Correlation of Retinopathy of Prematurity with Bronchopulmonary Dysplasia

Effects of bradycardia, hypoxemia and early intubation on bronchopulmonary dysplasia in very preterm infants: An observational study

BACKGROUND

Bronchopulmonary dysplasia (BPD) is the most common pulmonary complication in preterm infants.

OBJECTIVES

The study aimed to explore the effects of bradycardia, hypoxemia, and early intubation on BPD in very preterm infants.

METHODS

This is a prospective observational cohort study. Preterm infants with a mean gestational age of 28.67 weeks were recruited from two level III neonatal intensive care units (NICUs) in Taiwan. Continuous electrocardiography was used to monitor heart rates and oxygen saturation (SpO2). Infants were monitored for heart rates of <100 beats per minute and SpO2 levels of <90 % lasting for 30 s. Generalized estimating equations were used to analyze the effects of bradycardia, hypoxemia, and early intubation on BPD in very preterm infants. Model fit was visually assessed using receiver operating characteristic curve analysis.

RESULTS

Bradycardia, hypoxemia, and early intubation significantly increased the odds of BPD among the preterm infants (N = 39) during NICU stay; the odds ratios for bradycardia, hypoxemia, and early intubation for BPD versus non-BPD were 1.058, 1.013, and 29.631, respectively (all p < 0.05). A model combining bradycardia, hypoxemia, and early intubation accurately predicted BPD development (area under the curve = 0.919).

CONCLUSIONS

Bradycardia, hypoxemia, and early intubation significantly increased the odds of BPD among very preterm infants during NICU stay. The model combining bradycardia, hypoxemia, and early intubation accurately predicted BPD development.

Delineating morbidity patterns in preterm infants at near-term age using a data-driven approach

BACKGROUND

Long-term survival after premature birth is significantly determined by development of morbidities, primarily affecting the cardio-respiratory or central nervous system. Existing studies are limited to pairwise morbidity associations, thereby lacking a holistic understanding of morbidity co-occurrence and respective risk profiles.

METHODS

Our study, for the first time, aimed at delineating and characterizing morbidity profiles at near-term age and investigated the most prevalent morbidities in preterm infants: bronchopulmonary dysplasia (BPD), pulmonary hypertension (PH), mild cardiac defects, perinatal brain pathology and retinopathy of prematurity (ROP). For analysis, we employed two independent, prospective cohorts, comprising a total of 530 very preterm infants: AIRR ("Attention to Infants at Respiratory Risks") and NEuroSIS ("Neonatal European Study of Inhaled Steroids"). Using a data-driven strategy, we successfully characterized morbidity profiles of preterm infants in a stepwise approach and (1) quantified pairwise morbidity correlations, (2) assessed the discriminatory power of BPD (complemented by imaging-based structural and functional lung phenotyping) in relation to these morbidities, (3) investigated collective co-occurrence patterns, and (4) identified infant subgroups who share similar morbidity profiles using machine learning techniques.

RESULTS

First, we showed that, in line with pathophysiologic understanding, BPD and ROP have the highest pairwise correlation, followed by BPD and PH as well as BPD and mild cardiac defects. Second, we revealed that BPD exhibits only limited capacity in discriminating morbidity occurrence, despite its prevalence and clinical indication as a driver of comorbidities. Further, we demonstrated that structural and functional lung phenotyping did not exhibit higher association with morbidity severity than BPD. Lastly, we identified patient clusters that share similar morbidity patterns using machine learning in AIRR (n=6 clusters) and NEuroSIS (n=8 clusters).

CONCLUSIONS

By capturing correlations as well as more complex morbidity relations, we provided a comprehensive characterization of morbidity profiles at discharge, linked to shared disease pathophysiology. Future studies could benefit from identifying risk profiles to thereby develop personalized monitoring strategies.

TRIAL REGISTRATION

AIRR: DRKS.de, DRKS00004600, 28/01/2013. NEuroSIS: ClinicalTrials.gov, NCT01035190, 18/12/2009.

