corticosteroid treatment versus placebo or nothing initiated more than seven days after birth for preterm infants with evolving or established bronchopulmonary dysplasia.

DATA COLLECTION AND ANALYSIS

We used the GRADE approach to assess the quality of evidence.We extracted and analysed data regarding clinical outcomes including mortality, bronchopulmonary dysplasia, death or bronchopulmonary dysplasia, failure to extubate, complications during primary hospitalisation, and long-term health outcomes.

MAIN RESULTS

Twenty-one RCTs enrolling a total of 1424 participants were eligible for this review. All were RCTs, but methods used for random allocation were not always clear. Allocation concealment, blinding of the intervention, and blinding of outcome assessments most often were satisfactory. Late steroid treatment was associated with a reduction in neonatal mortality (at 28 days) but no reduction in mortality at 36 weeks, at discharge, or at latest reported age. Benefits of delayed steroid treatment included reductions in failure to extubate by 3, 7, or 28 days; bronchopulmonary dysplasia both at 28 days of life and at 36 weeks' postmenstrual age; need for late rescue treatment with dexamethasone; discharge on home oxygen; and death or bronchopulmonary dysplasia both at 28 days of life and at 36 weeks' postmenstrual age. Data revealed a trend towards increased risk of infection and gastrointestinal bleeding but no increase in risk of necrotising enterocolitis. Short-term adverse affects included hyperglycaemia, glycosuria, and hypertension. Investigators reported an increase in severe retinopathy of prematurity but no significant increase in blindness. Trial results showed a trend towards reduction in severe intraventricular haemorrhage, but only five studies enrolling 247 infants reported this outcome. Trends towards an increase in cerebral palsy or abnormal neurological examination findings were partly offset by a trend in the opposite direction involving 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, although there were fewer participants with a clinically important reduction in forced expired volume in one second (FEV₁) on respiratory function testing in the dexamethasone group.GRADE findings were high for all major outcomes considered, but review authors degraded the quality of evidence by one level because we found evidence of publication bias (bronchopulmonary dysplasia at 36 weeks).

AUTHORS' CONCLUSIONS

Benefits of late corticosteroid therapy may not outweigh actual or potential adverse effects. This review of postnatal systemic corticosteroid treatment for bronchopulmonary dysplasia 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 studies determining long-term outcomes is limited in some cases (some studies assessed surviving children only before school age, when some important neurological outcomes cannot be determined with certainty), and no studies were sufficiently powered to detect increased rates of important adverse long-term neurosensory outcomes. Evidence showing both benefits and harms of treatment and limitations of available evidence suggests that it may be prudent to reserve the use of late corticosteroids for infants who cannot be weaned from mechanical ventilation, and to minimise both dose and duration for any course of treatment.

Long-term postnatal steroid effect in very low birth weight infants

We examined whether hydrocortisone exposure≤1week in very low birth weight infants (VLBWI) was associated with poor neurodevelopmental outcomes at corrected 18months. Further, the clinical factors associated with worse long term outcome were also evaluated. Of a total of 191 VLBWI, the clinical data for these infants relating were retrospectively collected for analysis. Among the 191 VLBWI, 115 (60.2%) infants were exposed to early postnatal hydrocortisone≤1week of life in our NICU of Seoul St. Mary's Hospital, The Catholic University of Korea between December 2012 and December 2014. The morbidities were significantly higher in the group with early hydrocortisone exposure group. At corrected age of 18months, 109/183 (59.6%) infants in the early hydrocortisone exposure group had significantly lower scores in all three (cognitive, language and motor) composites of Bayley Scales of Infant and Toddler Development III. The multivariable logistic regression analysis showed that only periventricular leukomalacia (PVL) is consistently associated with poor long-term outcomes. Our results suggest that early hydrocortisone exposure≤1week in VLBWI may not increase the risk for poor long-term outcomes compared to those not exposed. Only PVL is considered as a risk factor for poor long-term neurodevelopmental outcomes.

Relevance of clinical features in the prognosis of bronchopulmonary dysplasia in premature infants

The aim of this study is to determine the accuracy rate of bronchopulmonary dysplasia (BPD) diagnosis and risk factors of short-term poor prognosis for premature infants. This study analyzed the clinical data of 81 premature infants (<32 weeks gestational age) with BPD, who were on oxygen therapy >28 days, and survived >36 weeks (corrected age). Outcome measures included treatments, conditions on the 28th day after birth, oxygen therapy conditions at the 36th week, occurrence of any serious complications during hospital stay. The major risk factors affecting prognosis were ventilation duration, duration of oxygen therapy, application of steroids, hypothyroidism and severity of BPD (all P<0.05). Interventions for complications (n=53) resulted in ceased inhalation of oxygen in 12 infants, improvement of symptoms in 26 infants, and were ineffective in 15 infants. BPD prognosis can be improved by shortening the duration of invasive ventilation and correcting thyroid function.

A Single Postnatal Dose of Dexamethasone Enhances Memory of Rat Pups Later in Life

Postnatal dexamethasone (Dex) therapy is associated with adverse neurodevelopmental outcomes, which might be related to its timing of administration. We used time-dated pregnant Wistar albino rats, whose litters were divided into experimental (Dex) and control groups intraperitoneally administered one dose of Dex (0.5 mg/kg) or normal saline (NS), respectively, at either day 1 (P1) or 7 (P7). The magnitude of the contextual freezing response and performance on the Morris water maze were significantly higher in the Dex-P7 group than in those of the other groups at P56. Dendritic spine density, membranous expression of the N-methyl-d-aspartate receptor (NMDAR) subunit NR2A/2B, and postsynaptic density-95 (PSD-95) were significantly higher in the Dex-P7 group than in the other groups. Furthermore, cytosolic expression of nuclear factor kappa B (NF-κB) and phosphatidylinositol 3-kinase (PI3K) was significantly higher in the Dex group than in NS group. Moreover, Dex administration at P7 increased cell proliferation, neuronal differentiation, and the survival of newly born neurons in the dentate gyrus. These results suggest Dex at P7 enhances the acquisition of contextual fear and spatial memory later in life due to the modulation of the newly born neurons, increase in dendritic spine number, and NMDAR expression.

Pharmacologic interventions for the prevention and treatment of retinopathy of prematurity

Retinopathy of prematurity (ROP), a significant morbidity in prematurely born infants, is the most common cause of visual impairment and blindness in children and persists till adulthood. Strict control of oxygen therapy and prevention of intermittent hypoxia are the keys in the prevention of ROP, but pharmacologic interventions have decreased risk of ROP. Various drug classes such as methylxanthines (caffeine), VEGF inhibitors, antioxidants, and others have decreased ROP occurrence. The timing of pharmacologic intervention remains unsettled, but early prevention rather than controlling disease progression may be preferred. These drugs act through different mechanisms, and synergistic approaches should be considered to maximize efficacy and safety.

