Impact of Early Hemodynamic Screening on Extremely Preterm Outcomes in a High-Performance Center.

Rationale: Increasing survival of extremely preterm infants with a stable rate of severe intraventricular hemorrhage represents a growing health risk for neonates. Objectives: To evaluate the role of early hemodynamic screening (HS) on the risk of death or severe intraventricular hemorrhage. Methods: All eligible patients 22-26+6 weeks' gestation born and/or admitted <24 hours postnatal age were included. As compared with standard neonatal care for control subjects (January 2010-December 2017), patients admitted in the second epoch (October 2018-April 2022) were exposed to HS using targeted neonatal echocardiography at 12-18 hours. Measurements and Main Results: A primary composite outcome of death or severe intraventricular hemorrhage was decided a priori using a 10% reduction in baseline rate to calculate sample size. A total of 423 control subjects and 191 screening patients were recruited with a mean gestation and birth weight of 24.7 ± 1.5 weeks and 699 ± 191 g, respectively. Infants born at 22-23 weeks represented 41% (n = 78) of the HS epoch versus 32% (n = 137) of the control subjects (P = 0.004). An increase in perinatal optimization (e.g., antepartum steroids) but with a decline in maternal health (e.g., increased obesity) was seen in the HS versus control epoch. A reduction in the primary outcome and each of severe intraventricular hemorrhage, death, death in the first postnatal week, necrotizing enterocolitis, and severe bronchopulmonary dysplasia was seen in the screening era. After adjustment for perinatal confounders and time, screening was independently associated with survival free of severe intraventricular hemorrhage (OR 2.09, 95% CI [1.19, 3.66]). Conclusions: Early HS and physiology-guided care may be an avenue to further improve neonatal outcomes; further evaluation is warranted.

The changing relationship between bronchopulmonary dysplasia and cognition in very preterm infants.

AIM: To characterise the relationship between bronchopulmonary dysplasia (BPD) severity and cognition in the post-surfactant era. METHODS: This was a single-centre retrospective analysis of a cohort of infants born 2009-2012. Inclusion criteria were as follows: admission within 48 hours of birth, gestational age 22-0/7-31-6/7 weeks, birthweight 400-1500 g and Bayley Scales of Infant and Toddler Development-III testing at 18-26 months corrected age. Infants (n = 151) were classified by BPD severity with the NIH Workshop definition. Generalised linear modelling and multivariate logistic regression were performed. RESULTS: Bayley cognitive score was not associated with BPD severity in univariate (p = 0.053) or multivariate (p = 0.503) analysis. About 27% of infants with no/mild BPD, 33% of infants with moderate BPD and 40% of infants with severe BPD had a cognitive score <85. There was no difference in the odds of cognitive score <85 based on BPD severity in univariate (p = 0.485) or multivariate analysis (p = 0.225). All infants with cognitive score <70 had severe BPD, although the association between cognitive score <70 and BPD severity was not significant. CONCLUSION: We found no independent effect of BPD severity level on cognition. The likelihood of a cognitive score <85 was not associated with BPD severity.

Polymorphisms in urea cycle enzyme genes are associated with persistent pulmonary hypertension of the newborn.

BackgroundPersistent pulmonary hypertension of the newborn (PPHN) is characterized by elevated pulmonary vascular resistance. Endogenous nitric oxide is critical for regulation of pulmonary vascular resistance. Nitric oxide is generated from L-arginine, supplied by the urea cycle (UC). We hypothesized that polymorphisms in UC enzyme genes and low concentrations of UC intermediates are associated with PPHN.MethodsWe performed a family-based candidate gene analysis to study 48 single-nucleotide polymorphisms (SNPs) in six UC enzyme genes. Genotyping was carried out in 94 infants with PPHN and their parents. We also performed a case-control analysis of 32 cases with PPHN and 64 controls to identify an association between amino-acid levels on initial newborn screening and PPHN.ResultsThree SNPs (rs41272673, rs4399666, and rs2287599) in carbamoyl phosphate synthase 1 gene (CPS1) showed a significant association with PPHN (P=0.02). Tyrosine levels were significantly lower (P=0.003) and phenylalanine levels were significantly higher (P=0.01) in cases with PPHN. There was no difference in the arginine or citrulline levels between the two groups.ConclusionsThis study suggests an association (P<0.05) between SNPs in CPS1 and PPHN. These findings warrant further replication in larger cohorts of patients.

