Phthalate exposure in the neonatal intensive care unit is associated with development of bronchopulmonary dysplasia.

OBJECTIVE: Bronchopulmonary dysplasia (BPD) is a serious yet common morbidity of preterm birth. Although prior work suggests a possible role for phthalate exposure in the development of BPD, no study has rigorously evaluated this. Our objective was to determine whether hospital-based phthalate exposure is associated with the development of BPD and to identify developmental windows sensitive to exposure. STUDY DESIGN: This is a prospective multicenter cohort study of 360 preterm infants born at 23-33 weeks gestation participating in the Developmental Impact of NICU Exposures (DINE) cohort. 939 urine specimens collected during the NICU stay were analyzed for biomarkers of phthalate exposure by liquid chromatography with tandem mass spectrometry. The modified Shennan definition was used to diagnose bronchopulmonary dysplasia. Reverse distributed-lag modeling identified developmental windows sensitive to specific phthalate exposure, controlling for relevant covariates including sex and respiratory support. RESULTS: Thirty-five percent of participants were diagnosed with BPD. Exposure to specific phthalate mixtures at susceptible points in preterm infant development are associated with later diagnosis of BPD in models adjusted for use of respiratory support. The weighted influence of specific phthalate metabolites in the mixtures varied by sex. Metabolites of di(2-ethylhexyl) phthalate, a phthalate previously linked to neonatal respiratory support equipment, drove this association, particularly among female infants, at 26- to 30-weeks post-menstrual age. CONCLUSIONS: This is the largest and only multi-site study of NICU-based phthalate exposure and clinical impact yet reported. In well-constructed models accounting for infant sex and respiratory support, we found a significant positive association between ultimate diagnosis of BPD and prior exposure to phthalate mixtures with DEHP predominance at 26- to 30-weeks PMA or 34-36-weeks PMA. This information is critically important as it identifies a previously unrecognized and modifiable contributing factor to BPD.

Hydrocortisone to Improve Survival without Bronchopulmonary Dysplasia.

BACKGROUND: Bronchopulmonary dysplasia is a prevalent complication after extremely preterm birth. Inflammation with mechanical ventilation may contribute to its development. Whether hydrocortisone treatment after the second postnatal week can improve survival without bronchopulmonary dysplasia and without adverse neurodevelopmental effects is unknown. METHODS: We conducted a trial involving infants who had a gestational age of less than 30 weeks and who had been intubated for at least 7 days at 14 to 28 days. Infants were randomly assigned to receive either hydrocortisone (4 mg per kilogram of body weight per day tapered over a period of 10 days) or placebo. Mandatory extubation thresholds were specified. The primary efficacy outcome was survival without moderate or severe bronchopulmonary dysplasia at 36 weeks of postmenstrual age, and the primary safety outcome was survival without moderate or severe neurodevelopmental impairment at 22 to 26 months of corrected age. RESULTS: We enrolled 800 infants (mean [±SD] birth weight, 715±167 g; mean gestational age, 24.9±1.5 weeks). Survival without moderate or severe bronchopulmonary dysplasia at 36 weeks occurred in 66 of 398 infants (16.6%) in the hydrocortisone group and in 53 of 402 (13.2%) in the placebo group (adjusted rate ratio, 1.27; 95% confidence interval [CI], 0.93 to 1.74). Two-year outcomes were known for 91.0% of the infants. Survival without moderate or severe neurodevelopmental impairment occurred in 132 of 358 infants (36.9%) in the hydrocortisone group and in 134 of 359 (37.3%) in the placebo group (adjusted rate ratio, 0.98; 95% CI, 0.81 to 1.18). Hypertension that was treated with medication occurred more frequently with hydrocortisone than with placebo (4.3% vs. 1.0%). Other adverse events were similar in the two groups. CONCLUSIONS: In this trial involving preterm infants, hydrocortisone treatment starting on postnatal day 14 to 28 did not result in substantially higher survival without moderate or severe bronchopulmonary dysplasia than placebo. Survival without moderate or severe neurodevelopmental impairment did not differ substantially between the two groups. (Funded by the National Institutes of Health; ClinicalTrials.gov number, NCT01353313.).