Drug therapy for the prevention and treatment of bronchopulmonary dysplasia

INTRODUCTION

As more infants are surviving at younger gestational ages, bronchopulmonary dysplasia (BPD) remains as a frequent neonatal complication occurring after preterm birth. The multifactorial nature of the disease process makes BPD a challenging condition to treat. While multiple pharmacologic therapies have been investigated over the past two decades, there have been limited advances in the field. Often multiple therapies are used concurrently without clear evidence of efficacy, with potential for significant side effects from drug-drug interactions.

METHODS

Systematic literature review.

CONCLUSION

Although there is physiologic rationale for the use of many of these therapies, none of them has single-handedly altered the incidence, severity, or progression of BPD. Future research should focus on developing clinically significant end-points (short and long term respiratory assessments), investigating biomarkers that accurately predict risk and progression of disease, and creating appropriate stratification models of BPD severity. Applying a multi-modal approach to the study of new and existing drugs should be the most effective way of establishing the optimal prevention and treatment regimens for BPD.

Anti-inflammatory actions of endogenous and exogenous interleukin-10 versus glucocorticoids on macrophage functions of the newly born

OBJECTIVE

To determine whether specific macrophage immune functions of the newly born are insensitive to the actions of therapeutic levels of dexamethasone (DEX), previously measured in infants with bronchopulmonary dysplasia (BPD), compared with betamethasone (BETA) and exogenous or endogenous interleukin-10 (IL-10).

STUDY DESIGN

Macrophages were differentiated from cord blood monocytes (N=18). A serial dose-response (around 10(-8 )M), in vitro study was used to examine the effect of DEX, BETA and IL-10, on proinflammatory (PI) cytokine release, phagocytosis and respiratory burst.

RESULT

Exogenous IL-10 (10(-8 )M) significantly (P<0.05) inhibited the endotoxin-stimulated release of IL-6, IL-8 and tumor necrosis factor by 63 to 82% with no significant effect by DEX and BETA. There was no inhibition by these three agents at 10(-8 )M on phagocytosis and respiratory burst. Inhibition of endogenous IL-10 with a monoclonal antibody significantly increased endotoxin-stimulated cytokine release by at least fourfold.

CONCLUSION

Macrophages were relatively insensitive to therapeutic levels of DEX and BETA with regard to PI cytokine release. This study provides rationale for translational and preclinical research using airway instillation of IL-10 for the treatment of BPD.

Steroids and injury to the developing brain: net harm or net benefit?

Deleterious effects result from both glucocorticoid insufficiency and excess glucocorticoid tissue exposure in the developing brain. Accumulating evidence suggests a net benefit of postnatal glucocorticoid therapy when administered shortly after the first week of life to premature infants with early and persistent pulmonary dysfunction, particularly in those with evidence of relative adrenal insufficiency. The decision to treat with steroids should ensure maximum respiratory benefit at the lowest possible neurologic risk, while avoiding serious systemic complications. Ongoing clinical trials must validate this approach.

Dopamine-resistant hypotension and severe retinopathy of prematurity

OBJECTIVE

To examine the relationship between the cause or severity of hypotension and the development of severe ROP (sROP) (≥stage 3 or stage 2 with plus disease in zone I or II).

STUDY DESIGN

Infants (<28 weeks' gestation, n = 242) were observed for hypotension and treated with a standardized hypotension-treatment protocol. Hypotension was classified as resulting from one of the following causes: (1) culture-positive infection and/or necrotizing enterocolitis; (2) patent ductus arteriosus ligation; or (3) "idiopathic" (no cause identified other than prematurity), and as being either dopamine responsive or dopamine resistant. Cortisol levels were measured for infants with dopamine-resistant hypotension. Eye examinations were performed until the retinopathy of prematurity resolved or the vasculature matured. Multivariable logistic regression analysis was performed to determine the relationship between the cause/severity of hypotension and sROP.

RESULTS

Overall, 66% of infants developed hypotension (41% were dopamine responsive and 25% were dopamine resistant). sROP developed in 19% of infants. "Idiopathic" dopamine-resistant hypotension was the only cause significantly related to sROP. Of the infants with dopamine-resistant hypotension, 66% had low serum cortisol (≤10 μg/dL). Low cortisol, in the presence of dopamine-resistant hypotension, was significantly associated with sROP and accounted for the relationship between "idiopathic" hypotension and sROP. When low cortisol was included in statistical models, other known risk factors, such as immature gestation, were no longer significantly related to sROP.

CONCLUSION

Low cortisol, in the presence of dopamine-resistant hypotension, has the greatest magnitude of association with sROP.

An update on pharmacologic approaches to bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is the most prevalent long-term morbidity in surviving extremely preterm infants and is linked to increased risk of reactive airways disease, pulmonary hypertension, post-neonatal mortality, and adverse neurodevelopmental outcomes. BPD affects approximately 20% of premature newborns, and up to 60% of premature infants born before completing 26 weeks of gestation. It is characterized by the need for assisted ventilation and/or supplemental oxygen at 36 weeks postmenstrual age. Approaches to prevention and treatment of BPD have evolved with improved understanding of its pathogenesis. This review will focus on recent advancements and detail current research in pharmacotherapy for BPD. The evidence for both current and potential future experimental therapies will be reviewed in detail. As our understanding of the complex and multifactorial pathophysiology of BPD changes, research into these current and future approaches must continue to evolve.

Novel treatments for NEC: keeping IBD in mind

Necrotizing enterocolitis (NEC) is an inflammatory intestinal disease of premature newborns, thought to result in part from overactivity of the innate immune system. NEC has been well-studied from the perspective of prevention; however, after the disease onset, there are limited treatment options to control its progression. This review discusses four potential therapies that target the overactive immune response in NEC: pentoxifylline, platelet activating factor modulators, glucocorticoids, and vasoactive substances. In addition, given the similar pathogenesis of NEC and inflammatory bowel disease (IBD), we propose that IBD therapies could provide promising leads for novel strategies with which to treat NEC.

