Rationale: Benefits of identifying risk factors for bronchopulmonary dysplasia in extremely premature infants include providing prognostic information, identifying infants likely to benefit from preventive strategies, and stratifying infants for clinical trial enrollment.
Objectives: To identify risk factors for bronchopulmonary dysplasia, and the competing outcome of death, by postnatal day; to identify which risk factors improve prediction; and to develop a Web-based estimator using readily available clinical information to predict risk of bronchopulmonary dysplasia or death.
Methods: We assessed infants of 23–30 weeks' gestation born in 17 centers of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network and enrolled in the Neonatal Research Network Benchmarking Trial from 2000–2004.
Measurements and Main Results: Bronchopulmonary dysplasia was defined as a categorical variable (none, mild, moderate, or severe). We developed and validated models for bronchopulmonary dysplasia risk at six postnatal ages using gestational age, birth weight, race and ethnicity, sex, respiratory support, and FiO2, and examined the models using a C statistic (area under the curve). A total of 3,636 infants were eligible for this study. Prediction improved with advancing postnatal age, increasing from a C statistic of 0.793 on Day 1 to a maximum of 0.854 on Day 28. On Postnatal Days 1 and 3, gestational age best improved outcome prediction; on Postnatal Days 7, 14, 21, and 28, type of respiratory support did so. A Web-based model providing predicted estimates for bronchopulmonary dysplasia by postnatal day is available at https://neonatal.rti.org.
Conclusions: The probability of bronchopulmonary dysplasia in extremely premature infants can be determined accurately using a limited amount of readily available clinical information.
bronchopulmonary dysplasia; prematurity; low-birth-weight infant
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
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
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
Extremely low birth weight infants often require rehospitalization during infancy. Our objective was to identify at the time of discharge which extremely low birth weight infants are at higher risk for rehospitalization.
Data from extremely low birth weight infants in Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network centers from 2002–2005 were analyzed. The primary outcome was rehospitalization by the 18- to 22-month follow-up, and secondary outcome was rehospitalization for respiratory causes in the first year. Using variables and odds ratios identified by stepwise logistic regression, scoring systems were developed with scores proportional to odds ratios. Classification and regression-tree analysis was performed by recursive partitioning and automatic selection of optimal cutoff points of variables.
A total of 3787 infants were evaluated (mean ± SD birth weight: 787 ± 136 g; gestational age: 26 ± 2 weeks; 48% male, 42% black). Forty-five percent of the infants were rehospitalized by 18 to 22 months; 14.7% were rehospitalized for respiratory causes in the first year. Both regression models (area under the curve: 0.63) and classification and regression-tree models (mean misclassification rate: 40%–42%) were moderately accurate. Predictors for the primary outcome by regression were shunt surgery for hydrocephalus, hospital stay of >120 days for pulmonary reasons, necrotizing enterocolitis stage II or higher or spontaneous gastrointestinal perforation, higher fraction of inspired oxygen at 36 weeks, and male gender. By classification and regression-tree analysis, infants with hospital stays of >120 days for pulmonary reasons had a 66% rehospitalization rate compared with 42% without such a stay.
The scoring systems and classification and regression-tree analysis models identified infants at higher risk of rehospitalization and might assist planning for care after discharge.
logistic models; infant; premature; predictive value of tests
To evaluate maternal and neonatal risk factors associated with post-neonatal intensive care unit (NICU) discharge mortality among ELBW infants.
This is a retrospective analysis of extremely low birth weight (<1,000 g) and <27 weeks' gestational age infants born in the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) Neonatal Research Network sites from January 2000 to June 2007. Infants were tracked until death or 18–22 months corrected age. Infants who died between NICU discharge and the 18–22 month follow-up visit were classified as post-NICU discharge mortality. Association of maternal and infant risk factors with post-NICU discharge mortality was determined using logistic regression analysis. A prediction model with six significant predictors was developed and validated.