Use of a Supplemental Oxygen Protocol to Suppress Progression of Retinopathy of Prematurity.

Purpose: To compare progression of retinopathy of prematurity (ROP) before and after institution of an oxygen therapy protocol to inhibit active proliferation and progression of ROP in premature infants. Methods: A retrospective cohort study was performed of premature infants undergoing ROP screening before (cohort A) and after (cohort B) implementation of an oxygen therapy protocol to inhibit further progression for those with stage 2 ROP or worse. Statistical analysis with χ2, Fisher's exact test, or Wilcoxon rank sum test was performed; and logistic regression models were created to determine the odds ratio of cohort B developing ROP progression beyond stage 2, compared to cohort A, adjusting for other risk factors for ROP. Results: In cohort A, without oxygen therapy protocol (2002-2007), 44% (54/122) of infants progressed beyond stage 2, compared to 23% (24/103) of infants after protocol implementation (cohort B, 2008-2012) (P = 0.001). No significant differences between cohort A and B were found for gestational age, birth weight, survival, sepsis, bronchopulmonary dysplasia, oxygen at discharge, or need for diuretics. Infants with stage 2 ROP in cohort B, with oxygen therapy protocol, had significantly decreased risk of ROP beyond stage 2 (odds ratio 0.37, 95% confidence interval 0.20-0.67; P = 0.0013), compared to cohort A, correcting for differences in birth weight and necrotizing enterocolitis. Conclusions: Progression from stage 2 to stage 3 ROP in premature infants was significantly decreased after implementation of an oxygen therapy protocol, without a corresponding increase in pulmonary morbidity. This study suggests that appropriate oxygen therapy may play a role in inhibiting progression of stage 2 ROP, potentially decreasing the risk of lifelong visual loss in this vulnerable population.

Development and validation of the Proxy-Reported Pulmonary Outcomes Scale for premature infants.

OBJECTIVE: Test the feasibility of using a bedside nurse-reported tool (Proxy-Reported Pulmonary Outcome Scale, PRPOS) for evaluating the severity of bronchopulmonary dysplasia (BPD) by assessing functional, disease-related measures. STUDY DESIGN: Bedside nurses tested the 26-item instrument by observing preterm infants (23-30 weeks at birth) at 36 to 37(4/7) weeks postmenstrual age before, during, and after a care time. We analyzed item reliability, validity, and model fit to determine the six items to include in the final measurement tool. RESULT: We completed assessments on 188 preterm infants. The frequency of an abnormal PRPOS item score increased with increasing National Institute of Child Health and Development (NICHD) BPD category. The six-candidate items produced an internally consistent scale. Addition of the NICHD BPD classification increased reliability moderately; addition of feeding items decreased reliability. The PRPOS score correlated with postmenstrual age at discharge. Infants discharged on oxygen or diuretics had higher median PRPOS scores than did infants who were not prescribed those therapies. CONCLUSION: The PRPOS is an internally consistent, proxy-reported measure of respiratory function in premature infants, based on observable, functional performance measures. Initial testing demonstrates known-groups validity and ongoing testing can assess predictive validity.

Inhaled PGE1 in neonates with hypoxemic respiratory failure: two pilot feasibility randomized clinical trials.

