Beneficial effects of the combined use of prenatal corticosteroids and postnatal surfactant on preterm infants

Trends in Procedures in the Neonatal Intensive Care Unit

OBJECTIVE

The aim of the study is to identify the rates and trends of various procedures performed on newborns.

STUDY DESIGN

The Healthcare Cost and Utilization Project (HCUP) database for the years 2002 to 2015 was queried for the number of livebirths, and various procedures using International Classification of Diseases, Ninth Revision (ICD-9) codes. These were adjusted to the rate of livebirths in each particular year. A hypothetical high-volume hospital based on data from the last 5 years was used to estimate the frequency of each procedure.

RESULTS

Over the study period, there was a decline in the rates of exchange transfusions and placement of arterial catheters. There was an increase in the rates of thoracentesis, abdominal paracentesis, placement of umbilical venous catheter (UVC) lines, and central lines with ultrasound or fluoroscopic guidance. No change was observed in the rates of unguided central lines, pericardiocentesis, bladder aspiration, intubations, and LP. Intubations were the most performed procedures. Placement of UVC, central venous lines (including PICCs), arterial catheters, and LP were relatively common, whereas others were rare such as pericardiocentesis and paracentesis.

CONCLUSION

Some potentially lifesaving procedures are extremely rare or decreasing in incidence. There has also been an increase in utilization of fluoroscopic/ultrasound guidance for the placement of central venous catheters.

KEY POINTS

· Advances in neonatal care have impacted the number of procedures performed in the NICU.. · It is unclear whether invasive procedures occur at rates sufficient for adequate training and maintenance of skills.. · Understanding the NICU procedural trends is important in designing simulation and competency-based medical education programs..

Postnatal steroids as lung protective and anti-inflammatory in preterm lambs exposed to antenatal inflammation

BACKGROUND

Lung inflammation and impaired alveolarization precede bronchopulmonary dysplasia (BPD). Glucocorticoids are anti-inflammatory and reduce ventilator requirements in preterm infants. However, high-dose glucocorticoids inhibit alveolarization. The effect of glucocorticoids on lung function and structure in preterm newborns exposed to antenatal inflammation is unknown. We hypothesise that postnatal low-dose dexamethasone reduces ventilator requirements, prevents inflammation and BPD-like lung pathology, following antenatal inflammation.

METHODS

Pregnant ewes received intra-amniotic LPS (E.coli, 4 mg/mL) or saline at 126 days gestation; preterm lambs were delivered 48 h later. Lambs were randomised to receive either tapered intravenous dexamethasone (LPS/Dex, n = 9) or saline (LPS/Sal, n = 10; Sal/Sal, n = 9) commencing <3 h after birth. Respiratory support was gradually de-escalated, using a standardised protocol aimed at weaning from ventilation towards unassisted respiration. Tissues were collected at day 7.

RESULTS

Lung morphology and mRNA levels for inflammatory mediators were measured. Respiratory support requirements were not different between groups. Histological analyses revealed higher tissue content and unchanged alveolarization in LPS/Sal compared to other groups. LPS/Dex lambs exhibited decreased markers of pulmonary inflammation compared to LPS/Sal.

CONCLUSION

Tapered low-dose dexamethasone reduces the impact of antenatal LPS on ventilation requirements throughout the first week of life and reduces inflammation and pathological thickening of the preterm lung IMPACT: We are the first to investigate the combination of antenatal inflammation and postnatal dexamethasone therapy in a pragmatic study design, akin to contemporary neonatal care. We show that antenatal inflammation with postnatal dexamethasone therapy does not reduce ventilator requirements, but has beneficial maturational impacts on the lungs of preterm lambs at 7 days of life. Appropriate tapered postnatal dexamethasone dosing should be explored for extuabtion of oxygen-dependant neonates.

Alternative routes of surfactant application - An update

Non-invasive modes of respiratory support have been shown to be the preferable way of primary respiratory support of preterm infants with respiratory distress syndrome (RDS). The avoidance of invasive mechanical ventilation can be beneficial for preterm infants in reduction of morbidity and even mortality. However, it is well-established that some infants managed with non-invasive respiratory support from the outset have symptomatic RDS to a degree that warrants surfactant administration. Infants for whom non-invasive respiratory support ultimately fails are prone to adverse outcomes, occurring at a frequency on par with the group intubated primarily. This raises the question how to combine non-invasive respiratory support with surfactant therapy. Several methods of less or minimally invasive surfactant therapy have been developed to address the dilemma between avoidance of mechanical ventilation and administration of surfactant. This paper describes the different methods of less invasive surfactant application, reports the existing evidence from clinical studies, discusses the limitations of each of the methods and the open and future research questions.

The minimal invasive surfactant therapy: experience from a low resource setting

OBJECTIVE

To evaluate all cases managed with the Minimal Invasive Surfactant Therapy (MIST) and its effect on outcome.

BACKGROUND

Respiratory distress syndrome (RDS), a major cause of morbidity and mortality in preterm new-borns is common in sub-Saharan Africa. Surfactant replacement therapy (SRT) is less practiced and the new MIST is just introduced in Asaba, Nigeria.

METHODS

This descriptive survey recruited new-borns of consenting parents who provided for the surfactant and other commodities. Demographic characteristics were obtained. Intervention included MIST Surfactant, nasal bubble Continuous Positive Airway Pressure (n b-CPAP). Aminophylline or Caffeine, early breast milk feeding and Kangaroo mother care (KMC). Data were collected over a 1-year period and Standard statistical methods were used for data analysis.

RESULTS

From 1 May 2019 to 30 April 2020, there were 1801 live births, preterm birth rate of 10.72% (193/1801) at the FMC, Asaba. Admissions to the Neonatal Unit (NNU) comprised a total of 731 newborn: 270 preterms. Of these preterm; 52(19.26%) were extreme preterms; 122 (16.15%) very preterm. Of these 731 total admissions there were 104 (14.23%). Their gestational ages (GA) ranged from 24 to 38 weeks and birthweights from 600 to 3400 g. A total of 51 Newborns received surfactant. Their GA ranged from 24 to 38 Weeks; birth weights 600 to 3400 g. These comprised 48 preterm and 3 terms. All 51 infants with RDS who received MIST surfactant included 48 preterms and 3 terms with perinatal Asphyxia and Meconium Aspiration Syndrome. The obstetric management of five mothers of early preterm included two doses of antenatal cortico-steroids prior to delivery. MIST was successful in 47 of 51 (92.2%) cases. Age range at administration was one to 48 h. Duration of n-bCPAP post surfactant: ranged 6 h to 96 h: 4 babies were weaned off CPAP within 24 h; 12 babies at <48 h, another 9 at <72 h; and 20 beyond 96 h. Five babies received a second dose of MIST after 48 h of the first dose. Twelve of 51 (23.5%) babies died; 4 at 48 h, 2 at 72 h, 3at 96 h and 3 beyond 7 days. Prior to the MIST, respiratory distress (RD) and severity rating as indicated by the Silverman Anderson Score (SA) scores in the survivors ranged from 6/10 to 8/10.

CONCLUSIONS

The MIST, at FMC Asaba, improves outcome of the extreme preterm. Financial barriers remain a major constraint to its use.