Initial Laparotomy Versus Peritoneal Drainage in Extremely Low Birthweight Infants With Surgical Necrotizing Enterocolitis or Isolated Intestinal Perforation: A Multicenter Randomized Clinical Trial.

OBJECTIVE: The aim of this study was to determine which initial surgical treatment results in the lowest rate of death or neurodevelopmental impairment (NDI) in premature infants with necrotizing enterocolitis (NEC) or isolated intestinal perforation (IP). SUMMARY BACKGROUND DATA: The impact of initial laparotomy versus peritoneal drainage for NEC or IP on the rate of death or NDI in extremely low birth weight infants is unknown. METHODS: We conducted the largest feasible randomized trial in 20 US centers, comparing initial laparotomy versus peritoneal drainage. The primary outcome was a composite of death or NDI at 18 to 22 months corrected age, analyzed using prespecified frequentist and Bayesian approaches. RESULTS: Of 992 eligible infants, 310 were randomized and 96% had primary outcome assessed. Death or NDI occurred in 69% of infants in the laparotomy group versus 70% with drainage [adjusted relative risk (aRR) 1.0; 95% confidence interval (CI): 0.87-1.14]. A preplanned analysis identified an interaction between preoperative diagnosis and treatment group (P = 0.03). With a preoperative diagnosis of NEC, death or NDI occurred in 69% after laparotomy versus 85% with drainage (aRR 0.81; 95% CI: 0.64-1.04). The Bayesian posterior probability that laparotomy was beneficial (risk difference <0) for a preoperative diagnosis of NEC was 97%. For preoperative diagnosis of IP, death or NDI occurred in 69% after laparotomy versus 63% with drainage (aRR, 1.11; 95% CI: 0.95-1.31); Bayesian probability of benefit with laparotomy = 18%. CONCLUSIONS: There was no overall difference in death or NDI rates at 18 to 22 months corrected age between initial laparotomy versus drainage. However, the preoperative diagnosis of NEC or IP modified the impact of initial treatment.

Association between Elevated Urine Neutrophil Gelatinase-Associated Lipocalin and Postoperative Acute Kidney Injury in Neonates.

OBJECTIVE: To examine the incidence of postoperative neonatal acute kidney injury (AKI) following general surgical procedures and to test the hypothesis that postoperative urine neutrophil gelatinase-associated lipocalin (uNGAL) concentrations predict AKI. The secondary objective was to evaluate for an association between AKI and hospital mortality. STUDY DESIGN: Prospective observational study of infants undergoing abdominal and thoracic surgical procedures in the neonatal intensive care unit from October 2018 to March 2020. The primary outcome was incidence of neonatal AKI (defined by the neonatal modified Kidney Diseases Improving Global Outcomes criteria) following each procedure to postoperative day 5. Severe AKI was defined as stage 2 or 3 AKI. Urine samples were obtained pre- and postoperatively at 6 time points to evaluate for levels of uNGAL. Secondary outcomes were in-hospital mortality and length of stay. RESULTS: Subjects (n = 141) underwent a total of 192 general surgical procedures during the study period. Neonatal AKI and severe AKI occurred following 36 (18%) and 15 (8%) procedures (n = 33 subjects). Percent change of uNGAL from 24 hours preoperatively to 24 hours postoperatively was greater in subjects with neonatal AKI (190.2% [IQR 0.0, 1666.7%] vs 0.7% [IQR -31.2%,140.2%], P = .0374). The strongest association of uNGAL and AKI occurred at 24 hours postoperatively (area under the receiver operator curves of 0.81, 95% CI 0.72, 0.89). Increased mortality risk was observed in subjects with any postoperative AKI (aOR 11.1 95% CI 2.0, 62.8, P = .0063) and severe AKI (aOR 13.8; 95% CI 3.0, 63.1, P = .0007). CONCLUSION: Elevation in uNGAL 24 hours postoperative was associated with AKI. Neonates with postoperative AKI had increased mortality.

