This report presents data from the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network on care of and morbidity and mortality rates for very low birth weight infants, according to gestational age (GA).
Perinatal/neonatal data were collected for 9575 infants of extremely low GA (22–28 weeks) and very low birth weight (401–1500 g) who were born at network centers between January 1, 2003, and December 31, 2007.
Rates of survival to discharge increased with increasing GA (6% at 22 weeks and 92% at 28 weeks); 1060 infants died at ≤ 12 hours, with most early deaths occurring at 22 and 23 weeks (85% and 43%, respectively). Rates of prenatal steroid use (13% and 53%, respectively), cesarean section (7% and 24%, respectively), and delivery room intubation (19% and 68%, respectively) increased markedly between 22 and 23 weeks. Infants at the lowest GAs were at greatest risk for morbidities. Overall, 93% had respiratory distress syndrome, 46% patent ductus arteriosus, 16% severe intraventricular hemorrhage, 11% necrotizing enterocolitis, and 36% late-onset sepsis. The new severity-based definition of bronchopulmonary dysplasia classified more infants as having bronchopulmonary dysplasia than did the traditional definition of supplemental oxygen use at 36 weeks (68%, compared with 42%). More than one-half of infants with extremely low GAs had undetermined retinopathy status at the time of discharge. Center differences in management and outcomes were identified.
Although the majority of infants with GAs of ≥24 weeks survive, high rates of morbidity among survivors continue to be observed.
extremely low gestation; very low birth weight; morbidity; death
There are limited data to inform the choice between early treatment
with continuous positive airway pressure (CPAP) and early surfactant
treatment as the initial support for extremely-low-birth-weight infants.
We performed a randomized, multicenter trial, with a 2-by-2 factorial
design, involving infants who were born between 24 weeks 0 days and 27 weeks
6 days of gestation. Infants were randomly assigned to intubation and
surfactant treatment (within 1 hour after birth) or to CPAP treatment
initiated in the delivery room, with subsequent use of a protocol-driven
limited ventilation strategy. Infants were also randomly assigned to one of
two target ranges of oxygen saturation. The primary outcome was death or
bronchopulmonary dysplasia as defined by the requirement for supplemental
oxygen at 36 weeks (with an attempt at withdrawal of supplemental oxygen in
neonates who were receiving less than 30% oxygen).
A total of 1316 infants were enrolled in the study. The rates of the
primary outcome did not differ significantly between the CPAP group and the
surfactant group (47.8% and 51.0%, respectively; relative
risk with CPAP, 0.95; 95% confidence interval [CI],
0.85 to 1.05) after adjustment for gestational age, center, and familial
clustering. The results were similar when bronchopulmonary dysplasia was
defined according to the need for any supplemental oxygen at 36 weeks (rates
of primary outcome, 48.7% and 54.1%, respectively; relative
risk with CPAP, 0.91; 95% CI, 0.83 to 1.01). Infants who received
CPAP treatment, as compared with infants who received surfactant treatment,
less frequently required intubation or postnatal corticosteroids for
bronchopulmonary dysplasia (P<0.001), required fewer days of
mechanical ventilation (P = 0.03), and were more likely to be alive
and free from the need for mechanical ventilation by day 7 (P =
0.01). The rates of other adverse neonatal outcomes did not differ
significantly between the two groups.
The results of this study support consideration of CPAP as an
alternative to intubation and surfactant in preterm infants.
(ClinicalTrials.gov number, NCT00233324.)
To determine (1) the magnitude of clustering of bronchopulmonary dysplasia (36 weeks) or death (the outcome) across centers of the Eunice Kennedy Shriver National Institute of Child and Human Development National Research Network, (2) the infant-level variables associated with the outcome and estimate their clustering, and (3) the center-specific practices associated with the differences and build predictive models.
Data on neonates with a birth weight of <1250 g from the cluster-randomized benchmarking trial were used to determine the magnitude of clustering of the outcome according to alternating logistic regression by using pairwise odds ratio and predictive modeling. Clinical variables associated with the outcome were identified by using multivariate analysis. The magnitude of clustering was then evaluated after correction for infant-level variables. Predictive models were developed by using center-specific and infant-level variables for data from 2001 2004 and projected to 2006.
In 2001–2004, clustering of bronchopulmonary dysplasia/death was significant (pairwise odds ratio: 1.3; P < .001) and increased in 2006 (pairwise odds ratio: 1.6; overall incidence: 52%; range across centers: 32%–74%); center rates were relatively stable over time. Variables that varied according to center and were associated with increased risk of outcome included lower body temperature at NICU admission, use of prophylactic indomethacin, specific drug therapy on day 1, and lack of endotracheal intubation. Center differences remained significant even after correction for clustered variables.