Bronchopulmonary Dysplasia: Then, Now, and Next

Bronchopulmonary dysplasia (BPD) has evolved considerably since its first description over 50 years ago. This review aims to provide a historical framework for conceptualizing BPD and a current understanding of the changing definition, epidemiology, pathophysiology, treatment, and outcomes of BPD. The transdisciplinary approach that led to the initial phenotypic description of BPD continues to hold promise today. Investigators are refining the definition of BPD in light of changes in clinical care and increasing survival rates of very preterm infants. Despite improvements in perinatal care the incidence of BPD continues to increase. There is growing recognition that antenatal risk factors play a key role in the development of BPD. Strategies designed to prevent or limit neonatal lung injury continue to evolve. Defining the phenotype of infants with BPD can meaningfully direct treatment. Infants with BPD benefit from an interdisciplinary approach to longitudinal care with a focus on growth and neurocognitive development. While the ultimate impact of BPD on long-term pulmonary morbidity remains an active area of investigation, current data indicate that most children and adolescents with a history of BPD have a quality of life comparable to that of other preterm infants.

Staphylococcus aureus Lung Infection Results in Down-Regulation of Surfactant Protein-A Mainly Caused by Pro-Inflammatory Macrophages

Pneumonia is the leading cause of hospitalization worldwide. Besides viruses, bacterial co-infections dramatically exacerbate infection. In general, surfactant protein-A (SP-A) represents a first line of immune defense. In this study, we analyzed whether influenza A virus (IAV) and/or Staphylococcus aureus (S. aureus) infections affect SP-A expression. To closely reflect the situation in the lung, we used a human alveolus-on-a-chip model and a murine pneumonia model. Our results show that S. aureus can reduce extracellular levels of SP-A, most likely attributed to bacterial proteases. Mono-epithelial cell culture experiments reveal that the expression of SP-A is not directly affected by IAV or S. aureus. Yet, the mRNA expression of SP-A is strongly down-regulated by TNF-α, which is highly produced by professional phagocytes in response to bacterial infection. By using the human alveolus-on-a-chip model, we show that the down-regulation of SP-A is strongly dependent on macrophages. In a murine model of pneumonia, we can confirm that S. aureus decreases SP-A levels in vivo. These findings indicate that (I) complex interactions of epithelial and immune cells induce down-regulation of SP-A expression and (II) bacterial mono- and super-infections reduce SP-A expression in the lung, which might contribute to a severe outcome of bacterial pneumonia.

Noninvasive Ventilation in the Age of Surfactant Administration

Numerous advances in neonatal care have improved outcomes in preterm infants. Antenatal steroids, through their ability to promote lung maturation and function, have led to significant improvements in death, intraventricular hemorrhage, necrotizing enterocolitis, and respiratory distress syndrome. For years, exogenous surfactant administration has been used in conjunction with antenatal steroids to further improve outcomes for preterm infants. However, as continuous positive airway pressure has been shown to be effective in treating respiratory distress syndrome, it has become less clear how exogenous surfactant should be used. Novel approaches combining these therapies may lead to further improvement in clinical outcome.

Efficacy and safety of antenatal steroids

Antenatal steroids (ANS) are among the most important and widely utilized interventions to improve outcomes for preterm infants. A significant body of evidence demonstrates improved outcomes in preterm infants (24-34 wk) delivered between 1 and 7 days after the administration of a single course of ANS. Moreover, ANS have the advantage of being widely available, low cost, and easily administered via maternal intramuscular injection. The use of ANS to mature the fetal lung is, however, not without contention. Their use in pregnancy is not FDA approved, and treatment doses and regimens remain largely unoptimized. Their mode of use varies considerably between countries, and there are lingering concerns regarding the safety of exposing the fetus to high doses of exogenous steroids. A significant proportion of women deliver outside the 1- to 7-day therapeutic window after ANS treatment, and this delay may be associated with an increased risk of adverse outcomes for both mother and baby. Today, animal-based studies are one means by which key questions of dosing and safety relating to ANS may be resolved, allowing for further refinement(s) of this important therapy. Complementary approaches using nonhuman primates, sheep, and rodents have provided invaluable advances to our understanding of how exogenous steroid exposure impacts fetal development. Focusing on these three major model groups, this review highlights the role of three key animal models (sheep, nonhuman primates, rodents) in the development of antenatal steroid therapy, and provides an up-to-date synthesis of current efforts to refine this therapy in an era of personalised medicine.

Review demonstrates that less invasive surfactant administration in preterm neonates leads to fewer complications

Surfactant treatment of neonatal respiratory distress syndrome (RDS) was introduced in Europe during the 1990s. Meta-analyses have indicated that using less invasive surfactant administration techniques on preterm neonates receiving continuous positive airway pressure (CPAP) results in improved survival rates without bronchopulmonary dysplasia. Surfactant should be administered early and ventilator settings adapted to changing oxygen requirements and lung mechanics. Side effects including initial bradycardia, oxygen desaturation, tube obstruction and isolated cases of pulmonary haemorrhage have been reported.

CONCLUSION

Less invasive surfactant therapy improves pulmonary outcomes in preterm neonates with RDS and should ideally be administered in combination with CPAP.

Birth Prevalence of Cerebral Palsy: A Population-Based Study

OBJECTIVE

Population-based data in the United States on trends in cerebral palsy (CP) birth prevalence are limited. The objective of this study was to examine trends in the birth prevalence of congenital spastic CP by birth weight, gestational age, and race/ethnicity in a heterogeneous US metropolitan area.

METHODS

Children with CP were identified by a population-based surveillance system for developmental disabilities (DDs). Children with CP were included if they were born in metropolitan Atlanta, Georgia, from 1985 to 2002, resided there at age 8 years, and did not have a postneonatal etiology (n = 766). Birth weight, gestational age, and race/ethnicity subanalyses were restricted to children with spastic CP (n = 640). Trends were examined by CP subtype, gender, race/ethnicity, co-occurring DDs, birth weight, and gestational age.

RESULTS

Birth prevalence of spastic CP per 1000 1-year survivors was stable from 1985 to 2002 (1.9 in 1985 to 1.8 in 2002; 0.3% annual average prevalence; 95% confidence interval [CI] -1.1 to 1.8). Whereas no significant trends were observed by gender, subtype, birth weight, or gestational age overall, CP prevalence with co-occurring moderate to severe intellectual disability significantly decreased (-2.6% [95% CI -4.3 to -0.8]). Racial disparities persisted over time between non-Hispanic black and non-Hispanic white children (prevalence ratio 1.8 [95% CI 1.5 to 2.1]). Different patterns emerged for non-Hispanic white and non-Hispanic black children by birth weight and gestational age.

CONCLUSIONS

Given improvements in neonatal survival, evidence of stability of CP prevalence is encouraging. Yet lack of overall decreases supports continued monitoring of trends and increased research and prevention efforts. Racial/ethnic disparities, in particular, warrant further study.

Interdependent TTF1 - ErbB4 interactions are critical for surfactant protein-B homeostasis in primary mouse lung alveolar type II cells

ErbB4 receptor and thyroid transcription factor (TTF)-1 are important modulators of fetal alveolar type II (ATII) cell development and injury. ErbB4 is an upstream regulator of TTF-1, promoting its expression in MLE-12 cells, an ATII cell line. Both proteins are known to promote surfactant protein-B gene (SftpB) and protein (SP-B) expression, but their feedback interactions on each other are not known. We hypothesized that TTF-1 expression has a feedback effect on ErbB4 expression in an in-vitro model of isolated mouse ATII cells. We tested this hypothesis by analyzing the effects of overexpressing HER4 and Nkx2.1, the genes of ErbB4 and TTF-1 on TTF-1 and ErbB4 protein expression, respectively, as well as SP-B protein expression in primary fetal mouse lung ATII cells. Transient ErbB4 protein overexpression upregulated TTF-1 protein expression in primary fetal ATII cells, similarly to results previously shown in MLE-12 cells. Transient TTF-1 protein overexpression down regulated ErbB4 protein expression in both cell types. TTF-1 protein was upregulated in primary transgenic ErbB4-depleted adult ATII cells, however SP-B protein expression in these adult transgenic ATII cells was not affected by the absence of ErbB4. The observation that TTF-1 is upregulated in fetal ATII cells by ErbB4 overexpression and also in ErbB4-deleted adult ATII cells suggests additional factors interact with ErbB4 to regulate TTF-1 levels. We conclude that the interdependency of TTF-1 and ErbB4 is important for surfactant protein levels. The interactive regulation of ErbB4 and TTF-1 needs further elucidation.