BACKGROUND: Inhaled nitric oxide (INO), a selective pulmonary vasodilator, has revolutionized the treatment of neonatal hypoxemic respiratory failure (NHRF). However, there is lack of sustained improvement in 30 to 46% of infants. Aerosolized prostaglandins I2 (PGI2) and E1 (PGE1) have been reported to be effective selective pulmonary vasodilators. The objective of this study was to evaluate the feasibility of a randomized controlled trial (RCT) of inhaled PGE1 (IPGE1) in NHRF. METHODS: Two pilot multicenter phase II RCTs are included in this report. In the first pilot, late preterm and term neonates with NHRF, who had an oxygenation index (OI) of ≥15 and <25 on two arterial blood gases and had not previously received INO, were randomly assigned to receive two doses of IPGE1 (300 and 150 ng/kg/min) or placebo. The primary outcome was the enrollment of 50 infants in six to nine months at 10 sites. The first pilot was halted after four months for failure to enroll a single infant. The most common cause for non-enrollment was prior initiation of INO. In a re-designed second pilot, co-administration of IPGE1 and INO was permitted. Infants with suboptimal response to INO received either aerosolized saline or IPGE1 at a low (150 ng/kg/min) or high dose (300 ng/kg/min) for a maximum duration of 72 hours. The primary outcome was the recruitment of an adequate number of patients (n = 50) in a nine-month-period, with fewer than 20% protocol violations. RESULTS: No infants were enrolled in the first pilot. Seven patients were enrolled in the second pilot; three in the control, two in the low-dose IPGE1, and two in the high-dose IPGE1 groups. The study was halted for recruitment futility after approximately six months as enrollment targets were not met. No serious adverse events, one minor protocol deviation and one pharmacy protocol violation were reported. CONCLUSIONS: These two pilot RCTs failed to recruit adequate eligible newborns with NHRF. Complex management RCTs of novel therapies for persistent pulmonary hypertension of the newborn (PPHN) may require novel study designs and a longer period of time from study approval to commencement of enrollment. TRIAL REGISTRATION: CLINICALTRIALS.GOV: Pilot one: NCT number: 00598429 registered on 10 January 2008. Last updated: 3 February 2011. Pilot two: NCT number: 01467076 17 October 2011. Last updated: 13 February 2013.

Prediction of survival in infants with congenital diaphragmatic hernia based on stomach position, surgical timing, and oxygenation index.

OBJECTIVE: To identify characteristics predictive of survival of patients with congenital diaphragmatic hernia (CDH). STUDY DESIGN: Retrospective analysis of clinical characteristics including severity of lung disease measured by oxygenation index (OI) associated with single-center survival in CDH patients (n = 81) from 1992 to 2008. Data were analyzed using univariate and multivariable logistic regression, effect plots, and receiver operating characteristic (ROC) plots. RESULTS: No patient died if the stomach was located in the abdomen. A left thoracic stomach position predicted decreased survival with ROC area under the curve (AUC) = 0.70. OI of ≤ 26 averaged over the first 12 hours of life predicted ≥ 50% survival for all patients, with AUC = 0.86. OI effect plots allow prediction of survival over a continuous OI range. No patient survived if mean OI was >51 in the first 12 hours of life. Delaying surgery for a median of 6 days improved survival probability for all patients with presurgery OI values ≤ 51. CONCLUSION: Position of the stomach in the abdomen, delayed surgery, and less severe cardiopulmonary disease during the first 12 hours of life, as measured by mean OI, predicted improved survival probability among patients with CDH. Our CDH model, using mean OI, permits specific individual prediction of survival probability over a range of OI values.

Variations in CRHR1 are associated with persistent pulmonary hypertension of the newborn.

INTRODUCTION: Persistent pulmonary hypertension of the newborn (PPHN) is associated with substantial infant morbidity and mortality. Recently, genetic associations have been found in idiopathic pulmonary arterial hypertension. RESULTS: PPHN was significantly (P < 0.05) associated with genetic variants in corticotropin-releasing hormone (CRH) receptor 1, CRHR1 and CRH-binding protein, CRHBP. Association with CRHR1 rs4458044 passed the Bonferroni threshold for significance. No mutations were found in the bone morphogenetic protein receptor type II (BMPR2) gene. DISCUSSION: We describe previously unreported genetic associations between PPHN and CRHR1 and CRHBP. These findings may have implications for further understanding the pathophysiology of PPHN and treatment. METHODS: We performed a family-based candidate gene study to examine a genetic association with PPHN and sequenced the BMPR2 gene in 72 individuals. We enrolled 110 families with infants diagnosed with PPHN based on inclusion criteria. After medical chart review, 22 subjects were excluded based on predefined criteria, and DNA samples from 88 affected infants and at least one parent per infant were collected and genotyped. Thirty-two single-nucleotide polymorphisms in 12 genes involved in vasoconstriction/vasodilation, lung development, surfactant regulation, or vascular endothelial cell function were investigated using family-based association tests.