Bronchopulmonary dysplasia/death rates demonstrated moderate clustering according to center. Clinical variables associated with the outcome were also clustered. Center differences after correction of clustered variables indicate presence of as-yet unmeasured center variables.
logistic models; infant; premature; predictive value of tests; clustering
Preterm infants with intrauterine growth restriction are at increased risk of respiratory distress syndrome and bronchopulmonary dysplasia (BPD). A randomized clinical trial by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) Neonatal Research Network demonstrated that vitamin A supplementation in extremely low-birth-weight (ELBW) preterm infants requiring early respiratory support decreased the risk of developing BPD.
A subgroup analysis of small-for-gestational-age (SGA) infants from the original NICHD trial was performed to test the hypothesis that in infants requiring early respiratory support, vitamin A supplementation decreases the relative risk of BPD or death in premature SGA infants to a greater extent than in gestational age–equivalent vitamin A–treated appropriate-for-gestational-age (AGA) infants.
Although vitamin A supplementation significantly increased serum retinol concentrations in AGA ELBW infants (median [5th percentile, 95th percentile]: 16.3 [−7.0, 68.8] versus 2.4 [−13.9, 55.1]; p < 0.001), no increases were noted in SGA ELBW infants.
Given the limited power of this analysis due to a low number of SGA infants, these data did not provide evidence to support the hypothesis that vitamin A supplementation in preterm SGA infants requiring early respiratory support decreases the relative risk of BPD or death as compared with preterm AGA infants.
vitamin A; IUGR–intrauterine growth restriction; BPD–bronchopulmonary dysplasia; SGA–small for gestational age; AGA–appropriate for gestational age
Ventilator injury has been implicated in the pathogenesis of bronchopulmonary dysplasia. Avoiding invasive ventilation could reduce lung injury, and early respiratory management may affect pulmonary outcomes.
To analyze the effect of initial respiratory support on survival without bronchopulmonary dysplasia at a gestational age of 36 weeks.
A prospective 3-year observational study. Preterm infants of <32 weeks gestational age were classified into 4 groups according to the support needed during the first 2 hours of life: room air, nasal continuous positive airway pressure, intubation/surfactant/extubation and prolonged mechanical ventilation (defined as needing mechanical ventilation for more than 2 hours).
Of the 329 eligible patients, a total of 49% did not need intubation, and 68.4% did not require prolonged mechanical ventilation. At a gestational age of 26 weeks, there was a significant correlation between survival without bronchopulmonary dysplasia and initial respiratory support. Preterm infants requiring mechanical ventilation showed a higher risk of death and bronchopulmonary dysplasia. After controlling for gestational age, antenatal corticosteroid use, maternal preeclampsia and chorioamnionitis, the survival rate without bronchopulmonary dysplasia remained significantly lower in the mechanically ventilated group.
In our population, the need for more than 2 hours of mechanical ventilation predicted the development of bronchopulmonary dysplasia in preterm infants with a gestational age >26 weeks (sensitivity = 89.5% and specificity = 67%). The need for prolonged mechanical ventilation could be an early marker for the development of bronchopulmonary dysplasia. This finding could help identify a target population with a high risk of chronic lung disease. Future research is needed to determine other strategies to prevent bronchopulmonary dysplasia in this high-risk group of patients.
Bronchopulmonary Dysplasia; Preterm; Nasal CPAP; Surfactant; Initial; Respiratory Support
Inflammation mediated by cytokines may be important in the pathogenesis of bronchopulmonary dysplasia and the competing outcome of death in extremely low birth weight infants.
To develop multi-variable logistic regression models for the outcome of bronchopulmonary dysplasia and/or death at 36w post-menstrual age using clinical and cytokine data from the first 28 days.
1067 extremely low birth weight infants in the Neonatal Research Network of the National Institute of Child Health and Human Development had 25 cytokines measured from blood collected within 4 h of birth and on days 3, 7, 14, and 21. Stepwise regression using peak values of the 25 cytokines and 15 clinical variables identified variables associated with BPD/death. Multi-variable logistic regression was done for bronchopulmonary dysplasia/death using variables selected by stepwise regression. Similar analyses were also done using average cytokine values from days 0–21, days 0–3, and from days 14–21.
Of 1062 infants with available data, 606 infants developed bronchopulmonary dysplasia or died. Combining results from all models, bronchopulmonary dysplasia/death was associated with higher concentrations of interleukins-1β, -6, -8, -10, and interferon-γ and lower concentrations of interleukin-17, RANTES, and tumor necrosis factor-β. Compared to models with only clinical variables, addition of cytokine data improved predictive ability by a statistically significant but clinically modest magnitude.
The overall pattern of cytokines suggests bronchopulmonary dysplasia/death may be associated with impairment in the transition from the innate immune response mediated by neutrophils to the adaptive immune response mediated by T-lymphocytes.
Logistic models; Infant; premature; Predictive value of tests
Eosinophilia is common in premature infants, and its incidence increases with a shorter gestation period. We investigated the clinical significance of eosinophilia in premature infants born at <34 weeks gestation.