Bronchopulmonary dysplasia: NHLBI Workshop on the Primary Prevention of Chronic Lung Diseases

Bronchopulmonary dysplasia (BPD) is the most common complication of extreme preterm birth. Infants who develop BPD manifest aberrant or arrested pulmonary development and can experience lifelong alterations in cardiopulmonary function. Despite decades of promising research, primary prevention of BPD has proven elusive. This workshop report identifies current barriers to the conduct of primary prevention studies for BPD and causal pathways implicated in BPD pathogenesis. Throughout, we highlight promising areas for research to improve understanding of normal and aberrant lung development, distinguish BPD endotypes, and ascertain biomarkers for more targeted therapeutic approaches to prevention. We conclude with research recommendations and priorities to accelerate discovery and promote lung health in infants born preterm.

Antenatal glucocorticoids: where are we after forty years?

Since their introduction more than forty years ago, antenatal glucocorticoids have become a cornerstone in the management of preterm birth and have been responsible for substantial reductions in neonatal mortality and morbidity. Clinical trials conducted over the past decade have shown that these benefits may be increased further through administration of repeat doses of antenatal glucocorticoids in women at ongoing risk of preterm and in those undergoing elective cesarean at term. At the same time, a growing body of experimental animal evidence and observational data in humans has linked fetal overexposure to maternal glucocorticoids with increased risk of cardiovascular, metabolic and other disorders in later life. Despite these concerns, and somewhat surprisingly, there has been little evidence to date from randomized trials of longer-term harm from clinical doses of synthetic glucocorticoids. However, with wider clinical application of antenatal glucocorticoid therapy there has been greater need to consider the potential for later adverse effects. This paper reviews current evidence for the short- and long-term health effects of antenatal glucocorticoids and discusses the apparent discrepancy between data from randomized clinical trials and other studies.

Surfactant replacement therapy for preterm and term neonates with respiratory distress

Respiratory failure secondary to surfactant deficiency is a major cause of morbidity and mortality in preterm infants. Surfactant therapy substantially reduces mortality and respiratory morbidity for this population. Secondary surfactant deficiency also contributes to acute respiratory morbidity in late-preterm and term neonates with meconium aspiration syndrome, pneumonia/sepsis, and perhaps pulmonary hemorrhage; surfactant replacement may be beneficial for these infants. This statement summarizes the evidence regarding indications, administration, formulations, and outcomes for surfactant-replacement therapy. The clinical strategy of intubation, surfactant administration, and extubation to continuous positive airway pressure and the effect of continuous positive airway pressure on outcomes and surfactant use in preterm infants are also reviewed.

Glucocorticoid metabolism in the developing lung: adrenal-like synthesis pathway

Glucocorticoids (GCs) are essential to normal lung development. They participate in the regulation of important developmental events including morphological changes, and lung maturation leading to the surge of surfactant synthesis by type II epithelial cells. Antenatal GC is administered to mothers at risk of premature delivery to reduce the risk of respiratory distress syndrome (RDS). Sex differences were reported in RDS, in the efficiency of antenatal GC treatment independently of surfactant levels, and in surfactant lipid synthesis. Type II epithelial cell maturation is regulated by epithelial-fibroblast cell-cell communication and involves paracrine factors secreted by fibroblasts under the stimulatory effect of GC. This positive action of GC can be inhibited by androgens through the androgen receptor (AR) present in fibroblasts. In fact, lung development is regulated not only by GC and androgens but also by GC and androgen metabolisms within the developing lung. We recently reviewed the metabolism of androgens in the fetal lung [45]. Here, we review multiple aspects of GC metabolism in the developing lung including inactivation and re-activation by 11β-HSDs, synthesis from the adrenal-like synthesis pathway expressed within the lung and the putative role of CRH and ACTH originating from lung in the regulation of this pathway. This article is part of a Special Issue entitled 'Pregnancy and Steroids'.

Delivery and performance of surfactant replacement therapies to treat pulmonary disorders

Lung surfactant is crucial for optimal pulmonary function throughout life. An absence or deficiency of surfactant can affect the surfactant pool leading to respiratory distress. Even if the coupling between surfactant dysfunction and the underlying disease is not always well understood, using exogenous surfactants as replacement is usually a standard therapeutic option in respiratory distress. Exogenous surfactants have been extensively studied in animal models and clinical trials. The present article provides an update on the evolution of surfactant therapy, types of surfactant treatment, and development of newer-generation surfactants. The differences in the performance between various surfactants are highlighted and advanced research that has been conducted so far in developing the optimal delivery of surfactant is discussed.

Early versus delayed selective surfactant treatment for neonatal respiratory distress syndrome

BACKGROUND

Clinical trials have confirmed that surfactant therapy is effective in improving the immediate need for respiratory support and the clinical outcome of premature newborns. Trials have studied a wide variety of surfactant preparations used either to prevent (prophylactic or delivery room administration) or treat (selective or rescue administration) respiratory distress syndrome (RDS). Using either treatment strategy, significant reductions in the incidence of pneumothorax, as well as significant improvement in survival, have been noted. It is unclear whether there are any advantages to treating infants with respiratory insufficiency earlier in the course of RDS.

OBJECTIVES

To compare the effects of early versus delayed selective surfactant therapy for newborns intubated for respiratory distress within the first two hours of life. Planned subgroup analyses included separate comparisons for studies utilizing natural surfactant extract and synthetic surfactant.

SEARCH METHODS

We searched the Oxford Database of Perinatal Trials, MEDLINE (MeSH terms: pulmonary surfactant; text word: early; limits: age, newborn: publication type, clinical trial), PubMed, abstracts, conference and symposia proceedings, expert informants, and journal handsearching in the English language. For the updated search in April 2012 we searched the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, 2012, Issue 1) and PubMed (January 1997 to April 2012).

SELECTION CRITERIA

Randomized and quasi-randomized controlled clinical trials comparing early selective surfactant administration (surfactant administration via the endotracheal tube in infants intubated for respiratory distress, not specifically for surfactant dosage) within the first two hours of life versus delayed selective surfactant administration to infants with established RDS were considered for review.

DATA COLLECTION AND ANALYSIS

Data regarding clinical outcomes were excerpted from the reports of the clinical trials by the review authors. Subgroup analyses were performed based on type of surfactant preparation, gestational age, and exposure to prenatal steroids. Data analysis was performed in accordance with the standards of the Cochrane Neonatal Review Group.