Neonatal Opioid Withdrawal Syndrome.

The opioid crisis has grown to affect pregnant women and infants across the United States, as evidenced by rising rates of opioid use disorder among pregnant women and neonatal opioid withdrawal syndrome among infants. Across the country, pregnant women lack access to evidence-based therapies, including medications for opioid use disorder, and infants with opioid exposure frequently receive variable care. In addition, public systems, such as child welfare and early intervention, are increasingly stretched by increasing numbers of children affected by the crisis. Systematic, enduring, coordinated, and holistic approaches are needed to improve care for the mother-infant dyad. In this statement, we provide an overview of the effect of the opioid crisis on the mother-infant dyad and provide recommendations for management of the infant with opioid exposure, including clinical presentation, assessment, treatment, and discharge.

Early angiogenic proteins associated with high risk for bronchopulmonary dysplasia and pulmonary hypertension in preterm infants.

Early pulmonary vascular disease in preterm infants is associated with the subsequent development of bronchopulmonary dysplasia (BPD) and pulmonary hypertension (PH); however, mechanisms that contribute to or identify infants with increased susceptibility for BPD and/or PH are incompletely understood. Therefore, we tested if changes in circulating angiogenic peptides during the first week of life are associated with the later development of BPD and/or PH. We further sought to determine alternate peptides and related signaling pathways with the risk for BPD or PH. We prospectively enrolled infants with gestational age <34 wk and collected blood samples during their first week of life. BPD and PH were assessed at 36 wk postmenstrual age. Samples were assayed for each of the 1,121 peptides included in the SOMAscan scan technology, with subsequent pathway analysis. Of 102 infants in the study, 82 had BPD, and 13 had PH. Multiple angiogenic proteins (PF-4, VEGF121, ANG-1, bone morphogenetic protein 10 [BMP10], hepatocyte growth factor (HGF), ANG-2) were associated with the subsequent diagnosis of BPD; and FGF-19, PF-4, connective tissue activating peptide (CTAP)-III, and PDGF-AA levels were associated with BPD severity. Early increases in BMP10 was strongly associated with the late risk for BPD and PH. We found that early alterations of circulating angiogenic peptides and others were associated with the subsequent development of BPD. We further identified peptides that were associated with BPD severity and BPD-associated PH, including BMP10. We speculate that proteomic biomarkers during the first week of life may identify infants at risk for BPD and/or PH to enhance care and research.

Urine gastrin-releasing peptide in the first week correlates with bronchopulmonary dysplasia and post-prematurity respiratory disease.

RATIONALE: Bronchopulmonary dysplasia (BPD) is associated with post-prematurity respiratory disease (PRD) in survivors of extreme preterm birth. Identifying early biomarkers that correlate with later development of BPD and PRD may provide insights for intervention. In a preterm baboon model, elevated gastrin-releasing peptide (GRP) is associated with BPD, and GRP inhibition mitigates BPD occurrence. OBJECTIVE: We performed a prospective cohort study to investigate whether urine GRP levels obtained in the first postnatal week were associated with BPD, PRD, and other urinary biomarkers of oxidative stress. METHODS: Extremely low gestational age infants (23-28 completed weeks) were enrolled in a US multicenter observational study, The Prematurity and Respiratory Outcomes Program (http://clinicaltrials.gov/ct2/show/NCT01435187). We used multivariable logistic regression to examine the association between urine GRP in the first postnatal week and multiple respiratory outcomes: BPD, defined as supplemental oxygen use at 36 + 0 weeks postmenstrual age, and post-PRD, defined by positive quarterly surveys for increased medical utilization over the first year (PRD score). RESULTS: A total of 109 of 257 (42%) infants had BPD, and 120 of 217 (55%) had PRD. On adjusted analysis, GRP level more than 80 was associated with BPD (adjusted odds ratio [aOR], 1.83; 95% confidence interval [CI], 1.03-3.25) and positive PRD score (aOR, 2.46; 95% CI, 1.35-4.48). Urine GRP levels correlated with duration of NICU ventilatory and oxygen support and with biomarkers of oxidative stress: allantoin and 8-hydroxydeoxyguanosine. CONCLUSIONS: Urine GRP in the first postnatal week was associated with concurrent urine biomarkers of oxidative stress and with later diagnoses of BPD and PRD.