We analyzed the medical records of premature infants born at <34 weeks gestation who were admitted to the neonatal intensive care unit at Ewha Womans University Mokdong Hospital between January 2003 and September 2010. Eosinophilia was defined as an eosinophil percentage of >3% of the total leukocytes. Perinatal parameters and clinical parameters were also analyzed.
Of the 261 infants born at <34 weeks gestation, 22.4% demonstrated eosinophilia at birth. The eosinophil percentage peaked in the fourth postnatal week at 7.5%. The incidence of severe eosinophilia increased after birth up to the fourth postnatal week when 8.8% of all patients had severe eosinophilia. Severity of eosinophilia was positively correlated with a lower gestational age, birth weight, and Apgar score. Respiratory distress syndrome, bronchopulmonary dysplasia, nephrocalcinosis, intraventricular hemorrhage, and sepsis were associated with a higher eosinophil percentage. The eosinophil percentage was significantly higher in infants with bronchopulmonary dysplasia from the first postnatal week and the percentage was the highest in the fourth postnatal week, with the maximal difference being 4.1% (P<0.001).
Eosinophilia is common in premature infants and reaches peak incidence and severity in the fourth postnatal week. The eosinophil percentage was significantly higher in bronchopulmonary dysplasia patients from the first postnatal week. Severe eosinophilia was significantly associated with the incidence of bronchopulmonary dysplasia even after adjusting for other variables.
Eosinophilia; Premature infants; Bronchopulmonary dysplasia
Previous results from our trial of early treatment with continuous positive airway pressure (CPAP) versus early surfactant treatment in infants showed no significant difference in the outcome of death or bronchopulmonary dysplasia. A lower (vs. higher) target range of oxygen saturation was associated with a lower rate of severe retinopathy but higher mortality. We now report longer-term results from our prespecified hypotheses.
Using a 2-by-2 factorial design, we randomly assigned infants born between 24 weeks 0 days and 27 weeks 6 days of gestation to early CPAP with a limited ventilation strategy or early surfactant administration and to lower or higher target ranges of oxygen saturation (85 to 89% or 91 to 95%). The primary composite outcome for the longer-term analysis was death before assessment at 18 to 22 months or neurodevelopmental impairment at 18 to 22 months of corrected age.
The primary outcome was determined for 1234 of 1316 enrolled infants (93.8%); 990 of the 1058 surviving infants (93.6%) were evaluated at 18 to 22 months of corrected age. Death or neurodevelopmental impairment occurred in 27.9% of the infants in the CPAP group (173 of 621 infants), versus 29.9% of those in the surfactant group (183 of 613) (relative risk, 0.93; 95% confidence interval [CI], 0.78 to 1.10; P = 0.38), and in 30.2% of the infants in the lower-oxygen-saturation group (185 of 612), versus 27.5% of those in the higher-oxygen-saturation group (171 of 622) (relative risk, 1.12; 95% CI, 0.94 to 1.32; P = 0.21). Mortality was increased with the lower-oxygen-saturation target (22.1%, vs. 18.2% with the higher-oxygen-saturation target; relative risk, 1.25; 95% CI, 1.00 to 1.55; P = 0.046).
We found no significant differences in the composite outcome of death or neurodevelopmental impairment among extremely premature infants randomly assigned to early CPAP or early surfactant administration and to a lower or higher target range of oxygen saturation. (Funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development and the National Heart, Lung, and Blood Institute; SUPPORT ClinicalTrials.gov number, NCT00233324.)
Late-onset hyponatremia (LOH), hyponatremia occurring after two weeks of age with the achievement of full feeding, is the result of a negative sodium balance caused by inadequate salt intake or excessive salt loss due to immature renal or intestinal function in preterm infants. The aims of our study were to identify the risk factors for LOH and its influence on neonatal outcomes. This was a retrospective cohort analysis of 161 preterm infants born before 34 weeks of gestation between June 2009 and December 2010 at Seoul National University Hospital. LOH was defined as a sodium level ≤ 132 mEq/L or 133-135 mEq/L with oral sodium supplementation. LOH occurred in 49 (30.4%) of the studied infants. A lower gestational age, a shorter duration of parenteral nutrition, the presence of respiratory distress syndrome, the use of furosemide, and feeding with breast milk were significant risk factors for LOH. In terms of neonatal outcomes, the infants with LOH had longer hospital stays and higher risks of bronchopulmonary dysplasia and retinopathy of prematurity requiring surgery. LOH lasting at least 7 days significantly increased moderate to severe bronchopulmonary dysplasia, periventricular leukomalacia, and extra-uterine growth retardation. LOH is commonly observed in preterm infants; it may be a risk factor for bronchopulmonary dysplasia and retinopathy of prematurity or a marker of illness severity.
Hyponatremia; Premature Infant; Prematurity; Risk Factors; Outcome
A count of 3 neonatal morbidities (bronchopulmonary dysplasia, brain injury, and severe retinopathy of prematurity) strongly predict the risk of death or neurosensory impairment in extremely low birth weight infants who survive to 36 weeks’ postmenstrual age. Neonatal infection has also been linked with later impairment. We examined whether the addition of infection to the count of 3 neonatal morbidities further improves the prediction of poor outcome.