5,364 infants survived to NICU discharge. 557 (10%) infants were lost to follow-up, and 107 infants died following NICU discharge. Post-NICU discharge mortality rate was 22.3 per 1000 ELBW infants. In the prediction model, African-American race, unknown maternal health insurance, and hospital stay ≥120 days significantly increased risk, and maternal exposure to intra-partum antibiotics was associated with decreased risk of post-NICU discharge mortality.
We identified African-American race, unknown medical insurance and prolonged NICU stay as risk factors associated with post-NICU discharge mortality among ELBW infants.
extremely preterm infants; discharge; mortality; predictive model
Birth defects (BDs) are an important cause of infant mortality and disproportionately occur among low birth weight infants. We determined the prevalence of BDs in a cohort of very low birth weight (VLBW) infants cared for at the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network (NRN) centers over a 10-year period and examined the relationship between anomalies, neonatal outcomes, and surgical care.
Infant and maternal data were collected prospectively for infants weighing 401 to 1500 g at NRN sites between January 1, 1998, and December 31, 2007. Poisson regression models were used to compare risk of outcomes for infants with versus without BDs while adjusting for gestational age and other characteristics.
A BD was present in 1776 (4.8%) of the 37 262 infants in our VLBW cohort. Yearly prevalence of BDs increased from 4.0% of infants born in 1998 to 5.6% in 2007, P < .001. Mean gestational age overall was 28 weeks, and mean birth weight was 1007 g. Infants with BDs were more mature but more likely to be small for gestational age compared with infants without BDs. Chromosomal and cardiovascular anomalies were most frequent with each occurring in 20% of affected infants. Mortality was higher among infants with BDs (49% vs 18%; adjusted relative risk: 3.66 [95% confidence interval: 3.41–3.92]; P < .001) and varied by diagnosis. Among those surviving >3 days, more infants with BDs underwent major surgery (48% vs 13%, P < .001).
Prevalence of BDs increased during the 10 years studied. BDs remain an important cause of neonatal morbidity and mortality among VLBW infants.
birth defects; prematurity; Neonatal Research Network; low birth weight
We compared neurodevelopmental outcomes at 18 to 22 months' corrected age of infants born with extremely low birth weight at an estimated gestational age of <25 weeks during 2 periods: 1999–2001 (epoch 1) and 2002–2004 (epoch 2).
PATIENTS AND METHODS:
We conducted a multicenter, retrospective analysis of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network. Perinatal and neonatal variables and outcomes were compared between epochs. Neurodevelopmental outcomes at 18 to 22 months' corrected age were evaluated with neurologic exams and Bayley Scales of Infant Development II. Logistic regression analyses determined the independent risk of epoch for adverse outcomes.
Infant survival was similar between epochs (epoch 1, 35.4%, vs epoch 2, 32.3%; P = .09). A total of 411 of 452 surviving infants in epoch 1 and 405 of 438 surviving infants in epoch 2 were evaluated at 18 to 22 months' corrected age. Cesarean delivery (P = .03), surgery for patent ductus arteriosus (P = .004), and late sepsis (P = .01) were more common in epoch 2, but postnatal steroid use was dramatically reduced (63.5% vs 32.8%; P < .0001). Adverse outcomes at 18 to 22 months' corrected age were common in both epochs. Moderate-to-severe cerebral palsy was diagnosed in 11.1% of surviving infants in epoch 1 and 14.9% in epoch 2 (adjusted odds ratio [OR]: 1.52 [95% confidence interval (CI): 0.86–2.71]; P = .15), the Mental Developmental Index was <70 in 44.9% in epoch 1 and 51% in epoch 2 (OR: 1.30 [95% CI: 0.91–1.87]; P = .15), and neurodevelopmental impairment was diagnosed in 50.1% of surviving infants in epoch 1 and 58.7% in epoch 2 (OR: 1.4 [95% CI: 0.98–2.04]; P = .07).