Respiratory medication use in extremely premature (<29 weeks) infants during initial NICU hospitalization: Results from the prematurity and respiratory outcomes program.

BACKGROUND: The use of medications to treat respiratory conditions of extreme prematurity is often based upon studies of adults or children over 2 years of age. Little is known about the spectrum of medications used or dosing ranges. To inform the design of future studies, we conducted a prospective analysis of respiratory medication exposure among 832 extremely low gestational age neonates. METHODS: The prematurity and respiratory outcomes program (PROP) enrolled neonates less than 29-week gestation from 6 centers incorporating 13 clinical sites. We collected recorded daily "respiratory" medications given along with dosing information through 40-week postmenstrual age or neonatal intensive care unit discharge if earlier. RESULTS: PROP participants were exposed to a wide range of respiratory medications, often at doses beyond published recommendations. Nearly 50% received caffeine and furosemide beyond published recommendations for cumulative dose. Those who developed bronchopulmonary dysplasia were more likely to receive treatment with respiratory medications. However, more than 30% of PROP subjects that did not develop bronchopulmonary dysplasia also were treated with diuretics, systemic steroids, and other respiratory medications. CONCLUSION: Extremely preterm neonates in PROP were exposed to high doses of medications at levels known to generate significant adverse effects. With limited evidence for efficacy, there is an urgent need for controlled trials in this vulnerable patient population.

The Diagnosis of Bronchopulmonary Dysplasia in Very Preterm Infants. An Evidence-based Approach.

Rationale: Current diagnostic criteria for bronchopulmonary dysplasia rely heavily on the level and duration of oxygen therapy, do not reflect contemporary neonatal care, and do not adequately predict childhood morbidity.Objectives: To determine which of 18 prespecified, revised definitions of bronchopulmonary dysplasia that variably define disease severity according to the level of respiratory support and supplemental oxygen administered at 36 weeks' postmenstrual age best predicts death or serious respiratory morbidity through 18-26 months' corrected age.Methods: We assessed infants born at less than 32 weeks of gestation between 2011 and 2015 at 18 centers of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network.Measurements and Main Results: Of 2,677 infants, 683 (26%) died or developed serious respiratory morbidity. The diagnostic criteria that best predicted this outcome defined bronchopulmonary dysplasia according to treatment with the following support at 36 weeks' postmenstrual age, regardless of prior or current oxygen therapy: no bronchopulmonary dysplasia, no support (n = 773); grade 1, nasal cannula ≤2 L/min (n = 1,038); grade 2, nasal cannula >2 L/min or noninvasive positive airway pressure (n = 617); and grade 3, invasive mechanical ventilation (n = 249). These criteria correctly predicted death or serious respiratory morbidity in 81% of study infants. Rates of this outcome increased stepwise from 10% among infants without bronchopulmonary dysplasia to 77% among those with grade 3 disease. A similar gradient (33-79%) was observed for death or neurodevelopmental impairment.Conclusions: The definition of bronchopulmonary dysplasia that best predicted early childhood morbidity categorized disease severity according to the mode of respiratory support administered at 36 weeks' postmenstrual age, regardless of supplemental oxygen use.

Respiratory Medications in Infants <29 Weeks during the First Year Postdischarge: The Prematurity and Respiratory Outcomes Program (PROP) Consortium.

