Neurodevelopmental outcomes of premature infants with severe respiratory failure enrolled in a randomized controlled trial of inhaled nitric oxide

Neurodevelopmental outcomes of preterm neonates receiving rescue inhaled nitric oxide in the first week of age: a cohort study

OBJECTIVE

To assess the neurodevelopmental outcomes of preterm neonates who received inhaled nitric oxide (iNO) in the first week of age for hypoxaemic respiratory failure (HRF).

METHODS

In this retrospective cohort study, we included neonates born at <29 weeks gestational age (GA) between January 2010 and December 2018 who had a neurodevelopmental assessment at 18-24 months corrected age (CA) at one of the Canadian Neonatal Follow-Up Network clinics. The primary outcome was neurodevelopmental impairment (NDI). We performed propensity score-matched analysis to compare the outcomes of those who received and did not receive iNO.

RESULTS

Of the 5612 eligible neonates, 460 (8.2%) received iNO in the first week of age. Maternal age, receipt of antenatal corticosteroids, GA and birth weight were lower in the iNO group compared with the no-iNO group. Neonates in the iNO group had higher illness severity scores and higher rates of preterm prolonged rupture of membranes and were small for GA. Severe brain injury, bronchopulmonary dysplasia and mortality were higher in the iNO group. Of the 4889 survivors, 3754 (77%) neonates had follow-up data at 18-24 months CA. After propensity score matching, surviving infants who received rescue iNO were not associated with higher odds of NDI (adjusted OR 1.34; 95% CI 0.85 to 2.12).

CONCLUSIONS

In preterm neonates <29 weeks GA with HRF, rescue iNO use was not associated with worse neurodevelopmental outcomes among survivors who were assessed at 18-24 months CA.

Efficacy of inhaled nitric oxide in preterm infants ≤ 34 weeks: a systematic review and meta-analysis of randomized controlled trials

Background: The effect of inhaled nitric oxide (iNO) in neonates >34 weeks on improving respiration is well documented. However, the efficacy of iNO in preterm infants ≤34 weeks remains controversial. Objectives: The main purpose of this review is to assess the effectiveness and safety of iNO treatment in preterm infants ≤34 weeks. Search methods: We systematically searched PubMed, Embase and Cochrane Libraries from their inception to 1 June 2023. We also reviewed the reference lists of retrieved studies. Selection criteria: Our study involved randomized controlled trials on preterm infants ≤34 weeks, especially those receiving iNO treatment, and mainly assessed outcomes such as bronchopulmonary dysplasia (BPD) and mortality. Two authors independently reviewed these trials, extracted data, and evaluated study biases. Disagreements were resolved by consensus. We used the GRADE method to assess evidence quality. Results: Our research included a total of 17 studies involving 4,080 neonates and 7 follow-up studies. The synthesis of results showed that in neonates, iNO treatment reduced the incidence of BPD (RR: 0.92; 95% CI: 0.86-0.98). It also decreased the composite outcome of death or BPD (RR: 0.94; 95% CI: 0.90-0.98), without increasing the risk of short-term (such as intraventricular hemorrhage, periventricular leukomalacia) and long-term neurological outcomes (including Bayley mental developmental index <70, cerebral palsy and neurodevelopmental impairment). Furthermore, iNO did not significantly affect other neonatal complications like sepsis, pulmonary hemorrhage, necrotizing enterocolitis, and symptomatic patent ductus arteriosus. Subgroup analysis revealed that iNO significantly reduced BPD incidence in neonates at 36 weeks under specific intervention conditions, including age less than 3 days, birth weight over 1,000 g, iNO dose of 10 ppm or higher, or treatment duration exceeding 7 days (p < 0.05). Conclusion: Inhaled NO reduced the incidence of BPD in neonates at 36 weeks of gestation, and the effect of the treatment depended on neonatal age, birth weight, duration and dose of iNO. Therefore, iNO can be considered a promising treatment for the potential prevention of BPD in premature infants. More data, however, would be needed to support nitric oxide registration in this specific patient population, to minimize its off-label use.

SIRT1 alleviates insulin resistance and respiratory distress in late preterm rats by activating QKI5-mediated PPARγ/PI3K/AKT pathway

Neonatal respiratory distress syndrome (NRDS) is a common complication of gestational diabetes mellitus (GDM) and late preterm births. Research suggests that SIRT1 was involved in LPS-induced acute respiratory distress syndrome, but its mechanism remains to be further explored. Here, pregnant rats were intraperitoneally injected with 45 mg/Kg streptozotocin at day 0 of gestation to induce GDM and injected with LPS at day 17 of gestation to induce late preterm birth. Pioglitazone (a PPARγ agonist) was administered from day 17 to parturition in GDM group, and it was administered for 3 days before LPS injection in late preterm birth group. SRT1720 (a SIRT1 activator) was administered by oral gavage from day 0 to day 17 in both groups. Our data showed that activation of SIRT1 or PPARγ alleviated the abnormal blood glucose metabolism and lung tissue injury, downregulated expression of surfactant proteins (SP-B and SP-C), and decreased activation of the PI3K/AKT pathway induced by GDM and late preterm birth in neonatal rats. Moreover, an insulin resistance model was established by treating primary AT-II cells with insulin. Activation of SIRT1 reversed insulin-induced reduction in cell proliferation, glucose consumption, SP-B and SP-C expression, and the activity of the PI3K/AKT pathway and increase in cellular inflammation and apoptosis. Mechanistically, SIRT1 upregulated PPARγ expression via deacetylation of QKI5, an RNA binding protein that can stabilize its target mRNA molecules, and then activated the PI3K/AKT pathway. In conclusion, SIRT1 promotes the expression of PPARγ via upregulation of QKI5 and activates the PI3K/AKT pathway, thus mitigating NRDS caused by GDM and late preterm birth.

The Effect of Betamethasone Dosing Interval on Perinatal Outcomes: 12 Hours or 24 Hours Apart

OBJECTIVE

Antenatal steroids are commonly used to stimulate fetal lung maturation, particularly in pregnancies at risk of early preterm labor. This study aimed to compare the effects of administering betamethasone at a 12- versus 24-hour interval on perinatal outcomes.

STUDY DESIGN

This retrospective study included 423 early preterm births from 26+0/7 to 33+6/7 weeks of gestation. Patients received betamethasone at either a 12- or 24-hour dosing interval.

RESULTS

When all patients in each group were evaluated together, there was no statistically significant difference between both groups for complications of prematurity, including respiratory distress syndrome (RDS). When the two groups were divided by gestational age (GA), the 32+0/7 to 33+6/7-week group that received betamethasone at a 24-hour interval had statistically lower 1- and 5-minute APGAR scores (p = 0.06 and p = 0.02, respectively). They also had a greater need for neonatal intensive care unit (NICU), NICU length of stay, RDS, and need for surfactant (p = 0.20, p = 0.09, p = 0.27, and p = 0.23, respectively) than did the infants at 32+0/7 to 33+6/7 weeks, who received betamethasone at a 12-hour interval. In the group with GA between 28+0/7 and 29+6/7 weeks, the 1-minute APGAR score was lower (p = 0.22), and the durations of hospital stay, and mechanical ventilation were longer (p = 0.048, p = 0.21, respectively) in the 24-hour interval group. No statistically significant difference was observed for all parameters in other GA groups.

CONCLUSION

A 12-hour dosing interval for betamethasone appears to be more appropriate, as it results in a reduction in some neonatal complications and provides a short dose interval.

KEY POINTS

· RDS is reduced when betamethasone is used 12 hours apart.. · When betamethasone is used 12 hours apart, the need for surfactant is reduced.. · The use of betamethasone 12 hours apart is advantageous with its short dose interval..

How lung injury and therapeutic oxygen could alter white matter development

Developmental brain injury describes a spectrum of neurological pathologies resulting from either antenatal or perinatal injury. This includes both cognitive and motor defects that affect patients for their entire lives. Developmental brain injury can be caused by a spectrum of conditions including stroke, perinatal hypoxia-ischemia, and intracranial hemorrhage. Additional risk factors have been identified including very low birth weight, mechanical ventilation, and oxygen (O2 ) supplementation. In fact, infants with bronchopulmonary dysplasia, an inflammatory disease associated with disrupted lung development, have been shown to have decreased cerebral white matter and decreased intracranial volumes. Thus, there appears to be a developmental link between the lung, O2 , and the brain that leads to proper myelination. Here, we will discuss what is currently known about the link between O2 and myelination and how scientists are exploring mechanisms through which supplemental O2 and/or lung injury can affect brain development. Consideration of a link between the diseased lung and developing brain will allow clinicians to fine tune their approaches in managing preterm lung disease in order to optimize brain health.