Early-childhood outcomes for infants born at <25 weeks' estimated gestational age were unchanged between the 2 periods.
extremely preterm; neurodevelopmental; outcome; cerebral palsy; Bayley Scales of Infant Development II
Data are limited on the impact of methicillin-resistant Staphylococcus aureus (MRSA) on morbidity and mortality among very low birth weight (VLBW) infants with S aureus (SA) bacteremia and/or meningitis (B/M).
Neonatal data for VLBW infants (birth weight 401–1500 g) born January 1, 2006, to December 31, 2008, who received care at centers of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network were collected prospectively. Early-onset (≤72 hours after birth) and late-onset (>72 hours) infections were defined by blood or cerebrospinal fluid cultures and antibiotic treatment of ≥5 days (or death <5 days with intent to treat). Outcomes were compared for infants with MRSA versus methicillin-susceptible S aureus (MSSA) B/M.
Of 8444 infants who survived >3 days, 316 (3.7%) had SA B/M. Eighty-eight had MRSA (1% of all infants, 28% of infants with SA); 228 had MSSA (2.7% of all infants, 72% of infants with SA). No infant had both MRSA and MSSA B/M. Ninety-nine percent of MRSA infections were late-onset. The percent of infants with MRSA varied by center (P < .001) with 9 of 20 centers reporting no cases. Need for mechanical ventilation, diagnosis of respiratory distress syndrome, necrotizing enterocolitis, and other morbidities did not differ between infants with MRSA and MSSA. Mortality was high with both MRSA (23 of 88, 26%) and MSSA (55 of 228, 24%).
Few VLBW infants had SA B/M. The 1% with MRSA had morbidity and mortality rates similar to infants with MSSA. Practices should provide equal focus on prevention and management of both MRSA and MSSA infections among VLBW infants.
Staphylococcus aureus; methicillin resistant; infant; newborn
A nationwide survey was conducted to determine the incidence of bronchopulmonary dysplasia (BPD) in Korea and the intercenter differences in survival and BPD rates among preterm infants. Questionnaires were sent to all registered neonatal intensive care units (NICUs). The questionnaires inquired about the survival and BPD rates of very low birth weight (VLBW, < 1,500 g) infants who had been admitted to each NICU from 2007 to 2008. BPD was defined as requiring oxygen at 36 weeks' postmenstrual age. Almost all level III NICUs replied. During the study period, 3,841 VLBW infants were born in the NICUs that responded to the survey. The survival rate was 81% and the BPD rate was 18%. Combined outcome of BPD or death rate was 37%. The BPD rate and combined outcome of BPD or death rate varied considerably from 5% to 50% and 11% to 73%, respectively across the centers. There was no significant correlation between the survival rate and the BPD rate across the centers. In conclusion, the incidence of BPD among VLBW infants in Korea during the study period was 18%, and a considerable intercenter difference in BPD rates was noted.
Bronchopulmonary Dysplasia; Epidemiology; Infant, Very Low Birth Weight
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
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
To determine if chronic oxygen dependency (discharge home on supplemental oxygen) in children with bronchopulmonary dysplasia (BPD; defined as requirement for supplemental O2 at 36 weeks postmenstrual age) predicts neurodevelopmental disability rates and growth outcomes at 36 months corrected age (CA).
Longitudinal cohort study.
Southern Alberta regional center located at high altitude.
Preterm infants weighing ≤1250 grams with no BPD, BPD, and BPD with chronic oxygen dependency.
Main outcome measures
Neurodevelopmental and growth outcomes.
Of 1563 preterm infants admitted from 1995–2007, 1212 survived. Complete follow-up data were available for 1030 (85%) children. Children in BPD and BPD with chronic oxygen dependency groups had significantly lower birth weights, gestational ages, prolonged mechanical ventilation and oxygen supplementation and received more postnatal steroids, compared to those without BPD. Children with BPD and BPD with chronic oxygen dependency were more likely to be below the 5th centile in weight and height compared to those without BPD but there was little difference between the BPD and BPD with chronic oxygen dependency groups. After controlling for confounding variables, children who had BPD and BPD with chronic oxygen dependency had higher odds of neurodevelopmental disability compared to those without BPD [OR (odds ratio) 1.9 (95%CI 1.1 to 3.5) and OR 1.8 (1.1 to 2.9), respectively], with no significant difference between BPD and BPD with chronic oxygen dependency [OR 0.9 (95% CI 0.6 to 1.5)].