Current pharmacologic approaches for prevention and treatment of bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is a major complication of preterm birth and has serious adverse long-term health consequences. The etiology of BPD is complex, multifactorial, and incompletely understood. Contributing factors include ventilator-induced lung injury, exposure to toxic oxygen levels, and infection. Several preventive and therapeutic strategies have been developed with variable success. These include lung protective ventilator strategies and pharmacological and nutritional interventions. These strategies target different components and stages of the disease process and they are commonly used in combination. The purpose of this review is to discuss the evidence for current pharmacological interventions and identify future therapeutic modalities that appear promising in the prevention and management of BPD. Continued improved understanding of BPD pathogenesis leads to opportunities for newer preventive approaches. These will need to be evaluated in the setting of current clinical practice in order to assess their efficacy.

Postnatal corticosteroids for prevention and treatment of chronic lung disease in the preterm newborn

Despite significant progress in the treatment of preterm neonates, bronchopulmonary dysplasia (BPD) continues to be a major cause of neonatal morbidity. Affected infants suffered from long-term pulmonary and nonpulmonary sequel. The pulmonary sequels include reactive airway disease and asthma during childhood and adolescence. Nonpulmonary sequels include poor coordination and muscle tone, difficulty in walking, vision and hearing problems, delayed cognitive development, and poor academic achievement. As inflammation seems to be a primary mediator of injury in pathogenesis of BPD, role of steroids as antiinflammatory agent has been extensively studied and proven to be efficacious in management. However, evidence is insufficient to make a recommendation regarding other glucocorticoid doses and preparations. Numerous studies have been performed to investigate the effects of steroid. The purpose of this paper is to evaluate these studies in order to elucidate the beneficial and harmful effects of steroid on the prevention and treatment of BPD.

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.

Oxidative stress in the developing brain: effects of postnatal glucocorticoid therapy and antioxidants in the rat

In premature infants, glucocorticoids ameliorate chronic lung disease, but have adverse effects on long-term neurological function. Glucocorticoid excess promotes free radical overproduction. We hypothesised that the adverse effects of postnatal glucocorticoid therapy on the developing brain are secondary to oxidative stress and that antioxidant treatment would diminish unwanted effects. Male rat pups received a clinically-relevant tapering course of dexamethasone (DEX; 0.5, 0.3, and 0.1 mg.kg⁻¹.day⁻¹), with or without antioxidant vitamins C and E (DEXCE; 200 mg.kg⁻¹.day⁻¹ and 100 mg.kg⁻¹.day⁻¹, respectively), on postnatal days 1–6 (P1–6). Controls received saline or saline with vitamins. At weaning, relative to controls, DEX decreased total brain volume (704.4±34.7 mm³ vs. 564.0±20.0 mm³), the soma volume of neurons in the CA1 (1172.6±30.4 µm³ vs. 1002.4±11.8 µm³) and in the dentate gyrus (525.9±27.2 µm³ vs. 421.5±24.6 µm³) of the hippocampus, and induced oxidative stress in the cortex (protein expression: heat shock protein 70 [Hsp70]: +68%; 4-hydroxynonenal [4-HNE]: +118% and nitrotyrosine [NT]: +20%). Dexamethasone in combination with vitamins resulted in improvements in total brain volume (637.5±43.1 mm³), and soma volume of neurons in the CA1 (1157.5±42.4 µm³) and the dentate gyrus (536.1±27.2 µm³). Hsp70 protein expression was unaltered in the cortex (+9%), however, 4-HNE (+95%) and NT (+24%) protein expression remained upregulated. Treatment of neonates with vitamins alone induced oxidative stress in the cortex (Hsp70: +67%; 4-HNE: +73%; NT: +22%) and in the hippocampus (NT: +35%). Combined glucocorticoid and antioxidant therapy in premature infants may be safer for the developing brain than glucocorticoids alone in the treatment of chronic lung disease. However, antioxidant therapy in healthy offspring is not recommended.

Nephrocalcinosis in preterm neonates

The prevalence of nephrocalcinosis (NC) in preterm neonates in recent reports is 7-41%. The wide range in prevalence is a consequence of different study populations and ultrasound equipment and criteria, in addition to a moderate interobserver variation. NC in preterm neonates has a multifactorial aetiology, consisting of low gestational age and birth weight, often in combination with severe respiratory disease, and occurs as a result of an imbalance between stone-promoting and stone-inhibiting factors. A limited number of histological studies suggest that calcium oxalate crystals play an important role in NC in premature neonates. In 85% of children resolution of NC occurs in the first years of life. Prematurity, per se, is associated with high blood pressure, relatively small kidneys, and (distal) tubular dysfunction. In addition, NC in preterm neonates can have long-term sequelae for glomerular and tubular function. Long-term follow-up of blood pressure and renal function of prematurely born children, especially with neonatal NC, is recommended. Prevention of NC with (low) oral doses of citrate has not resulted in a significant decrease in the prevalence of NC; a higher citrate dosage deserves further study. Future research pertaining to prevention of NC in preterm neonates is crucial.

Time-related changes in steroid use and bronchopulmonary dysplasia in preterm infants

OBJECTIVE

To assess dexamethasone (DEX) and hydrocortisone (HC) use in premature infants over time and the association of steroid use with the incidence of bronchopulmonary dysplasia (BPD) at 36 weeks' postmenstrual age.

METHODS

We analyzed data from the Pediatrix database for neonates of 23 to 32 weeks' gestation managed during 1997-2006 (N = 77520). We compared the use of DEX, HC and BPD (defined by oxygen use at 36 weeks' postmenstrual age) according to year and estimated gestational age. Mantel-Haenszel chi(2) was used to compare the trends in steroid use and BPD rates according to year.

RESULTS

There were no differences by year in the proportion of births at each gestation or in early or late neonatal death. DEX use decreased from a peak of 25.0% in 1998 to 6.8% in 2006, but HC use increased from 1.1% in 1997 to a peak of 6.5% in 2006. The median age at initiation of DEX use increased >2 weeks from 1997 to 2006. BPD rates increased from 19% in 1997 to 25% by 2006. Rates for severe BPD (defined by positive pressure support) also increased significantly over time. Between 23 and 28 weeks, there was a significant increase in BPD rates associated with the decrease in DEX over time.

CONCLUSIONS

Steroid use and preference have changed significantly over the past decade. Decreased use of DEX was associated with increased rates of BPD, any or severe, among very preterm infants. Well-designed, randomized, noncrossover trials with long-term outcome analysis of high-risk infants are needed.