MAIN RESULTS

Six randomized controlled trials met selection criteria. Two of the trials utilized synthetic surfactant (Exosurf Neonatal) and four utilized animal-derived surfactant preparations.The meta-analyses demonstrate significant reductions in the risk of neonatal mortality (typical risk ratio (RR) 0.84; 95% confidence interval (CI) 0.74 to 0.95; typical risk difference (RD) -0.04; 95% CI -0.06 to -0.01; 6 studies; 3577 infants), chronic lung disease (typical RR 0.69; 95% CI 0.55 to 0.86; typical RD -0.04; 95% CI -0.06 to -0.01; 3 studies; 3041 infants), and chronic lung disease or death at 36 weeks (typical RR 0.83; 95% CI 0.75 to 0.91; typical RD -0.06; 95% CI -0.09 to -0.03; 3 studies; 3050 infants) associated with early treatment of intubated infants with RDS.Intubated infants randomized to early selective surfactant administration also demonstrated a decreased risk of acute lung injury including a decreased risk of pneumothorax (typical RR 0.69; 95% CI 0.59 to 0.82; typical RD -0.05; 95% CI -0.08 to -0.03; 5 studies; 3545 infants), pulmonary interstitial emphysema (typical RR 0.60; 95% CI 0.41 to 0.89; typical RD -0.06; 95% CI -0.10 to -0.02; 3 studies; 780 infants), and overall air leak syndromes (typical RR 0.61; 95% CI 0.48 to 0.78; typical RD -0.18; 95% CI -0.26 to -0.09; 2 studies; 463 infants).A trend toward risk reduction for bronchopulmonary dysplasia (BPD) or death at 28 days was also evident (typical RR 0.94; 95% CI 0.88 to 1.00; typical RD -0.04; 95% CI -0.07 to -0.00; 3 studies; 3039 infants). No differences in other complications of RDS or prematurity were noted.Only two studies reported on infants under 30 weeks' gestation. Decreased risk of neonatal mortality and chronic lung disease or death at 36 weeks' postmenstrual age was noted.

AUTHORS' CONCLUSIONS

Early selective surfactant administration given to infants with RDS requiring assisted ventilation leads to a decreased risk of acute pulmonary injury (decreased risk of pneumothorax and pulmonary interstitial emphysema) and a decreased risk of neonatal mortality and chronic lung disease compared to delaying treatment of such infants until they develop worsening RDS.

Antenatal dexamethasone has no adverse effects on child physical and cognitive development: a long-term cohort follow-up investigation

OBJECTIVE

Antenatal corticosteroids are extensively given in pregnancies with threatened preterm labour as a prophylactic method to reduce some kinds of neonatal diseases. Dexamethasone is one kind of commonly used corticosteroid, but controversies still remain whether it leads to adverse effects on neonatal long-term development or not. The purpose of this study was to investigate the influence of prenatal exposure to one or two dosages of dexamethasone on neonatal physical and cognitive development of children at 1, 3 and 6 years of age.

METHODS

This was a retrospective cohort study. The body length, head circumference and body weight were measured in every infant and child to evaluate physical development. The mental development index (MDI) and a psychomotor development index (PDI) were used to evaluate mental and cognitive development in children of ages 1 year and 3 years while verbal intelligence quotient (VIQ) and performance intelligence quotient (PIQ) scores were used to evaluate mental and cognitive development in children of age of 6 years. There were 1554 infants at 1 year, 1328 children at 3 years and 1297 preschool children at 6 years followed.

RESULTS

There were no significant differences between antenatal dexamethasone exposure groups and antenatal dexamethasone non-exposure groups on physical development index and MDI, PDI, VIQ and PIQ.

CONCLUSIONS

The results of this investigation suggested that one or two dosages of antenatal dexamethasone is safe for the use of inevitable preterm birth.

Percutaneous evacuation of diffuse pulmonary interstitial emphysema by lung puncture in a baby with extremely low birth weight: a case report

Introduction

Pulmonary interstitial emphysema is a serious complication of mechanical ventilation and can become life-threatening if progression occurs. Therapeutic lung puncture is a treatment option for severe pulmonary interstitial emphysema but has a limited use in babies with extremely low birth weight. We present a case of pulmonary interstitial emphysema in a Japanese baby (1-day-old) boy with extremely low birth weight. The emphysema was successfully decompressed by therapeutic lung puncture performed with a trocar catheter.

Case presentation

The baby was born with a weight of 420g, which, to the best of our knowledge, is the lowest reported birth weight among babies with pulmonary interstitial emphysema. A chest X-ray on postnatal day 2 revealed pulmonary interstitial emphysema, which gradually progressed to diffuse pseudocystic changes. His condition became life-threatening despite the use of high-frequency oscillatory ventilation and lateral decubitus positioning. We evacuated the pulmonary interstitial emphysema by lung puncture with a trocar catheter to avoid respiratory and cardiovascular collapse. This resulted in adequate evacuation of the emphysema and a dramatic improvement in his clinical condition.

Conclusions

Therapeutic lung puncture performed with a trocar catheter is beneficial in babies with extremely low birth weight and diffuse pulmonary interstitial emphysema. This treatment option may be broadly applicable, especially in an emergency situation.

Repeat antenatal glucocorticoids for women at risk of preterm birth: a Cochrane Systematic Review

Administration of antenatal glucocorticoids to women at risk of preterm birth has major benefits for infants but the use of repeat dose(s) is controversial. We performed a systematic review of randomized trials, using standard Cochrane methodology, to assess the effectiveness and safety of 1 or more repeat doses given to women at risk of preterm birth 7 or more days after an initial course. Ten trials were included involving over 4730 women and 5700 infants. Treatment with repeat dose(s) compared with no repeat treatment reduced the risk of respiratory distress syndrome (risk ratio, 0.83; 95% confidence interval, 0.75-0.91) and serious neonatal morbidity (risk ratio, 0.84; 95% confidence interval, 0.75-0.94). At 2- to 3-year follow-up (4 trials, 4170 children), there was no evidence of either significant benefit or harm. Repeat doses of glucocorticoids should be considered in women at risk of preterm birth 7 or more days after an initial course, in view of the neonatal benefits.

Neonatal and infant outcome in boys and girls born very prematurely

INTRODUCTION

Although important new strategies have improved outcomes for very preterm infants, males have greater mortality/morbidity than females. We investigated whether the excess of adverse later effects in males operated through poorer neonatal profile or if there was an intrinsic male effect.

RESULTS

Male sex was significantly associated with higher birth weight, death or oxygen dependency (72% vs. 61%, boys vs. girls), hospital stay (97 vs. 86 days), pulmonary hemorrhage (15% vs. 10%), postnatal steroids (37% vs. 21%), and major cranial ultrasound abnormality (20% vs. 12%). Differences remained significant after adjusting for birth weight and gestation. At follow-up, disability, cognitive delay, and use of inhalers remained significant after further adjustment.

DISCUSSION

We conclude that in very preterm infants, male sex is an important risk factor for poor neonatal outcome and poor neurological and respiratory outcome at follow-up. The increased risks at follow-up are not explained by neonatal factors and lend support to the concept of male vulnerability following preterm birth.

METHODS

Data came from the United Kingdom Oscillation Study, with 797 infants (428 boys) born at 23-28 wk gestational age. Thirteen maternal factors, 8 infant factors, 11 acute outcomes, and neurological and respiratory outcomes at follow-up were analyzed. Follow-up outcomes were adjusted for birth and neonatal factors sequentially to explore mechanisms for differences by sex.