Early neurodevelopmental follow-up in the NICHD neonatal research network: Advancing neonatal care and outcomes, opportunities for the future

At the inception of the Eunice Kennedy Shriver National Institute of Child Health and Development Neonatal Research Network (NRN), provision of care for extremely preterm (EPT) infants was considered experimental. The NRN Follow-up Study Group, initiated in 1993, developed infrastructure with certification processes and standards, allowing the NRN to assess 2-year outcomes for EPT and to provide important metrics for randomized clinical trials. This chapter will review the NRN Follow-up Study Group's contributions to understanding factors related to improved neurodevelopmental, behavioral, and social-emotional outcomes of EPT infants. We will also discuss follow up challenges, including reassessing which outcomes are most meaningful for parents and investigators. Finally, we will explore how outcome studies have informed clinical decisions and ethical considerations, given limitations of prediction of complex later childhood outcomes from early neurodevelopmental findings.

Effects of Inhaled Iloprost for the Management of Persistent Pulmonary Hypertension of the Newborn

OBJECTIVE

The study aimed to evaluate the effects of inhaled iloprost on oxygenation indices in neonates with persistent pulmonary hypertension of the newborn (PPHN).

STUDY DESIGN

We conducted a retrospective chart review of 30 patients with PPHN from January 2014 to November 2018, who did not respond to inhaled nitric oxide (iNO) alone and received inhaled iloprost. Twenty-two patients met the inclusion criteria and eight patients were excluded from the study (complex cardiac disease and extreme prematurity). Patients were categorized as responders or nonresponders (patients who required extracorporeal membrane oxygenation or died). Oxygenation index, mean airway pressure (MAP), and arterial partial pressure of oxygen (PaO₂) were recorded.

RESULTS

Among a total of 22 patients who were included in the study, 10 were classified as nonresponders as they required either extracorporeal membrane oxygenation or died. Gestational age and gender did not differ between responders and nonresponders. The median PaO₂ was lower (37 vs. 42 mm Hg; p < 0.05) and median MAP was higher (20 vs. 17 cm H₂O; p < 0.02) in nonresponders compared with responders just prior to initiating iloprost. Iloprost responders had a significant increase in median PaO₂ and decrease in median oxygenation index in the 24 hours after initiating treatment (p < 0.05), with no significant change in required mean airway pressure over that same period. There was no change in vasopressor use or clinically significant worsening of platelets count, liver, and kidney functions after initiating iloprost.

CONCLUSION

Inhaled iloprost is well tolerated and seems to have beneficial effects in improving oxygenation indices in neonates with PPHN who do not respond to iNO. There is a need of well-designed prospective trials to further ascertain the benefits of using inhaled iloprost as an adjunct treatment in neonates with PPHN who do not respond to iNO alone.

KEY POINTS

· Inhaled iloprost seems to have beneficial effects in improving oxygenation indices in PPHN.. · Inhaled iloprost is generally well tolerated in newborns with PPHN.. · There is a need for prospective randomized controlled trials to further ascertain the benefits of using inhaled iloprost..

Epidemiologic evaluation of inhaled nitric oxide use among neonates with gestational age less than 35 weeks

BACKGROUND AND OBJECTIVES

The use of inhaled nitric oxide (iNO) in +late preterm and term infants with pulmonary hypertension is Food and Drug Administration (FDA) approved and has improved outcomes and survival. iNO use is not FDA approved for preterm infants and previous studies show no mortality benefit. The objectives were 1) to determine the usage of iNO among preterm neonates <35 weeks before and after the 2010 National Institutes of Health consensus statement and 2) to evaluate characteristics and outcomes among preterm neonates who received iNO.

METHODS

This is a population-based cross-sectional study. Billing and procedure codes were used to determine iNO usage. Data were queried from the National Inpatient Sample from 2004 to 2016. Neonates were included if gestational age was <35 weeks. The epochs were spilt into 2004-2010 (Epoch 1) and 2011-2016 (Epoch 2). Prevalence of iNO use, mortality, bronchopulmonary dysplasia (BPD), intraventricular hemorrhage, length of stay, mechanical ventilation, and cost of hospitalization.

RESULTS

There were 4865 preterm neonates <35 weeks who received iNO. There was a significant increase in iNO use during Epoch 2 (p < 0.001). There was significantly higher use in Epoch 2 among neonates small for gestational age (SGA) 2.3% versus 7.2%, congenital heart disease (CHD) 11.1% versus 18.6%, and BPD 35.2% versus 46.8%. Mortality was significantly lower in Epoch 2 19.8% versus 22.7%.

CONCLUSION

Usage of iNO was higher after the release of the consensus statement. The increased use of iNO among preterm neonates may be targeted at specific high-risk populations such as SGA and CHD neonates. There was lower mortality in Epoch 2; however, the cost was doubled.

Neurodevelopmental and Growth Outcomes of Extremely Preterm Infants with Short Bowel Syndrome

OBJECTIVE

To determine if preterm infants with surgical necrotizing enterocolitis (sNEC) or spontaneous intestinal perforation (SIP) with short bowel syndrome (SBS) have worse neurodevelopmental and growth outcomes than those with sNEC/SIP without SBS, and those with no necrotizing enterocolitis, SIP, or SBS.

STUDY DESIGN

We undertook a retrospective analysis of prospectively collected data from infants born between 22 and 26 weeks of gestation in the National Institute of Child Health and Human Development Neonatal Research Network centers from January 1, 2008, to December 31, 2016. Survivors were assessed at 18-26 months corrected age by standardized neurologic examination and Bayley Scales of Infant and Toddler Development, Third Edition. The primary outcome was moderate-severe neurodevelopmental impairment. Growth was assessed using World Health Organization z-score standards. Adjusted relative risks were estimated using modified Poisson regression models.

RESULTS

Mortality was 32%, 45%, and 21% in the 3 groups, respectively. Eighty-nine percent of survivors were seen at 18-26 months corrected age. Moderate-severe neurodevelopmental impairment was present in 77% of children with SBS compared with 62% with sNEC/SIP without SBS (adjusted relative risk, 1.22; 95% CI, 1.02-1.45; P = .03) and 44% with no necrotizing enterocolitis, SIP, or SBS (adjusted relative risk, 1.60; 95% CI, 1.37-1.88; P < .001). Children with SBS had lowcognitive, language, and motor scores than children with sNEC/SIP without SBS. At follow-up, length and head circumference z-scores remained more than 1 SD below the mean for children with SBS.

CONCLUSIONS

Preterm infants with sNEC/SIP and SBS had increased risk of adverse neurodevelopmental outcomes at 18-26 months corrected age and impaired growth compared with peers with sNEC/SIP without SBS or without any of these conditions.

Antenatal corticosteroids for accelerating fetal lung maturation for women at risk of preterm birth

BACKGROUND

Respiratory morbidity including respiratory distress syndrome (RDS) is a serious complication of preterm birth and the primary cause of early neonatal mortality and disability. Despite early evidence indicating a beneficial effect of antenatal corticosteroids on fetal lung maturation and widespread recommendations to use this treatment in women at risk of preterm delivery, some uncertainty remains about their effectiveness particularly with regard to their use in lower-resource settings, different gestational ages and high-risk obstetric groups such as women with hypertension or multiple pregnancies. This updated review (which supersedes an earlier review Crowley 1996) was first published in 2006 and subsequently updated in 2017.

OBJECTIVES

To assess the effects of administering a course of corticosteroids to women prior to anticipated preterm birth (before 37 weeks of pregnancy) on fetal and neonatal morbidity and mortality, maternal mortality and morbidity, and on the child in later life.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (3 September 2020), ClinicalTrials.gov, the databases that contribute to the WHO International Clinical Trials Registry Platform (ICTRP) (3 September 2020), and reference lists of the retrieved studies.

SELECTION CRITERIA

We considered all randomised controlled comparisons of antenatal corticosteroid administration with placebo, or with no treatment, given to women with a singleton or multiple pregnancy, prior to anticipated preterm delivery (elective, or following rupture of membranes or spontaneous labour), regardless of other co-morbidity, for inclusion in this review.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane Pregnancy and Childbirth methods for data collection and analysis. Two review authors independently assessed trials for inclusion, assessed risk of bias, evaluated trustworthiness based on predefined criteria developed by Cochrane Pregnancy and Childbirth, extracted data and checked them for accuracy, and assessed the certainty of the evidence using the GRADE approach. Primary outcomes included perinatal death, neonatal death, RDS, intraventricular haemorrhage (IVH), birthweight, developmental delay in childhood and maternal death.