We studied 944 infants who participated in the Trial of Indomethacin Prophylaxis in Preterms and survived to 36 weeks’ postmenstrual age. Culture-proven sepsis, meningitis, and stage II or III necrotizing enterocolitis were recorded prospectively. We investigated the incremental prognostic importance of neonatal infection by adding terms for the different types of infection to a logistic model that already contained terms for the count of bronchopulmonary dysplasia, brain injury, and severe retinopathy. Poor outcome at 18 months of age was death or survival with 1 or more of the following: cerebral palsy, cognitive delay, severe hearing loss, and bilateral blindness.
There were 414 (44%) infants with at least 1 episode of infection or necrotizing enterocolitis. Meningitis and the presence of any type of infection added independent prognostic information to the morbidity-count model. The odds ratio associated with infection or necrotizing enterocolitis in this model was 50% smaller than the odds ratio associated with each count of the other 3 neonatal morbidities. Meningitis was rare and occurred in 22 (2.3%) of 944 infants.
In this cohort of extremely low birth weight infants who survived to 36 weeks’ postmenstrual age, neonatal infection increased the risk of a late death or survival with neurosensory impairment. However, infection was a weaker predictor of poor outcome than bronchopulmonary dysplasia, brain injury, and severe retinopathy.
extremely low birth weight infant; infection; bronchopulmonary dysplasia; brain injury; retinopathy; neurosensory impairment
De novo heterozygous mutations in HRAS cause Costello syndrome (CS), a condition with high mortality and morbidity in infancy and early childhood due to cardiac, respiratory, and muscular complications. HRAS mutations predicting p.Gly12Val, p.Gly12Asp, and p.Gly12Cys substitutions have been associated with severe, lethal, CS. We report on molecular, clinical, and pathological findings in patients with mutations predicting HRAS p.Gly12Val that were identified in our clinical molecular genetic testing service. Such mutations were identified in four patients. Remarkably, three were deletion/insertion mutations affecting coding nucleotides 35 and 36. All patients died within 6 postnatal weeks, providing further evidence that p.Gly12Val mutations predict a very poor prognosis. High birth weight, polyhydramnios (and premature birth), cardiac hypertrophy, respiratory distress, muscle weakness, and postnatal growth failure were present. Dysmorphism was subtle or non-specific, with edema, coarsened facial features, prominent forehead, depressed nasal bridge, anteverted nares, and low-set ears. Proximal upper limb shortening, a small bell-shaped chest, talipes, and fixed flexion deformities of the wrists were seen. Neonatal atrial arrhythmia, highly suggestive of CS, was also present in two patients. One patient had congenital alveolar dysplasia, and another, born after 36 weeks' gestation, bronchopulmonary dysplasia. A rapidly fatal disease course, and the difficulty of identifying subtle dysmorphism in neonates requiring intensive care, suggest that this condition remains under-recognized, and should enter the differential diagnosis for very sick infants with a range of clinical problems including cardiac hypertrophy and disordered pulmonary development. Clinical management should be informed by knowledge of the poor prognosis of this condition. © 2012 Wiley Periodicals, Inc.
Costello syndrome; HRAS; neonatal cardiomyopathy; congenital alveolar dysplasia; dinucleotide insertion/deletion mutation
Aim. To determine among infants born before the 28th week of gestation to what extent blood gas abnormalities during the first three postnatal days provide information about the risk of bronchopulmonary dysplasia (BPD). Methods. We studied the association of extreme quartiles of blood gas measurements (hypoxemia, hyperoxemia, hypocapnea, and hypercapnea) in the first three postnatal days, with bronchopulmonary dysplasia, among 906 newborns, using multivariable models adjusting for potential confounders. We approximated NIH criteria by classifying severity of BPD on the basis of the receipt of any O2 on postnatal day 28 and at 36 weeks PMA and assisted ventilation. Results. In models that did not adjust for ventilation, hypoxemia was associated with increased risk of severe BPD and very severe BPD, while infants who had hypercapnea were at increased risk of very severe BPD only. In contrast, infants who had hypocapnea were at reduced risk of severe BPD. Including ventilation for 14 or more days eliminated the associations with hypoxemia and with hypercapnea and made the decreased risk of very severe BPD statistically significant. Conclusions. Among ELGANs, recurrent/persistent blood gas abnormalities in the first three postnatal days convey information about the risk of severe and very severe BPD.
To determine the risks and benefits associated with the transfusion of packed red blood cells (PRBCs) in extremely low birth weight (ELBW) infants. We hypothesized that when ELBW infants underwent transfusion with the University of Washington Neonatal Intensive Care Unit (NICU) 2006 guidelines, no clinical benefit would be discernible.
