Blood protein concentrations in the first two postnatal weeks that predict bronchopulmonary dysplasia among infants born before the 28th week of gestation

Lung inflammation contributes to the pathogenesis of bronchopulmonary dysplasia (BPD) and may be accompanied by a systematic inflammatory response. The objective of this study was to investigate the role of systemic inflammation in the development of BPD in a cohort of extremely low GA newborns (ELGANs) by examining the relationships between inflammation-associated proteins in neonatal blood samples and pulmonary outcomes. Proteins were measured in blood specimens collected on postnatal d 1-3, 5-8, and 12-15 from 932 ELGANs. Increased risk of BPD was associated with elevated blood concentrations of a variety of proinflammatory cytokines, adhesion molecules, and proteases. Reduced risk was prominently associated with increased concentrations of one chemokine, RANTES. Elevations of inflammatory proteins associated with BPD risk occurred during the first days after birth and inflammation intensified thereafter. Therefore, exposures that promote inflammation after the first postnatal days may be more critical in the pathogenesis of BPD. Fetal growth restriction, a known BPD risk factor, was not accompanied by proteins elevations and therefore does not seem to be mediated by systemic inflammation. By contrast, mechanical ventilation altered protein levels and may be associated with systemic inflammation

Antecedents of chronic lung disease following three patterns of early respiratory disease in preterm infants

INTRODUCTION

The incidence of chronic lung disease (CLD) varies among groups defined by their early pattern of respiratory disease.

METHODS

The study examined data collected prospectively on 1204 of the 1506 infants born in 2002-2004 at 23-27 weeks gestation who survived to 36 weeks post-menstrual age. Based on their initial respiratory presentation and need for supplemental oxygen during the first 2 weeks, infants were classified as having early and persistent pulmonary dysfunction (EPPD), early recovery of pulmonary function followed by deterioration (PD) or consistently good pulmonary function characterised by low FiO(2) (Low FiO(2)).

RESULTS

CLD was diagnosed in 69% of infants with EPPD, 52% with PD, and 17% in the Low FiO(2) group. Birth weight z score <-1 conveyed information about CLD risk in all three groups and was the major risk factor for infants in the Low FiO(2) group (OR 27; 95% CI 7 to 95). Mechanical ventilation at 7 days was associated with increased risk in the PD (OR 4.2, 95% CI 2.5 to 6.9) and EPPD groups (OR 2.7, 95% CI 1.5 to 4.7), but not the Low FiO(2) group (OR 1.5, 95% CI 0.5 to 3.9).

CONCLUSION

The likelihood of a very preterm infant developing CLD and the profile of risk factors linked with CLD are related to the infant's pattern of respiratory disease during the first 2 postnatal weeks. Among infants with little exposure to oxygen during this period, fetal growth restriction, not mechanical ventilation, is the factor with the strongest association with CLD.

Does bronchopulmonary dysplasia contribute to the occurrence of cerebral palsy among infants born before 28 weeks of gestation?

OBJECTIVE

To evaluate the relationships among cerebral palsy (CP) phenotypes and bronchopulmonary dysplasia (BPD) severity and, in the process, to generate hypotheses regarding causal pathways linking BPD to CP.

STUDY DESIGN

We studied 1047 infants born before the 28th week of gestation. Receipt of supplemental oxygen at 36 weeks postmenstrual age (PMA), with or without the need for mechanical ventilation (MV) at 36 weeks PMA, defined two levels of BPD. At 24 months, the children underwent neurologic examinations and CP diagnoses were made using an algorithm based on topographic localisation.

RESULTS

The 536 infants with BPD were at increased risk of all three CP phenotypes. In time-oriented multivariable analyses that adjusted for potential confounders, receipt of supplemental oxygen without MV at 36 weeks PMA (BPD) was not associated with increased risk of any CP phenotype. In contrast, BPD accompanied by MV at 36 weeks PMA (BPD/MV) was associated with a nearly sixfold increased risk of quadriparesis and a fourfold increased risk of diparesis.

CONCLUSIONS

Combined treatment with both MV and supplemental oxygen at 36 weeks PMA strongly predicts the more common bilateral CP phenotypes. BPD without MV at 36 weeks PMA was not significantly associated with any form of CP.