MAIN RESULTS

We included 27 studies (11,272 randomised women and 11,925 neonates) from 20 countries. Ten trials (4422 randomised women) took place in lower- or middle-resource settings. We removed six trials from the analysis that were included in the previous version of the review; this review only includes trials that meet our pre-defined trustworthiness criteria. In 19 trials the women received a single course of steroids. In the remaining eight trials repeated courses may have been prescribed. Fifteen trials were judged to be at low risk of bias, two had a high risk of bias in two or more domains and we ten trials had a high risk of bias due to lack of blinding (placebo was not used in the control arm. Overall, the certainty of evidence was moderate to high, but it was downgraded for IVH due to indirectness; for developmental delay due to risk of bias and for maternal adverse outcomes (death, chorioamnionitis and endometritis) due to imprecision. Neonatal/child outcomes Antenatal corticosteroids reduce the risk of: - perinatal death (risk ratio (RR) 0.85, 95% confidence interval (CI) 0.77 to 0.93; 9833 infants; 14 studies; high-certainty evidence; 2.3% fewer, 95% CI 1.1% to 3.6% fewer), - neonatal death (RR 0.78, 95% CI 0.70 to 0.87; 10,609 infants; 22 studies; high-certainty evidence; 2.6% fewer, 95% CI 1.5% to 3.6% fewer), - respiratory distress syndrome (RR 0.71, 95% CI 0.65 to 0.78; 11,183 infants; studies = 26; high-certainty evidence; 4.3% fewer, 95% CI 3.2% to 5.2% fewer). Antenatal corticosteroids probably reduce the risk of IVH (RR 0.58, 95% CI 0.45 to 0.75; 8475 infants; 12 studies; moderate-certainty evidence; 1.4% fewer, 95% CI 0.8% to1.8% fewer), and probably have little to no effect on birthweight (mean difference (MD) -14.02 g, 95% CI -33.79 to 5.76; 9551 infants; 19 studies; high-certainty evidence). Antenatal corticosteroids probably lead to a reduction in developmental delay in childhood (RR 0.51, 95% CI 0.27 to 0.97; 600 children; 3 studies; moderate-certainty evidence; 3.8% fewer, 95% CI 0.2% to 5.7% fewer). Maternal outcomes Antenatal corticosteroids probably result in little to no difference in maternal death (RR 1.19, 95% CI 0.36 to 3.89; 6244 women; 6 studies; moderate-certainty evidence; 0.0% fewer, 95% CI 0.1% fewer to 0.5% more), chorioamnionitis (RR 0.86, 95% CI 0.69 to 1.08; 8374 women; 15 studies; moderate-certainty evidence; 0.5% fewer, 95% CI 1.1% fewer to 0.3% more), and endometritis (RR 1.14, 95% CI 0.82 to 1.58; 6764 women; 10 studies; moderate-certainty; 0.3% more, 95% CI 0.3% fewer to 1.1% more) The wide 95% CIs in all of these outcomes include possible benefit and possible harm.

AUTHORS' CONCLUSIONS

Evidence from this updated review supports the continued use of a single course of antenatal corticosteroids to accelerate fetal lung maturation in women at risk of preterm birth. Treatment with antenatal corticosteroids reduces the risk of perinatal death, neonatal death and RDS and probably reduces the risk of IVH. This evidence is robust, regardless of resource setting (high, middle or low). Further research should focus on variations in the treatment regimen, effectiveness of the intervention in specific understudied subgroups such as multiple pregnancies and other high-risk obstetric groups, and the risks and benefits in the very early or very late preterm periods. Additionally, outcomes from existing trials with follow-up into childhood and adulthood are needed in order to investigate any longer-term effects of antenatal corticosteroids. We encourage authors of previous studies to provide further information which may answer any remaining questions about the use of antenatal corticosteroids without the need for further randomised controlled trials. Individual patient data meta-analyses from published trials are likely to provide answers for most of the remaining clinical uncertainties.

Early Hypoxic Respiratory Failure in Extreme Prematurity: Mortality and Neurodevelopmental Outcomes

OBJECTIVES

To evaluate the survival and neurodevelopmental impairment (NDI) in extremely low birth weight (ELBW) infants at 18 to 26 months with early hypoxemic respiratory failure (HRF). We also assessed whether African American infants with early HRF had improved outcomes after exposure to inhaled nitric oxide (iNO).

METHODS

ELBW infants ≤1000 g and gestational age ≤26 weeks with maximal oxygen ≥60% on either day 1 or day 3 were labeled as "early HRF" and born between 2007 and 2015 in the Neonatal Research Network were included. Using a propensity score regression model, we analyzed outcomes and effects of exposure to iNO overall and separately by race.

RESULTS

Among 7639 ELBW infants born ≤26 weeks, 22.7% had early HRF. Early HRF was associated with a mortality of 51.3%. The incidence of moderate-severe NDI among survivors was 41.2% at 18 to 26 months. Mortality among infants treated with iNO was 59.4%. Female sex (adjusted odds ratio [aOR]: 2.4, 95% confidence interval [CI]: 1.8-3.3), birth weight ≥720 g (aOR: 2.3, 95% CI: 1.7-3.1) and complete course of antenatal steroids (aOR: 1.6, 95% CI: 1.1-2.2) were associated with intact survival. African American infants had a similar incidence of early HRF (21.7% vs 23.3%) but lower exposure to iNO (16.4% vs 21.6%). Among infants with HRF exposed to iNO, intact survival (no death or NDI) was not significantly different between African American and other races (aOR: 1.5, 95% CI: 0.6-3.6).

CONCLUSIONS

Early HRF in infants ≤26 weeks' gestation is associated with high mortality and NDI at 18 to 26 months. Use of iNO did not decrease mortality or NDI. Outcomes following iNO exposure were not different in African American infants.

Inhaled nitric oxide (iNO) for preventing prematurity-related bronchopulmonary dysplasia (BPD): 7-year follow-up of the European Union Nitric Oxide (EUNO) trial

OBJECTIVES

Most studies of inhaled nitric oxide (iNO) for prevention of bronchopulmonary dysplasia (BPD) in premature infants have focused on short-term mortality and morbidity. Our aim was to determine the long-term effects of iNO.

METHODS

A 7-year follow-up was undertaken of infants entered into a multicenter, double-blind, randomized, placebo-controlled trial of iNO for prevention of BPD in premature infants born between 24 and 28 weeks plus six days of gestation. At 7 years, survival and hospital admissions since the 2-year follow-up, home oxygen therapy in the past year, therapies used in the previous month and growth assessments were determined. Questionnaires were used to compare general health, well-being, and quality of life.

RESULTS

A total of 305 children were assessed. No deaths were reported. Rates of hospitalization for respiratory problems (6.6 vs. 10.5%, iNO and placebo group, respectively) and use of respiratory medications (6.6 vs. 9.2%) were similar. Two patients who received iNO and one who received placebo had received home oxygen therapy. There were no significant differences in any questionnaire-documented health outcomes.

CONCLUSIONS

iNO for prevention of BPD in very premature infants with respiratory distress did not result in long-term benefits or adverse long-term sequelae. In the light of current evidence, routine use of iNO cannot be recommended for prevention of BPD in preterm infants.

Prenatal Administration of Betamethasone and Neonatal Respiratory Distress Syndrome in Multifetal Pregnancies: A Randomized Controlled Trial

BACKGROUND

Neonatal Respiratory Distress Syndrome (NRDS) is one of the most frequent causes of neonatal mortality especially in premature infants. Although it has been well established that maternal antenatal corticosteroid therapy has a positive effect on NRDS reduction, yet the effectiveness of this treatment in multifetal pregnancies is dubious.

OBJECTIVE

We aimed to investigate the effect of betamethasone therapy on the incidence of NRDS in multifetal pregnancies through a randomized controlled trial.

METHODS

140 women with a multifetal pregnancy at less than 28 weeks' gestational age were randomly allocated into intervention and control groups. Women at the intervention group received intramuscularly betamethasone (12 mg/kg/BW twice). Neonatal outcomes were evaluated between two groups of intervention and control, and two subgroups of preterm and term births. This study is registered with the Iranian Clinical Trials Registry, number IRCT20180227038879N1.

RESULTS

The incidence of NRDS was significantly lower in infants of betamethasone group than the ones in the control group (4.9% vs 18.1%, P=0.034) while it did not show a significant reduction in preterm infants compared to mature ones. Also, the intervention group presented a significant lower neonatal ventilation than the control group (47.2% vs 63.2%, P=0.041). Other neonatal outcomes, including age at birth, birth weight, Apgar score, NICU admission, and the number of mortalities were not significantly different between study groups.

CONCLUSION

Betamethasone therapy during 28-32 weeks of gestation in multifetal pregnancies was associated with better neonatal outcomes through significant reductions in NRDS incidence and requiring ventilator treatment. However, betamethasone administration did not reduce the chance of NRDS in premature infants.

Inhaled Nitric Oxide in Extremely Premature Neonates With Respiratory Distress Syndrome

BACKGROUND

Inhaled nitric oxide (iNO) is increasingly prescribed to extremely premature neonates with respiratory distress syndrome (RDS). Most of this off-label use occurs during the first week of life. We studied this practice, hypothesizing that it would not be associated with improved survival.

METHODS

We queried the Pediatrix Medical Group Clinical Data Warehouse to identify all neonates born at 22 to 29 weeks' gestation from 2004 to 2014. In our study sample, we included singletons who required mechanical ventilation for treatment of RDS and excluded those with anomalies. The primary outcome was death before discharge. Through a sequential risk set approach, each patient who received iNO during the first 7 days of life ("case patient") was matched by using propensity scores to a patient who had not received iNO at a chronological age before the case patient's iNO initiation age (defined as the index age for the matched pair). The association between iNO status and in-hospital mortality was evaluated in a Cox proportional hazards regression model by using age as the time scale with patients entering the risk set at their respective index age.