Pitfalls, problems, and progress in bronchopulmonary dysplasia

Bronchopulmonary dysplasia is a chronic lung disease associated with premature birth and characterized by early lung injury. In this review we discuss some pitfalls, problems, and progress in this condition over the last decade, focusing mainly on the last 5 years, limited to studies in human neonates. Changes in the definition, pathogenesis, genetic susceptibility, and recent biomarkers associated with bronchopulmonary dysplasia will be discussed. Progress in current management strategies, along with novel approaches/therapies, will be critically appraised. Finally, recent data on long-term pulmonary and neurodevelopmental outcomes of infants with bronchopulmonary dysplasia will be summarized.

Glucocorticoids and neonatal brain injury: the hedgehog connection

Glucocorticoids (GCs) play a critical role in neural development; however, their prenatal or neonatal therapeutic use can have detrimental effects on the developing brain. In this issue of the JCI, Heine and Rowitch report that the molecular mechanisms underlying these detrimental effects involve the sonic hedgehog (Shh) signaling pathway, a crucial regulator of brain development and neural stem/progenitor cells (see the related study beginning on page 267). They show that GCs suppress Shh-induced proliferation of cerebellar progenitor cells in postnatal mice and that, conversely, Shh signaling is protective against GC-induced neonatal cerebellar injury by inducing the enzyme 11betaHSD2, which inactivates the GCs corticosterone and prednisolone, but not dexamethasone. The data provide a rationale for the therapeutic use of 11betaHSD2-sensitive GCs, but not dexamethasone, or for the exploitation of the neuroprotective effect of Shh agonists to prevent GC-induced pre- or neonatal brain injury.

Postnatal corticosteroids for bronchopulmonary dysplasia

Corticosteroids are used to improve lung function in infants who are progressing toward bronchopulmonary dysplasia. Corticosteroids facilitate extubation, but there is conflicting information about adverse effects on the developing brain. An approach to minimizing risk is to use low-dose, short-duration treatments in the highest risk ventilator-dependent patients. Questions remain about which corticosteroid is the safest and how to dose that corticosteroid.

Impact of postnatal corticosteroid use on neurodevelopment at 18 to 22 months' adjusted age: effects of dose, timing, and risk of bronchopulmonary dysplasia in extremely low birth weight infants

OBJECTIVE

Postnatal steroid use decreases lung inflammation but increases impairment. We hypothesized that increased dose is associated with increased neurodevelopmental impairment, lower postmenstrual age at exposure increases impairment, and risk of bronchopulmonary dysplasia modifies the effect of postnatal corticosteroid.

METHODS

Steroid dose and timing of exposure beyond 7 days was assessed among 2358 extremely low birth weight infants nested in a prospective trial, with 1667 (84%) survivors examined at 18 to 22 months' postmenstrual age. Logistic regression tested the relationship between impairment (Bayley Mental Developmental Index/Psychomotor Developmental Index of <70, disabling cerebral palsy, or sensory impairment), total dose (tertiles: <0.9, 0.9-1.9, and >/=1.9 mg/kg), and postmenstrual age at first dose. Separate logistic regression tested effect modification according to bronchopulmonary dysplasia severity (Romagnoli risk > 0.5 as high risk, n = 2336 (99%) for days of life 4-7).

RESULTS

Three hundred sixty-six (16%) neonates were steroid-treated (94% dexamethasone). Treated neonates were smaller and less mature; 72% of those treated were at high risk for bronchopulmonary dysplasia. Exposure was associated with neurodevelopmental impairment/death. Impairment increased with higher dose; 71% dead or impaired at highest dose tertile. Each 1 mg/kg dose was associated with a 2.0-point reduction on the Mental Developmental Index and a 40% risk increase for disabling cerebral palsy. Older age did not mitigate the harm. Treatment after 33 weeks' postmenstrual age was associated with greatest harm despite not receiving the highest dose. The relationship between steroid exposure and impairment was modified by the bronchopulmonary dysplasia risk, with those at highest risk experiencing less harm.

CONCLUSIONS

Higher steroid dose was associated with increased neurodevelopmental impairment. There is no "safe" window for steroid use in extremely low birth weight infants. Neonates with low bronchopulmonary dysplasia risk should not be exposed. A randomized trial of steroid use in infants at highest risk is warranted.

Finding the optimal postnatal dexamethasone regimen for preterm infants at risk of bronchopulmonary dysplasia: a systematic review of placebo-controlled trials

CONTEXT

Postnatal dexamethasone therapy reduces the incidence of bronchopulmonary dysplasia in preterm infants but may be associated with an increased risk for adverse neurodevelopmental outcome.

OBJECTIVE

Our goal was to determine if the effects of dexamethasone on mortality and pulmonary and neurodevelopmental sequelae in preterm infants are modified by the cumulative dose given.

METHODS

Randomized, controlled trials comparing dexamethasone with placebo in ventilated preterm infants >7 days old were identified by searching the electronic databases and the abstracts from the Pediatric Academic societies and by performing manual reference searches. Two reviewers independently assessed eligibility and quality of trials and extracted data on study design, patient characteristics, and relevant outcomes. Original trialists were asked to provide additional data.

RESULTS

Sixteen trials including 1136 patients were analyzed by using meta-analysis and metaregression. Additional data were provided by 12 original trialists. Trials with a moderately early (7- to 14-day) or delayed (>3-week) postnatal treatment onset were analyzed separately. Higher dexamethasone doses reduced the relative risk for the combined outcome, mortality or bronchopulmonary dysplasia, with the largest effect in trials that used a cumulative dose of >4 mg/kg. No effect was found of doses on the risk of neurodevelopmental sequelae in the delayed treatment studies, but in the moderately-early-treatment studies the risk of mortality or cerebral palsy decreased by 6.2%, and the risk of a Mental Developmental Index below -2 SDs decreased by 6.6% for each incremental mg/kg cumulative dexamethasone dose.

CONCLUSIONS

Higher cumulative dexamethasone doses administered after the first week of life may decrease the risk for bronchopulmonary dysplasia without increasing the risk for neurodevelopmental sequelae in ventilated preterm infants. A large randomized trial is needed to confirm or refute these findings.

