Effect of bronchopulmonary dysplasia on early intellectual development in preterm infants

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.

Intellectual functioning in survivors of extremely low birthweight: Cognitive outcomes in childhood and adolescence

BACKGROUND

Infants born at extremely low birthweight (ELBW: ≤1000 g) are vulnerable to intellectual disabilities, but the factors that may distinguish between ELBW survivors with and without these impairments are not well understood. In this study, prospective associations between neonatal factors and functional outcomes in childhood and adolescence were compared in ELBW survivors with and without borderline intellectual functioning (BIF).

METHODS

Borderline intellectual functioning was defined by IQ < 85, assessed at 8 years. Among 146 ELBW survivors, 48 (33%) had IQ scores under 85, and 98 (67%) had scores equal to or over 85. Group differences in demographic and risk factors were assessed via t-test, chi-squared analysis or non-parametric tests. Neonatal factors that differed between ELBW groups were tested for association with adaptive behaviour assessed at age 5 years, and reading and arithmetic skills assessed at ages 8 and 15 years, using hierarchical regression models.

RESULTS

Extremely low birthweight survivors with BIF had significantly lower birthweights than ELBW survivors without BIF (790 vs. 855 g, P < 0.01) and were more likely to be born to mothers with lower socioeconomic status (SES) (78% vs. 48%, P < 0.01). These ELBW survivors also were more likely to be diagnosed with significant neurosensory impairment (NSI; 35% vs. 19%, P < 0.04), experienced more bronchopulmonary dysplasia (56% vs. 38%, P < 0.04), received more days of respiratory support (median 33 vs. 14 days, P < 0.01) and remained in hospital for longer periods (median 81 vs. 63 days, P < 0.03). Birthweight, familial SES, NSI and duration of respiratory support were significant predictors for one or more outcomes. Across groups, lower familial SES was associated with lower academic scores (Ps < 0.05), and NSI predicted lower adaptive functioning (Ps < 0.001). Other associations were moderated by group: among ELBW survivors with BIF, heavier birthweights predicted better arithmetic skills, the presence of NSI was associated with poorer arithmetic skills and more ventilation days predicted poorer reading skills.

CONCLUSIONS

At birth, ELBW survivors with BIF faced more physiological and social disadvantages and required more medical intervention than their ELBW peers without BIF. Smaller birth size, NSI burden and prolonged neonatal ventilatory support displayed gradients of risk for childhood and adolescent academic outcomes across groups. Whereas academic performance in ELBW survivors with BIF was sensitive to variation in birth size, NSI or ventilation days, ELBW survivors without BIF attained thresholds of intellectual ability that were sufficient to support higher levels of academic performance at both ages, regardless of their status on these factors. The findings are discussed in relation to Zigler's developmental theory of intellectual disability.

Prevalence of Language Delay among Healthy Preterm Children, Language Outcomes and Predictive Factors

Language delay (LD) and its relationship with later language impairment in preterm children is a topic of major concern. Previous studies comparing LD in preterm (PT) and full-term (FT) children were mainly carried out with samples of extremely preterm and very preterm children (sometimes with additional medical problems). Very few of them were longitudinal studies, which is essential to understand developmental relationships between LD and later language impairment. In this study, we compare the prevalence of LD in low-risk preterm children to that of FT children in a longitudinal design ranging from 10 to 60 months of age. We also analyze which variables are related to a higher risk of LD at 22, 30 and 60 months of age. Different language tests were administered to three groups of preterm children of different gestational ages and to one group of full-term children from the ages of 10 to 60 months. ANOVA comparisons between groups and logistic regression analyses to identify possible predictors of language delay at 22, 30 and 60 months of age were performed. The results found indicate that there were practically no differences between gestational age groups. Healthy PT children, therefore, do not have, in general terms, a higher risk of language delay than FT children. Previous language delay and cognitive delay are the strongest and longest-lasting predictors of later language impairment. Other factors, such as a scarce use of gestures at 10 months or male gender, affect early LD at 22 months of age, although their effect disappears as children grow older. Low maternal education appears to have a late effect. Gestational age does not have any significant effect on the appearance of LD.

Language skills at corrected age 2;0 are poorer in extremely and very preterm boys but not girls compared with their full-term peers

PURPOSE

To date, there are contradictory findings concerning if, at which age, and to what extent children's language development is affected by prematurity at birth. The objective was to compare language skills of extremely preterm (EPT) and very preterm (VPT) girls and boys at 24 months corrected for gestational age (GA) at birth with those of full-term (FT) girls and boys, and to explore the effect of perinatal and demographic factors.