We conducted a retrospective chart review of all ELBW infants admitted to the NICU in 2006. Information on weight gain, apnea, heart rate, and respiratory support was collected for 2 days preceding, the day of, and 3 days after PRBC transfusion. The incidence, timing, and severity of complications of prematurity were documented.
Of the 60 ELBW infants admitted to the NICU in 2006, 78% received PRBC transfusions. Transfusions were not associated with improved weight gain, apnea, or ventilatory/oxygen needs. However, they were associated with increased risk of bronchopulmonary dysplasia, necrotizing enterocolitis, and diuretic use (P < .05). Transfusions correlated with phlebotomy losses, gestational age, and birth weight. No association was found between transfusions and sepsis, retinopathy of prematurity, or erythropoietin use.
When our 2006 PRBC transfusion guidelines were used, no identifiable clinical benefits were identified, but increased complications of prematurity were noted. New, more restrictive guidelines were developed as a result of this study.
Early fluid and electrolyte imbalances may be associated with an increased risk of bronchopulmonary dysplasia.
We sought to establish an association between fluid and electrolyte balance in the first week of life and the risk of bronchopulmonary dysplasia.
Clinical charts of 205 neonates <32 weeks gestational age and/or <1,250 g birth weight (admitted to our NICU between 1997 and 2008) were analyzed. Clinical features, fluid and electrolyte balance were analyzed for the first 7 days of life using multivariate models of generalized estimation equations. A p value <0.05 was considered significant in all of the hypothesis tests.
The prevalence of bronchopulmonary dysplasia was 22%. Lower gestational age and birth weight, male gender, less frequent use of antenatal steroids, respiratory distress syndrome, use of surfactant, patent ductus arteriosus, duration of invasive ventilation and NICU stay were significantly associated with bronchopulmonary dysplasia. The variation in serum values of potassium, phosphorus and creatinine during the first week of life also revealed an association with bronchopulmonary dysplasia. Higher mean plasma calcium values were associated with spontaneous closure of the patent ductus arteriosus. The use of indomethacin to induce patent ductus arteriosus closure was significantly higher in bronchopulmonary dysplasia patients.
Differences in renal function and tubular handling of potassium and phosphorus are present during the first week of life among preterm neonates who will develop bronchopulmonary dysplasia. The higher rate of patent ductus arteriosus and indomethacin use may influence these differences. Serum levels of calcium also appear to play a role in spontaneous ductus arteriosus closure.
Fluid; Electrolyte; Bronchopulmonary dysplasia; Preterm neonate; Phosphorus
This study aimed to determine the impact of maternal cervical incompetence (with or without McDonald cerclage) on mortality and morbidity of preterm infant with birth weight <2000g.
581 neonates were eligible for this study, 79 with cervical incompetence and 502 without it (control). Incidences of neonatal respiratory distress syndrome (RDS), bronchopulmonary dysplasia (BPD), intraventricular hemorrhage (IVH), neonatal necrotizing enterocolitis (NEC), retinopathy of prematurity (ROP), periventricular leukomalacia (PVL), severe asphyxia, small for gestational age (SGA), early-onset sepsis (EOS), and mortality were compared between the two groups.
Mean gestational age was earlier in cervical incompetence group than in control (30.2±2.1 vs 30.7±1.9, P<0.05). Except lower frequency of SGA, there were no significant differences in the incidences of RDS, BPD, ROP, PVL, IVH, NEC, EOS, severe asphyxia and mortality between the two groups. Infants with no cerclage had a higher prevalence of RDS (21/66 vs 9/13, P<0.05) compared to cerclage group due to lower mean gestational age (30.68±2.1 vs 28.6±1.4, P<0.01) and birth weight (1519.5±274.6 vs 1205.8±204.4, P<0.001), and clinical neonatal outcomes of the elective cerclage were similar to emergency cerclage in cervical incompetence groups.
Maternal cervical incompetence was not associated with postnatal adverse neonatal outcomes. Lower mean gestational age was a major risk associated with higher prevalence of RDS in preterm neonates with no McDonald cerclage, and emergency cerclage did not predict poor clinical neonatal outcomes.
Uterine Cervical Incompetence; Neonate; Mortality; Morbidity; McDonald Cerclage
Pulmonary hypertension (PH) is an increasingly recognized complication of premature birth and bronchopulmonary dysplasia (BPD), and is associated with increased morbidity and mortality. Extreme phenotypic variability exists among preterm infants of similar gestational ages, making it difficult to predict which infants are at increased risk for developing PH. Intrauterine growth retardation or drug exposures, postnatal therapy with prolonged positive pressure ventilation, cardiovascular shunts, poor postnatal lung and somatic growth, and genetic or epigenetic factors may all contribute to the development of PH in preterm infants with BPD. In addition to the variability of severity of PH, there is also qualitative variability seen in PH, such as the variable responses to vasoactive medications. To reduce the morbidity and mortality associated with PH, a multi-pronged approach is needed. First, improved screening for and increased recognition of PH may allow for earlier treatment and better clinical outcomes. Second, identification of both prenatal and postnatal risk factors for the development of PH may allow targeting of therapy and resources for those at highest risk. Third, understanding the pathophysiology of the preterm pulmonary vascular bed may help improve outcomes through recognizing pathways that are dysregulated in PH, identifying novel biomarkers, and testing novel treatments. Finally, the recognition of conditions and exposures that may exacerbate or lead to recurrent PH is needed to help with developing treatment guidelines and preventative strategies that can be used to reduce the burden of disease.