BPD and BPD with chronic oxygen dependency in children predicts abnormal neurodevelopmental outcomes at 36 months CA. However, the neurodevelopmental disability rates were not significantly higher in BPD with chronic oxygen dependency children compared to children with BPD only. Compared to those without BPD, growth is impaired in children with BPD and BPD with chronic oxygen dependency, but no difference between the latter two groups.
Pulmonary hypertension is associated with bronchopulmonary dysplasia in extremely low birth weight (ELBW) infants and contributes to morbidity and mortality. The objective was to determine the prevalence of pulmonary hypertension among ELBW infants by screening echocardiography and evaluate subsequent outcomes.
All ELBW infants admitted to a regional perinatal center were evaluated for pulmonary hypertension with echocardiography at 4 weeks of age and subsequently if clinical signs suggestive of right-sided heart failure or severe lung disease were evident. Management was at discretion of the clinician, and infants were evaluated until discharge from the hospital or pre-discharge death occurred.
One hundred forty-five ELBW infants (birth weight: 755 ± 144 g; median gestational age: 26 weeks [interquartile range: 24–27]) were screened from December 2008 to February 2011. Overall, 26 (17.9%) were diagnosed with pulmonary hypertension at any time during hospitalization (birth weight: 665 ± 140 g; median gestational age: 26 weeks [interquartile range: 24–27]): 9 (6.2%) by initial screening (early pulmonary hypertension) and 17 (11.7%) who were identified later (late pulmonary hypertension). Infants with pulmonary hypertension were more likely to receive oxygen treatment on day 28 compared with those without pulmonary hypertension (96% vs 75%, P < .05). Of the 26 infants, 3 died (all in the late group because of cor pulmonale) before being discharged from the hospital.
Pulmonary hypertension is relatively common, affecting at least 1 in 6 ELBW infants, and persists to discharge in most survivors. Routine screening of ELBW infants with echocardiography at 4 weeks of age identifies only one-third of the infants diagnosed with pulmonary hypertension. Further research is required to determine optimal detection and intervention strategies.
premature infant; bronchopulmonary dysplasia; pulmonary hypertension
Guidelines for prevention of group B streptococcal (GBS) infection have successfully reduced early onset (EO) GBS disease. Study results suggest that Escherichia coli is an important EO pathogen.
To determine EO infection rates, pathogens, morbidity, and mortality in a national network of neonatal centers.
Infants with EO infection were identified by prospective surveillance at Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Network centers. Infection was defined by positive culture results for blood and cerebrospinal fluid obtained from infants aged ≤72 hours plus treatment with antibiotic therapy for ≥5 days. Mother and infant characteristics, treatments, and outcomes were studied. Numbers of cases and total live births (LBs) were used to calculate incidence.
Among 396 586 LBs (2006–2009), 389 infants developed EO infection (0.98 cases per 1000 LBs). Infection rates increased with decreasing birth weight. GBS (43%, 0.41 per 1000 LBs) and E coli (29%, 0.28 per 1000 LBs) were most frequently isolated. Most infants with GBS were term (73%); 81% with E coli were preterm. Mothers of 67% of infected term and 58% of infected preterm infants were screened for GBS, and results were positive for 25% of those mothers. Only 76% of mothers with GBS colonization received intrapartum chemoprophylaxis. Although 77% of infected infants required intensive care, 20% of term infants were treated in the normal newborn nursery. Sixteen percent of infected infants died, most commonly with E coli infection (33%).