METHOD

Parents of 138 preterm (PT) children born <32 weeks' gestation (48 EPT with GA below 28 weeks, 90 VPT with GA 28-31 weeks) and of 150 FT controls completed the short Estonian version of the MacArthur-Bates Communicative Development Inventory: Words and Sentences (ECDI-II SF). Language skills of PT children were also assessed with the Bayley-III Language Scale (BSID-III), and compared with data from 152 FT controls.

RESULTS

Mean scores of all language measurements were significantly lower in boys (not girls) from both PT groups compared to FT girls and boys, while no significant differences were found between PT groups. Across groups, girls obtained significantly better language scores than boys. In PT children, being a girl, and attending day care at corrected age (CA) 2;0 years, predicted a larger expressive vocabulary (measured by the ECDI-II SF). Bayley language composite scores (sum of expressive and receptive language) were higher in PT girls than in boys, and the scores were negatively affected by the number of severe neonatal morbidities.

CONCLUSIONS

The findings highlight the importance of systematic language-focused assessments (using parents and trained examiners) of EPT and VPT boys, as well as the need to support their development.

[An assessment of white matter development in preterm infants with bronchopulmonary dysplasia using diffusion tensor imaging]

OBJECTIVE

To assess white matter development in preterm infants with bronchopulmonary dysplasia (BPD) using fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values of diffusion tensor imaging (DTI).

METHODS

Ninety-six infants with a gestational age of ≤32 weeks and a birth weight of <1 500 g who were admitted to the neonatal intensive care unit within 24 hours after birth from August 2016 to April 2019 and underwent head MRI and DTI before discharge were enrolled. According to the discharge diagnosis, they were divided into BPD group with 48 infants and non-BPD group with 48 infants. The two groups were compared in terms of FA and ADC values of the same regions of interest on DTI image.

RESULTS

There were no significant differences in the incidence rates of periventricular/intraventricular hemorrhage, periventricular leukomalacia, and punctate white matter lesions between the two groups (P>0.05). Compared with the non-BPD group, the BPD group had significantly lower FA values and significantly higher ADC values of the posterior limb of the internal capsule, the splenium of the corpus callosum, the occipital white matter, the cerebellum, and the cerebral peduncle (P<0.05). Compared with the non-BPD group, the BPD group had a significantly higher frequency of apnea, a significantly higher proportion of infants with pneumonia or mechanical ventilation, and a significantly longer duration of assisted ventilation (P<0.05).

CONCLUSIONS

BPD may has potential adverse effects to white matter development in preterm infants, leading to delayed white matter development. Therefore, it is necessary to pay attention to the neurological function of these infants.

[A clinical analysis of neurobehavioral development within one year after birth in preterm infants with bronchopulmonary dysplasia]

OBJECTIVE

To study the effect of bronchopulmonary dysplasia (BPD) on neurobehavioral development within one year after birth in preterm infants.

METHODS

A retrospective analysis was performed for the preterm infants with a gestational age of <34 weeks who were born from September 2017 to December 2019 and completed the follow-up assessments of neurobehavioral development at the corrected gestational ages of 40 weeks and 3, 6, and 12 months. According to their diagnosis, they were divided into a BPD group with 23 infants and a non-BPD group with 27 infants. The outcome of neurobehavioral development was compared between the two groups at different time points.

RESULTS

There was no significant difference in the neonatal behavioral neurological assessment score between the BPD and non-BPD groups at the corrected gestational age of 40 weeks (P>0.05). Based on the Gesell Developmental Scale, compared with the non-BPD group, the BPD group had significantly lower global developmental quotient (DQ) and DQs of fine motor, adaptive behavior, and personal-social behavior at the corrected gestational ages of 3, 6, and 12 months (P<0.05). For both groups, the DQ of language at the corrected gestational age of 6 months was significantly higher than that at the corrected gestational age of 12 months (P<0.017), the DQ of personal-social behavior at the corrected gestational age of 6 months was significantly higher than that at the corrected gestational age of 3 months (P<0.017), and the DQ of adaptive behavior at the corrected gestational age of 12 months was significantly higher than that at the corrected gestational ages of 3 and 6 months (P<0.017). Based on the BSID-II scale, there were no significant differences in mental development index and psychomotor development index at each time point between the two groups (P>0.05). The mental development index at the corrected gestational age of 3 months was significantly higher than that at the corrected gestational ages of 6 and 12 months in both groups (P<0.001).

CONCLUSIONS

Preterm infants with BPD have delayed neurodevelopment within one year after birth compared with those without BPD, which should be taken seriously in clinical practice.