Fetal growth restriction and chronic lung disease among infants born before the 28th week of gestation

OBJECTIVE

Improvement in survival of extremely premature infants over the past several decades has resulted in an increase in the number of infants with chronic lung disease (CLD). Historical neonatal exposures associated with CLD now less frequently precede the disease. There is now increasing interest in exposures and events before delivery that predict CLD. The objective of this study was to identify current prenatal predictors of CLD.

METHODS

We collected data about prenatal, placental, and neonatal characteristics of 1241 newborns who were delivered before completion of the 28th week of gestation. Associations between prenatal factors, microbiologic and histologic characteristics of the placenta, and selected neonatal characteristics and CLD risk were first evaluated in univariate analyses. Subsequent multivariate analyses investigated the contribution of prenatal factors, particularly fetal growth restriction (FGR), to CLD risk.

RESULTS

Among the prenatal factors, birth weight z scores, used as a marker of FGR, provided the most information about CLD risk. Indicators of placental inflammation and infection were not associated with increased risk of CLD. Within nearly all strata of prenatal, placental, and neonatal variables, growth-restricted infants were at increased CLD risk, compared with infants who were not growth-restricted. FGR was the only maternal or prenatal characteristic that was highly predictive of CLD after adjustment for other risk factors.

CONCLUSIONS

FGR is independently associated with the risk of CLD. Thus, factors that control fetal somatic growth may have a significant impact on vulnerability to lung injury and in this way increase CLD risk.

Chronic lung disease and developmental delay at 2 years of age in children born before 28 weeks' gestation

INTRODUCTION

Extremely low gestational age newborns (ELGANs) are at increased risk of chronic lung disease (CLD) and of developmental delay. Some studies have suggested that CLD contributes to developmental delay.

PATIENTS AND METHODS

We examined data collected prospectively on 915 infants born before the 28th week of gestation in 2002-2004 who were assessed at 24 months of age with the Bayley Scales of Infant Development-2nd Edition or the Vineland Adaptive Behavior Scales. We excluded infants who were not able to walk independently (Gross Motor Function Classification System score < 1) and, therefore, more likely to have functionally important fine motor impairments. We defined CLD as receipt of oxygen at 36 weeks' postmenstrual age and classified infants as either not receiving mechanical ventilation (MV) (CLD without MV) or receiving MV (CLD with MV).

RESULTS

Forty-nine percent of ELGANs had CLD; of these, 14% were receiving MV at 36 weeks' postmenstrual age. ELGANs without CLD had the lowest risk of a Mental Developmental Index (MDI) or a Psychomotor Developmental Index (PDI) of <55, followed by ELGANs with CLD not receiving MV, and ELGANs with CLD receiving MV (9%, 12%, and 18% for the MDI and 7%, 10%, and 20% for the PDI, respectively). In time-oriented multivariate models, the risk of an MDI of <55 was associated with the following variables: gestational age of <25 weeks; single mother; late bacteremia; pneumothorax; and necrotizing enterocolitis. The risk of a PDI of <55 was associated with variables such as single mother, a complete course of antenatal corticosteroids, early and persistent pulmonary dysfunction, pulmonary deterioration during the second postnatal week, pneumothorax, and pulmonary interstitial emphysema. CLD, without or with MV, was not associated with the risk of either a low MDI or a low PDI. However, CLD with MV approached, but did not achieve, nominal statistical significance (odds ratio: 1.9 [95% confidence interval: 0.97-3.9]) for the association with a PDI of <55.

CONCLUSIONS

Among children without severe gross motor delays, risk factors for CLD account for the association between CLD and developmental delay. Once those factors are considered in time-oriented risk models, CLD does not seem to increase the risk of either a low MDI or a low PDI. However, severe CLD might increase the risk of a low PDI.

Patterns of respiratory disease during the first 2 postnatal weeks in extremely premature infants

BACKGROUND

Pulmonary disease among infants of <28 weeks' gestation (extremely low gestational age newborns) often has the following pattern: the infant starts out with little need for supplemental oxygen and ventilatory support in the first postnatal week but then has pulmonary deterioration in the second postnatal week, with an increased need for supplemental oxygen and respiratory support. We evaluated the antecedents and correlates of patterns of early lung disease, with particular emphasis on pulmonary deterioration, in a large cohort study (the Extremely Low Gestational Age Newborn [ELGAN] study).