pulmonary hypertension; bronchopulmonary dysplasia; prematurity; chronic lung disease
We sought to determine if a center’s approach to care of premature infants at the youngest gestational ages (22–24 weeks’ gestation) is associated with clinical outcomes among infants of older gestational ages (25–27 weeks’ gestation).
Inborn infants of 401 to 1000 g birth weight and 22 0/7 to 27 6/7 weeks’ gestation at birth from 2002 to 2008 were enrolled into a prospectively collected database at 20 centers participating in the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network. Markers of an aggressive approach to care for 22- to 24-week infants included use of antenatal corticosteroids, cesarean delivery, and resuscitation. The primary outcome was death before postnatal day 120 for infants of 25 to 27 weeks’ gestation. Secondary outcomes were the combined outcomes of death or a number of morbidities associated with prematurity.
Our study included 3631 infants 22 to 24 weeks’ gestation and 5227 infants 25 to 27 weeks’ gestation. Among the 22- to 24-week infants, use of antenatal corticosteroids ranged from 28% to 100%, cesarean delivery from 13% to 65%, and resuscitation from 30% to 100% by center. Centers with higher rates of antenatal corticosteroid use in 22- to 24-week infants had reduced rates of death, death or retinopathy of prematurity, death or late-onset sepsis, death or necrotizing enterocolitis, and death or neurodevelopmental impairment in 25- to 27-week infants.
This study suggests that physicians’ willingness to provide care to extremely low gestation infants as measured by frequency of use of antenatal corticosteroids is associated with improved outcomes for more-mature infants.
low-birth weight infant; NICUs; treatment; patient outcome assessment
Background. An abnormally high incidence (44%) of bronchopulmonary dysplasia with variations in rates among cities was observed in Colombia among premature infants. Objective. To identify risk factors that could explain the observed high incidence and regional variations of bronchopulmonary dysplasia. Study Design. A case-control study was designed for testing the hypothesis that differences in the disease rates were not explained by differences in city-of-birth specific population characteristics or by differences in respiratory management practices in the first 7 days of life, among cities. Results. Multivariate analysis showed that premature rupture of membranes, exposure to mechanical ventilation after received nasal CPAP, no surfactant exposure, use of rescue surfactant (instead of early surfactant), PDA, sepsis and the median daily FIO2, were associated with a higher risk of dysplasia. Significant differences between cases and controls were found among cities. Models exploring for associations between city of birth and dysplasia showed that being born in the highest altitude city (Bogotá) was associated with a higher risk of dysplasia (OR 1.82 95% CI 1.31–2.53). Conclusions. Bronchopulmonary dysplasia was manly explained by traditional risk factors. Findings suggest that altitude may play an important role in the development of this disease. Prenatal steroids did not appear to be protective at high altitude.
To determine demographic and clinical variables associated with inhaled corticosteroid administration and to evaluate between-hospital variation in inhaled steroid use for infants with bronchopulmonary dysplasia (BPD).
Retrospective Cohort Study.
Neonatal units of 35 US children's hospitals; as recorded in the Pediatric Health Information System (PHIS) database.
1429 infants with evolving BPD at 28 days who were born at <29 weeks gestation with birth weight <1500 grams, admitted within the first 7 postnatal days, and discharged between January 2007–June 2011.
Inhaled steroids were prescribed to 25% (n = 352) of the cohort with use steadily increasing during the first two months of hospitalization. The most frequently prescribed steroid was beclomethasone (n = 194, 14%), followed by budesonide (n = 125, 9%), and then fluticasone (n = 90, 6%). Birth gestation <24 weeks, birth weight 500–999 grams, and prolonged ventilation all increased the adjusted odds of ever receiving inhaled corticosteroids (p<0.05). Wide variations between hospitals in the frequency of infants ever receiving inhaled steroids (range: 0–60%) and the specific drug prescribed were noted. This variation persisted, even after controlling for observed confounders.
Inhaled corticosteroid administration to infants with BPD is common in neonatal units within U.S. Children's hospitals. However, its utilization varies markedly between centers from no treatment at some institutions to the majority of infants with BPD being treated at others. This supports the need for further research to identify the benefits and potential risks of inhaled steroid usage in infants with BPD.
The purpose of this work was to evaluate therapy for patent ductus arteri-osus as a risk factor for death or neurodevelopmental impairment at 18 to 22 months, bronchopulmonary dysplasia, or necrotizing enterocolitis in extremely low birth weight infants.