Neonatal outcomes of very preterm infants admitted to a tertiary center in Lithuania between the years 2003 and 2005

The objectives of the study are to investigate gestational age-specific mortality and neonatal outcomes in preterm infants admitted to a tertiary center in Lithuania, and to make comparison with tertiary centers in western countries. Three hundred thirty-eight newborns born at ≤ 32 weeks of gestation and with birth weight ≤ 1,500 g between 1 January 2003 and 31 December 2005, admitted to the neonatal intensive care unit at Kaunas Medical University Hospital, were prospectively investigated. Mortality and associations between maternal, perinatal, and neonatal variables and short-term outcomes were examined for two gestational age (GA) groups (group I, extremely preterm, 22-27 weeks GA; group II, very preterm, 28-32 weeks GA). Mortality in group I was 53.5% and 2.9% in group II. GA <28 weeks, Apgar score <5 at 5 min, and birth weight <1,000 g posed the highest risk for death. Overall, 78.2% of the surviving infants were discharged from hospital without adverse short-term outcomes. The incidence of bronchopulmonary dysplasia (BPD) was 6.3%, of retinopathy of prematurity (ROP) requiring treatment 4.2%, of intraventricular hemorrhage (IVH) III-IV 10.9%, and for cystic periventricular leukomalacia (cPVL) 8.0%. In conclusion, a decade after introduction of perinatal programs, mortality in the very preterm group is similar to those reported from cohorts in western countries. In the extremely preterm group, however, mortality is still higher. Neonatal outcomes such as ROP are now similar, and BPD is lower to those in other cohorts, whereas the incidence of brain lesions is still higher. We speculate that differences in outcomes between studies may be explained by differences in resources, definitions, and treatment routines.

Preterm birth and respiratory disease in later life

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

Antenatal Corticosteroids and Outcome in a Very Low Birth Weight in Qatar

Respiratory Distress Syndrome (RDS) causes significant mortality and morbidity in babies born before 32 weeks gestation. To determine the effectiveness of antenatal steroid treatment (ANS) in reducing neonatal morbidity from respiratory distress syndrome, and patent ductus arteriosus (PDA), intra-ventricular haemorrhage (IVH), and retinopathy of prematurity (ROP) in very low birth weight infants, a retrospective case control study examined the medical records of 125 babies born before 32 weeks gestation. Divided into two groups according to whether or not antenatal corticosteroids were given, the groups did not differ in rates of RDS, IVH, PDA, or ROP but the group that did not receive ANS had a significantly higher risk of death (p < 0.05).

Antenatal steroids in preterm labour for the prevention of neonatal deaths due to complications of preterm birth

BACKGROUND

In high-income countries, administration of antenatal steroids is standard care for women with anticipated preterm labour. However, although >1 million deaths due to preterm birth occur annually, antenatal steroids are not routine practice in low-income countries where most of these deaths occur.

OBJECTIVES

To review the evidence for and estimate the effect on cause-specific neonatal mortality of administration of antenatal steroids to women with anticipated preterm labour, with additional analysis for the effect in low- and middle-income countries.

METHODS

We conducted systematic reviews using standardized abstraction forms. Quality of evidence was assessed using an adapted GRADE approach. Existing meta-analyses were reviewed for relevance to low/middle-income countries, and new meta-analysis was performed.

RESULTS

We identified 44 studies, including 18 randomised control trials (RCTs) (14 in high-income countries) in a Cochrane meta-analysis, which suggested that antenatal steroids decrease neonatal mortality among preterm infants (<36 weeks gestation) by 31% [relative risk (RR) = 0.69; 95% confidence interval (CI) 0.58-0.81]. Our new meta-analysis of four RCTs from middle-income countries suggests 53% mortality reduction (RR = 0.47; 95% CI 0.35-0.64) and 37% morbidity reduction (RR = 0.63; 95% CI 0.49-0.81). Observational study mortality data were consistent. The control group in these equivalent studies was routine care (ventilation and, in many cases, surfactant). In low-income countries, many preterm babies currently receive little or no medical care. It is plausible that antenatal steroids may be of even greater effect when tested in these settings.

CONCLUSIONS

Based on high-grade evidence, antenatal steroid therapy is very effective in preventing neonatal mortality and morbidity, yet remains at low coverage in low/middle-income countries. If fully scaled up, this intervention could save up to 500 000 neonatal lives annually.

Global report on preterm birth and stillbirth (3 of 7): evidence for effectiveness of interventions

INTRODUCTION

Interventions directed toward mothers before and during pregnancy and childbirth may help reduce preterm births and stillbirths. Survival of preterm newborns may also be improved with interventions given during these times or soon after birth. This comprehensive review assesses existing interventions for low- and middle-income countries (LMICs).

METHODS

Approximately 2,000 intervention studies were systematically evaluated through December 31, 2008. They addressed preterm birth or low birth weight; stillbirth or perinatal mortality; and management of preterm newborns. Out of 82 identified interventions, 49 were relevant to LMICs and had reasonable amounts of evidence, and therefore selected for in-depth reviews. Each was classified and assessed by the quality of available evidence and its potential to treat or prevent preterm birth and stillbirth. Impacts on other maternal, fetal, newborn or child health outcomes were also considered. Assessments were based on an adaptation of the Grades of Recommendation Assessment, Development and Evaluation criteria.

RESULTS

Most interventions require additional research to improve the quality of evidence. Others had little evidence of benefit and should be discontinued. The following are supported by moderate- to high-quality evidence and strongly recommended for LMICs: Two interventions prevent preterm births--smoking cessation and progesterone. Eight interventions prevent stillbirths--balanced protein energy supplementation, screening and treatment of syphilis, intermittant presumptive treatment for malaria during pregnancy, insecticide-treated mosquito nets, birth preparedness, emergency obstetric care, cesarean section for breech presentation, and elective induction for post-term delivery. Eleven interventions improve survival of preterm newborns--prophylactic steroids in preterm labor, antibiotics for PROM, vitamin K supplementation at delivery, case management of neonatal sepsis and pneumonia, delayed cord clamping, room air (vs. 100% oxygen) for resuscitation, hospital-based kangaroo mother care, early breastfeeding, thermal care, and surfactant therapy and application of continued distending pressure to the lungs for respiratory distress syndrome

CONCLUSION

The research paradigm for discovery science and intervention development must be balanced to address prevention as well as improve morbidity and mortality in all settings. This review also reveals significant gaps in current knowledge of interventions spanning the continuum of maternal and fetal outcomes, and the critical need to generate further high-quality evidence for promising interventions.

Lung maturation: the survival miracle of very low birth weight infants

The increased survival of very preterm infants is generally attributed to improved care strategies. This review develops the thesis that the features of abnormal pregnancies responsible for very preterm deliveries also provide an explanation of why very preterm infants often survive. A normal fetus born at 24 weeks is very unlikely to survive. However, pregnancies that result in deliveries at 24 weeks are generally highly abnormal, and may have been so for prolonged periods prior to the preterm deliveries. Inflammatory or vascular developmental abnormalities resulting in very preterm birth can alter fetal development in such a way that organ system maturation is induced. This is supported clinically by the relative lack of very preterm infants with respiratory distress syndrome. Interventions such as antenatal corticosteroid treatment and postnatal surfactant treatment for infants with respiratory distress syndrome and gentle ventilation strategies maximize fetal adaptations to the abnormal fetal environment and improve outcomes.