RESULTS

Among 37 909 neonates in our study sample, we identified 993 (2.6%) who received iNO. The 2 matched cohorts each contained 971 patients. We did not observe a significant association between iNO exposure and mortality (hazard ratio, 1.08; 95% confidence interval, 0.94-1.25; P = .29).

CONCLUSIONS

Off-label prescription of iNO is not associated with reduced in-hospital mortality among extremely premature neonates with RDS.

Mortality among infants with evolving bronchopulmonary dysplasia increases with major surgery and with pulmonary hypertension

OBJECTIVE

To assess whether mortality in patients with evolving bronchopulmonary dysplasia (BPD, defined as ⩾28 days of oxygen exposure with lung disease) is independently associated with pulmonary arterial hypertension (PAH) and surgery.

STUDY DESIGN

Single institution retrospective birth cohort of preterm infants with gestational age (GA) 23^0/7 to 36^6/7 weeks, and evolving BPD delivered between 2001 and 2014. Surgery was classified as minor or major using published criteria. Mortality was analyzed by stepwise logistic regression analysis.

RESULTS

Among 577 patients with evolving BPD, 33 (6%) died prior to discharge. Mortality decreased with GA (adjusted odds ratio (aOR): 0.69; 95% confidence interval (CI): 0.55, 0.87), birth weight Z-score (aOR: 0.69, 95% CI: 0.47, 0.996) and increased with PAH (aOR: 30, 95% CI: 2.1, 415), major surgery (aOR; 2.8, 95% CI: 1.3, 6.3), and PAH and surgery (aOR: 10.3, 95% CI: 2.5, 42.1).

CONCLUSION

Among preterm patients with evolving BPD, PAH and surgery are independently associated with mortality.

Diagnostic Approach to Pulmonary Hypertension in Premature Neonates

Bronchopulmonary dysplasia (BPD) is a form of chronic lung disease in premature infants following respiratory distress at birth. With increasing survival of extremely low birth weight infants, alveolar simplification is the defining lung characteristic of infants with BPD, and along with pulmonary hypertension, increasingly contributes to both respiratory morbidity and mortality in these infants. Growth restricted infants, infants born to mothers with oligohydramnios or following prolonged preterm rupture of membranes are at particular risk for early onset pulmonary hypertension. Altered vascular and alveolar growth particularly in canalicular and early saccular stages of lung development following mechanical ventilation and oxygen therapy, results in developmental lung arrest leading to BPD with pulmonary hypertension (PH). Early recognition of PH in infants with risk factors is important for optimal management of these infants. Screening tools for early diagnosis of PH are evolving; however, echocardiography is the mainstay for non-invasive diagnosis of PH in infants. Cardiac computed tomography (CT) and magnetic resonance are being used as imaging modalities, however their role in improving outcomes in these patients is uncertain. Follow-up of infants at risk for PH will help not only in early diagnosis, but also in appropriate management of these infants. Aggressive management of lung disease, avoidance of hypoxemic episodes, and optimal nutrition determine the progression of PH, as epigenetic factors may have significant effects, particularly in growth-restricted infants. Infants with diagnosis of PH are managed with pulmonary vasodilators and those resistant to therapy need to be worked up for the presence of cardio-vascular anomalies. The management of infants and toddlers with PH, especially following premature birth is an emerging field. Nonetheless, combination therapies in a multi-disciplinary setting improves outcomes for these infants.

Milrinone Pharmacokinetics and Pharmacodynamics in Neonates with Persistent Pulmonary Hypertension of the Newborn

Objective To describe the pharmacokinetics and pharmacodynamics of milrinone in infants with persistent pulmonary hypertension of the newborn (PPHN) and to explore the impact of age on milrinone disposition. Design Randomized, open label pilot study. Setting Multicenter; level 3 and level 4 neonatal intensive care units. Patients Six infants ≥34 weeks' gestational age and <10 days of life with persistent hypoxemia receiving inhaled nitric oxide. Intervention Intravenous milrinone lactate in one of two dosing regimens: (1) low dose, 20 mcg/kg bolus followed by 0.2 mcg/kg/minute, and (2) standard dose, 50 mcg/kg bolus followed by 0.5 mcg/kg/minute. Measurements and Main Results The final structural model was a two-compartment disposition model with interindividual variability estimated on clearance (CL). The estimated value of CL is 7.65 mL/minute/3.4 kg (3.05 mL/minute/kg). The addition of age improved the precision of the CL estimate, and CL increased with chronological age in days. The oxygenation index was highly variable within each participant and improved with time. There were no observed safety concerns in either dosing group. Conclusion The CL of milrinone in newborns with PPHN is reduced and increases with age. In this pilot study, we did not see significant pharmacodynamic or safety effects associated with drug exposure.

Antenatal corticosteroids for accelerating fetal lung maturation for women at risk of preterm birth

BACKGROUND

Respiratory morbidity including respiratory distress syndrome (RDS) is a serious complication of preterm birth and the primary cause of early neonatal mortality and disability. While researching the effects of the steroid dexamethasone on premature parturition in fetal sheep in 1969, Liggins found that there was some inflation of the lungs of lambs born at gestations at which the lungs would be expected to be airless. Liggins and Howie published the first randomised controlled trial in humans in 1972 and many others followed.

OBJECTIVES

To assess the effects of administering a course of corticosteroids to the mother prior to anticipated preterm birth on fetal and neonatal morbidity and mortality, maternal mortality and morbidity, and on the child in later life.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register (17 February 2016) and reference lists of retrieved studies.

SELECTION CRITERIA

We considered all randomised controlled comparisons of antenatal corticosteroid administration (betamethasone, dexamethasone, or hydrocortisone) with placebo, or with no treatment, given to women with a singleton or multiple pregnancy, prior to anticipated preterm delivery (elective, or following spontaneous labour), regardless of other co-morbidity, for inclusion in this review. Most women in this review received a single course of steroids; however, nine of the included trials allowed for women to have weekly repeats.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. The quality of the evidence was assessed using the GRADE approach.

MAIN RESULTS

This update includes 30 studies (7774 women and 8158 infants). Most studies are of low or unclear risk for most bias domains. An assessment of high risk usually meant a trial had potential for performance bias due to lack of blinding. Two trials had low risks of bias for all risk of bias domains.Treatment with antenatal corticosteroids (compared with placebo or no treatment) is associated with a reduction in the most serious adverse outcomes related to prematurity, including: perinatal death (average risk ratio (RR) 0.72, 95% confidence interval (CI) 0.58 to 0.89; participants = 6729; studies = 15; Tau² = 0.05, I² = 34%; moderate-quality); neonatal death (RR 0.69, 95% CI 0.59 to 0.81; participants = 7188; studies = 22), RDS (average RR 0.66, 95% CI 0.56 to 0.77; participants = 7764; studies = 28; Tau² = 0.06, I² = 48%; moderate-quality); moderate/severe RDS (average RR 0.59, 95% CI 0.38 to 0.91; participants = 1686; studies = 6; Tau² = 0.14, I² = 52%); intraventricular haemorrhage (IVH) (average RR 0.55, 95% CI 0.40 to 0.76; participants = 6093; studies = 16; Tau² = 0.10, I² = 33%; moderate-quality), necrotising enterocolitis (RR 0.50, 95% CI 0.32 to 0.78; participants = 4702; studies = 10); need for mechanical ventilation (RR 0.68, 95% CI 0.56 to 0.84; participants = 1368; studies = 9); and systemic infections in the first 48 hours of life (RR 0.60, 95% CI 0.41 to 0.88; participants = 1753; studies = 8).There was no obvious benefit for: chronic lung disease (average RR 0.86, 95% CI 0.42 to 1.79; participants = 818; studies = 6; Tau² = 0.38 I² = 65%); mean birthweight (g) (MD -18.47, 95% CI -40.83 to 3.90; participants = 6182; studies = 16; moderate-quality); death in childhood (RR 0.68, 95% CI 0.36 to 1.27; participants = 1010; studies = 4); neurodevelopment delay in childhood (RR 0.64, 95% CI 0.14 to 2.98; participants = 82; studies = 1); or death into adulthood (RR 1.00, 95% CI 0.56 to 1.81; participants = 988; studies = 1).Treatment with antenatal corticosteroids does not increase the risk of chorioamnionitis (RR 0.83, 95% CI 0.66 to 1.06; participants = 5546; studies = 15; moderate-quality evidence) or endometritis (RR 1.20, 95% CI 0.87 to 1.63; participants = 4030; studies = 10; Tau² = 0.11, I² = 28%; moderate-quality). No increased risk in maternal death was observed. However, the data on maternal death is based on data from a single trial with two deaths; four other trials reporting maternal death had zero events (participants = 3392; studies = 5; moderate-quality).There is no definitive evidence to suggest that antenatal corticosteroids work differently in any pre-specified subgroups (singleton versus multiple pregnancy; membrane status; presence of hypertension) or for different study protocols (type of corticosteroid; single course or weekly repeats).GRADE outcomes were downgraded to moderate-quality. Downgrading decisions (for perinatal death, RDS, IVH, and mean birthweight) were due to limitations in study design or concerns regarding precision (chorioamnionitis, endometritis). Maternal death was downgraded for imprecision due to few events.