PATIENTS AND METHODS

We examined data collected prospectively on 1340 infants born between 2002 and 2004 at 23 to 27 completed weeks of gestation and who survived to 14 days. Pulmonary deterioration was defined as receipt of fraction of inspired oxygen < 0.23 on any day between days 3 and 7 and receipt of fraction of inspired oxygen > or = 0.25 on day 14.

RESULTS

One fifth (20%) of the infants had consistently low fraction of inspired oxygen, approximately two fifths (38%) had pulmonary deterioration, and the remaining approximately two fifths (43%) had consistently high fraction of inspired oxygen (early and persistent lung dysfunction). Compared with infants who had consistently low fraction of inspired oxygen, infants who experienced pulmonary deterioration had lower gestational ages and lower birth weights, had higher scores for neonatal acute physiology, and received more intensive modes of respiratory support. Gender, multifetal pregnancy, cesarean delivery, antenatal steroids, chorioamnionitis, and funisitis were not associated with pulmonary deterioration. The incidence of chronic lung disease, defined as oxygen therapy at 36 weeks' postmenstrual age, was 17% in the consistently low fraction of inspired oxygen group, 51% in the pulmonary deterioration group, and 67% in the early and persistent pulmonary dysfunction group. The incidence of death in these 3 groups before 36 weeks' postmenstrual age was 1%, 3%, and 5%, respectively.

CONCLUSIONS

Nearly 40% of extremely low gestational age newborns experience pulmonary deterioration in the first 2 postnatal weeks, and half of these infants develop chronic lung disease. Indicators of developmental immaturity and illness severity were associated with both pulmonary deterioration and chronic lung disease. Studying the antecedents of pulmonary deterioration might provide new insights about chronic lung disease pathogenesis.

Spontaneous closure of the patent ductus arteriosus in very low birth weight infants following discharge from the neonatal unit

OBJECTIVE

To determine the incidence of spontaneous closure of the patent ductus arteriosus (PDA) and the use of medical therapies for treatment of PDA-related conditions among very low birth weight (VLBW) infants with ductal patency at the time of initial hospital discharge.

STUDY DESIGN

We conducted a single-centre, retrospective, observational study of VLBW infants (birth weight <1500 g) born during 2004 and 2005 and discharged with a PDA. PDA was defined by echocardiographic and/or clinical criteria. We identified the related discharge needs, subsequent interventions, and the post-menstrual age (PMA) at which there was no longer evidence of a PDA.

RESULTS

Three hundred and ninety one VLBW infants were admitted; 310 survived to discharge. Ninety five were diagnosed with a PDA during their hospitalisations; 21 had a PDA at discharge (10 received indomethacin, 11 were never treated). Among these, mean gestational age was 28 weeks, mean birth weight was 998 g, and median duration of hospitalisation was 73 days. Two infants were discharged on oxygen, two on diuretics, and two on both. None had congestive heart failure, and none died during infancy. Spontaneous closure occurred in 18 of 21 infants at a median PMA of 48 weeks (range 34-76; interquartile range 46-56). Two infants had coil occlusion at 11 months of age. One patient had a PDA at 14 months of age.

CONCLUSIONS

Among a select group of VLBW infants with a PDA at initial hospital discharge, spontaneous closure during early infancy occurred in most infants.

Very early surfactant without mandatory ventilation in premature infants treated with early continuous positive airway pressure: a randomized, controlled trial

BACKGROUND

Chronic lung disease is one of the most frequent and serious complications of premature birth. Because mechanical ventilation is a major risk factor for chronic lung disease, the early application of nasal continuous positive airway pressure has been used as a strategy for avoiding mechanical ventilation in premature infants. Surfactant therapy improves the short-term respiratory status of premature infants, but its use is traditionally limited to infants being mechanically ventilated. Administration of very early surfactant during a brief period of intubation to infants treated with nasal continuous positive airway pressure may improve their outcome and further decrease the need for mechanical ventilation.

OBJECTIVE

Our goal was to determine if very early surfactant therapy without mandatory ventilation improves outcome and decreases the need for mechanical ventilation when used in very premature infants treated with nasal continuous positive airway pressure soon after birth.

DESIGN/METHODS

Eight centers in Colombia participated in this randomized, controlled trial. Infants born between 27 and 31 weeks' gestation with evidence of respiratory distress and treated with supplemental oxygen in the delivery room were randomly assigned within the first hour of life to intubation, very early surfactant, extubation, and nasal continuous positive airway pressure (treatment group) or nasal continuous airway pressure alone (control group). The primary outcome was the need for subsequent mechanical ventilation using predefined criteria.