OBJECTIVE: To determine patterns of respiratory medications used in neonatal intensive care unit graduates. STUDY DESIGN: The Prematurity Respiratory Outcomes Program enrolled 835 babies <29 weeks of gestation in the first week. Of 751 survivors, 738 (98%) completed at least 1, and 85% completed all 4, postdischarge medication usage in-person/telephone parental questionnaires requested at 3, 6, 9, and 12 months of corrected age. Respiratory drug usage over the first year of life after in neonatal intensive care unit discharge was analyzed. RESULTS: During any given quarter, 66%-75% of the babies received no respiratory medication and 45% of the infants received no respiratory drug over the first year. The most common postdischarge medication was the inhaled bronchodilator albuterol; its use increased significantly from 13% to 31%. Diuretic usage decreased significantly from 11% to 2% over the first year. Systemic steroids (prednisone, most commonly) were used in approximately 5% of subjects in any one quarter. Inhaled steroids significantly increased over the first year from 9% to 14% at 12 months. Drug exposure changed significantly based on gestational age with 72% of babies born at 23-24 weeks receiving at least 1 respiratory medication but only 40% of babies born at 28 weeks. Overall, at some time in the first year, 55% of infants received at least 1 drug including an inhaled bronchodilator (45%), an inhaled steroid (22%), a systemic steroid (15%), or diuretic (12%). CONCLUSION: Many babies born at <29 weeks have no respiratory medication exposure postdischarge during the first year of life. Inhaled medications, including bronchodilators and steroids, increase over the first year.

Black Race Is Associated with a Lower Risk of Bronchopulmonary Dysplasia.

OBJECTIVE: To use a large current prospective cohort of infants <29 weeks to compare bronchopulmonary dysplasia (BPD) rates in black and white infants. STUDY DESIGN: The Prematurity and Respiratory Outcome Program (PROP) enrolled 835 infants born in 2011-2013 at <29 weeks of gestation; 728 black or white infants survived to 36 weeks postmenstrual age (PMA). Logistic regression was used to compare BPD outcomes (defined as supplemental oxygen requirement at 36 weeks PMA) between the races, adjusted for gestational age (GA), antenatal steroid use, intubation at birth, and surfactant use at birth. RESULTS: Of 707 black or white infants with available BPD outcomes, BPD was lower in black infants (38% vs 45%), even though they were of significantly lower GA. At every GA, BPD was more common in white infants. The aOR for BPD was 0.60 (95% CI, 0.42-0.85; P = .004) for black infants compared with white infants after adjusting for GA. Despite the lower rate of BPD, black infants had a higher rate of first-year post-prematurity respiratory disease (black, 79%; white, 63%). CONCLUSIONS: In this large cohort of recently born preterm infants at <29 weeks GA, compared with white infants, black infants had a lower risk of BPD but an increased risk of persistent respiratory morbidity.

Early Pulmonary Vascular Disease in Preterm Infants Is Associated with Late Respiratory Outcomes in Childhood.

RATIONALE: Early pulmonary vascular disease (PVD) after preterm birth is associated with a high risk for developing bronchopulmonary dysplasia (BPD), but its relationship with late respiratory outcomes during early childhood remains uncertain. OBJECTIVES: To determine whether PVD at 7 days after preterm birth is associated with late respiratory disease (LRD) during early childhood. METHODS: This was a prospective study of preterm infants born before 34 weeks postmenstrual age (PMA). Echocardiograms were performed at 7 days and 36 weeks PMA. Prenatal and early postnatal factors and postdischarge follow-up survey data obtained at 6, 12, 18, and 24 months of age were analyzed in logistic regression models to identify early risk factors for LRD, defined as a physician diagnosis of asthma, reactive airways disease, BPD exacerbation, bronchiolitis, or pneumonia, or a respiratory-related hospitalization during follow-up. MEASUREMENTS AND MAIN RESULTS: Of the 221 subjects (median, 27 wk PMA; interquartile range, 25-28 and 920 g; interquartile range, 770-1090 g) completing follow-up, 61% met LRD criteria. Gestational diabetes and both mechanical ventilator support and PVD at 7 days were associated with LRD. The combination of PVD and mechanical ventilator support at 7 days was among the strongest prognosticators of LRD (odds ratio, 8.1; confidence interval, 3.1-21.9; P < 0.001). Modeled prenatal and early postnatal factors accurately informed LRD (area under the curve, 0.764). Adding BPD status at 36 weeks PMA to the model did not change the accuracy (area under the curve, 0.771). CONCLUSIONS: Early echocardiographic evidence of PVD after preterm birth in combination with other perinatal factors is a strong risk factor for LRD, suggesting that early PVD may contribute to the pathobiology of BPD.

