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

Learning from those who thrive: protective factors and neuroimaging markers in adolescents with complex congenital heart disease and with a favorable neurodevelopmental profile

Patients with complex congenital heart disease (cCHD) are at risk for neurodevelopmental impairments, yet many patients develop normally. This study investigated associations between a favorable neurodevelopmental profile and protective factors, quality of life (QoL), resilience, and brain development. Adolescents with cCHD (n = 100) were prospectively enrolled. Neurodevelopmental profiles comprised IQ, executive functions, and behavior. Standardized neuropsychological tests and questionnaires were used to assess neurodevelopmental outcomes, family factors, QoL, and resilience. Clinical data were obtained from medical charts. Cerebral MRI was acquired. Specific neurodevelopmental profiles were identified by latent profile analysis and were associated with clinical and family factors, QoL and resilience, and MRI markers. We identified two distinct groups of neurodevelopmental profiles (favorable profile: n = 57, vulnerable profile: n = 43). The favorable profile group had significantly better neurodevelopmental outcome, better family functioning, and better parental mental health compared to the vulnerable profile group. Clinical factors were not significantly associated with profile group. The favorable profile group reported significantly better QoL and resilience and had larger total brain volumes. A positive family environment may be protective for long-term neurodevelopment and may outweigh the role of clinical factors. This study underlines the importance of family-centered care to promote favorable brain development and neurodevelopmental outcome.

The cumulative impact of clinical risk on brain networks and associations with executive function impairments in adolescents with congenital heart disease

Patients with congenital heart disease (CHD) demonstrate altered structural brain network connectivity. However, there is large variability between reported results and little information is available to identify those patients at highest risk for brain alterations. Thus, we aimed to investigate if network connectivity measures were associated with the individual patient's cumulative load of clinical risk factors and with family-environmental factors in a cohort of adolescents with CHD. Further, we investigated associations with executive function impairments. In 53 adolescents with CHD who underwent open-heart surgery during infancy, and 75 healthy controls, diffusion magnetic resonance imaging and neuropsychological assessment was conducted at a mean age of 13.2 ± 1.3 years. Structural connectomes were constructed using constrained spherical deconvolution tractography. Graph theory and network-based statistics were applied to investigate network connectivity measures. A cumulative clinical risk (CCR) score was built by summing up binary risk factors (neonatal, cardiac, neurologic) based on clinically relevant thresholds. The role of family-environmental factors (parental education, parental mental health, and family function) was investigated. An age-adjusted executive function summary score was built from nine neuropsychological tests. While network integration and segregation were preserved in adolescents with CHD, they showed lower edge strength in a dense subnetwork. A higher CCR score was associated with lower network segregation, edge strength, and executive function performance. Edge strength was particularly reduced in a subnetwork including inter-frontal and fronto-parietal-thalamic connections. There was no association with family-environmental factors. Poorer executive functioning was associated with lower network integration and segregation. We demonstrated evidence for alterations of network connectivity strength in adolescents with CHD - particularly in those patients who face a cumulative exposure to multiple clinical risk factors over time. Quantifying the cumulative load of risk early in life may help to better predict trajectories of brain development in order to identify and support the most vulnerable patients as early as possible.

Retrospective study of preterm infants exposed to inhaled nitric oxide in Kaiser Permanente Southern California: morbidity, mortality and follow-up

OBJECTIVE

Describe characteristics of preterm infants exposed to inhaled nitric oxide (iNO) in Kaiser Permanente Southern California.

STUDY DESIGN

Case review of preterm infants <34-weeks exposed to iNO during 2010-2020 including respiratory and echocardiographic status, NICU course, and 12-month follow-up.