In the era of intrapartum chemoprophylaxis to reduce GBS, rates of EO infection have declined but reflect a continued burden of disease. GBS remains the most frequent pathogen in term infants, and E coli the most significant pathogen in preterm infants. Missed opportunities for GBS prevention continue. Prevention of E coli sepsis, especially among preterm infants, remains a challenge.
neonatal sepsis; group B streptococcal disease; Escherichia coli infection
To study the association between reduced use of postnatal steroids for bronchopulmonary dysplasia (BPD) in very low birthweight (VLBW) infants and oxygen (O2)‐dependency at 28 days of age and at 36 weeks postmenstrual age.
Large national database study.
The Israel National VLBW Neonatal Database.
The sample included infants born between 1997 and 2004, of gestational age 24–32 weeks, who required mechanical ventilation or O2 therapy. Four time periods were compared: 1997–8 (era 1, peak use), 1999–2000 (era 2, intermediate), 2001–2 (era 3, expected reduction) and 2003–4 (era 4, lowest). The outcome variable “oxygen dependency” was based on clinical criteria. Multivariate regression models were used to account for confounding variables.
Steroid use fell significantly from 23.5% in 1997–8 to 11% in 2003–4 (p<0.005). After adjustment for relevant confounding variables, the odds ratio for O2 therapy at 28 days in era 4 versus era 1 was 1.75, 95% confidence interval (CI) 1.47 to 2.09 and 1.41, 95% CI 1.15 to 1.73 at 36 weeks postmenstrual age. The mean duration of O2 therapy increased from 25.3 days (95% CI 23.3 to 26.3) in era 1, to 28.0 days (95% CI 26.6 to 29.4) in era 4. Survival increased from 78.5% in era 1 to 81.6% in era 4 (p<0.005).
The use of steroids has fallen considerably since the awareness of the adverse effects of this treatment. This change has been temporally associated with increased O2 dependency at 28 days of age and at 36 weeks postmenstrual age. The prolongation of O2 therapy was modest in degree.
Randomized controlled trials have shown that treatment of chronically ventilated preterm infants after the first week of life with dexamethasone reduces the incidence of the combined outcome death or bronchopulmonary dysplasia (BPD). However, there are concerns that dexamethasone may increase the risk of adverse neurodevelopmental outcome. Hydrocortisone has been suggested as an alternative therapy. So far no randomized controlled trial has investigated its efficacy when administered after the first week of life to ventilated preterm infants.
The SToP-BPD trial is a randomized double blind placebo controlled multicenter study including 400 very low birth weight infants (gestational age < 30 weeks and/or birth weight < 1250 grams), who are ventilator dependent at a postnatal age of 7 - 14 days. Hydrocortisone (cumulative dose 72.5 mg/kg) or placebo is administered during a 22 day tapering schedule. Primary outcome measure is the combined outcome mortality or BPD at 36 weeks postmenstrual age. Secondary outcomes are short term effects on the pulmonary condition, adverse effects during hospitalization, and long-term neurodevelopmental sequelae assessed at 2 years corrected gestational age. Analysis will be on an intention to treat basis.
This trial will determine the efficacy and safety of postnatal hydrocortisone administration at a moderately early postnatal onset compared to placebo for the reduction of the combined outcome mortality and BPD at 36 weeks postmenstrual age in ventilator dependent preterm infants.
Trial registration number
Netherlands Trial Register (NTR): NTR2768
To investigate associations between early low neutrophil count from routine blood samples, white blood count (WBC), pregnancy complications and neonatal outcomes for very low birth weight infants (VLBW ≤1500g) with gestational age <32 weeks.
Patients and Methods
Information was abstracted on all infants admitted to level III NICUs in Wisconsin 2003-2004. 1002 (78%) had differential and corrected total white counts within 2 ½ hours of birth. Data analyses included frequency tables, binary logistic, ordinal logistc and ordinary regression.
Low neutrophil count (<1000/μL) was strongly associated with low WBC, pregnancy complications and antenatal steroids. Low neutrophil count predicted bronchopulmonary dysplasia severity level (BPD) (OR: 1.7, 95% CI: 1.1-2.7) and intraventricular hemorrhage (IVH) grade (OR: 2.2, 95% CI: 1.3-3.8).