Echocardiographic Measurements of Right Ventricular Mechanics in Infants with Bronchopulmonary Dysplasia at 36 Weeks Postmenstrual Age.

OBJECTIVE: To test the hypothesis that specific echocardiographic measurements of right ventricular (RV) mechanics at 36 weeks postmenstrual age (PMA) are associated with the severity of bronchopulmonary dysplasia (BPD). STUDY DESIGN: A subset of 93 preterm infants (born between 27 and 29 weeks of gestation) was selected retrospectively from a prospectively enrolled cohort. BPD was defined using the National Institutes of Health workshop definition, with modifications for oxygen reduction testing and altitude. The cohort was divided into no-BPD and BPD groups using previously published methodology for analyses. Echocardiographic measurements of RV function (ie, tricuspid annular plane systolic excursion, fractional area of change, systolic-to-diastolic ratio, tissue Doppler myocardial performance index, and RV strain), RV remodeling/morphology (end-systolic left ventricular eccentricity index), and RV afterload (pulmonary artery acceleration time measure) were evaluated at 36 weeks PMA. Multivariable logistic regression determined associations between RV measurements and BPD severity. RESULTS: Compared with the no-BPD cohort, the BPD group had lower birth weight z-scores (P = .04) and trended toward a male predominance (P = .08). After adjusting for birth weight z-score, gestational age, and sex, there were no between-group differences in echocardiographic measurements except for the eccentricity index (scaled OR [0.1-unit increase], 1.49; 95% CI, 1.13-2.12; P = .01). CONCLUSIONS: Among conventional and emerging echocardiographic measurements of RV mechanics, eccentricity index was the sole variable independently associated with BPD severity in this study. The eccentricity index may be a useful echocardiographic measurement for characterizing RV mechanics in patients with BPD at 36 weeks PMA.

Neonatal outcomes of moderately preterm infants compared to extremely preterm infants.

BackgroundExtremely preterm infants (EPT, <29 weeks' gestation) represent only 0.9% of births in the United States; yet these infants are the focus of most published research. Moderately preterm neonates (MPT, 29-336/7 weeks) are an understudied group of high-risk infants.MethodsTo determine the neonatal outcomes of MPT infants across the gestational age spectrum, and to compare these with EPT infants. A prospective observational cohort was formed in 18 level 3-4 neonatal intensive care units (NICUs) in the Eunice Kennedy Shriver NICHD Neonatal Research Network. Participants included all MPT infants admitted to NICUs and all EPT infants born at sites between January 2012 and November 2013. Antenatal characteristics and neonatal morbidities were abstracted from records using pre-specified definitions by trained neonatal research nurses.ResultsMPT infants experienced morbidities similar to, although at lower rates than, those of EPT infants. The main cause of mortality was congenital malformation, accounting for 43% of deaths. Central Nervous System injury occurred, including intraventricular hemorrhage. Most MPT infants required respiratory support, but sequelae such as bronchopulmonary dysplasia were rare. The primary contributors to hospitalization beyond 36 weeks' gestation were inability to achieve adequate oral intake and persistent apnea.ConclusionsMPT infants experience morbidity and prolonged hospitalization. Such morbidity deserves focused research to improve therapeutic and prevention strategies.

Reliability of Echocardiographic Indicators of Pulmonary Vascular Disease in Preterm Infants at Risk for Bronchopulmonary Dysplasia.