11-Beta hydroxysteroid dehydrogenase type 2 in human adult and fetal lung and its regulation by sex steroids.

11-Beta hydroxysteroid dehydrogenase type 2 (HSD2) oxidizes the biologically active glucocorticoid (GC), cortisol, to inactive cortisone. We characterized HSD2 gene expression and activity in human adult and fetal lung tissues and in cultured fetal lung explants, and examined the potential regulation of HSD2 in the fetal lung by sex steroids. Human adult lung, fetal lung, and cultured fetal lung explant tissues contained similar amounts of HSD2 mRNA. However, higher levels of HSD2 protein were detected in human fetal lung tissue than in adult lung, with expression being restricted to a subset of epithelial cells in the fetal lung tissue. Differentiated fetal lung explants maintained in culture expressed higher levels of HSD2 protein and enzymatic activity than undifferentiated fetal lung tissues. Finally, HSD2 protein levels were decreased in male, but not female, fetal lung explants treated with 17-beta estradiol. In contrast, 5-alpha dihydrotestosterone did not significantly affect HSD2 levels. These data indicate that HSD2 protein and activity levels increase in parallel with the differentiation of alveolar type II epithelial cells in vitro, and that HSD2 protein levels are regulated by 17-beta estradiol in male fetal lung tissue.

Periventricular leukomalacia and prenatal methamphetamine exposure: a case report.

Periventricular leukomalacia (PVL) is a complication of prematurity that carries a high risk of long-term neurologic morbidity. We report the first case, to our knowledge, of unexpected PVL associated with in utero methamphetamine exposure in a 30-week gestation premature infant with a benign hospital course, who subsequently developed cerebral palsy by 24 months of life.

Controversy surrounding the use of home oxygen for premature infants with bronchopulmonary dysplasia.

OBJECTIVE: To determine the criteria used in the current practice of neonatology for the initiation of home oxygen therapy in premature infants with bronchopulmonary dysplasia and to compare these criteria with the available literature regarding the use of home oxygen therapy. STUDY DESIGN: Participants in the December 2000 meeting of the Vermont Oxford Network were surveyed regarding their current use of home oxygen therapy for infants with bronchopulmonary dysplasia. RESULTS: Surveys were returned by 181 out of 297 participants. Pulse oximetry saturation (SpO2) thresholds for the initiation of home oxygen therapy varied widely from <84% to <98%. The most common threshold was <90% chosen by only 43% of the respondents. Additionally, 22% of the respondents did not initiate therapy until the oxygen saturation in room air was below 88%. Once on oxygen therapy, the target SpO2 also varied widely from >84% to >98%, with only 27% of respondents aiming for an SpO2 of >94%. CONCLUSIONS: There is a clear lack of consensus among neonatologists regarding the initiation of home oxygen therapy for bronchopulmonary dysplasia. Furthermore, the criteria used for home oxygen therapy varies widely with the majority of neonatologists surveyed using oxygen saturation levels not supported by the literature. We speculate that a significant underutilization of home oxygen therapy exists for infants with bronchopulmonary dysplasia.

Variability in the use of supplemental oxygen for bronchopulmonary dysplasia.

Despite the use of "oxygen dependence at 36 weeks postmenstrual age" to define bronchopulmonary dysplasia, criteria for the use of oxygen is rarely defined. We surveyed members of the Vermont Oxford Network regarding their criteria. Pulse oximetry saturation thresholds varied widely from <84% to <96%, with only 41% of the respondents using the same criteria (<90%). This lack of uniformity in the use of oxygen casts doubt on conclusions derived from multicenter trials that use oxygen dependence at 36 weeks postmenstrual age as an outcome.