Pulmonary diseases and corticosteroids

Steroids (corticosteroids) are anti-inflammatory drugs. Corticosteroids are used in many pulmonary conditions. Corticosteroids have a proven beneficial role in asthma, croup (Laryngotracheobronchitis), decreasing the risk and severity of respiratory distress syndrome (RDS), allergic bronchopulmonary aspergillosis, interstitial lung disease, hemangioma of trachea, Pulmonary eosinophillic disorders. Role of corticosteroids is controversial in many conditions e.g. idiopathic pulmonary hemosiderosis, bronchiolitis, hypersensitivity pneumonitis, hyperplasia of thymus, bronchiolitis, acute respiratory distress syndrome, aspiration syndromes, atypical pneumonias, laryngeal diphtheria, AIDS, SARS, sarcoidosis, meconium aspiration syndrome (MAS), pulmonary haemorrhage, bronchitis, bronchiolitis obliterans with organizing pneumonia in JRA, histiocytosis, alpha-1 antitrypsin deficiency, bordtella pertusis, pulmonary involvement in histiocytosis. However these are used empirically in many of these conditions despite lack of clear evidence in favour. There is concern about their side effects, especially on growth. Systemic steroids are associated with significant adverse effects. Pulmonary conditions have a strategic advantage that inhaled corticosteroids are useful in many of these. Although inhaled preparations of corticosteroids have been developed to maximise effective treatment of lung diseases characterised by inflammation and reduce the frequency of harmful effects, these have not been eliminated. There are situations where only systemic steroids are useful. Clinicians must weigh the benefits against the potential detrimental effects. It is recommended that standard protocols for use of steroids available in literature should be followed, always keeping a watch on the potential hazards of prolonged use.

Effects of higher versus lower dexamethasone doses on pulmonary and neurodevelopmental sequelae in preterm infants at risk for chronic lung disease: a meta-analysis

OBJECTIVES

Systemic postnatal dexamethasone treatment reduces the risk of chronic lung disease in preterm infants but also may be associated with increased risk of neurodevelopmental impairment. Because it is not known whether these effects are modulated by the cumulative dexamethasone dose, we systematically reviewed the available randomized evidence on the effects of lower versus higher cumulative dexamethasone doses, in terms of death, pulmonary morbidity, and neurodevelopmental outcomes, in preterm infants.

METHODS

Randomized, controlled trials comparing higher- versus lower-dosage dexamethasone regimens in ventilated preterm infants were identified by searching the main electronic databases, references from relevant studies, and abstracts from the Societies for Pediatric Research (from 1990 onward). Eligibility and quality of trials were assessed, and data on study design, patient characteristics, and relevant outcomes were extracted.

RESULTS

Six studies that enrolled a total of 209 participants were included; 2 studies contrasted cumulative dexamethasone doses in the higher ranges (>2.7 mg/kg in the higher-dosage regimen) and 4 in the lower ranges (<or=2.7 mg/kg in the higher-dosage regimen). Meta-analysis revealed no effect of dexamethasone dose on rates of death and neurodevelopmental sequelae in these 2 subgroups. Subgroup analysis of the studies contrasting dexamethasone doses in the higher ranges showed that the higher dose of dexamethasone was more effective in reducing the occurrence of chronic lung disease than was the lower dose. Interpretation of these data was hampered by the small samples of randomly assigned children, heterogeneity of study populations and designs, use of late rescue glucocorticoids, and lack of long-term neurodevelopmental data in some studies.

CONCLUSIONS

Recommendations for optimal dexamethasone doses for preterm infants at risk for chronic lung disease cannot be based on current evidence. A well-designed, large, randomized, controlled trial is urgently needed to establish the optimal dexamethasone dosage regimen.

Cumulative perinatal steroids: child development of preterm infants

The development of premature infants may be altered due to exposure to high cumulative doses of the perinatal corticosteroid dexamethasone during critical growth periods. To compare child behavioral development of prematurely born infants who were exposed to higher perinatal steroids (PNS; >0.2 mg/kg) with that of infants exposed to lower PNS ( Collapse

Key Words

• perinatal steroids
• dexamethasone
• preterm infants
• neurodevelopment

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MESH Headings

• Adult
• Analysis of Variance
• Anthropometry
• Chi-Square Distribution
• Child
• Developmental Disabilities/chemically induced
• Developmental Disabilities/diagnosis
• Developmental Disabilities/epidemiology
• Dexamethasone/administration & dosage
• Dexamethasone/adverse effects
• Female
• Glucocorticoids/administration & dosage
• Glucocorticoids/adverse effects
• Humans
• Infant, Newborn
• Intensive Care, Neonatal
• Male
• Morbidity
• Obstetric Labor, Premature/drug therapy
• Parents/psychology
• Perinatal Care
• Pregnancy
• Prospective Studies
• Regression Analysis
• Risk Factors
• Severity of Illness Index
• Surveys and Questionnaires
• Treatment Outcome

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Grants

• T32 NR007077 NINR NIH HHS
• T32 NR007077-05 NINR NIH HHS

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Affiliation(s)

Isabell B Purdy University of California, Los Angeles, CA 90095-1752, USA.
Dorothy J Wiley
Lynne M Smith
Carollee Howes
Anna Gawlinski
Wendy Robbins
Lina K Badr

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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.

Effect of a short course of prednisolone in infants with oxygen-dependent bronchopulmonary dysplasia

OBJECTIVE

The purpose of this work was to determine whether oral prednisolone is effective in weaning infants with bronchopulmonary dysplasia, after 36 weeks' postmenstrual age, off supplemental oxygen and to identify factors associated with successful weaning.

METHODS

Data were abstracted from a standardized prospectively collected database at the John Dempsey Hospital NICU. Logistic regression and receiver operating curve analyses were used.

RESULTS

Of 385 infants, 131 (34%) received oral prednisolone and 254 (66%) did not. There was no significant difference in race, gender, birth weight, or gestational age between the groups receiving and not receiving oral prednisolone. Infants in the oral prednisolone group were more likely to have received previous dexamethasone therapy, had longer duration of mechanical ventilation, had longer length of hospital stay, and were more likely to be discharged from the hospital on oxygen. Of those in the oral prednisolone group, 63% responded to treatment. Pulmonary acuity score and PCO2 were the only parameters that remained significant on multiple logistic regression analyses. The oral prednisolone-responsive group had a lower pulmonary acuity score compared with the oral prednisolone-nonresponsive group. A pulmonary acuity score value of < or = 0.5 had a sensitivity of 20% and specificity of 97.4%, with positive and negative predictive values of 94.1% and 42.1%, respectively. Capillary PCO2 values were significantly lower in the oral prednisolone-responsive group compared with the oral prednisolone-nonresponsive group. In predicting a successful response to oral prednisolone, a capillary PCO2 value of < 48.5 mmHg had a sensitivity of 50% and specificity of 89.7%, with positive and negative predictive values of 89.1% and 51.8%, respectively.