OBJECTIVES: To determine the assessment and inter-rater reliability of echocardiographic evaluations of pulmonary vascular disease (PVD) in preterm infants at risk for bronchopulmonary dysplasia. STUDY DESIGN: We prospectively studied echocardiograms from preterm infants (birthweights 500-1250 g) at 7 days of age and 36 weeks postmenstrual age (PMA). Echocardiograms were assessed by both a cardiologist on clinical service and a single research cardiologist. Interpretations were reviewed for inclusion of determinants of PVD and assessed for inter-rater reliability using the Prevalence Adjusted Bias Adjusted Kappa Score (PABAK). RESULTS: One hundred eighty and 188 matching research and clinical echocardiogram reports were available for the 7-day and 36-week PMA studies. At least one of the specific qualitative measures of PVD was missing from 54% of the clinical reports. PVD was diagnosed at 7 days in 31% and 20% of research and clinical interpretations, respectively (PABAK score of 0.54). At 36 weeks, PH was diagnosed in 15.6% and 17.8% of research and clinical interpretations, respectively (PABAK score of 0.80). CONCLUSIONS: Although all qualitative variables of PVD are not consistently provided in echocardiogram reports, the inter-rater reliability of cardiologists evaluating measures of PVD revealed strong agreement, especially at 36 weeks PMA. We speculate that establishment of a protocol for echocardiographic evaluation may improve the identification of PVD in preterm infants.

Antenatal Determinants of Bronchopulmonary Dysplasia and Late Respiratory Disease in Preterm Infants.

RATIONALE: Mechanisms contributing to chronic lung disease after preterm birth are incompletely understood. OBJECTIVES: To identify antenatal risk factors associated with increased risk for bronchopulmonary dysplasia (BPD) and respiratory disease during early childhood after preterm birth, we performed a prospective, longitudinal study of 587 preterm infants with gestational age less than 34 weeks and birth weights between 500 and 1,250 g. METHODS: Data collected included perinatal information and assessments during the neonatal intensive care unit admission and longitudinal follow-up by questionnaire until 2 years of age. MEASUREMENTS AND MAIN RESULTS: After adjusting for covariates, we found that maternal smoking prior to preterm birth increased the odds of having an infant with BPD by twofold (P = 0.02). Maternal smoking was associated with prolonged mechanical ventilation and respiratory support during the neonatal intensive care unit admission. Preexisting hypertension was associated with a twofold (P = 0.04) increase in odds for BPD. Lower gestational age and birth weight z-scores were associated with BPD. Preterm infants who were exposed to maternal smoking had higher rates of late respiratory disease during childhood. Twenty-two percent of infants diagnosed with BPD and 34% of preterm infants without BPD had no clinical signs of late respiratory disease during early childhood. CONCLUSIONS: We conclude that maternal smoking and hypertension increase the odds for developing BPD after preterm birth, and that maternal smoking is strongly associated with increased odds for late respiratory morbidities during early childhood. These findings suggest that in addition to the BPD diagnosis at 36 weeks, other factors modulate late respiratory outcomes during childhood. We speculate that measures to reduce maternal smoking not only will lower the risk for preterm birth but also will improve late respiratory morbidities after preterm birth.

Association between Use of Prophylactic Indomethacin and the Risk for Bronchopulmonary Dysplasia in Extremely Preterm Infants.

OBJECTIVE: To assess the association between prophylactic indomethacin and bronchopulmonary dysplasia (BPD) in a recent, large cohort of extremely preterm infants. STUDY DESIGN: Retrospective cohort study using prospectively collected data for infants with gestational ages < 29 weeks or birth weights of 401-1000 g born between 2008 and 2012 at participating hospitals of the National Institute of Child Health and Human Development Neonatal Research Network. Infants treated with indomethacin in the first 24 hours of life were compared with those who were not. Study outcomes were BPD, defined as use of supplemental oxygen at 36 weeks postmenstrual age among survivors to that time point, death, and the composite of death or BPD. Prespecified subgroup analyses were performed. RESULTS: Prophylactic indomethacin use varied by hospital. Treatment of a patent ductus arteriosus after the first day of life was less common among 2587 infants who received prophylactic indomethacin compared with 5244 who did not (21.0% vs 36.1%, P < .001). After adjustment for potential confounders, use of prophylactic indomethacin was not associated with higher or lower odds of BPD (OR 0.89, 95% CI 0.72-1.10), death (OR 0.80, 95% CI 0.64-1.01), or death or BPD (OR 0.87, 95% CI 0.71-1.05). The only evidence of subgroup effects associated with prophylactic indomethacin were lower odds of death among infants with birth weights above the 10th percentile and those who were not treated for a patent ductus arteriosus after the first day of life. CONCLUSIONS: Prophylactic indomethacin was not associated with either reduced or increased risk for BPD or death. TRIAL REGISTRATION: ClinicalTrials.gov: NCT00063063.