Association between bronchopulmonary dysplasia and death or neurodevelopmental impairment at 3 years in preterm infants without severe brain injury

Objective

We investigated the association between bronchopulmonary dysplasia (BPD) and 3 years death or neurodevelopmental impairment (NDI) in very preterm infants without severe brain injury.

Method

Our prospective cohort study recruited preterm infants who were born prior to 32 weeks of gestational age and survived in the neonatal intensive care unit until 36 weeks of corrected age. Upon reaching 3 years of age, each infant was assessed for death or NDI such as cerebral palsy, cognitive deficit, hearing loss, and blindness. Correlations between BPD and death or NDI were determined using multiple logistic regression analyses adjusted for confounding factors.

Result

A total of 1,417 infants without severe brain injury who survived until 36 weeks of corrected age were initially enrolled in the study. Over the study period, 201 infants were lost to follow-up and 5 infants were excluded. Our final dataset, therefore, included 1,211 infants, of which 17 died after 36 weeks of corrected age and 1,194 were followed up to 3 years of age. Among these infants, 337 (27.8%) developed BPD. Interestingly, by 3 years of age, BPD was demonstrated to be independently associated with death or NDI, with an adjusted odds ratio of 1.935 (95% confidence interval: 1.292-2.899, p = 0.001), in preterm infants without severe neonatal brain injury.

Conclusion

Our findings indicate that BPD is strongly associated with death or NDI in preterm infants without severe neonatal brain injury at 3 years of age. Further research is needed to understand the mechanisms linking the development of BPD with death or NDI and whether appropriate treatment of BPD may ameliorate or prevent the development of neurological complications.

Association of Positive Bacterial Cultures Obtained from the Throat, Anus, Ear, Bronchi and Blood in Very-Low-Birth-Weight Premature Infants with Severe Retinopathy of Prematurity-Own Observations

BACKGROUND

The causative factors responsible for the development of Retinopathy of Prematurity (ROP) are still unexplored. Therefore, one of the most important factors can be perinatal inflammation.

METHODS

This retrospective study included 114 premature infants (228 eyes) meeting a birth criteria of ≤ 32 weeks gestational age (GA) and a birth weight (BW) ≤ 1710. Examined Group (EG) n = 51 of BW 852.7 ± 255.7; GA 26.3 ± 2.0 with severe ROP treated by diode laser or anti-VEGF intravitreal injection. Control Group (CG) n = 63 of BW 1313.9 ± 284.5; GA 28.8 ± 1.6 without ROP. Microbiological bacterial and fungal cultures of the ear, anus, bronchial throat and blood were taken. Medical data and laboratory tests in correlation to 3 ROP and A-ROP were analysed.

RESULTS

Positive bacterial tests dominated in EG, 47% vs. CG, 23%. Significant correlations between positive cultures obtained from natural cavities: anus (p < 0.001), throat (p = 0.002), as well as from blood (p = 0.001) and severe ROP which requires diode laser and anti-VEGF treatment were noted. Significant inflammation markers which correlate with the development of severe ROP are Klebsiella pneumoniae (KP) (p = 0.002) and Coagulase-negative Staphylococci (CoNS) (p < 0.001). CoNS, p < 0.001; KP, p = 0.002; the remaining Maltophilia stenotrophomonas (MS); Staphylococcus aureus (SA), p = 0.005; and Enterobacter cloacae (EC), p = 0.02 were the most frequent bacteria in severe ROP. High levels of white blood cells (WBC), C-reactive protein (CRP), lymphocytes (LYM) and low thrombocytes (PLT) correlated sequentially with (Odds Ratio, OR) CoNS (2.3); MS (5.9); KP (3.1); and all positive cultures (APC) (9.5). An important correlation between the BPD-EC (4.3); intrauterine inflammation-KP (3.4); PDA-EC (3.9); and asphyxia-CoNS (3.0) was identified.

CONCLUSIONS

It cannot be ruled out that positive microbiological results of blood, anal and pharyngeal cultures may become prognostic markers for the early development of ROP, which would enable early initiation of ophthalmological treatment in premature infants from the VLBW group.