RESULTS

270 infants, 2.63% of births<34 weeks, (median, range: 26.1, 225/7-336/7 weeks gestation) were exposed to iNO. Median FiO2 at iNO initiation was 1.0 (IQR 0.94-1.0). Pulmonary hypertension (PH) was not associated with risk-adjusted 2 h oxygenation response or improved survival. Mortality to NICU discharge was 37.4%. Median cost of iNO was $7,695/patient. Discharged survivors experienced frequent rehospitalization (34.9%), use of supplemental oxygen, sildenafil, diuretics, bronchodilators, and steroids. Four infants had persistent PH. Five infants died after NICU discharge.

CONCLUSIONS

Preterm infants receiving iNO have high mortality and 1st year morbidity. As currently used, iNO may be an indicator of respiratory disease severity rather than mediator of improved outcomes.

Treating very preterm European infants with inhaled nitric oxide increased in-hospital mortality but did not affect neurodevelopment at 5 years of age

AIM

We examined the outcomes of using inhaled nitric oxide (iNO) to treat very preterm born (VPT) infants across Europe.

METHODS

This was a sub-study of the Screening to Improve Health in Very Preterm Infants in Europe research. It focused on all infants born between 22 + 0 and 31 + 6 weeks/days of gestation from 2011 to 2012, in 19 regions in 11 European countries. We studied 7268 infants admitted to neonatal care and 5 years later, we followed up the outcomes of 103 who had received iNO treatment. They were compared with 3502 propensity score-matched controls of the same age who did not receive treatment.

RESULTS

All countries used iNO and 292/7268 (4.0%) infants received this treatment, ranging from 1.2% in the UK to 10.5% in France. There were also large regional variations within some countries. Infants treated with iNO faced higher in-hospital mortality than matched controls (odds ratio 2.03, 95% confidence interval 1.33-3.09). The 5-year follow-up analysis of 103 survivors showed no increased risk of neurodevelopmental impairment after iNO treatment.

CONCLUSION

iNO was used for VPT patients in all 11 countries. In-hospital mortality was increased in infants treated with iNO, but long-term neurodevelopmental outcomes were not affected in 103 5-year-old survivors.

Comorbidities and Late Outcomes in Neonatal Pulmonary Hypertension

Long-term outcomes of persistent pulmonary hypertension of newborn (PPHN) depend on disease severity, duration of ventilation, and associated anomalies. Congenital diaphragmatic hernia survivors may have respiratory morbidities and developmental delay. The presence of PPHN is associated with increased mortality in hypoxic-ischemic encephalopathy, though the effects on neurodevelopment are less clear. Preterm infants can develop pulmonary hypertension (PH) early in the postnatal course or later in the setting of bronchopulmonary dysplasia (BPD). BPD-PH is associated with higher mortality, particularly within the first year. Evidence suggests that both early and late PH in preterm infants are associated with neurodevelopmental impairment.

Early Pulmonary Hypertension in Preterm Infants

Pulmonary hypertension (PH) in preterm neonates has multifactorial pathogenesis with unique characteristics. Premature surfactant-deficient lungs are injured following exposure to positive pressure ventilation and high oxygen concentrations resulting in variable phenotypes of PH. The prevalence of early PH is variable and reported to be between 8% and 55% of extremely preterm infants. Disruption of the lung development and vascular signaling pathway could lead to abnormal pulmonary vascular transition. The management of early PH and the off-label use of selective pulmonary vasodilators continue to be controversial.

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.

[Recent research on inhaled nitric oxide in preterm infants with a gestational age of <34 weeks]

Nitric oxide is a messenger molecule for vasodilation of vascular smooth muscle cells, and inhaled nitric oxide (iNO) can dilate pulmonary blood vessels and reduce pulmonary vascular resistance, thereby reducing pulmonary artery pressure, but with no influence on systemic circulation pressure. Guidelines in China and overseas recommend the use of iNO in full-term infants and late preterm infants, and it has been proved that it has a marked effect on persistent pulmonary hypertension and hypoxic respiratory failure in such infants. However, recent studies have shown that there is an increase in the off-label use of iNO in preterm infants with a gestational age of <34 weeks. This article reviews the research progress on the efficacy, safety, timing, dose, and withdrawal mode of iNO and its combination with vasoactive drugs in the treatment of preterm infants with a gestational age of <34 weeks in China and overseas, so as to provide a reference for clinical application.