Early neutrophil counts may have multiple causes interfering with their routine use as an inflammatory marker. Nonetheless, low neutrophil count has consistent independent associations with outcomes.
WBC; BPD; IVH; SNAP-II; NICU; risk factors
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
We compared neurodevelopmental outcomes of extremely low birth weight (ELBW) infants with and without bronchopulmonary dysplasia (BPD), using the physiologic definition.
ELBW (birth weights <1000 grams) infants admitted to the Neonatal Research Network centers and hospitalized at 36 weeks postmenstrual age (n=1,189) were classified using the physiologic definition of BPD. Infants underwent Bayley III assessment at 18-22 months corrected age. Multivariable logistic regression was used to determine the association between physiologic BPD and cognitive impairment (score < 70).
BPD by the physiologic definition was diagnosed in 603 (52%) infants, 537 of whom were mechanically ventilated or on FiO2 > 30% and 66 who failed the room air challenge. Infants on room air (n=505) and those who passed the room air challenge (n=51) were classified as “no BPD” (n=556). At follow up, infants with BPD had significantly lower mean weight and head circumference. Moderate to severe cerebral palsy (7 vs. 2.1%) and spastic diplegia (7.8 vs. 4.1%) and quadriplegia (3.9 vs. 0.9%) phenotypes as well as cognitive (12.8 vs. 4.6%) and language scores < 70 (24.2 vs. 12.3%) were significantly more frequent in those with BPD compared to those without BPD. BPD was independently associated (adjusted OR 2.4; 95% CI 1.40-4.13) with cognitive impairment.
Rates of adverse neurodevelopmental outcomes in early childhood were significantly higher in those with BPD. BPD by the physiologic definition was independently associated with cognitive impairment using Bayley Scales III. These findings have implications for targeted post-discharge surveillance and early intervention.
Outcome; preterm; bronchopulmonary dysplasia; physiologic definition
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
Current literature suggests that use of synchronized nasal intermittent positive pressure ventilation (SNIPPV), following extubation, reduces the rate of reintubation compared to nasal continuous positive airway pressure (NCPAP). However, there is limited information available on the outcomes of infants managed with SNIPPV.
To compare the outcomes of infants managed with SNIPPV (postextubation or for apnea) to infants not treated with SNIPPV at 2 sites.
Clinical retrospective data was used to evaluate the use of SNIPPV in infants ≤1250 g birth weight (BW); and 3 BW subgroups (500 –750, 751–1000, and 1001–1250 g, decided a priori). SNIPPV was not assigned randomly. Bronchopulmonary dysplasia (BPD) was defined as treatment with supplemental oxygen at 36 weeks’ postmenstrual age.
Overall, infants who were treated with SNIPPV had significantly lower mean BW (863g vs. 964g) and gestational age (26.4 weeks vs. 27.9 weeks), more frequently received surfactant (85% vs. 68%), and had a higher incidence of BPD or death (39% vs. 27%) (all p<0.01), compared to infants treated with NCPAP. In the subgroup analysis, SNIPPV was associated with lower rates of BPD (43% vs 67%, P = .03) and BPD/death (51% vs 76%, P = .02) in the 500- to 750g infants, with no significant differences in the other BW groups. Logistic regression analysis, adjusting for significant covariates, revealed infants with 500 –700-g BW who received SNIPPV were significantly less likely to have the outcomes of BPD (OR: 0.29 [95% CI: 0.11– 0.77]; P = .01), BPD/death (OR: 0.30 [95% CI: 0.11– 0.79]; P = .01), neurodevelopmental impairment (NDI) (OR: 0.29 [95% CI: 0.09–0.94]; P = .04), and NDI/death (OR: 0.18 [95% CI: 0.05– 0.62]; P = .006).
SNIPPV use in infants at greatest risk of BPD or death (500-750g) was associated with decreased BPD, BPD/death, NDI, and NDI/death when compared to infants managed with NCPAP.
premature newborn; respiratory distress syndrome; non-invasive ventilation
To compare continuous positive airway pressure (CPAP) vs. traditional mechanical ventilation (MV) at 24 h of age as predictors of neurodevelopmental (ND) outcomes in extremely low birth weight (ELBW) infants at 18-22 mo corrected gestational age (CGA).
