Failed alveolar formation and excess, disordered elastin are key features of neonatal chronic lung disease (CLD). We previously found fewer alveoli and more elastin in lungs of preterm compared with term lambs that had mechanical ventilation (MV) with O(2)-rich gas for 3 wk (MV-3 wk). We hypothesized that, in preterm more than in term lambs, MV-3 wk would reduce lung expression of growth factors that regulate alveolarization (VEGF, PDGF-A) and increase lung expression of growth factors [transforming growth factor (TGF)-alpha, TGF-beta(1)] and matrix molecules (tropoelastin, fibrillin-1, fibulin-5, lysyl oxidases) that regulate elastin synthesis and assembly. We measured lung expression of these genes in preterm and term lambs after MV for 1 day, 3 days, or 3 wk, and in fetal controls. Lung mRNA for VEGF, PDGF-A, and their receptors (VEGF-R2, PDGF-Ralpha) decreased in preterm and term lambs after MV-3 wk, with reduced lung content of the relevant proteins in preterm lambs with CLD. TGF-alpha and TGF-beta(1) expression increased only in lungs of preterm lambs. Tropoelastin mRNA increased more with MV of preterm than term lambs, and expression levels remained high in lambs with CLD. In contrast, fibrillin-1 and lysyl oxidase-like-1 mRNA increased transiently, and lung abundance of other elastin-assembly genes/proteins was unchanged (fibulin-5) or reduced (lysyl oxidase) in preterm lambs with CLD. Thus MV-3 wk reduces lung expression of growth factors that regulate alveolarization and differentially alters expression of growth factors and matrix proteins that regulate elastin assembly. These changes, coupled with increased lung elastase activity measured in preterm lambs after MV for 1-3 days, likely contribute to CLD.

IMPORTANCE Hypothermia at 33.5°C for 72 hours for neonatal hypoxic ischemic encephalopathy reduces death or disability to 44% to 55%; longer cooling and deeper cooling are neuroprotective in animal models. OBJECTIVE To determine if longer duration cooling (120 hours), deeper cooling (32.0°C), or both are superior to cooling at 33.5°C for 72 hours in neonates who are full-term with moderate or severe hypoxic ischemic encephalopathy. DESIGN, SETTING, AND PARTICIPANTS Arandomized, 2 × 2 factorial design clinical trial performed in 18 US centers in the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) Neonatal Research Network between October 2010 and November 2013. INTERVENTIONS Neonates were assigned to 4 hypothermia groups; 33.5°C for 72 hours, 32.0°C for 72 hours, 33.5°C for 120 hours, and 32.0°C for 120 hours. MAIN OUTCOMES AND MEASURES The primary outcome of death or disability at 18 to 22 months is ongoing. The independent data and safety monitoring committee paused the trial to evaluate safety (cardiac arrhythmia, persistent acidosis, major vessel thrombosis and bleeding, and death in the neonatal intensive care unit [NICU]) after the first 50 neonates were enrolled, then after every subsequent 25 neonates. The trial was closed for emerging safety profile and futility analysis after the eighth review with 364 neonates enrolled (of 726 planned). This report focuses on safety and NICU deaths by marginal comparisons of 72 hours’ vs 120 hours’ duration and 33.5°C depth vs 32.0°C depth (predefined secondary outcomes). RESULTS The NICU death rates were 7 of 95 neonates (7%) for the 33.5°C for 72 hours group, 13 of 90 neonates (14%) for the 32.0°C for 72 hours group, 15 of 96 neonates (16%) for the 33.5°C for 120 hours group, and 14 of 83 neonates (17%) for the 32.0°C for 120 hours group. The adjusted risk ratio (RR) for NICU deaths for the 120 hours group vs 72 hours group was 1.37 (95% CI, 0.92–2.04) and for the 32.0°C group vs 33.5°C group was 1.24 (95% CI, 0.69–2.25). Safety outcomes were similar between the 120 hours group vs 72 hours group and the 32.0°C group vs 33.5°C group, except major bleeding occurred among 1% in the 120 hours group vs 3% in the 72 hours group (RR, 0.25 [95% CI, 0.07–0.91]). Futility analysis determined that the probability of detecting a statistically significant benefit for longer cooling, deeper cooling, or both for NICU death was less than 2%. CONCLUSIONS AND RELEVANCE Among neonates who were full-term with moderate or severe hypoxic ischemic encephalopathy, longer cooling, deeper cooling, or both compared with hypothermia at 33.5°C for 72 hours did not reduce NICU death. These results have implications for patient care and design of future trials.