RESULTS

From January 1, 2004, to December 31, 2006, 279 infants were randomly assigned, 141 to the treatment group and 138 to the control group. The need for mechanical ventilation was lower in the treatment group (26%) compared with the control group (39%). Air-leak syndrome occurred less frequently in the treatment group (2%) compared with the control group (9%). The percentage of patients receiving surfactant after the first hour of life was also significantly less in the treatment group (12%) compared with the control group (26%). The incidence of chronic lung disease (oxygen treatment at 36 weeks' postmenstrual age) was 49% in the treatment group compared with 59% in the control group. All other outcomes, including mortality, intraventricular hemorrhage, and periventricular leukomalacia were similar between the groups.

CONCLUSIONS

In premature infants treated with nasal continuous positive airway pressure early after birth, the addition of very early surfactant therapy without mandatory ventilation decreased the need for subsequent mechanical ventilation, decreased the incidence of air-leak syndrome, and seemed to be safe. Reduction in the need for mechanical ventilation is an important outcome when medical resources are limited and may result in less chronic lung disease in both developed and developing countries.

A pilot randomized, controlled trial of later treatment with a peptide-containing, synthetic surfactant for the prevention of bronchopulmonary dysplasia

OBJECTIVE

Oxidant injury and lung inflammation in extremely premature infants are associated with the development of bronchopulmonary dysplasia. Surfactant dysfunction resulting from these events may contribute to the pathogenesis of bronchopulmonary dysplasia. Treatment with exogenous surfactant may decrease the incidence or severity of bronchopulmonary dysplasia. We conducted a masked, multicenter, multinational, randomized, controlled, pilot study to estimate the effects of treating infants at high risk for developing bronchopulmonary dysplasia with lucinactant, a synthetic, peptide-containing surfactant, on safety during dosing and the incidence of death or bronchopulmonary dysplasia.

METHODS

Preterm infants between 600 and 900 g requiring mechanical ventilation and a fraction of inspired oxygen of > or =0.30 between 3 and 10 days of age were randomly assigned to receive either sham air (placebo) or 1 of 2 doses of lucinactant (90 or 175 mg/kg total phospholipid) every 48 hours to a maximum of 5 doses, if they remained on mechanical ventilation.

RESULTS

Of 136 infants enrolled at 34 sites, 44 received placebo, 47 received 90 mg/kg total phospholipid, and 45 received 175 mg/kg total phospholipid. The 90 mg/kg group had a significantly higher percentage of boys (64%) compared with the placebo group (39%); no other significant differences in baseline characteristics among groups were present. Compared with placebo, both the 90 mg/kg and 175 mg/kg groups experienced a significantly higher incidence of desaturation and bradycardia during dosing. Twenty-four hours after dosing, the mean fraction of inspired oxygen was lower in both lucinactant groups (33%) compared with the placebo group (39%). The incidence of mortality or bronchopulmonary dysplasia was 66% in the placebo group, 79% in the 90 mg/kg group, and 58% in the 175 mg/kg group. These differences were not statistically significant. There were no statistical differences among groups for pneumothorax, pulmonary interstitial emphysema, intraventricular hemorrhage, periventricular leukomalacia, retinopathy of prematurity, or mortality.

CONCLUSIONS

There were trends toward lower oxygen requirements and toward a lower incidence of mortality or bronchopulmonary dysplasia at 36 weeks' postmenstrual age in infants who received the higher dose of lucinactant, and this warrants further investigation.

Treatment strategies to prevent or close a patent ductus arteriosus in preterm infants and outcomes

OBJECTIVE

To describe the current use of treatments to prevent or treat patent ductus arteriosus (PDA) in preterm infants, examine the association between different treatment strategies and neonatal outcomes and review the variation in these practices between centers.

STUDY DESIGN

Cohort study of infants born between 23 and 30 weeks gestation managed by the Pediatrix Medical Group from 1997 to 2004. We collected data on demographics, indomethacin and ligation, and outcomes of the following five groups: prophylactic indomethacin treatment: infants treated with indomethacin on day of life (DOL) 0 or 1; indicated indomethacin treatment: infants treated with indomethacin after DOL 1; PDA without treatment: infants with a PDA without report of treatment; ligation only: infants with a PDA ligation without use of indomethacin and no PDA: infants without a PDA and without treatment.