L'utilisation du monoxyde d'azote inhalé chez les nouveau-nés

Le monoxyde d'azote inhalé (NOi), un vasodilatateur pulmonaire sélectif, est utilisé pour le traitement des nouveau-nés en insuffisance respiratoire hypoxémique (IRH) associée à une hypertension pulmonaire persistante du nouveau-né. Idéalement, il doit commencer à être administré après la confirmation échocardiographique de ce type d'hypertension. L'utilisation de NOi est recommandée chez les nouveau-nés peu prématurés ou à terme chez qui survient une IRH malgré des stratégies d'oxygénation ou de ventilation optimales. Cependant, il n'est pas recommandé d'y recourir systématiquement chez les nouveau-nés prématurés sous assistance respiratoire. On peut l'envisager comme traitement de secours chez les nouveau-nés prématurés en IRH précoce associée à une rupture prolongée des membranes ou à un oligoamnios, ou en IRH tardive en cas d'hypertension pulmonaire liée à une dysplasie bronchopulmonaire et accompagnée d'une insuffisance ventriculaire droite marquée. On peut aussi l'envisager chez les nouveau-nés atteints d'une hernie diaphragmatique congénitale qui présentent une IRH persistante, malgré un recrutement pulmonaire optimal, des signes échocardiographiques d'hypertension pulmonaire suprasystémique et un fonctionnement ventriculaire gauche approprié.

Inhaled nitric oxide use in newborns

Inhaled nitric oxide (iNO), a selective pulmonary vasodilator, is used as a therapeutic modality in infants with hypoxemic respiratory failure (HRF) associated with persistent pulmonary hypertension of the newborn (PPHN). iNO should ideally be initiated following echocardiographic confirmation of PPHN. Use of iNO is recommended in late preterm and term infants who develop HRF despite optimal oxygenation and ventilation strategies. However, routine iNO use in preterm infants on respiratory support is not recommended. iNO may be considered as a rescue modality in preterm infants with early-onset HRF when associated with prolonged rupture of membranes or oligohydramnios, or late-onset HRF in the context of bronchopulmonary dysplasia-associated pulmonary hypertension (PH) with severe right ventricular failure. A trial of iNO may also be considered for infants with congenital diaphragmatic hernia with persistent HRF despite optimal lung recruitment, and with echocardiographic evidence of supra-systemic PH and adequate left ventricular function.

Use of Inhaled Nitric Oxide in Preterm Infants: Is There Sufficient Evidence?

Nitric oxide (NO) is a potent vasodilator. The inhaled form (iNO) improves outcomes in term infants with persistent pulmonary hypertension of the newborn (PPHN) or bronchopulmonary dysplasia-associated pulmonary hypertension in preterm infants. However, in preterm infants, the risks and benefits of iNO use are controversial. Substantial evidence reveals no significant impact on survival or other morbidities in preterm infants with iNO treatment, independent of indication, timing, or duration of use. Many scientific organizations do not recommend the use of iNO in preterm infants, except in unique clinical circumstances with echocardiographic findings of PPHN in the setting of presumed pulmonary hypoplasia.