AUTHORS' CONCLUSIONS

Evidence from this update supports the continued use of a single course of antenatal corticosteroids to accelerate fetal lung maturation in women at risk of preterm birth. A single course of antenatal corticosteroids could be considered routine for preterm delivery. It is important to note that most of the evidence comes from high income countries and hospital settings; therefore, the results may not be applicable to low-resource settings with high rates of infections.There is little need for further trials of a single course of antenatal corticosteroids versus placebo in singleton pregnancies in higher income countries and hospital settings. However, data are sparse in lower income settings. There are also few data regarding risks and benefits of antenatal corticosteroids in multiple pregnancies and other high-risk obstetric groups. Further information is also required concerning the optimal dose-to-delivery interval, and the optimal corticosteroid to use.We encourage authors of previous studies to provide further information, which may answer any remaining questions about the use of antenatal corticosteroids in such pregnancies without the need for further randomised controlled trials. Individual patient data meta-analysis from published trials is likely to answer some of the evidence gaps. Follow-up studies into childhood and adulthood, particularly in the late preterm gestation and repeat courses groups, are needed. We have not examined the possible harmful effects of antenatal corticosteroids in low-resource settings in this review. It would be particularly relevant to explore this finding in adequately powered prospective trials.

Inhaled nitric oxide for respiratory failure in preterm infants

BACKGROUND

Inhaled nitric oxide (iNO) is effective in term infants with hypoxic respiratory failure. The pathophysiology of respiratory failure and the potential risks of iNO differ substantially in preterm infants, necessitating specific study in this population.

OBJECTIVES

To determine effects of treatment with inhaled nitric oxide (iNO) on death, bronchopulmonary dysplasia (BPD), intraventricular haemorrhage (IVH) or other serious brain injury and on adverse long-term neurodevelopmental outcomes in preterm newborn infants with hypoxic respiratory failure.Owing to substantial variation in study eligibility criteria, which decreases the utility of an overall analysis, we divided participants post hoc into three groups: (1) infants treated over the first three days of life because of defects in oxygenation, (2) preterm infants with evidence of pulmonary disease treated routinely with iNO and (3) infants treated later (after three days of age) because of elevated risk of BPD.

SEARCH METHODS

We used standard methods of the Cochrane Neonatal Review Group. We searched MEDLINE, Embase, Healthstar and the Cochrane Central Register of Controlled Trials in the Cochrane Library through January 2016. We also searched the abstracts of the Pediatric Academic Societies.

SELECTION CRITERIA

Eligible for inclusion were randomised and quasi-randomised studies in preterm infants with respiratory disease that compared effects of iNO gas versus control, with or without placebo.

DATA COLLECTION AND ANALYSIS

We used standard methods of the Cochrane Neonatal Review Group and applied the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to assess the quality of evidence.

MAIN RESULTS

We found 17 randomised controlled trials of iNO therapy in preterm infants. We grouped these trials post hoc into three categories on the basis of entry criteria: treatment during the first three days of life for impaired oxygenation, routine use in preterm babies along with respiratory support and later treatment for infants at increased risk for bronchopulmonary dysplasia (BPD). We performed no overall analyses.Eight trials providing early rescue treatment for infants on the basis of oxygenation criteria demonstrated no significant effect of iNO on mortality or BPD (typical risk ratio (RR) 0.94, 95% confidence interval (CI) 0.87 to 1.01; 958 infants). Four studies examining routine use of iNO in infants with pulmonary disease reported no significant reduction in death or BPD (typical RR 0.94, 95% CI 0.87 to 1.02; 1924 infants), although this small effect approached significance. Later treatment with iNO based on risk of BPD (three trials) revealed no significant benefit for this outcome in analyses of summary data (typical RR 0.92, 95% CI 0.85 to 1.01; 1075 infants).Investigators found no clear effect of iNO on the frequency of all grades of IVH nor severe IVH. Early rescue treatment was associated with a non-significant 20% increase in severe IVH.We found no effect on the incidence of neurodevelopmental impairment.

AUTHORS' CONCLUSIONS

iNO does not appear to be effective as rescue therapy for the very ill preterm infant. Early routine use of iNO in preterm infants with respiratory disease does not prevent serious brain injury or improve survival without BPD. Later use of iNO to prevent BPD could be effective, but current 95% confidence intervals include no effect; the effect size is likely small (RR 0.92) and requires further study.

Inhaled nitric oxide therapy for pulmonary disorders of the term and preterm infant

The 21st century began with the FDA approval of inhaled nitric oxide therapy for the treatment of neonatal hypoxic respiratory failure associated with pulmonary hypertension in recognition of the 2 randomized clinical trials demostrating a significant reduction in the need for extracorporeal support in the term and near-term infant. Inhaled nitric oxide is one of only a few therapeutic agents approved for use through clinical investigations primarily in the neonate. This article provides an overview of the pertinent biology and chemistry of nitric oxide, discusses potential toxicities, and reviews the results of pertinent clinical investigations and large randomized clinical trials including neurodevelopmental follow-up in term and preterm neonates. The clinical investigations conducted by the Eunice Kennedy Shriver NICHD Neonatal Research Network will be discussed and placed in context with other pertinent clinical investigations exploring the efficacy of inhaled nitric oxide therapy in neonatal hypoxic respiratory failure.

Inhaled nitric oxide in preterm infants: An updated meta-analysis

Background:

In the past several years, randomized controlled trials (RCTs) have indicated that inhaled nitric oxide (iNO) can potentially lower for both the incidence of bronchopulmonary dysplasia (BPD) and mortality in affected infants. Other research has, however, disagreed with these findings.

Materials and Methods:

We performed an updated meta analysis of all relevant RCTs to assess the benefits of iNO in preterm infants by searching PubMed, EMBASE, Cochrane databases, Wanfang, VIP, and CNKI databases for English and Chinese references.

Results:

Ultimately, 22 RCTs were incorporated. (1) Risk of BPD was significantly lower in preterm infants supplemented with iNO (relative risk [RR] = 0.88; P = 0.0007). There are no differences concerning pulmonary hemorrhage (PH) (RR = 0.94; P = 0.72). (2) Incidences of necrotizing enterocolitis (NEC), retinopathy of prematurity (ROP), and severe intracranial hemorrhage (ICH) were compared. No significant difference was discovered concerning these risks (RR = 1.21, P = 0.08; RR = 1.01, P = 0.89; and RR = 0.99, P = 0.86). (3) In addition, no significant differences were found between experimental and control groups with respect to morality. (RR = 1.00, P = 0.98).

Conclusion:

Our meta analysis has shown a beneficial effect in BPD and morality. In addition, our meta analysis suggests that iNO therapy does not increase the risk of common complications, such as NEC and ROP, and that it may also have no adverse effect on bleeding tendency diseases (severe ICH and PH).

Off-label use of inhaled nitric oxide after release of NIH consensus statement

BACKGROUND

Inhaled nitric oxide (iNO) therapy is an off-label medication in infants <34 weeks' gestational age. In 2011, the National Institutes of Health released a statement discouraging routine iNO use in premature infants. The objective of this study was to describe utilization patterns of iNO in American NICUs in the years surrounding the release of the National Institutes of Health statement. We hypothesized that iNO prescription rates in premature infants have remained unchanged since 2011.

METHODS

The Pediatrix Medical Group Clinical Data Warehouse was queried for the years 2009-2013 to describe first exposure iNO use among all admitted neonates stratified by gestational age.

RESULTS

Between 2009 and 2013, the rate of iNO utilization in 23- to 29-week neonates increased from 5.03% to 6.19%, a relative increase of 23% (confidence interval: 8%-40%; P = .003). Of all neonates who received iNO therapy in 2013, nearly half were <34 weeks' gestation, with these infants accounting for more than half of all first exposure iNO days each year of the study period.

CONCLUSIONS

The rates of off-label iNO use in preterm infants continue to rise despite evidence revealing no clear benefit in this population. This pattern of iNO prescription is not benign and comes with economic consequences.

Use of inhaled nitric oxide in preterm infants

Nitric oxide, an important signaling molecule with multiple regulatory effects throughout the body, is an important tool for the treatment of full-term and late-preterm infants with persistent pulmonary hypertension of the newborn and hypoxemic respiratory failure. Several randomized controlled trials have evaluated its role in the management of preterm infants ≤ 34 weeks' gestational age with varying results. The purpose of this clinical report is to summarize the existing evidence for the use of inhaled nitric oxide in preterm infants and provide guidance regarding its use in this population.