Airway Microbial Community Turnover Differs by BPD Severity in Ventilated Preterm Infants.

Preterm birth exposes the developing lung to an environment with direct exposure to bacteria, often facilitated by endotracheal intubation. Despite evidence linking bacterial infections to the pathogenesis of bronchopulmonary dysplasia (BPD), systematic studies of airway microbiota are limited. The objective was to identify specific patterns of the early respiratory tract microbiome from tracheal aspirates of mechanically ventilated preterm infants that are associated with the development and severity of BPD. Infants with gestational age ≤34 weeks, and birth weight 500-1250g were prospectively enrolled. Mechanically ventilated infants had tracheal aspirate samples collected at enrollment, 7, 14, and 21 days of age. BPD was determined by modified NIH criteria with oxygen reduction tests; infants without BPD were excluded due to low numbers. Aspirates were processed for bacterial identification by 16S rRNA sequencing, and bacterial load by qPCR. Cross-sectional analysis was performed using 7 day samples and longitudinal analysis was performed from subjects with at least 2 aspirates. Microbiome analysis was performed on tracheal aspirates from 152 infants (51, 49, and 52 with mild, moderate, and severe BPD, respectively). Seventy-nine of the infants were included in the cross-sectional analysis and 94 in the longitudinal. Shannon Diversity, bacterial load, and relative abundance of individual taxa were not strongly associated with BPD status. Longitudinal analysis revealed that preterm infants who eventually developed severe BPD exhibited greater bacterial community turnover with age, acquired less Staphylococcus in the first days after birth, and had higher initial relative abundance of Ureaplasma. In conclusion, longitudinal changes in the airway microbial communities of mechanically ventilated preterm infants may be associated with BPD severity, whereas cross-sectional analysis of airway ecology at 7 days of age did not reveal an association with BPD severity. Further evaluation is necessary to determine whether the observed longitudinal changes are causal or in response to clinical management or other factors that lead to BPD.

Safety and pharmacokinetics of multiple dose myo-inositol in preterm infants.

BACKGROUND: Preterm infants with respiratory distress syndrome (RDS) given inositol had reduced bronchopulmonary dysplasia (BPD), death and severe retinopathy of prematurity (ROP). We assessed the safety and pharmacokinetics of daily inositol to select a dose providing serum levels previously associated with benefit, and to learn if accumulation occurred when administered throughout the normal period of retinal vascularization. METHODS: Infants ≤ 29 wk GA (n = 122, 14 centers) were randomized and treated with placebo or inositol at 10, 40, or 80 mg/kg/d. Intravenous administration converted to enteral when feedings were established, and continued to the first of 10 wk, 34 wk postmenstrual age (PMA) or discharge. Serum collection employed a sparse sampling population pharmacokinetics design. Inositol urine losses and feeding intakes were measured. Safety was prospectively monitored. RESULTS: At 80 mg/kg/d mean serum levels reached 140 mg/l, similar to Hallman's findings. Levels declined after 2 wk, converging in all groups by 6 wk. Analyses showed a mean volume of distribution 0.657 l/kg, clearance 0.058 l/kg/h, and half-life 7.90 h. Adverse events and comorbidities were fewer in the inositol groups, but not significantly so. CONCLUSION: Multiple dose inositol at 80 mg/kg/d was not associated with increased adverse events, achieves previously effective serum levels, and is appropriate for investigation in a phase III trial.