RESULTS

There were 6189 (18%) patients who received prophylactic indomethacin, 5690 (16%) patients received indicated treatment, 3886 (11%) patients had a PDA without treatment, 702 (2%) patients received ligation only and 18 136 (52%) patients had no PDA. In multivariate analysis, mortality among survivors to 2 days of age was lower (odds ratio (OR) 0.6, 95% confidence interval (CI) 0.5 to 0.7, P<0.01) and chronic lung disease, isolated intestinal perforation and severe retinopathy of prematurity (stages 3 and 4) were higher (OR 1.5, 95% CI 1.3 to 1.6, P<0.01; OR 1.5, 95% CI 1.1 to 2.0, P<0.01 and 1.4, 95% CI 1.2 to 1.6, P<0.01, respectively) in the indicated treatment group compared with the PDA without treatment group. The proportion of infants receiving prophylactic indomethacin among all infants and infants receiving indicated treatment among neonates with a report of a PDA varied by site from 0 to 59% (median 9.5%) and 0 to 100% (median 62%), respectively.

CONCLUSIONS

Indomethacin use for intraventricular hemorrhage prevention and/or treatment of a PDA is common, but the selection of infants for treatment, and the decision of when and how to treat vary widely between centers. Our findings suggest the need for randomized, placebo-controlled trials of the effect of treatment of the PDA in preterm infants.

Factors associated with treatment for hypotension in extremely low gestational age newborns during the first postnatal week

OBJECTIVE

The goals were to identify the blood pressures of extremely low gestational age newborns that prompt intervention, to identify other infant characteristics associated with receipt of therapies intended to increase blood pressure, and to assess the interinstitutional variability in the use of these therapies.

METHODS

The cohort included 1507 extremely low gestational age newborns born at 23 weeks to 27 weeks of gestation, at 14 institutions, between March 2002 and August 2004; 1387 survived the first postnatal week. Blood pressures were measured as clinically indicated. Interventions were grouped as any treatment (ie, vasopressor and/or fluid boluses of >10 mL/kg) and vasopressor treatment, and logistic regression analyses were performed.

RESULTS

At each gestational age, the lowest mean arterial pressures in treated and untreated infants tended to increase with advancing postnatal age. Infants who received any therapy tended to have lower mean arterial pressures than infants who did not, but uniform thresholds for treatment were not apparent. The proportion of infants receiving any treatment decreased with increasing gestational age from 93% at 23 weeks to 73% at 27 weeks. Treatment nearly always began during the first 24 hours of life. Lower gestational age, lower birth weight, male gender, and higher Score for Neonatal Acute Physiology-II values were associated with any treatment and vasopressor treatment. Institutions varied greatly in their tendency to offer any treatment and vasopressor treatment. Neither the lowest mean arterial pressure on the day of treatment nor other characteristics of the infants accounted for center differences in treatment.

CONCLUSIONS

Blood pressure in extremely premature infants not treated for hypotension increased directly with both increasing gestational age and postnatal age. The decision to provide treatment was associated more strongly with the center where care was provided than with infant attributes.

Rising birth prevalence of gastroschisis

OBJECTIVE

Gastroschisis is a congenital anomaly that has been reported to be increasing in frequency. The objective of this study was to determine the birth prevalence of gastroschisis using two large databases.

STUDY DESIGN

We reviewed data from a statewide database and a national database from a neonatal health care provider, abstracting cases of gastroschisis.

RESULTS

In North Carolina, the birth prevalence of gastroschisis increased from 1.96 per 10,000 births in 1997 to 4.49 per 10,000 births in 2000 (p=0.0007). The overall increase was almost entirely because of the increase in infants born to mothers less than 20 years old. Among infants receiving care from the national neonatal provider, the prevalence of gastroschisis increased from 2.9 per 1000 patients in 1997 to five per 1000 patients in 2001 (p=0.044).

CONCLUSION

The birth prevalence of gastroschisis is increasing in North Carolina, and this trend may be occurring nationally. The rapid change in the birth prevalence in the subset of population most at risk for gastroschisis implicates environmental or pharmacologic teratogens rather than changing population characteristics as a causal factor in the development of gastroschisis.