Two-year outcomes of a randomized controlled trial of inhaled nitric oxide in premature infants

BACKGROUND AND OBJECTIVES

The European Union Nitric Oxide trial was designed to assess the potential benefits of inhaled nitric oxide (iNO) compared with placebo in infants with respiratory failure. This follow-up study evaluated respiratory, neurodevelopmental, and other outcomes for infants entered into the European Union Nitric Oxide trial to age 2 years.

METHODS

In a multicenter, randomized, double-blind study, preterm infants born at <29 weeks' gestation with moderate respiratory failure were allocated to receive iNO (5 ppm) or placebo for 7 to 21 days. Subjects underwent assessments at 1 and 2 years corrected for prematurity.

RESULTS

At 36 weeks' postmenstrual age, 696 of 792 infants were alive; 4 in the iNO arm subsequently died before age 2 years compared with 7 in the control arm. We evaluated 95% of the survivors at 12 months and 90% at 2 years. In the iNO arm, 244 of 363 (67.2%) infants had survived without disability at age 2 years compared with 270 of 374 (72.2%) who received placebo (P = .094). Mean (SD) cognitive composite scores (Bayley Scales of Infant and Toddler Development, third edition) were 94 (13) in the iNO group and 95 (14) in the placebo group; in the iNO group, 19% scored <85 and 9.5% developed cerebral palsy compared with 13.3% and 9%, respectively. There were no significant differences in hospitalizations overall or due to respiratory illness in use of home oxygen therapy or respiratory medications, in growth, or in other health outcomes.

CONCLUSIONS

At 2 years of age, low-dose (5 ppm) iNO started early (<24 hours after birth) for a median of 20 days did not affect neurodevelopmental or other health outcomes.

Can nitric oxide-based therapy prevent bronchopulmonary dysplasia?

A growing understanding of endogenous nitric oxide (NO) biology is helping to explain how and when exogenous NO may confer benefit or harm; this knowledge is also helping to identify new better-targeted NO-based therapies. In this review, results of the bronchopulmonary dysplasia clinical trials that used inhaled NO in the preterm population are placed in context, the biologic basis for novel NO therapeutics is considered, and possible future directions for NO-focused clinical and basic research in developmental lung disease are identified.

Inhaled nitric oxide in preterm infants: a systematic review

CONTEXT

Studies of the efficacy of inhaled nitric oxide (iNO) to prevent or treat respiratory failure in preterm infants have had variable and contradictory findings.

OBJECTIVES

To systematically review the evidence on the use of iNO in infants born at ≤ 34 weeks' gestation who receive respiratory support.

METHODS

Medline, Embase, the Cochrane Central Register of Controlled Studies, PsycInfo, ClinicalTrials.gov, and proceedings of the 2009 and 2010 Pediatric Academic Societies meetings were searched in June 2010. Additional studies from reference lists of eligible articles, relevant reviews, and technical experts were considered. Two investigators independently screened search results and abstracted data from eligible articles. We focus here on mortality, bronchopulmonary dysplasia (BPD), the composite outcome of death or BPD, and neurodevelopmental impairment.

RESULTS

Fourteen randomized controlled trials, 7 follow-up studies, and 1 observational study were eligible for inclusion. Mortality rates in the NICU did not differ for infants treated with iNO compared with controls (risk ratio [RR]: 0.97 [95% confidence interval (CI): 0.82-1.15]). BPD at 36 weeks for iNO and control groups also did not differ for survivors (RR: 0.93 [95% CI: 0.86-1.003]). A small difference was found in favor of iNO in the composite outcome of death or BPD (RR: 0.93 [95% CI: 0.87-0.99]). There was no evidence to suggest a difference in the incidence of cerebral palsy (RR: 1.36 [95% CI: 0.88-2.10]), neurodevelopmental impairment (RR: 0.91 [95% CI: 0.77-1.12]), or cognitive impairment (RR: 0.72 [95% CI: 0.35-1.45]).

CONCLUSIONS

There was a 7% reduction in the risk of the composite outcome of death or BPD at 36 weeks for infants treated with iNO compared with controls but no reduction in death alone or BPD. There is currently no evidence to support the use of iNO in preterm infants with respiratory failure outside the context of rigorously conducted randomized clinical trials.

Inhaled nitric oxide for respiratory failure in preterm infants

BACKGROUND

Inhaled nitric oxide (iNO) is effective in term infants with hypoxic respiratory failure. The pathophysiology of respiratory failure and the potential risks of iNO differ substantially in preterm infants, necessitating study in this population.

OBJECTIVES

To determine the effect of treatment with iNO on death, bronchopulmonary dysplasia (BPD), intraventricular hemorrhage (IVH), and neurodevelopmental disability in preterm newborn infants with respiratory disease.

SEARCH STRATEGY

Standard methods of the Cochrane Neonatal Review Group were used. MEDLINE, EMBASE, Healthstar and the Cochrane Central Register of Controlled Trials (The Cochrane Library) were searched covering the years from 1985 to 2010. In addition, the abstracts of the Pediatric Academic Societies were also searched.

SELECTION CRITERIA

Randomized and quasi-randomized studies in preterm infants with respiratory disease that compared the effects of iNO gas to control, with or without placebo were eligible.

DATA COLLECTION AND ANALYSIS

Standard methods of the Cochrane Neonatal Review Group were used.

MAIN RESULTS

Fourteen randomized controlled trials of inhaled nitric oxide therapy in preterm infants were found. The trials have been grouped post hoc into three categories depending on entry criteria; entry in the first three days of life based on oxygenation criteria, routine use in preterm babies with pulmonary disease, and later enrolment based on an increased risk of BPD. No overall analyses were performed.Nine trials of early rescue treatment of infants based on oxygenation criteria demonstrated no significant effect of iNO on mortality or BPD. Three studies with routine use of iNO in infants with pulmonary disease also demonstrated no significant reduction in death or BPD [typical RR 0.93 (95% CI 0.86 to 1.01)] although this small effect approached significance. Later treatment with iNO based on the risk of BPD (two trials) demonstrated no significant benefit for this outcome in analyses which are possible using summary data.There is no clear effect of iNO on the frequency of all grades of IVH or of severe IVH. Early rescue treatment was associated with a non-significant 20% increase in severe IVH.No effect on the incidence of neurodevelopmental impairment was found.

AUTHORS' CONCLUSIONS

iNO as rescue therapy for the very ill preterm infant does not appear to be effective. Early routine use of iNO in preterm infants with respiratory disease does not affect serious brain injury or improve survival without BPD. Later use of iNO to prevent BPD might be effective, but requires further study.

Reader variability in the use of diagnostic terms to describe white matter lesions seen on cranial scans of severely premature infants: the ELGAN study

PURPOSE

To evaluate reader variability of white matter lesions seen on cranial sonographic scans of extreme low gestational age neonates (ELGANs).

METHODS

In 1,452 ELGANs, cranial sonographic scans were obtained in the first and second postnatal weeks, and between the third postnatal week and term. All sets of scans were read independently by two sonologists. We reviewed the use of four diagnostic labels: early periventricular leucomalacia, cystic periventricular leucomalacia, periventricular hemorrhagic infarction (PVHI), and other white matter diagnosis, by 16 sonologists at 14 institutions. We evaluated the association of these labels with location and laterality of hyperechoic and hypoechoic lesions, location of intraventricular hemorrhage, and characteristics of ventricular enlargement.

RESULTS

Experienced sonologists differed substantially in their application of the diagnostic labels. Three readers applied early periventricular leucomalacia to more than one fourth of all the scans they read, whereas eight applied this label to ≤5% of scans. Five applied PVHI to ≥10% of scans, while three applied this label to ≤5% of scans. More than one third of scans labeled cystic periventricular leucomalacia had unilateral hypoechoic lesions. White matter abnormalities in PVHI were more extensive than in periventricular leucomalacia and were more anteriorly located. Hypoechoic lesions on late scans tended to be in the same locations, regardless of the diagnostic label applied.

CONCLUSIONS

Experienced sonologists differ considerably in their tendency to apply diagnostic labels for white matter lesions. This is due to lack of universally agreed-upon definitions. We recommend reducing this variability to improve the validity of large multicenter studies.

Inhaled nitric oxide for prevention of bronchopulmonary dysplasia in premature babies (EUNO): a randomised controlled trial

BACKGROUND

In animal models, inhaled nitric oxide improved gas exchange and lung structural development, but its use in premature infants at risk of developing bronchopulmonary dysplasia remains controversial. We therefore tested the hypothesis that inhaled nitric oxide at a low concentration, started early and maintained for an extended period in babies with mild respiratory failure, might reduce the incidence of bronchopulmonary dysplasia.

METHODS

800 preterm infants with a gestational age at birth of between 24 weeks and 28 weeks plus 6 days (inclusive), weighing at least 500 g, requiring surfactant or continuous positive airway pressure for respiratory distress syndrome within 24 h of birth were randomly assigned in a one-to-one ratio to inhaled nitric oxide (5 parts per million) or placebo gas (nitrogen gas) for a minimum of 7 days and a maximum of 21 days in a double-blind study done at 36 centres in nine countries in the European Union. Care providers and investigators were masked to the computer-generated treatment assignment. The primary outcome was survival without development of bronchopulmonary dysplasia at postmenstrual age 36 weeks. Analysis was by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00551642.