Antenatal corticosteroids increase fetal, but not postnatal, pulmonary blood flow in sheep

The lungs of very preterm infants have immature airways and gas exchange structures and are usually surfactant deficient. Antenatal corticosteroids are commonly used to enhance fetal lung maturation in preterm infants, but little is known of their effects on pulmonary blood flow (PBF) before and immediately after birth. Our aim was to determine the effects of antenatal betamethasone on PBF before birth and during the postnatal transition in very preterm lambs. Antenatal betamethasone treatment significantly increased mean fetal PBF from 20.2 +/- 5.1 to 84.3 +/- 18.3 mL/min at 30 h after administration; the PBF waveform was also significantly altered. Mean diastolic PBF increased from -38.5 +/- 4.9 pretreatment to -10.2 +/- 11.0 mL/min at approximately 36 h after the initial betamethasone dose (negative values indicate retrograde flow away from the lungs). Within 10 min after delivery, PBF was similar in control and betamethasone-treated lambs. These data demonstrate that antenatal betamethasone significantly increases fetal PBF and alters the PBF waveform but has little effect on postnatal PBF.

The effects of antenatal corticosteroids and surfactant replacement on neonatal respiratory distress syndrome

The goal of this study was to determine the effects of antenatal corticosteroids and surfactant replacement on the severity and frequency of Respiratory Distress Syndrome (RDS) in a cohort of premature infants born in Sarajevo, Bosnia and Herzegovina, from 2005 to 2007. The cohort consisted of 172 premature neonates with estimated gestational age between 26 and 34 weeks. Babies with IUGR, babies of diabetic mothers and babies with major congenital defects were excluded. Out of 172 neonates, 80 were treated antenatally with corticosteroids (single course of dexamethasone) and 92/172 were not. There was no statistical difference (p>0,5) in average gestational age (31,2 vs. 31,0 GW) and male/female ratio between investigated groups; there were significantly more male patients (p<0,05) in both groups. Frequency of RDS was significantly lower in the corticosteroid group (24/80) in relation to the control group (54/92) (p<0,001). Severe RDS was significantly (p<0,01) more frequent in the control group 34/53 (62,96%) then in the corticosteroid group 6/24 (25,0%). Bovine surfactant (Survanta) was given as a rescue therapy to 78 babies with clinical and radiological signs of RDS who required FiO2>0,40 and mechanical ventilation. Early surfactant administration within six hours after birth appeared to be effective at reducing mortality then later surfactant administration (p<0,005). In the group of babies requiring FiO2> or =0,6 at the time of surfactant replacement, the mortality rate was significantly higher (p<0,05). In conclusion, we confirm the efficacy of antenatal corticosteroid treatment and early surfactant treatment in a cohort of premature infants born in Sarajevo.

Gastrin-releasing peptide, immune responses, and lung disease

Gastrin-releasing peptide (GRP) is produced by pulmonary neuroendocrine cells (PNECs), with highest numbers of GRP-positive cells present in fetal lung. Normally GRP-positive PNECs are relatively infrequent after birth, but PNEC hyperplasia is frequently associated with chronic lung diseases. To address the hypothesis that GRP mediates chronic lung injury, we present the cumulative evidence implicating GRP in bronchopulmonary dysplasia (BPD), the chronic lung disease of premature infants who survive acute respiratory distress syndrome. The availability of well-characterized animal models of BPD was a critical tool for demonstrating that GRP plays a direct role in the early pathogenesis of this disease. Potential mechanisms by which GRP contributes to injury are analyzed, with the main focus on innate immunity. Autoreactive T cells may contribute to lung injury late in the course of disease. A working model is proposed with GRP triggering multiple cell types in both the innate and adaptive immune systems, promoting cascades culminating in chronic lung disease. These observations represent a paradigm shift in the understanding of the early pathogenesis of BPD, and suggest that GRP blockade could be a novel treatment to prevent this lung disease in premature infants.

The role of antenatal corticosteroids for improving the maturation of choroid plexus capillaries in fetal mice

We investigated whether the use of antenatal corticosteroids could improve the maturation of choroid plexus capillaries in fetal mice. The study was carried out in two groups of preterm mice. The study group consisted of pregnant mice that received dexamethasone at a dose of 4 mg/kg intraperitoneally. This group was further subdivided into four subgroups according to the timing of steroid administration as follows: day 13, day 14, day 15, and day 16 of pregnancy, and each subgroup included 12 premature mice. All animals received a second injection 24 hours after the first injection. The control group was given normal saline. The pregnant mice were operated on to obtain premature mice. The choroid plexus capillaries were assessed for integrity and thickness of their basement membranes by electronmicroscopy. We found that, in the study group, the maturity of the basement membrane of the choroid plexus capillaries was more precise, in that capillaries were better in control animals at term for the following reasons: (a) the basement membrane becomes more intact, (b) thickness of the basement membrane increased, and (c) the protein particles become tighter. Antenatal dexamethasone improved the maturation of the choroid plexus capillaries in fetal mice but also decreased the incidence of periventricular-intraventricular hemorrhage (PIVH). Using two doses of steroids had no influence on birthweight or brainweight of the mice. In conclusion, these findings provide an experimental basis for the use of antenatal steroids for decreasing the incidence of PIVH in premature infants.

Surfactant-replacement therapy for respiratory distress in the preterm and term neonate

Respiratory failure secondary to surfactant deficiency is a major cause of morbidity and mortality in preterm infants. Surfactant therapy substantially reduces mortality and respiratory morbidity for this population. Secondary surfactant deficiency also contributes to acute respiratory morbidity in late-preterm and term neonates with meconium aspiration syndrome, pneumonia/sepsis, and perhaps pulmonary hemorrhage; surfactant replacement may be beneficial for these infants. This statement summarizes indications, administration, formulations, and outcomes for surfactant-replacement therapy. The impact of antenatal steroids and continuous positive airway pressure on outcomes and surfactant use in preterm infants is reviewed. Because respiratory insufficiency may be a component of multiorgan dysfunction, preterm and term infants receiving surfactant-replacement therapy should be managed in facilities with technical and clinical expertise to administer surfactant and provide multisystem support.

Antenatal steroid therapy and childhood asthma: Is there a possible link?

This paper presents a hypothesis that fetal exposure to corticosteroids is an independent risk factor for the development of asthma in childhood. The prevalence of childhood asthma saw a dramatic rise from the 1980s up until the early 2000s. Among the explanations for the increase in asthma prevalence included interest in exposures arising in the gestational period. Overlapping the time period of the increasing prevalence of childhood asthma is the increased use of antenatal corticosteroid therapy for fetal lung maturation. Through an examination of the published literature, a time dependent association between year of birth (and hence exposure to the antenatal corticosteroids) and the relationship between preterm birth and childhood asthma is noted. A brief review of the trends in the prevalence of asthma, the use of antenatal corticosteroids including their established latent effects and the time dependant association between preterm birth and the risk of childhood asthma are provided.

Outcome following preterm birth

Preterm birth currently occurs in approximately 12% of pregnancies and appears to be increasing despite improvements in obstetric care. Improvements in neonatal care have led to increased survival, particularly at extreme prematurity, but survival may be associated with significant morbidity. This may be acute, reflecting the difficulties in supporting an individual in a hostile extrauterine environment to which they should not be exposed, or chronic, reflecting disturbances to fragile, immature body systems. Brain, lungs, intestines and eyes are particularly vulnerable and damage may be severe. For some infants the consequences of this damage may be permanent disability and impairment. Despite this, the limited information currently available suggests that adult outcomes may be comparable with those for infants born at term.

Efficacy of a single dose of antenatal corticosteroids on morbidity and mortality of preterm infants

OBJECTIVE

To assess the effectiveness of an incomplete course of antenatal corticosteroids (ACS) on neonatal morbidity and mortality of preterm infants.