Infants ≤ 1000g birth weight born from January 2000 through December 2006 at two hospitals at the Cincinnati site of the National Institute of Child Health and Human Development Neonatal Research Network were evaluated comparing CPAP (N = 198) vs. MV (N = 109). Primary outcomes included the Bayley Score of Infant Development Version II (BSID-II), presence of deafness, blindness, cerebral palsy, bronchopulmonary dysplasia and death.
Ventilatory groups were similar in gender, rates of preterm prolonged rupture of membranes, antepartum hemorrhage, use of antenatal antibiotics, steroids, and tocolytics. Infants receiving CPAP weighed more, were older, were more likely to be non-Caucasian and from a singleton pregnancy. Infants receiving CPAP had better BSID-II scores, and lower rates of BPD and death.
After adjusting for acuity differences, ventilatory strategy at 24 h of age independently predicts long-term neurodevelopmental outcome in ELBW infants.
To compare neurodevelopmental outcomes at 18–22 months corrected age for extremely low gestational age infants with low grade (Grade 1 or 2) periventricular-intraventricular hemorrhage to infants with either no hemorrhage or severe (Grade 3 or 4) hemorrhage on cranial ultrasound.
Longitudinal observational study
Sixteen centers of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network
1472 infants born at <27 weeks gestational age between 2006–2008 with ultrasound results within the first 28 days of life and surviving to 18–22 months with complete follow-up assessments were eligible.
Low grade periventricular-intraventricular hemorrhage
Outcomes included cerebral palsy, gross motor functional limitation, Bayley III cognitive and language scores, and composite measures of neurodevelopmental impairment. Regression modeling evaluated the association of hemorrhage severity with adverse outcomes while controlling for potentially confounding variables and center differences.
Low grade hemorrhage was not associated with significant differences in unadjusted or adjusted risk of any adverse neurodevelopmental outcome compared to infants without hemorrhage. Compared with low grade hemorrhage, severe hemorrhage was associated with decrease in adjusted continuous cognitive (−3.91, [95% Confidence Interval [CI]: −6.41, −1.42]) and language (−3.19 [−6.19, −0.19]) scores as well as increased odds of each adjusted categorical outcome except severe cognitive impairment (OR: 1.46 [0.74, 2.88]) and mild language impairment (OR: 1.35 [0.88, 2.06]).
At 18–22 months, the neurodevelopmental outcomes of extremely low gestational age infants with low grade periventricular-intraventricular hemorrhage are not significantly different from those without hemorrhage.
Infants born with intrauterine growth retardation (IUGR) are at increased risk of adverse pulmonary outcomes at birth, including meconium aspiration and persistent pulmonary hypertension. Preterm infants with IUGR are at especially high risk of developing bronchopulmonary dysplasia (BPD), a disease hallmarked by alveolar hypoplasia. Although vitamin A supplementation has been shown to decrease the incidence of BPD or death in preterm very low birth weight infants, its potential to reduce BPD or death in preterm infants with IUGR remains unknown. We used a well-characterized rat model of caloric restriction to mimic IUGR and determine the impact of IUGR on lung development. We hypothesized that retinoic acid treatment would preserve alveolar formation through increases in key signaling molecules of the retinoic acid signaling pathway. Our results showed that alveolar hypoplasia caused by caloric restriction can be reversed with refeeding, and that retinoic acid prevents the alveolar hypoplasia coincident with the increased expression of elastin and retinoic acid receptor–α and decreased transforming growth factor–β activity in developing rat lungs. These findings suggest that alveolar hypoplasia attributable to caloric restriction is reversible, and raises the possibility that retinoic acid therapy may prove a useful strategy to prevent adverse pulmonary sequelae such as BPD in preterm infants with IUGR.
intrauterine growth retardation; bronchopulmonary dysplasia; vitamin A; RARα; TGF-β