FINDINGS

399 infants were assigned to inhaled nitric oxide, and 401 to placebo. 395 and 400, respectively, were analysed. Treatment with inhaled nitric oxide and placebo did not result in significant differences in survival of infants without development of bronchopulmonary dysplasia (258 [65%] of 395 vs 262 [66%] of 400, respectively; relative risk 1.05, 95% CI 0.78-1.43); in survival at 36 weeks' postmenstrual age (343 [86%) of 399 vs 359 [90%] of 401, respectively; 0.74, 0.48-1.15); and in development of bronchopulmonary dysplasia (81 [24%] of 339 vs 96 [27%] of 358, respectively; 0.83, 0.58-1.17).

INTERPRETATION

Early use of low-dose inhaled nitric oxide in very premature babies did not improve survival without bronchopulmonary dysplasia or brain injury, suggesting that such a preventive treatment strategy is unsuccessful.

FUNDING

INO Therapeutics.

Two-year neurodevelopmental outcomes of ventilated preterm infants treated with inhaled nitric oxide

OBJECTIVE

In a randomized multi-center trial, we demonstrated that inhaled nitric oxide begun between 7 and 21 days and given for 24 days significantly increased survival without bronchopulmonary dysplasia (BPD) in ventilated premature infants weighing <1250 g. Because some preventative BPD treatments are associated with neurodevelopmental impairment, we designed a follow-up study to assess the safety of nitric oxide.

STUDY DESIGN

Our hypothesis was that inhaled nitric oxide would not increase neurodevelopmental impairment compared with placebo. We prospectively evaluated neurodevelopmental and growth outcomes at 24 months postmenstrual age in 477 of 535 surviving infants (89%) enrolled in the trial.

RESULTS

In the treated group, 109 of 243 children (45%) had neurodevelopmental impairment (moderate or severe cerebral palsy, bilateral blindness, bilateral hearing loss, or score <70 on the Bayley Scales II), compared with 114 of 234 (49%) in the placebo group (relative risk, 0.92; 95% CI, 0.75-1.12; P = .39). No differences on any subcomponent of neurodevelopmental impairment or growth variables were found between inhaled nitric oxide or placebo.

CONCLUSIONS

Inhaled nitric oxide improved survival free of BPD, with no adverse neurodevelopmental effects at 2 years of age.

The effect of betamethasone treatment on neuroactive steroid synthesis in a foetal Guinea pig model of growth restriction

There are ongoing concerns that antenatal corticosteroids, which are administered to women at high risk of delivering preterm to reduce the incidence of respiratory distress syndrome, have adverse effects on foetal brain development and subsequent effects on behaviour and learning, when administered as repeated courses. The present study aimed to examine whether repeated betamethasone treatment alters the expression of the key-rate limiting enzyme, 5alpha-reductase, in the synthetic pathway of the potent neuroactive steroid allopregnanolone in the brain and placenta and whether this effect is potentiated in growth restricted foetuses. To investigate this, pregnant guinea pigs carrying either control (sham surgery) or growth-restricted foetuses were treated with vehicle or betamethasone (1 mg/kg/day) for 4 days prior to sacrifice (65d). Placental insufficiency was induced by the ablation of uterine artery branches supplying each placenta at mid gestation, resulting in foetal growth restriction characterised by 'brain sparing'. Real-time reverse transcriptase polymerase chain reaction was used to determine relative 5alpha-reductase type 1 and 2 mRNA expression in the placenta and brain. Immunohistochemistry was used to examine the glial fibrillary acidic protein (GFAP) expression in the subcortical white matter, CA1 and dentate regions of the hippocampus. 5alpha-reductase type 2 mRNA expression in the brain was markedly reduced by betamethasone treatment in male foetuses compared to vehicle-treated controls but not in female foetuses. In addition, 5alpha-reductase type 1 expression in the brain was increased by growth restriction and/or betamethasone treatment in female foetuses but expression in males foetuses did not increase. 5alpha-reductase type 2 expression in the placenta was markedly reduced by betamethasone treatment compared to vehicle-treated control. Intrauterine growth restriction and betamethasone treatment reduced GFAP expression in the CA1 region of the hippocampus in the brains of male but not female foetuses. These data indicate that betamethasone treatment suppresses placental expression and has sexually dimorphic effects on expression of neuroactive steroid synthetic enzymes in the brain. These actions may lead to adverse effects on the developing brain, particularly in male foetuses, such as the observed effects on GFAP expression.

CO and NO pulmonary diffusing capacity during pregnancy: Safety and diagnostic potential

This paper reviews the scientific evidence for the safety of carbon monoxide (CO) and nitric oxide (NO) inhalation to measure pulmonary diffusing capacity (DL(CO) and DL(NO)) in pregnant women and their fetuses. In eight earlier studies, 650 pregnant women had DL(CO) measurements performed at various times during pregnancy, with a minimum of two to four tests per session. Both pregnant subjects that were healthy and those with medical complications were tested. No study reported adverse maternal, fetal, or neonatal outcomes from the CO inhalation in association with measuring DL(CO). Eleven pregnant women, chiefly with pulmonary hypertension, and 1105 pre-term neonates, mostly with respiratory failure, were administered various dosages of NO (5-80ppm for 4 weeks continuously in pregnant women, and 1-20ppm for 15min to 3 weeks for the neonates). NO treatment was found to be an effective therapy for pregnant women with pulmonary hypertension. In neonates with respiratory failure and pulmonary hypertension, NO therapy improved oxygenation and survival and has been associated with only minor, transient adverse effects. In conclusion, maternal carboxyhemoglobin ([Hb(CO)]) levels can safely increase to 5% per testing session when the dose-exposure limit is 0.3% CO inhalation for <or=3min, and for NO, 80ppm for <or=3min. The risk of late fetal or neonatal death from increased Hb(CO) from diffusion testing is considerably less than the risk of death from all causes reported by the Centers for Disease Control, and is therefore considered "minimal risk".

Dynamic Hemodynamic Energy Loss in Normal and Stenosed Aortic Valves

Aortic valve (AV) stenosis, if untreated, leads to heart failure. From a mechanics standpoint, heart failure can be interpreted as the failure of the heart to generate sufficient power to overcome energy losses in the circulation. Thus, energy efficiency-based measures for evaluating AV performance and disease severity have the advantage of being a direct measure of the contribution of the AV hydrodynamic characteristics toward heart failure. We present a new method for computing the rate of energy dissipation as a function of systolic time, by modifying the Navier–Stokes momentum equation. This method preserves the dynamic term of the Navier–Stokes momentum equation, and allows the investigation of the trend of the rate of energy dissipation over time. This method is applied to a series of in vitro experiments, where a trimmed porcine valve is exposed to various conditions: varying stroke volumes (50 ml to 90 ml) at the fixed heart rate; varying heart rates (60–80 beats/min) at fixed stroke volume; and varying stenosis levels (normal, mild stenosis, moderate stenosis). The results are: (1) energy dissipation waveform has a distinctive pattern of being skewed toward late systole, due to flow instabilities during deceleration phases; (2) increasing heart rate and stroke volume increases energy dissipation, but the normalized shape of the energy dissipation waveform is preserved across heart rates and stroke volumes; (3) increasing stenosis level increases energy dissipation, and also alters the normalized shape of the energy dissipation waveform. Since stenosis produces a signature energy dissipation waveform shape, dynamic energy dissipation analysis can potentially be extended into a clinical tool for AV evaluation.

Epidemiology of bronchopulmonary dysplasia

First described more than 40 years ago, bronchopulmonary dysplasia (BPD) remains one of the most serious and vexing challenges in the care of very preterm infants. Affecting approximately one-quarter of infants born <1500g birth weight, BPD is associated with prolonged neonatal intensive care unit hospitalization, greater risk of neonatal and post-neonatal mortality and a host of associated medical and neurodevelopmental sequelae. This seminar focuses on the epidemiology and definition of BPD as well as the current evidence pertaining to a number of potential preventive treatments for BPD: non-invasive respiratory support technologies, inhaled nitric oxide, vitamin A, and caffeine.

Clinical and economic effects of iNO in premature newborns with respiratory failure at 1 year

BACKGROUND

The long-term consequences of inhaled nitric oxide (iNO) use in premature newborns with respiratory failure are unknown. We therefore studied the clinical and economic outcomes to 1 year of corrected age after a randomized controlled trial of prophylactic iNO.

METHODS

Premature newborns (gestational age <or=34 w, birth weight 500-1250 g) with respiratory failure randomly received 5 ppm iNO or placebo within 48 h of birth until 21 d or extubation. We assessed clinical outcomes via in-person neurodevelopmental evaluation at 1 y corrected age and telephone interviews every 3 m. We estimated costs from detailed hospital bills and interviews, converting all costs to 2008 US$. Of 793 trial subjects, 631 (79.6%) contributed economic data, and 455 (77.1% of survivors) underwent neurodevelopmental evaluation.