We studied infants in the National Institute of Child Health and Human Development Neonatal Research Network Generic Data Base born between 2000 and 2004 at 23 to 28 weeks’ gestation and at <1000-g birth weight with patent ductus arteriosus. Patent ductus arteriosus therapy was evaluated as a risk factor for outcomes in bivariable and multivariable analyses.
Treatment for subjects with patent ductus arteriosus (n = 2838) included 403 receiving supportive treatment only, 1525 treated with indomethacin only, 775 with indomethacin followed by secondary surgical closure, and 135 treated with primary surgery. Patients who received supportive therapy for patent ductus arteriosus did not differ from subjects treated with indomethacin only for any of the outcomes of interest. Compared with indomethacin treatment only, patients undergoing primary or secondary surgery were smaller and more premature. When compared with indomethacin alone, primary surgery was associated with increased adjusted odds for neurodevelopmental impairment and bronchopulmonary dysplasia in multivariable logistic regression. Secondary surgical closure was associated with increased odds for neurodevelopmental impairment and increased adjusted odds for bronchopulmonary dysplasia but decreased adjusted odds for death. Risk of necrotizing enterocolitis did not differ among treatments. Indomethacin prophylaxis did not significantly modify these results.
Our results suggest that infants treated with primary or secondary surgery for patent ductus arteriosus may be at increased risk for poor short- and long-term outcomes compared with those treated with indomethacin. Prophylaxis with indomethacin in the first 24 hours of life did not modify the subsequent outcomes of patent ductus arteriosus therapy.
patent ductus arteriosus; bronchopulmonary dysplasia; necrotizing enterocolitis; neurodevelopmental impairment; therapy ductus arteriosus
To characterize postnatal changes in serum insulin-like growth factor-1 (IGF-I) in relation to development of bronchopulmonary dysplasia (BPD) in very preterm infants.
Longitudinal study of 108 infants with mean (SD) gestational age (GA) 27.2 (2.2) weeks. Weekly serum samples of IGF-I were analysed from birth until postmenstrual age (PMA) 36 weeks. Multivariate models were developed to identify independent predictors of BPD.
Postnatal mean IGF-I levels at postnatal day (PND) 3–21 were lower in infants with BPD compared with infants with no BPD (16 vs. 26 μg/L, p < 0.001). Longitudinal postnatal change in IGF-I levels (IGF-I regression coefficient (β)), PNDs 3–21, was lower in infants with BPD compared with infants with no BPD (0.28 vs. 0.97, p = 0.002) and mean IGF-I during PMA 30–33 weeks was lower in infants with BPD as compared with infants without BPD (22 vs. 29 μg/L, p < 0.001). In a binomial multiple regression model, lower GA, male gender and lower mean serum IGF-I levels during PND 3–21 were the most predictive risk factors associated with BPD (r2 = 0.634, p < 0.001).
Lower IGF-I concentrations during the first weeks after very preterm birth are associated with later development of BPD.
Bronchopulmonary dysplasia; Insulin-like growth factor-1; Premature infants
Bronchopulmonary dysplasia is one of the most serious complications observed in premature infants. Thanks to microarray technique, expression of nearly all human genes can be reliably evaluated.
To compare whole genome expression in the first month of life in groups of infants with and without bronchopulmonary dysplasia.
111 newborns were included in the study. The mean birth weight was 1029g (SD:290), and the mean gestational age was 27.8 weeks (SD:2.5). Blood samples were drawn from the study participants on the 5th, 14th and 28th day of life. The mRNA samples were evaluated for gene expression with the use of GeneChip® Human Gene 1.0 ST microarrays. The infants were divided into two groups: bronchopulmonary dysplasia (n=68) and control (n=43).
Overall 2086 genes were differentially expressed on the day 5, only 324 on the day 14 and 3498 on the day 28. Based on pathway enrichment analysis we found that the cell cycle pathway was up-regulated in the bronchopulmonary dysplasia group. The activation of this pathway does not seem to be related with the maturity of the infant. Four pathways related to inflammatory response were continuously on the 5th, 14th and 28th day of life down-regulated in the bronchopulmonary dysplasia group. However, the expression of genes depended on both factors: immaturity and disease severity. The most significantly down-regulated pathway was the T cell receptor signaling pathway.
The results of the whole genome expression study revealed alteration of the expression of nearly 10% of the genome in bronchopulmonary dysplasia patients.
While survival rates of extremely preterm infants have improved over the last decades, the incidence of neurodevelopmental disability (ND) in survivors remains high. Representative current data on the severity of disability and of risk factors associated with poor outcome in this growing population are necessary for clinical guidance and parent counselling.
Prospective longitudinal multicentre cohort study of preterm infants born in Switzerland between 240/7 and 276/7 weeks gestational age during 2000–2008. Mortality, adverse outcome (death or severe ND) at two years, and predictors for poor outcome were analysed using multilevel multivariate logistic regression. Neurodevelopment was assessed using Bayley Scales of Infant Development II. Cerebral palsy was graded after the Gross Motor Function Classification System.