METHODS

Preterm infants born at 25-34 weeks' gestational age between January 1, 1998 and December 31, 2003 were included in this study. Studied infants were divided in two groups: the ACS group included those infants who had been exposed to a single 12-mg dose of betamethasone before delivery while the control group included those infants who had been delivered without any antenatal corticosteroids treatment. The most important neonatal outcomes were compared between the two groups.

RESULTS

One hundred and seventy neonates (41.4%) were exposed to one 12-mg dose of betamethasone before delivery, while 241 neonates (58.6%) did not receive any antenatal corticosteroids treatment. Mean gestational age at delivery (30.4+/-2.4 weeks versus 31.2+/-2.9 weeks, p=0.004) and mean birth weight (1375+/-454 g versus 1625+/-580 g, p<0.001) were lower in the ACS group. The univariate analysis showed that delivery room intubation and respiratory distress syndrome were more frequent in the ACS group and that the length of stay was also significantly longer in this group. No differences were found concerning survival, neonatal morbidity, need for and duration of mechanical ventilation and oxygen therapy. The incidence of major outcomes in survivors was also similar. Logistic regression adjusted for gestational age showed that the exposure to a single dose of betamethasone before delivery was not associated with a significant reduction in the rate of any neonatal outcome. We also compared the outcomes in function of gestational age subclasses. In the 25-27 weeks subgroup, delivery room intubation, surfactant treatment and patent ductus arteriosus (PDA) were less frequent in ACS infants; they had also shorter ventilation and oxygen duration. In the 30-31 weeks subgroup, ACS infants had a lower incidence of mechanical ventilation and a shorter duration of oxygen therapy. Finally, no differences were found in the 28-29 weeks subgroup and in the 32-34 weeks subgroup.

CONCLUSION

Effects of incomplete antenatal corticosteroids are variable: they give some benefits to infants of 25-27 weeks gestational age, fail to show any difference in outcomes in the 32-34 weeks subgroup and are doubtful between these extremes.

Fetal-to-neonatal maladaptation

Although the majority of newly born babies will establish normal respiratory and circulatory function without help, 1-2% might run into difficulties because of a disturbance in the normal adaptive processes required for a smooth transition from intrauterine to extrauterine life. An understanding of the normal and abnormal perinatal physiology is important to appreciate the practical differences in the approach to caring for such babies, and also for avoiding actions that might be detrimental in the longer term.

Actuarial survival of a large Canadian cohort of preterm infants

Background

The increased survival of preterm and very low birth weight infants in recent years has been well documented but continued surveillance is required in order to monitor the effects of new therapeutic interventions. Gestation and birth weight specific survival rates most accurately reflect the outcome of perinatal care. Our aims were to determine survival to discharge for a large Canadian cohort of preterm infants admitted to the neonatal intensive care unit (NICU), and to examine the effect of gender on survival and the effect of increasing postnatal age on predicted survival.

Methods

Outcomes for all 19,507 infants admitted to 17 NICUs throughout Canada between January 1996 and October 1997 were collected prospectively. Babies with congenital anomalies were excluded from the study population. Gestation and birth weight specific survival for all infants with birth weight <1,500 g (n = 3419) or gestation ≤30 weeks (n = 3119) were recorded. Actuarial survival curves were constructed to show changes in expected survival with increasing postnatal age.

Results

Survival to discharge at 24 weeks gestation was 54%, compared to 82% at 26 weeks and 95% at 30 weeks. In infants with birth weights 600–699, survival to discharge was 62%, compared to 79% at 700–799 g and 96% at 1,000–1,099 g. In infants born at 24 weeks gestational age, survival was higher in females but there were no significant gender differences above 24 weeks gestation. Actuarial analysis showed that risk of death was highest in the first 5 days. For infants born at 24 weeks gestation, estimated survival probability to 48 hours, 7 days and 4 weeks were 88 (CI 84,92)%, 70 (CI 64, 76)% and 60 (CI 53,66)% respectively. For smaller birth weights, female survival probabilities were higher than males for the first 40 days of life.

Conclusion

Actuarial analysis provides useful information when counseling parents and highlights the importance of frequently revising the prediction for long term survival particularly after the first few days of life.

Neonatal morbidity and growth in very low birth-weight infants after multiple courses of antenatal steroids

OBJECTIVE

To evaluate the neonatal morbidity and the growth in very low birth-weight (VLBW) infants after exposure to multiple courses of antenatal steroids.

STUDY DESIGN

A total of 319 VLBW infants were placed in one of the two groups based on exposure to antenatal steroids: Group 1: less than two complete courses; Group 2: two complete courses or more. Anthropometric measurements at birth and discharge and neonatal morbidity were recorded. Composite morbidity was defined as presence of any of the following: death, chronic lung disease, major intraventricular hemorrhage and periventricular leukomalacia.

RESULTS

The composite morbidity was not significantly different between the two groups (p=0.26). A significantly higher percentage of infants born after multiple courses of antenatal steroids had head circumference below 10th percentile at discharge (23 vs 9%, adjusted OR, 3.25, (95% CI, 1.4, 7.3); p=0.015).

CONCLUSIONS

Multiple courses of antenatal steroids may predispose VLBW infants to impairment of postnatal somatic growth without providing any additional benefit for immediate neonatal outcome.

Epidemiology of necrotizing enterocolitis--Part I: Changing regional trends in extremely preterm infants over 14 years

OBJECTIVES

Advances in perinatal care include exogenous surfactant, unequivocal acceptance of antenatal steroids and in utero and ex utero transfers to tertiary centres. Increased survival of extremely premature infants may change the incidence and outcome of necrotizing enterocolitis (NEC). Our aim was to examine the trends in the incidence of NEC, surgery and mortality in infants of 24-28 weeks gestation in a retrospective regional review of three epochs over a span of 14 years.

METHODS

Radiologically or surgically proven NEC cases were determined from the New South Wales Neonatal Intensive Care Unit Study database. Three epochs were examined. A total of 360 infants were admitted in 1986-87 (Epoch 1), 622 in 1992-93 (Epoch 2) and 673 in 1998-99 (Epoch 3).

RESULTS

There was an increase in neonatal intensive care unit admissions and a decrease in early and overall mortality of these very premature infants across the epochs. None of the early deaths was due to NEC. The incidence of NEC decreased in post day 5 survivors: 33 cases in Epoch 1 (12%), 60 cases in Epoch 2 (12%) and 34 cases in Epoch 3 (6%, P < 0.001). There was no change in surgical intervention (45%, 57% and 41%, respectively) or mortality due to NEC (37%, 27% and 32%). The reduced incidence of NEC was not singularly influenced by antenatal steroids, exogenous surfactant or outborn delivery. In a multivariate analysis, only later epoch of birth was independently associated with reduced NEC risk.

CONCLUSIONS

With improved care and survival of extremely premature infants, the incidence of NEC has decreased, but it remains a disease of high mortality and morbidity.

[Prenatal corticosteroid and early surfactant therapy in infants born at < or = 30 weeks gestation]

BACKGROUND

Prenatal corticosteroid (PNC) exposure and postnatal surfactant therapy improve outcome in very low birth weight infants (VLBWI). However, the efficacy of PNC in the prevention of chronic lung disease is debated.

OBJECTIVE

To study the effects of PNC exposure on outcome in VLBWI born at < or = 30 weeks' gestation.