RESULTS

At 1 y corrected age, survival was not different by treatment arm (79.2% iNO vs. 74.5% placebo, P = .12), nor were other post-discharge outcomes. For subjects weighing 750-999 g, those receiving iNO had greater survival free from neurodevelopmental impairment (67.9% vs. 55.6%, P = .04). However, in subjects weighing 500-749 g, iNO led to greater oxygen dependency (11.7% vs. 4.0%, P = .04). Median total costs were similar ($235,800 iNO vs. $198,300 placebo, P = .19). Quality-adjusted survival was marginally better with iNO (by 0.011 quality-adjusted life-years/subject). The incremental cost-effectiveness ratio was $2.25 million/quality-adjusted life-year.

CONCLUSIONS

Subjects in both arms commonly experienced neurodevelopmental and pulmonary morbidity, consuming substantial health care resources. Prophylactic iNO beginning in the first days of life did not lower costs and had a poor cost-effectiveness profile.

Permanent bilateral sensory and neural hearing loss of children after neonatal intensive care because of extreme prematurity: a thirty-year study

OBJECTIVE

We present population-based, childhood prevalence rates of and neonatal risk factors for permanent hearing loss among extremely premature infants.

METHODS

By using an inception-cohort, longitudinal study design for 1974-2003, we studied permanent hearing loss among 1279 survivors with gestational age of < or =28 weeks and birth weight of <1250 g (mortality rate: 42.7%; lost to follow-up monitoring: 4.7%) Newborn hearing screening, performed by experienced pediatric audiologists, used click-evoked auditory brainstem response testing after 1975. Survivors underwent repeated behavioral audiologic testing and multidisciplinary follow-up monitoring. Permanent hearing loss was defined as mild/moderate (26-70 dB hearing level), severe/profound (71 to >90 dB hearing level), delayed-onset (diagnosed after previously normal hearing), or progressive (increase in loss of > or =15 dB hearing level). Permanent hearing loss rates were established at 3 years of age, with newborn, infant, and >5-year final hearing outcomes being recorded. Risk factors were compared for children with and without hearing loss, odds ratios were calculated, and prediction performance was determined through area under the curve analysis.

RESULTS

Forty (3.1%) of 1279 survivors 3 years of age had permanent hearing loss and 24 (1.9%) had severe/profound loss, with no changes over time. Bilateral delayed-onset loss occurred for 4 children (10%) and progressive loss for 11 children (28%). One child had auditory neuropathy, and 29 (73%) had multiple disabilities. Prolonged oxygen use, gastrointestinal surgery, patent ductus arteriosus ligation, and low socioeconomic index yielded good prediction of permanent hearing loss; oxygen use was the most significant predictor of severe/profound loss.

CONCLUSIONS

Permanent hearing loss remains an adverse outcome of extreme prematurity, complicated by significant delayed-onset and progressive loss. Prolonged supplemental oxygen use is a marker for predicting permanent hearing loss; this requires detailed analysis of the pathophysiologic features, to reduce the prevalence of permanent hearing loss.

Inhaled nitric oxide for preterm neonates

The evidence for the benefits of inhaled nitric oxide (iNO) on gas exchange, cytokine-induced lung inflammation, and vascular dysfunction has been demonstrated by several animal and human studies. The use of iNO in extremely low birth weight neonates for the prevention of adverse outcomes like chronic lung disease and neurologic injury has been investigated, but the findings remain inconclusive. This review briefly outlines the biologic rationale for the use of iNO in preterm neonates and the results on the outcome measures of bronchopulmonary dysplasia and brain injury from the recent clinical trials. This article focuses on the potential toxicities, persistent controversies, and unanswered questions regarding the use of this treatment modality in this patient population at high risk for adverse outcomes.

Inhaled nitric oxide and neuroprotection in preterm infants

Although inhaled nitric oxide-mediated decreases in chronic lung disease and severe intraventricular hemorrhage/periventricular leukomalacia undoubtedly contribute to improved neurodevelopmental outcomes, inhaled nitric oxide has an independent neuroprotective effect. Although these data are encouraging, additional studies are required before recommending the routine use of inhaled nitric oxide for neuroprotection in preterm infants.

Inhaled nitric oxide in the treatment of preterm infants

Inhaled nitric oxide (iNO) has been used successfully in select term and near-term infants with respiratory failure. The use of iNO in the premature infant population, however, remains controversial. This article will review some of the current literature regarding the use of iNO in premature infants and discuss current recommendations and future research directions.

Effect of inhaled nitric oxide on cerebrospinal fluid and blood nitrite concentrations in newborn lambs

Inhaled nitric oxide (iNO) has many extrapulmonary effects. As the half-life of nitric oxide (NO) in blood is orders of magnitude less than the circulation time from lungs to the brain, the mediator of systemic effects of iNO is unknown. We hypothesized that concentrations of nitrite, a circulating byproduct of NO with demonstrated NO bioactivity, would increase in blood and cerebrospinal fluid (CSF) during iNO therapy. iNO (80 ppm) was given to six newborn lambs and results compared with six control lambs. Blood and CSF nitrite concentrations increased 2-fold in response to iNO. cGMP increased in blood but not CSF suggesting brain guanylate cyclase activity was not increased. When sodium nitrite was infused i.v. blood and CSF nitrite levels increased within 10 min and reached similar levels of 14.6 +/- 1.5 microM after 40 min. The reactivity of nitrite in Hb-free brain homogenates was investigated, with the findings that nitrite did not disappear nor did measurable amounts of s-nitroso, n-nitroso, or iron-nitrosyl-species appear. We conclude that although nitrite diffuses freely between blood and CSF, due to its lack of reactivity in the brain, nitrite's putative role as the mediator of the systemic effects of iNO is limited to intravascular reactions.

Neurodevelopmental outcomes of preterm infants

PURPOSE OF REVIEW

Preterm birth is emerging as a major public health problem in the USA. Improvements in preterm birth and survival rates translate to increasing numbers of preterm survivors, and many develop motor, cognitive and sensory impairments.

RECENT FINDINGS

The review discusses the recently reported prevalence of neurodevelopmental disabilities in preterm survivors, in addition to studies of factors associated with neurodevelopmental outcome.

SUMMARY

A 2007 report from the Institute of Medicine emphasizes preterm birth as an increasingly common complex condition with multiple risk factors resulting from multiple gene-environmental interactions, leading to birth before 37 weeks gestation, neonatal complications and a disproportionately high contribution to neurodevelopmental disability rates. The increased risk of cerebral palsy with decreasing gestational age categories is well documented, but recent studies highlight the range and severity of cognitive, sensory, language, visual-perceptual, attention and learning deficits in very preterm children. Combined with increasingly sophisticated neuroimaging studies to identify perinatal risk factors, neurodevelopmental follow-up of neonatal intensive care unit trials offers the potential to really improve our understanding of how the preterm brain develops, is injured and recovers from injuries. Knowledge of what influences neurodevelopmental outcomes is key to developing better treatment strategies.

Is cerebral palsy preventable?

PURPOSE OF REVIEW

To use evidence of good medical quality to update information on strategies for prevention of cerebral palsy, and on the success of these preventive efforts to date.

RECENT FINDINGS

Causes of cerebral palsy, and therefore promising approaches to prevention, differ by gestational age group and by clinical subtype. Neuroimaging and neuropathology indicate the importance of white matter disorders and of ischemic stroke in cerebral palsy; birth asphyxia, congenital malformations, placental pathology, and genetic variants also contribute to cerebral palsy risk. Multiplicity of risk factors markedly increases risk. Recent studies indicate that mild hypothermia lessens cerebral palsy risk in term infants with moderate neonatal encephalopathy, and the possibility that administration of magnesium sulphate to women in preterm labor may aid in primary prevention of cerebral palsy in very preterm infants.

SUMMARY

Past efforts to prevent cerebral palsy have not had the benefits sought, but recent results provide new hope and new challenges.

Inhaled nitric oxide for the treatment of preterm infants with respiratory distress syndrome

Many authors have hypothesized that inhaled nitric oxide (iNO) might acutely improve oxygenation in preterm neonates with infant respiratory distress syndrome (iRDS) and decrease the risk of bronchopulmonary dysplasia. The studies on the effects of iNO in preterm infants with iRDS have given contradictory results. We report their main methodological characteristics and the observed effects of iNO in preterm infants. Moreover, we discuss the infants' age at the beginning of the study, the dose and duration of iNO therapy, its potential effect on neurodevelopment, its relationship with surfactant properties, and the need to identify patients who are likely to respond to this therapy. We advise caution against the widespread use of iNO in preterm infants with iRDS. At present, it appears to be premature to have specific recommendations regarding the indications for iNO therapy in this group of patients. The conclusion of current trials and the follow-up studies of recently completed trials will give further data to guide neonatologists' decisions, and until then it is likely that clinicians will continue to make case-by-case decisions for the treatment of iNO in preterm infants with hypoxia that is unresponsive to other therapies. However, this decision should always be discussed with the parents.