ABSTRACT:The effect of oxygen concentration on lowering pulmonary vascular resistance (PVR) during resuscitation in a model of persistent pulmonary hypertension of the newborn (PPHN) is not known. PPHN was induced in fetal lambs by ductal ligation 9 d before delivery. After delivery by cesarean section, resuscitation of PPHN lambs with 21%, 50%, or 100% O 2 (n ϭ 6 each) for 30 min produced similar decreases in PVR. Lambs were then ventilated with 50% O 2 for 60 min and exposed to inhaled nitric oxide (iNO, 20 ppm (2), some suggest that it may be appropriate for initial resuscitation of term infants (3). Although there is increasing availability of oxygen blenders for neonatal resuscitation (4), few studies have addressed the effect of resuscitation with an intermediate range of oxygen in the delivery room. We recently reported that ventilation of normal term lambs for 30 min at birth (referred to as "resuscitation") with 50% and 100% O 2 resulted in greater decrease in pulmonary vascular resistance (PVR) compared with 21% O 2 (5).As oxygen mediates reduction of high fetal PVR at birth (1,6), 100% O 2 is often recommended as the first line of resuscitation for circumstances associated with persistent pulmonary hypertension of the newborn (PPHN) (7). However, it is not always possible to anticipate conditions that might lead to in utero pulmonary hypertension (8,9). If PPHN infants are resuscitated at birth with 21% O 2 , PVR may remain high, resulting in severe PPHN and altered response to inhaled nitric oxide (iNO).Once identified, babies with PPHN are traditionally managed with mechanical ventilation with high FiO 2 (fraction of inspired oxygen) and iNO. Hyperoxic ventilation may increase production of reactive oxygen species (ROS), which in turn impair pulmonary vasodilation (10,11). However, little is known about the optimal FiO 2 or PaO 2 that maximizes pulmonary vasodilation in PPHN (12). We recently reported that ventilation with 100% O 2 increases contractile responses of pulmonary arteries (PA) to norepinephrine from both control (13) and PPHN lambs (14), and blunts vascular responses to iNO in newborn lambs with acute pharmacologically induced PPHN (5). The effect of resuscitation with high FiO 2 at birth on subsequent vasodilation to iNO in PPHN associated with vascular remodeling is not known.This study examines the impact of FiO 2 during resuscitation on the initial decrease in PVR at birth in lambs with PPHN induced by antenatal ductal ligation. We hypothesized that ventilation with 100% O 2 would lead to a more rapid decline in PVR at birth in PPHN lambs compared with 21% or 50% O 2 but would impair subsequent pulmonary vasodilation to iNO. Finally, at 2-3 h of age, when PVR had decreased from high fetal values, we studied the effect of change in FiO 2 on PVR. We hypothesized that higher FiO 2 and PaO 2 would result in lower PVR in control and PPHN lambs. METHODSThe Institutional Animal Care and Use 1 Committee at Buffalo approved this study. Time-dated pregnant ewes were obtained from the Swartz...

Objective To evaluate the temperature distribution among moderately preterm (MPT, 29–33 weeks) and extremely preterm (EPT, <29 weeks) infants upon neonatal intensive care unit (NICU) admission in 2012–2013, the change in admission temperature distribution for EPT infants between 2002–2003 and 2012–2013, and associations between admission temperature and mortality and morbidity for both MPT and EPT infants. Study design Prospectively collected data from 18 centers in the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network were used to examine NICU admission temperature of inborn MPT and EPT infants. Associations between admission temperature and mortality and morbidity were determined by multivariable logistic regression. EPT infants from 2002–2003 and 2012–2013 were compared. Results MPT and EPT cohorts consisted of 5818 and 3213 infants, respectively. The distribution of admission temperatures differed between the MPT vs EPT (P < .01), including the percentage <36.5°C (38.6% vs 40.9%), 36.5°C–37.5°C (57.3% vs 52.9%), and >37.5°C (4.2% vs 6.2%). For EPT infants in 2012–2013 compared with 2002–2003, the percentage of temperatures between 36.5°C and 37.5°C more than doubled and the percentage of temperatures >37.5°C more than tripled. Admission temperature was inversely associated with in-hospital mortality. Conclusions Low and high admission temperatures are more frequent among EPT than MPT infants. Compared with a decade earlier, fewer EPT infants experience low admission temperatures but more have elevated temperatures. In spite of a change in distribution of NICU admission temperature, an inverse association between temperature and mortality risk persists.