PATIENTS AND METHODS

We performed a multicenter, longitudinal study. The Spanish Surfactant Group database (n 5 1,275) was searched and 211 VLBWI born at < or = 30 weeks who received early surfactant therapy (< or = 30 min) were identified. Perinatal events, neonatal management and rates of mortality and complications were evaluated. Data on the subgroup of infants who received PNC (157, 74.4 %) were compared with data on 54 infants who did not receive this therapy.

RESULTS

Mean (+/- SD) birth weight and gestational age were 944 (226) g and 27 (1.8) weeks. Surfactant was given at 16 +/- 13 min (61 % < or = 15 min). A total of 124 infants (58.8 %) developed respiratory distress syndrome. No differences were found in birth weight, gestational age, or Apgar score at 1 and 5 min. However the age at first surfactant dose was lower in infants exposed to PNC. PNC-exposed infants required fewer doses of surfactant, were extubated earlier (58.9 vs. 161 h) and needed a lower FiO2 at 48 h (0.28 vs. 0.35). Moreover, neonatal mortality (15.9 vs. 27.8 %), the incidence of intraventricular hemorrhage (25.2 vs. 50 %), ductus arteriosus (40.3 vs. 63.5 %) and necrotizing enterocolitis (9 vs. 19.2 %) were lower in infants receiving PNC. However, the incidence of chronic lung disease was similar in both groups.

CONCLUSIONS

PNC exposure of VLBWI born at < or = 30 weeks receiving early surfactant therapy reduced mortality and the incidence of certain complications but did not decrease the incidence of chronic lung disease.

Evidence for developmental hypopituitarism in ill preterm infants

OBJECTIVE

The relationship between the concentrations of cortisol and T4 with outcome in the preterm infants has not been well studied.

STUDY DESIGN

Mean cortisol (days 2, 4, and 6) and T4 values were correlated to gestational age, illness, and outcome in 210 infants using ANOVA.

RESULTS

Cortisol significantly decreased and T4 increased across gestational age. For both hormones, higher values were found in infants on low ventilatory settings. Combined lower cortisol (mean < 5 microg/dl (138 nmol/l)) and T4 concentrations (<4 microg/dl) were found in 20/210 (9.5%) infants; 11/20 in a high-acuity group (22% of total) including 48% (12/25) of the deaths. Lower cortisol values were found in infants who died (p<0.005) in contrast to a lack of relationship with T4.

CONCLUSIONS

Lower cortisol values in infants who died are consistent with the role for cortisol in survival. Combined lower cortisol and T4 concentrations in infants who failed to improve clinical status may suggest that these hormones are markers of a poor physiological state. In contrast, we suggest that these results reflect a developmental hypopituitarism, a necessary role for cortisone and T4 in successful early neonatal transition. Treatment of hypothyroidism in the setting of coexistent low cortisol concentrations (central dysfunction of the hypothalamic-pituitary axes) is known to precipitate cortisol crisis in older populations. Therefore, we caution against treatment of low neonatal thyroid concentrations until more is known about the relationship between cortisol and T4 preterm infant population.

Respiratory distress syndrome in twin infants compared with singletons

OBJECTIVE

The purpose of this study was to determine gestational age-specific incidence and risk factors of respiratory distress syndrome (RDS) in twins compared with singletons.

STUDY DESIGN

An analysis of 850,406 singleton and 23,278 twin infants born alive in Finland between 1987 and 2000 was performed. A number of antenatal and perinatal/intranatal factors were evaluated.

RESULTS

At less than 28 weeks of gestation, the incidence of RDS was higher in both first- and second-born twins compared with singletons. At more advanced gestation, first-born twins had a significantly lower incidence of RDS compared with the others. There was no difference in the concordance of RDS between same-sex and opposite-sex twin pairs. Vaginal delivery, female sex, being born first, and being the lighter of the twins protected from RDS.

CONCLUSION

After taking into account gestation, twins are not at higher risk of RDS compared with singletons except at very early gestation. Environmental factors predominate over genetic ones in the predisposition to RDS in twins.

Narrowing of sex differences in infant mortality in Massachusetts

OBJECTIVES

To examine whether the improved survival of preterm infants has influenced the known male excess in infant mortality.

STUDY DESIGN

We analyzed sex-specific infant mortality using linked birth and death certificates for all 619,811 live born infants in Massachusetts between 1989 and 1995.

RESULTS

Between 1989 and 1995 the male excess in infant mortality decreased by 50%, from 1.6/1000 to 0.8/1000 live births (LB). This narrowing resulted primarily from a more rapid decline in neonatal mortality among male infants (1.5/1000 LB) than among female infants (0.9/1000 LB). The largest declines in the male excess in neonatal mortality occurred among very premature infants (GA < or = 30 weeks) and resulted primarily from a more rapid decrease in male deaths from respiratory distress syndrome.

CONCLUSIONS

The narrowing of the sex difference in mortality between 1989 and 1995 suggests that newer treatments like antenatal steroids, and surfactants may have differentially benefited male infants.

Prostaglandin endoperoxide H synthase inhibitors and other tocolytics in preterm labour

Preterm delivery (<37 weeks of gestation) is the major obstetrical complication in developed countries, yet attempts to delay labour and prolong pregnancy have largely been unsuccessful. One of the many reasons it is so difficult to prevent preterm birth is that the nature of preterm labour changes as a function of gestational age, maternal lifestyle factors or infection, to list a few of the reasons. The inhibitors of prostaglandin endoperoxide H synthase (PGHS), known as the Non-steroidal Antiinflammatory Drugs, have been viewed with interest as tocolytics with promising effectiveness under most conditions of preterm labour. Three isoforms of PGHS exist; the first two, PGHS-1 and -2, have been studied for their catalytic activity, X-ray crystallographic structure, and physiological roles in the adult and the foetus. Mixed inhibitors and isoform-specific inhibitors of PGHS have been developed, and their roles in delaying preterm labour are examined and compared to other tocolytics.

Antenatal corticosteroid therapy: benefits and risks

Antenatal glucocorticoid therapy remains one the most striking successes in perinatal management of complicated pregnancies leading to premature birth. All women at risk of preterm delivery before 34 weeks gestation should be treated, given the anti-inflammatory and maturative properties of fluorocorticoids. Betamethasone is preferred to dexamethasone and no more than two courses, two weeks apart, should be given, until the evidence from further controlled trials on repeated doses becomes available.

Partial or complete antenatal steroids treatment and neonatal outcome in extremely low birth weight infants < or =1000 g: is there a dose-dependent effect?

OBJECTIVES

To assess the outcome of extremely low birth weight (ELBW) infants < or =1000 g as it relates to antenatal steroids (ANS) therapy.

STUDY DESIGN

A retrospective analysis of 124 infants born between January 1995 and December 1997. Infants born to mothers with pregnancy-induced hypertension, diabetes, and severe growth restriction were excluded. In all, 77 (62%) infants were exposed to ANS, of whom 31 (25%) received one to two doses (partial course), and 46 (37%) received three to four doses (complete course). A total of 47 infants (38%) were not exposed to ANS.

RESULTS

Infants not exposed to ANS, who exhibited more HMD, PDA, and IVH, were administered more surfactants, and were more likely to die versus infants with complete ANS dosing. Regression models revealed a dose-dependent effect of ANS on HMD, surfactant use, IVH, and CLD or death, with a significant decrease in HMD with > or =2 ANS doses.

CONCLUSIONS

ANS, in a dose-dependent way, are associated with improved outcome in ELBW infants < or =1000 g, with the best outcome seen after a complete course.