Factors Associated with Neurodevelopmental Impairment in Bronchopulmonary Dysplasia

OBJECTIVE

To identify factors associated with neurodevelopmental impairment (NDI) in patients with bronchopulmonary dysplasia (BPD).

STUDY DESIGN

We identified 151 patients with moderate to severe BPD from 2010 to 2014 with complete Bayley Scales of Infant Development (BSID) scores at 24 months corrected age. We defined NDI as any diagnosis of cerebral palsy or ≥1 BSID composite scores of <80.

RESULTS

The mean corrected age at BSID was 23 ± 1 months; 18% had a cognitive score of <80, 37% had a communication score of <80, and 26% had a motor score of <80. Cerebral palsy was diagnosed in 22 patients (15%); 84 (56%) patients did not have NDI. Patients with NDI had lower birth weight, but there was no difference in gestational age at birth, severe intraventricular hemorrhage (IVH), necrotizing enterocolitis, or patent ductus arteriosus ligation compared with patients with no NDI. Ventilator days were greater in patients with NDI than in patients without NDI. More patients with NDI received furosemide and systemic corticosteroids and the hospital length of stay was longer than in patients with no NDI. Logistic regression modeling demonstrated that for every additional 100 g of birth weight the odds of NDI decreased by 35% and for every additional hospital day the odds of NDI increased by 1.3%.

CONCLUSIONS

In our cohort of patients with moderate to severe BPD, the majority had no NDI, and low birth weight and length of hospital stay were associated with increased risk of developing NDI. This finding suggests that there are potentially modifiable factors associated with better neurodevelopmental outcomes in patients with BPD that deserve further study.

Recent advances in our understanding of the mechanisms of lung alveolarization and bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is the most common cause of morbidity and mortality in preterm infants. A key histopathological feature of BPD is stunted late lung development, where the process of alveolarization-the generation of alveolar gas exchange units-is impeded, through mechanisms that remain largely unclear. As such, there is interest in the clarification both of the pathomechanisms at play in affected lungs, and the mechanisms of de novo alveoli generation in healthy, developing lungs. A better understanding of normal and pathological alveolarization might reveal opportunities for improved medical management of affected infants. Furthermore, disturbances to the alveolar architecture are a key histopathological feature of several adult chronic lung diseases, including emphysema and fibrosis, and it is envisaged that knowledge about the mechanisms of alveologenesis might facilitate regeneration of healthy lung parenchyma in affected patients. To this end, recent efforts have interrogated clinical data, developed new-and refined existing-in vivo and in vitro models of BPD, have applied new microscopic and radiographic approaches, and have developed advanced cell-culture approaches, including organoid generation. Advances have also been made in the development of other methodologies, including single-cell analysis, metabolomics, lipidomics, and proteomics, as well as the generation and use of complex mouse genetics tools. The objective of this review is to present advances made in our understanding of the mechanisms of lung alveolarization and BPD over the period 1 January 2017-30 June 2019, a period that spans the 50th anniversary of the original clinical description of BPD in preterm infants.

High Neutrophil-to-Lymphocyte Ratio Is an Early Predictor of Bronchopulmonary Dysplasia

Background and Objective: Bronchopulmonary dysplasia (BPD) is a common complication in preterm infants; predicting the degree of BPD at an early life stage is difficult. Inflammation is a crucial risk factor for BPD pathogenesis, and the neutrophil-to-lymphocyte ratio (NLR) is a potential systemic inflammatory biomarker. We aimed to assess the predictive value of the NLR for BPD. Methods: We carried out a retrospective, single-center, observational study of neonates with gestational ages (GAs) <32 weeks and assessed the association between the NLR and BPD. Results: The study population included 296 preterm infants with BPD (n = 144) or without BPD (n = 152). Among the infants, 75 (25.3%) had mild BPD, 37 (12.5%) had moderate BPD, and 32 (10.8%) had severe BPD. The BPD group had a higher NLR at birth and at 72 h than the non-BPD group. The NLR cutoff value at 72 h for the prediction of BPD was 3.035 (sensitivity = 0.519, specificity = 0.964), and the area under the curve (AUC) was 0.714. The NLR cutoff value at 72 h for predicting severe BPD was 3.105 (sensitivity = 0.607, specificity = 0.819), with an AUC of 0.756. At the NLR cutoff value at 72 for the prediction of BPD, the AUCs were 0.640 and 0.970 in the preterm infants with EOS and congenital pneumonia, respectively. Conclusions: The NLR is an inexpensive, accessible and convenient tool; an increase in the NLR at 72 h could be an early predictor of BPD, especially severe BPD. Additionally, the NLR at 72 h could be a predictor of BPD in preterm infants with intrauterine infections.