Bronchopulmonary Dysplasia: A Five-Year Retrospective Cohort Study on Differences in Clinical Characteristics and Morbidities According to Severity Grading

INTRODUCTION

Bronchopulmonary dysplasia (BPD) is the most common complication associated with extreme prematurity. Although several criteria defining severity were developed over time, there are a few studies describing the differences in BPD phenotype and neonatal morbidities and complications between severity groups. We aimed to describe these differences in BPD patients of a neonatal intensive care unit (NICU).

METHODS

We conducted an observational retrospective cohort study through a medical record review over a five-year period. Participants were newborns admitted to an NICU who were diagnosed with BPD. We performed a descriptive statistical analysis of gestational complications and the use of antenatal corticosteroid therapy, birth-related data, and complications throughout the NICU stay, as well as the respiratory support used. We also compared different severity groups across these variables. The patients were divided into severe and non-severe BPD using the severity criteria of the 2001 NICHD/NHLBI/ORD consensus workshop.

RESULTS

A total of 101 newborns with BPD participated in the study and 73 had data on BPD severity. The median gestational age was 27 weeks, ranging from 23 to 32 weeks. Of these 73 newborns, 36 had mild BPD (49.3%), 10 had moderate BPD (13.7%), and 27 had severe BPD (37.0%). When comparing severe and non-severe BPD, we found that extreme prematurity, extremely low birth weight, and small size for gestational age were more frequent in the severe BPD group (p-value=0.012, p-value<0.001, and p-value=0.012, respectively). Infants with severe BPD had a longer duration of invasive ventilation than those with mild or moderate BPD (p-value<0.001). Late sepsis, necrotizing enterocolitis, severe brain injury, and retinopathy of prematurity were more frequent in severe BPD (p-value=0.017, p-value=0.045, p-value=0.033, p-value=0.003, respectively).

DISCUSSION

Previously published evidence describing causal links between BPD development and comorbidities exists but data on their impact on BPD severity are scarce. In our study, severe BPD seemed to be associated with a higher frequency of comorbidities and complications. Further studies are needed to ascertain the impact of each morbidity on the severity of BPD and if measures to prevent them could lead to potentially milder BPD disease.

Low flow nasal cannula requirement among preterm infants: predictors and description of clinical course

OBJECTIVE

We aim to identify potential risk factors associated with longer duration of supplemental oxygen use in preterm infants at risk for bronchopulmonary dysplasia (BPD) to better inform families and weaning protocols.

STUDY DESIGN

This is a retrospective study of infants with a birth gestational age (GA) < 32 0/7 weeks admitted to the neonatal intensive care unit (NICU) between October 2017 and September 2019.

RESULTS

A total of 172 infants met criteria for inclusion and analysis, of which 69 (40.1%) infants required LFNC. Risk factors for longer duration included lower birth GA or birth weight, increased ventilator days, and diagnosis of a patent ductus arteriosus (PDA). BPD was diagnosed in 69.6% who required LFNC, of which 47.8% were discharged on home oxygen.

CONCLUSION

Younger birth GA, lower birth weight, increased ventilator days, and presence of a PDA were identified as risk factors for longer LFNC duration.

Development and Validation of a Deep Learning Model to Predict the Occurrence and Severity of Retinopathy of Prematurity

Importance

Retinopathy of prematurity (ROP) is the leading cause of childhood blindness worldwide. Prediction of ROP before onset holds great promise for reducing the risk of blindness.

Objective

To develop and validate a deep learning (DL) system to predict the occurrence and severity of ROP before 45 weeks' postmenstrual age.

Design, Setting, and Participants

This retrospective prognostic study included 7033 retinal photographs of 725 infants in the training set and 763 retinal photographs of 90 infants in the external validation set, along with 46 characteristics for each infant. All images of both eyes from the same infant taken at the first screening were labeled according to the final diagnosis made between the first screening and 45 weeks' postmenstrual age. The DL system was developed using retinal photographs from the first ROP screening and clinical characteristics before or at the first screening in infants born between June 3, 2017, and August 28, 2019.

Exposures

Two models were specifically designed for predictions of the occurrence (occurrence network [OC-Net]) and severity (severity network [SE-Net]) of ROP. Five-fold cross-validation was applied for internal validation.