CONCLUSIONS

Oral prednisolone therapy is effective in weaning off supplemental oxygen in a postterm infant with oxygen-dependent bronchopulmonary dysplasia who has a pulmonary acuity score of < 0.5 and PCO2 of < 48.5 mmHg. In addition, if a single course of prednisolone fails, there is no clear benefit of using multiple courses.

Outcomes of extremely low birth weight (<1 kg) and extremely low gestational age (<28 weeks) infants with bronchopulmonary dysplasia: effects of practice changes in 2000 to 2003

OBJECTIVE

The goal was to evaluate whether changes in neonatal intensive care have improved outcomes for children with bronchopulmonary dysplasia (oxygen dependence at corrected age of 36 weeks).

METHODS

We compared outcomes of extremely low birth weight (<1 kg) and extremely low gestational age (<28 weeks) infants with bronchopulmonary dysplasia between 2 periods (period I, 1996-1999: extremely low birth weight, n = 122; extremely low gestational age, n = 118; period II, 2000-2003: extremely low birth weight, n = 109; extremely low gestational age, n = 107).

RESULTS

For both groups, significant practice changes between period I and period II included increased prenatal and decreased postnatal steroid therapy and increased surfactant therapy, indomethacin therapy, and patent ductus arteriosus ligation. Significant morbidity changes included decreased rates of severe cranial ultrasound abnormalities and increased rates of ventilator dependence. Rates of bronchopulmonary dysplasia did not change (52% vs 53%). Follow-up evaluation revealed significantly lower rates of neurosensory abnormalities during period II (extremely low birth weight: 29% vs 16%; extremely low gestational age: 31% vs 16%). There were no changes in rates of Mental Developmental Index scores of <70 (extremely low birth weight: 42% vs 42%; extremely low gestational age: 37% vs 45%) or overall developmental impairment (extremely low birth weight: 51% vs 49%; extremely low gestational age: 50% vs 51%). For the extremely low gestational age group, predictors of neurosensory abnormalities were severe cranial ultrasound abnormality and postnatal steroid therapy. Predictors of overall impairment included severe cranial ultrasound abnormalities, ventilator dependence, postnatal steroid therapy, and patent ductus arteriosus ligation. For the extremely low birth weight group, the only predictor of neurosensory abnormalities was severe cranial ultrasound abnormality. Predictors of overall impairment included multiple birth, ventilator dependence, and severe cranial ultrasound abnormalities.

CONCLUSIONS

Neurosensory outcomes of infants with bronchopulmonary dysplasia improved during 2000 to 2003 but overall neurodevelopmental outcomes did not change.

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.

Follow-up of a randomized, placebo-controlled trial of dexamethasone to decrease the duration of ventilator dependency in very low birth weight infants: neurodevelopmental outcomes at 4 to 11 years of age

OBJECTIVE

High doses of dexamethasone reduce the risk of chronic lung disease among premature infants but may increase the risk of developmental impairments. The objective of this study was to compare developmental outcomes beyond infancy for children who, as neonates, participated in a randomized trial of dexamethasone.

PATIENTS AND METHODS

One hundred eighteen children with birth weights <1500 g were randomly assigned at 15 to 25 days of life to a 42-day tapering course of dexamethasone or placebo. All 95 survivors were assessed by using standardized measures of developmental outcome at least once at or beyond 1 year of age, and 84 were examined at 4 to 11 years. For this follow-up study, the outcome of primary interest was death or major neurodevelopmental impairment, which was defined as cerebral palsy, cognitive impairment, or blindness.

RESULTS

On the basis of each child's most recent follow-up, the rates of major neurodevelopmental impairments were 40% for the dexamethasone group and 20% for the placebo group. The higher impairment rate for the dexamethasone group was mainly attributed to a higher prevalence of cerebral palsy. Rates of the composite outcome of death or major neurodevelopmental impairment were 47% and 41%, respectively.

CONCLUSION

A 42-day tapering course of dexamethasone, which was shown previously to decrease the risk of chronic lung disease in very low birth weight infants, does not increase the risk of the composite outcome of death or major neurodevelopmental impairment.

Are postnatal steroids ever justified to treat severe bronchopulmonary dysplasia?

Current evidence does not favour use of corticosteroids as neurological side effects may outweigh the benefits of treatment, except perhaps in critically ill infants with respiratory failure

Follow-up study of a randomized controlled trial of postnatal dexamethasone therapy in very low birth weight infants: effects on pulmonary outcomes at age 8 to 11 years

OBJECTIVE

To determine whether postnatal dexamethasone (DEX) exposure affects pulmonary outcomes at school age in children born with very low birth weight (VLBW).

STUDY DESIGN

Follow-up study of 68 VLBW children who participated in a randomized controlled trial of postnatal DEX. Pulmonary function was assessed by spirometry. Current asthma status was obtained from a parent.

RESULTS

Sixty-eight percent of the placebo group had below-normal forced expiratory volume in 1 second (FEV1), compared with 40% of the DEX group (chi2 = 4.84; P = .03), with trends for lower forced vital capacity (FVC) and FEV1 values in the placebo group. Fifty percent of the placebo group and 34% of DEX group had below normal FEV1/FVC (chi2 =1.59; P =.21). Parent-reported prevalence of asthma did not differ between groups. Logistic regression analysis suggested that the positive effects of DEX on pulmonary function at follow-up were mediated in part by shortened exposure to mechanical ventilation.

CONCLUSIONS

Postnatal DEX exposure was associated with higher expiratory flow with no adverse effects on pulmonary outcomes at school age. The prevalences of asthma and impaired pulmonary function underscore the influence of neonatal illness on health at school age, and stress the importance of repeated follow-up examinations of these children.

Outcome at 2 years of age of infants from the DART study: a multicenter, international, randomized, controlled trial of low-dose dexamethasone

OBJECTIVE

Low-dose dexamethasone facilitates extubation in chronically ventilator-dependent infants with no obvious short-term complications. The objective of this study was to determine the long-term effects of low-dose dexamethasone.

METHODS

Very preterm (<28 weeks' gestation) or extremely low birth weight (birth weight <1000 g) infants who were ventilator dependent after the first week of life for whom clinicians considered corticosteroids were indicated were eligible. After informed consent, infants were randomly assigned to masked dexamethasone (0.89 mg/kg over 10 days) or saline placebo. Survivors were assessed at 2 years' corrected age by staff blinded to treatment group allocation to determine neurosensory outcome, growth, and health.