Of 1266 live born infants, 422 (33%) died. Follow-up information was available for 684 (81%) survivors: 440 (64%) showed favourable outcome, 166 (24%) moderate ND, and 78 (11%) severe ND. At birth, lower gestational age, intrauterine growth restriction and absence of antenatal corticosteroids were associated with mortality and adverse outcome (p < 0.001). At 360/7 weeks postmenstrual age, bronchopulmonary dysplasia, major brain injury and retinopathy of prematurity were the main predictors for adverse outcome (p < 0.05). Survival without moderate or severe ND increased from 27% to 39% during the observation period (p = 0.02).
In this recent Swiss national cohort study of extremely preterm infants, neonatal mortality was determined by gestational age, birth weight, and antenatal corticosteroids while neurodevelopmental outcome was determined by the major neonatal morbidities. We observed an increase of survival without moderate or severe disability.
Development; Disability; Mortality; Outcome; Preterm
To assess pulmonary function and the prevalence of atopy in school-age children who were very low birth weight as infants and to compare those who had bronchopulmonary dysplasia to those who did not.
We studied 85 (39 male and 46 female) at a mean age of 84 (range, 62 to 107) months who were very low birth weight infants. Bronchopulmonary dysplasia was defined as oxygen dependency at 36 weeks gestational age. We excluded 8 patients (4 for cerebral palsy and 4 for no collaboration). Detailed perinatal and clinical data were collected. Lung function was evaluated using conventional spirometry. Atopy (assessed by the allergy skin-prick test) was considered when at least one positive skin test occurred in a panel of the most common environmental allergens in the local region. Comparisons between the bronchopulmonary dysplasia and no bronchopulmonary dysplasia groups were performed using the Mann-Whitney, χ2 and Fisher's exact tests.
We compared the bronchopulmonary dysplasia (n = 13) and no bronchopulmonary dysplasia (n = 64) groups. Atopy was observed in 4 (30.8%) of the bronchopulmonary dysplasia patients and in 17 (26.6%) of the no bronchopulmonary dysplasia patients (p = 0.742). Two (15.4%) patients with bronchopulmonary dysplasia had a family history of atopy vs. 17 (26.6%) in the no bronchopulmonary dysplasia group (p = 0.5). Lung function tests showed airway obstruction in 2 (15.4%) of the bronchopulmonary dysplasia patients and in 10 (15.6%) of the no bronchopulmonary dysplasia patients (p = 1.0). Four (33.3%) of the bronchopulmonary dysplasia patients had small airway obstruction vs. 14 (22.2%) of the no bronchopulmonary dysplasia patients (p = 0.466).
Our data showed no significant differences in lung function between bronchopulmonary dysplasia and no bronchopulmonary dysplasia patients at school age and no evidence of an association between atopy and bronchopulmonary dysplasia.
We tested the hypothesis that the use of supplemental oxygen (sO2) at discharge from the NICU in extremely preterm neonates is associated with a greater risk of neurodevelopmental impairment (NDI) at 18 months corrected gestational age (CGA) than the risk of NDI of those neonates discharged in room air. Four hundred twenty-four charts were retrospectively reviewed from infants born at <27 weeks and transferred to Nationwide Children’s Hospital from December 1, 2004 to June 14, 2010. Use of sO2 was evaluated on day of life (dol) 28, at 36 weeks post-menstrual age (PMA), and at discharge. Logistic regression was used to identify postnatal risk factors associated with sO2 at discharge and NDI. At dol 28, 96 % of surviving patients received sO2, and therefore had bronchopulmonary dysplasia (BPD) by definition from a National Institutes of Child Health and Human Development workshop. At 36 weeks PMA, 89 % continued on sO2 (moderate/severe BPD), and at discharge, 74 % continued on sO2. When factors associated with NDI were examined, the need for mechanical ventilation ≥28 days (adjOR = 3.21, p = 0.01), grade III–IV intraventricular hemorrhage (IVH) (adjOR = 4.61, p < 0.01), and discharge at >43 weeks PMA (adjOR = 2.12, p = 0.04) were the strongest predictors of NDI at 18 months CGA. There was no difference in Bayley Scales of Infant Development, third edition composite scores between patients with no/mild BPD and patients with moderate/severe BPD (cognitive p = 0.60, communication p = 0.53, motor p = 0.19) or those scores between patients on and off oxygen at discharge (cognitive p = 0.58, communication p = 0.70, motor p = 0.62). Conclusions: The need for sO2 at discharge is not associated with an increased risk of NDI in these patients. The strongest predictors of poor neurodevelopmental outcome in this population were prolonged positive pressure support, grade III–IV IVH, and discharge at >43 weeks PMA.
Mechanical ventilation; Supplemental oxygen; Very low birth weight; Intraventricular hemorrhage; Necrotizing enterocolitis