Main Outcomes and Measures

Area under the receiver operating characteristic curve (AUC), accuracy, sensitivity, and specificity to evaluate the performance in ROP prediction.

Results

This study included 815 infants (450 [55.2%] boys) with mean birth weight of 1.91 kg (95% CI, 1.87-1.95 kg) and mean gestational age of 33.1 weeks (95% CI, 32.9-33.3 weeks). In internal validation, mean AUC, accuracy, sensitivity, and specificity were 0.90 (95% CI, 0.88-0.92), 52.8% (95% CI, 49.2%-56.4%), 100% (95% CI, 97.4%-100%), and 37.8% (95% CI, 33.7%-42.1%), respectively, for OC-Net to predict ROP occurrence and 0.87 (95% CI, 0.82-0.91), 68.0% (95% CI, 61.2%-74.8%), 100% (95% CI, 93.2%-100%), and 46.6% (95% CI, 37.3%-56.0%), respectively, for SE-Net to predict severe ROP. In external validation, the AUC, accuracy, sensitivity, and specificity were 0.94, 33.3%, 100%, and 7.5%, respectively, for OC-Net, and 0.88, 56.0%, 100%, and 35.3%, respectively, for SE-Net.

Conclusions and Relevance

In this study, the DL system achieved promising accuracy in ROP prediction. This DL system is potentially useful in identifying infants with high risk of developing ROP.

Longitudinal Serum Metabolomics in Extremely Premature Infants: Relationships With Gestational Age, Nutrition, and Morbidities

An increasing number of extremely premature infants survive the neonatal period and beyond. Little is known about the maturation of the preterm infant’s metabolome and its relation to the development of morbidities. Using 1H-NMR, we investigated the serum metabolic profile of 87 infants born at a gestational age (GA) <28 weeks [mean GA (SD) 25.4 (1.4) weeks] in samples longitudinally collected from birth to term equivalent age. The infant metabolome was analyzed in relation to GA, postnatal age, nutrition, and preterm morbidities. At postnatal day 1, low GA correlated with high levels of 3-hydroxyisobutyrate, acetate, acetoacetate, acetone, formate, glucose, and valine. Nearly all quantified metabolites displayed postnatal concentration changes. For example, the two phospholipid-related metabolites myo-inositol and ethanolamine displayed a similar decline from birth over the first weeks of life, irrespectively of GA. The proportion of enteral/parenteral energy intake in the first 28 days significantly correlated with mean levels of 52% of the analyzed metabolites. Low enteral energy intake was associated with high serum levels of 3-hydroxyisobutyrate, creatinine, glucose, glycerol, histidine, lactate, leucine, lysine, methionine, ornithine, phenylalanine, proline, threonine, and uridine. There were also significant correlations between high enteral intake and high serum levels of isoleucine and tyrosine. Retinopathy of prematurity (ROP) and bronchopulmonary dysplasia (BPD) outcomes were not significantly associated with metabolite levels in the neonatal period after correcting for multiple testing. In conclusion, the serum metabolome of extremely premature infants changes substantially in the neonatal period, largely driven by the gradual transfer from total parenteral nutrition to full enteral feeding. Further studies are needed to disentangle the intricate relationships between the metabolome, nutritional management, GA, and the development of preterm morbidities.

The possible effect of pentoxifylline on development and severity of retinopathy of prematurity

BACKGROUND AND AIM

Retinopathy of prematurity (ROP) is the major ocular problem of preterm infants that occurs with abnormal proliferation of immature retinal vessels. Although pentoxifylline (PTX) was reported to inhibit vasculogenesis and neovascularization in experimental studies, there is no clinical data about the effects of PTX treatment on the development and severity of ROP. This clinical study aimed to investigate the possible effects of PTX on the development of ROP.

MATERIALS AND METHODS

A single-centre retrospective study was conducted including preterm infants who were hospitalised in the neonatal intensive care unit between 2015-2017 years. Infants were divided into two groups in terms of PTX administration for adjuvant therapy, as PTX and non-PTX groups.