Gestational Age-Related Associations between Early-Life Feeding Trajectories and Growth Outcomes at Term Equivalent Age in Very Preterm Infants

Establishing the different feeding trajectories based on daily enteral feeding data in preterm infants at different gestational ages (GAs), may help to identify the risks and extrauterine growth restriction (EUGR) outcomes associated with the adverse feeding pattern. In a single center, we retrospectively included 625 infants born at 23-30 weeks of gestation who survived to term-equivalent age (TEA) from 2009 to 2020. The infants were designated into three GA groups: 23-26, 27-28, and 29-30 weeks. The daily enteral feeding amounts in the first 56 postnatal days were analyzed to determine the feeding trajectories. The primary outcomes were EUGR in body weight and head circumference calculated, respectively, by the changes between birth and TEA. Clustering analysis identified two feeding trajectories, namely the improving and adverse patterns in each GA group. The adverse feeding pattern that occurred in 49%, 20%, and 17% of GA 23-26, 27-28, and 29-30 weeks, respectively, was differentiated from the improving feeding pattern as early as day 7 in infants at GA 23-26 and 27-28 weeks, in contrast to day 21 in infants at GA 29-30 weeks. The adverse feeding patterns were associated with sepsis, respiratory, and gastrointestinal morbidities at GA 23-26 weeks; sepsis, hemodynamic and gastrointestinal morbidities at GA 27-28 weeks; and preeclampsia, respiratory, and gastrointestinal morbidities at GA 29-30 weeks. Using the improving feeding group as a reference, the adverse feeding group showed significantly higher adjusted odds ratios of EUGR in body weight and head circumference in infants at GA 23-26 and 27-28 weeks. Identifying the early-life adverse feeding trajectories may help recognize the related EUGR outcomes of preterm infants in a GA-related manner.

Creating experiences from active treatment towards extremely preterm infants born at less than 25 weeks in Japan

Treatment for extremely preterm infants born at less than 25 weeks of gestation in Japan was initiated mainly due to the amendment of the Maternal Health Act lowering the upper limit of abortion from 24 weeks to 22 weeks in 1990. Five years after the amendment, the Japanese national government started a nationwide project to improve the perinatal care system. Once selected perinatal centers reported improvements in survival rates, more centers have adopted aggressive treatments. They have accumulated their knowledge by experiencing the treatment of infants with a limit of viability. As a result, more than 50% of infants born even at 22 weeks of gestation can survive to discharge currently. This progress has resulted from the accumulation of experience at each perinatal center rather than the results from clinical trials. Furthermore, these experiences have been standardized to some extent through sharing information.

Prematurity and Long-Term Respiratory Morbidity—What Is the Critical Gestational Age Threshold?

Respiratory morbidity is a hallmark complication of prematurity. Children born preterm are exposed to both short- and long-term respiratory morbidity. This study aimed to investigate whether a critical gestational age threshold exists for significant long-term respiratory morbidity. A 23-year, population-based cohort analysis was performed comparing singleton deliveries at a single tertiary medical center. A comparison of four gestational age groups was performed according to the WHO classification: term (≥37.0 weeks, reference group), moderate to late preterm (32.0–36.6 weeks), very preterm (28.0–31.6 weeks) and extremely preterm (24.0–27.6 weeks). Hospitalizations of the offspring up to the age of 18 years involving respiratory morbidities were evaluated. A Kaplan–Meier survival curve was used to compare cumulative hospitalization incidence between the groups. A Cox proportional hazards model was used to control for confounders and time to event. Overall, 220,563 singleton deliveries were included: 93.6% term deliveries, 6% moderate to late preterm, 0.4% very preterm and 0.1% extremely preterm. Hospitalizations involving respiratory morbidity were significantly higher in children born preterm (12.7% in extremely preterm children, 11.7% in very preterm, 7.0% in late preterm vs. 4.7% in term, p < 0.001). The Kaplan–Meier survival curve demonstrated a significantly higher cumulative incidence of respiratory-related hospitalizations in the preterm groups (log-rank, p < 0.001). In the Cox regression model, delivery before 32 weeks had twice the risk of long-term respiratory morbidity. Searching for a specific gestational age threshold, the slope for hospitalization rate was attenuated beyond 30 weeks’ gestation. In our population, it seems that 30 weeks’ gestation may be the critical threshold for long-term respiratory morbidity of the offspring, as the risk for long-term respiratory-related hospitalization seems to be attenuated beyond this point until term.