RESULTS

The trial was abandoned well short of its target sample size because of recruitment difficulties. Seventy infants were recruited from 11 centers, 35 in each group: 59 survived to 2 years of age, and 58 (98%) were assessed at follow-up, but data for cerebral palsy were available for only 56 survivors. There was little evidence for a difference in the major end point, the rate of the combined outcome of death, or major disability at 2 years of age (dexamethasone group: 46%; controls: 43%). Rates of mortality before follow-up (11% vs 20%), major disability (41% vs 31%), cerebral palsy (14% vs 22%), or of the combined outcomes of death or cerebral palsy (23% vs 37%) were not substantially different between the groups. There were no obvious effects of low-dose dexamethasone on growth or readmissions to hospital after discharge.

CONCLUSIONS

Although this trial was not able to provide definitive evidence on the long-term effects of low-dose dexamethasone after the first week of life in chronically ventilator-dependent infants, our data indicate no strong association with long-term morbidity.

A scoring system to predict chronic oxygen dependency

INTRODUCTION

Chronic oxygen dependency (COD) is a common adverse outcome of very premature birth. It is, therefore, important to develop an accurate and simple predictive test to facilitate targeting of interventions to prevent COD. Our aim was to determine if a simple score based on respiratory support requirements predicted COD development.

METHODS

A retrospective study of 136 infants, median gestation age (GA) 28 weeks (range: 23-33 weeks) and a prospective study of 75 infants, median GA 30 weeks (range: 23-32 weeks), were performed. The score was calculated by multiplying the inspired oxygen concentration by the level of respiratory support (mechanical ventilation: 2.5; continuous positive airway pressure: 1.5; nasal cannula or head box oxygen or air: 1.0). Scores were calculated on data from days 2 and 7, and their predictive ability compared to that of the maximum inspired oxygen concentration at those ages and (retrospective study) the results of lung volume measurement.

RESULTS

Infants that were oxygen dependent at 28 days and 36 weeks post-menstrual age (PMA) had higher scores on days 2 (p<0.0001, p<0.0001, respectively) and 7 (p<0.0001, p<0.0001, respectively) than the non-oxygen dependent infants in both the retrospective and prospective cohorts. Construction of receiver operator characteristic curves demonstrated the score performed better than the inspired oxygen level and lung volume measurement results. A score on day 7 >0.323 had 95% specificity and 78% sensitivity in predicting COD at 28 days, and 80% specificity and 73% sensitivity in predicting COD at 36 weeks PMA.

CONCLUSION

Chronic oxygen dependency can be predicted using a simple scoring system.

Minimising neonatal brain injury: how research in the past five years has changed my clinical practice

With improving neonatal survival for extremely premature babies, the challenge for neonatology is to improve outcome of surviving babies. This review concentrates on best evidence emerging in recent years on prevention of brain damage by early administration of drugs as well as avoidance of induced brain damage by hyperventilation and dexamethasone therapy given postnatally for chronic lung disease.

Bronchopulmonary dysplasia: an update

Bronchopulmonary dysplasia (BPD) is a chronic lung disease associated with premature birth and characterized by early lung injury. Over the past 4 decades, there have been significant changes in its definition, pathology and radiological findings as well as management of BPD. Management of the acute phase and later stages of this lung disease continue to evolve. Use of non-invasive ventilatory techniques, recombinant human SOD and CC10 and inhaled NO are some novel approaches that are being studied. Adequate nutrition is vital to optimize lung growth and repair. The widely accepted practice of prophylaxis against viral infections has markedly decreased the rates of rehospitalization. Infants with BPD, however, continue to have significant pulmonary and neurodevelopmental sequelae. Unraveling the genetic contribution to BPD will potentially pave the way to improved preventive and therapeutic approaches.

Changes in the use of postnatal steroids for bronchopulmonary dysplasia in 3 large neonatal networks

BACKGROUND

Postnatal corticosteroids were widely used in the 1990s in an attempt to reduce the incidence of bronchopulmonary dysplasia. However, high rates of short-term adverse effects and impaired neurodevelopmental outcomes were seen. In early 2002, a joint statement of the American Academy of Pediatrics and Canadian Paediatric Society called for limitation in the use of postnatal corticosteroids. The impact of this statement is not known.

OBJECTIVES

The purpose of this work was to determine the frequency of postnatal corticosteroid use and mortality and morbidities over time, particularly before and after the joint statement.

DESIGN/METHODS

We conducted a retrospective analysis of cohort data within 3 large network registries (the National Institute of Child Health and Development Neonatal Research Network [18 centers], the Vermont Oxford Network [444 centers], and the Canadian Neonatal Network [10 centers]) for the following 3 periods: prestatement (2001), statement (2002), and poststatement (2003) of very low birth-weight infants (501-1500 g). The National Institute of Child Health and Development Neonatal Research Network and the Vermont Oxford Network were also analyzed for longer-term trends from 1990 to 2003. Postnatal corticosteroid use, mortality at discharge, and neonatal morbidities (bronchopulmonary dysplasia at 36 weeks, late-onset infection >72 hours of age, necrotizing enterocolitis treated with surgery, and length of stay) between periods were compared.

RESULTS

Mean birth weight (range: 1022-1060 g), postmenstrual age (28 weeks), and gender (51% male) were similar between the networks. Race differed with more black infants in the National Institute of Child Health and Development Neonatal Research Network than the Vermont Oxford Network (38% vs 24%). Antenatal steroid use was similar (range: 61%-75%). Postnatal corticosteroid use rose from 1990 (8%-16%), peaked in 1996-1998 (24%-28%), and began to decline in 1999. Use in 2003 was significantly less than in 2001. Mortality and major morbidities were similar.

CONCLUSIONS

Postnatal corticosteroid use had decreased significantly in 3 large neonatal networks before the joint statement with further decreases after the statement with no apparent impact on mortality and short-term morbidity. Despite substantial decreases, approximately 8% of very low birth-weight infants continue to be treated with postnatal corticosteroid.

Increased energy intake for preterm infants with (or developing) bronchopulmonary dysplasia/ chronic lung disease

BACKGROUND

Preterm infants with bronchopulmonary dysplasia/chronic lung disease have nutritional deficits that may contribute to short and long term morbidity and mortality. Increasing the daily energy intake for these infants may improve their respiratory, growth and neurodevelopmental outcomes.

OBJECTIVES

To assess the effect of increased energy intake on mortality and respiratory, growth and neurodevelopmental outcomes for preterm infants with (or developing) CLD/BPD. Secondarily, the review examines any adverse effects associated with increased energy intake.

SEARCH STRATEGY

The standard search strategy of the Cochrane Neonatal Review Group was used. This included searches of the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 1, 2006) , MEDLINE (accessed via Ovid), references cited in previous relevant Cochrane reviews and in other relevant studies, review articles, standard textbooks, and manuals of neonatal medicine. Hand search results of the Cochrane Neonatal Review Group were also assessed.

SELECTION CRITERIA

All randomized and quasi-randomized trials comparing the outcomes of preterm infants with (or developing) CLD/BPD who had either increased (> 135 kcal/kg/day) or standard energy intake (98 to 135 kcal/kg/day). Increasing energy intake might be achieved enterally and/or parenterally, enterally by increasing the energy content of the milk, increasing feed volume, or by nutrient supplementation with protein, carbohydrate or fat. The primary outcomes were the development of CLD and neonatal mortality; secondary outcomes included respiratory morbidities, growth, neurodevelopmental status and possible complications with increased energy intake.

DATA COLLECTION AND ANALYSIS

We planned to extract data using the standard methods of the Cochrane Neonatal Review Group. Relevant trials would be scrutinized for methodological quality independently by the reviewers to determine their eligibility for inclusion. Data of the included trials would be expressed as relative risk, risk difference, NNT and weighted mean difference where appropriate, using a fixed effect model.

MAIN RESULTS

No eligible trials were identified. Twelve studies that appeared to be relevant were excluded, as no study directly compared increased versus standard energy intakes in infants with CLD/BPD. However, two excluded trials provided some insights into the topic. One study showed that infants with CLD/BPD who were fed formula enriched with protein and minerals had improved growth parameters up until the cessation of the intervention at three months of corrected age. The other study compared different energy density of formula but identical energy intake by setting different feed volumes for both groups. It showed that both groups were unable to achieve the pre-designated feed volumes, and that there were no differences in growth, respiratory outcomes, oedema and the diuretic requirements.

AUTHORS' CONCLUSIONS

To date, no randomized controlled trials are available that examine the effects of increased versus standard energy intake for preterm infants with (or developing) CLD/BPD. Research should be directed at evaluating the effects of various levels of energy intake on this group of infants on clinically important outcomes like mortality, respiratory status, growth and neurodevelopment. The benefits and harms of various ways of increasing energy intake, including higher energy density of milk feed and/or fluid volume (clinically realistic target volume should be set), parenteral nutrition, and the use of various constituents of energy like carbohydrate, protein and fat for this purpose also need to be assessed.

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.

Lung disease and brain development

With the technical progress made in fetal and neonatal intensive care, perinatal mortality has decreased by 25% over the last decade and has expanded the surviving premature population. Prematurity drastically changes the environment of the developing organism. Striking evidence from a number of disciplines has focused attention on the interplay between the developing organism and the circumstances in which it finds itself. The environmental event during a sensitive period in development, induces injury and/or biological adaptations that lead to altered differentiation of tissues. The organism can express specific adaptive responses to its environment which include short-term changes in physiology as well as long-term adjustments. This review addresses these short-term as well as longer-term changes occurring in lung and brain tissue and illustrates how these changes can be studied using advanced imaging techniques such as magnetic resonance imaging

Long term effects of antenatal betamethasone on lung function: 30 year follow up of a randomised controlled trial

BACKGROUND

Antenatal betamethasone is routinely used for the prevention of neonatal respiratory distress syndrome in preterm infants. However, little is known of the long term effects of exposure to antenatal betamethasone on lung function in adulthood.

METHODS

Five hundred and thirty four 30 year olds whose mothers had participated in the first and largest randomised controlled trial of antenatal betamethasone were followed. Lung function was assessed by portable spirometric testing. The prevalence of asthma symptoms was assessed using the European Community Respiratory Health Survey questionnaire.

RESULTS

Fifty (20%) betamethasone exposed and 53 (19%) placebo exposed participants met the criteria for current asthma (relative risk 0.98 (95% CI 0.74 to 1.30), p = 0.89). 181 betamethasone exposed and 202 placebo exposed participants had acceptable spirometric data. There were no differences in lung function between betamethasone and placebo exposed groups (mean (SD) forced vital capacity in the betamethasone and placebo groups 105.9 (12.0) v 106.6 (12.6)% predicted, difference = -0.7 (95% CI -3.2 to 1.8), p = 0.59; mean (SD) forced expiratory volume in 1 second in the betamethasone and placebo groups 98.9 (13.4) v 98.5 (13.6)% predicted, difference = 0.3 (95% CI -2.4 to 3.1, p = 0.80)).

CONCLUSIONS

Antenatal exposure to a single course of betamethasone does not alter lung function or the prevalence of wheeze and asthma at age 30.

Growth in the neonatal intensive care unit influences neurodevelopmental and growth outcomes of extremely low birth weight infants

OBJECTIVES

The objectives of this study were to assess whether (1) in-hospital growth velocity is predictive of neurodevelopmental and growth outcomes at 18 to 22 months' corrected age among extremely low birth weight (ELBW) infants and (2) in-hospital growth velocity contributes to these outcomes after controlling for confounding demographic and clinical variables.

METHODS

Infants 501 to 1000 g birth weight from a multicenter cohort study were divided into quartiles of in-hospital growth velocity rates. Variables considered for the logistic-regression models included gender, race, gestational age, small for gestational age, mother's education, severe intraventricular hemorrhage, periventricular leukomalacia, age at regaining birth weight, necrotizing enterocolitis, late-onset infection, bronchopulmonary dysplasia, postnatal steroid therapy for pulmonary disease, and center.

RESULTS

Of the 600 discharged infants, 495 (83%) were evaluated at 18 to 22 months' corrected age. As the rate of weight gain increased between quartile 1 and quartile 4, from 12.0 to 21.2 g/kg per day, the incidence of cerebral palsy, Bayley II Mental Developmental Index (MDI) <70 and Psychomotor Developmental Index (PDI) <70, abnormal neurologic examination, neurodevelopmental impairment, and need for rehospitalization fell significantly. Similar findings were observed as the rate of head circumference growth increased. The in-hospital rate of growth was associated with the likelihood of anthropometric measurements at 18 months' corrected age below the 10th percentile values of the Centers for Disease Control and Prevention 2000 growth curve. Logistic-regression analyses, controlling for potential demographic or clinical cofounders, and adjusted for center, identified a significant relationship between growth velocity and the likelihood of cerebral palsy, MDI and PDI scores of <70, and neurodevelopmental impairment.

CONCLUSIONS

These analyses suggest that growth velocity during an ELBW infant's NICU hospitalization exerts a significant, and possibly independent, effect on neurodevelopmental and growth outcomes at 18 to 22 months' corrected age.