RESULTS

A total of 211 infants were included in the study [gestational age 29 (27-31) weeks, birth weight 1140 (960-1340) g]. From these, 97 infants (46%) were given PTX treatment. The two groups were similar in terms of demographic data and baseline clinical characteristics. Any stage of ROP was detected in 47.4% of infants in the PTX group, which was significantly higher than those in the non-PTX group (27.2%) (p = 0.002). The incidence of advanced-stage ROP in the PTX group (10.3%) was also higher than in the non-PTX group (2.6%) (p = 0.021). Repeated usage of PTX was not found to be related to the development of ROP (p = 0.059). The time of PTX administration was similar between the ROP and no-ROP groups (median; one vs one week, p = 0.825). Surfactant therapy, duration of hospital stay, and PTX treatment were found as significant risk factors for ROP in the logistic regression analysis.

CONCLUSIONS

In contrast to the experimental studies and also promising results of PTX treatment in some neonatal morbidities, it may be associated with increased incidence and stage of ROP.

Early Postnatal Oxygen Exposure Predicts Choroidal Thinning in Neonates

Purpose

To evaluate whether choroidal thickness (CT) using arm-mounted optical coherence tomography (OCT) in infants screened for retinopathy of prematurity (ROP) correlates with oxygen exposure in neonates.

Methods

OCT images were obtained in infants screened for ROP in a single level IV neonatal intensive care unit. CT was measured at three different locations: the subfoveal center and 1.5 mm from the fovea center in each direction. Correlation and regression analyses were performed to determine the relationship between clinical factors and CT. Clinical factors included gestational age, birth weight, presence of bronchopulmonary dysplasia (BPD), and fraction of inspired oxygen (FiO₂) at defined time points: 30 weeks postmenstrual age (PMA), 36 weeks PMA, and on day of imaging.

Results

Mean subfoveal, nasal, and temporal choroidal thicknesses CT (SFCT, NCT, and TCT, respectively) were 228.0 ± 51.4 µm, 179.7 ± 50.3 µm, and 186.4 ± 43.8 µm, respectively. SFCT was found to be significantly thicker than NCT and TCT (P < 0.0001 and P = 0.0002, respectively), but no significant difference was found between NCT and TCT (P = 0.547). Compared with infants without BPD, infants with BPD had thinner SFCT and NCT (P = 0.01 and P = 0.0008, respectively). Birth weight was positively correlated with SFCT (r = 0.39, P = 0.01) and NCT (r = 0.33, P = 0.045) but not TCT. Gestational age and ROP stage were not significantly associated with CT. SFCT was found to be significantly thinner with higher average FiO₂ supplementation levels at 30 weeks PMA (r = –0.51, P = 0.01) but not at 36 weeks PMA. Regression analysis revealed that FiO₂ at 30 weeks PMA was an independent predictor of SFCT in infants screened for ROP (P = 0.01).

Conclusions

Early postnatal exposure (<32 weeks PMA) to higher oxygen supplementation in premature neonates statistically predicts choroidal thinning.

Validation of the DIGIROP-birth model in a Chinese cohort

Background

We aimed to validate the predictive performance of the DIGIROP-Birth model for identifying treatment-requiring retinopathy of prematurity (TR-ROP) in Chinese preterm infants to evaluate its generalizability across countries and races.

Methods

We retrospectively reviewed the medical records of preterm infants who were screened for retinopathy of prematurity (ROP) in a single Chinese hospital between June 2015 and August 2020. The predictive performance of the model for TR-ROP was assessed through the construction of a receiver-operating characteristic (ROC) curve and calculating the areas under the ROC curve (AUC), sensitivity, specificity, and positive and negative predictive values.

Results

Four hundred and forty-two infants (mean (SD) gestational age = 28.8 (1.3) weeks; mean (SD) birth weight = 1237.0 (236.9) g; 64.7% males) were included in the study. Analyses showed that the DIGIROP-Birth model demonstrated less satisfactory performance than previously reported in identifying infants with TR-ROP, with an area under the receiver-operating characteristic curve of 0.634 (95% confidence interval = 0.564–0.705). With a cutoff value of 0.0084, the DIGIROP-Birth model showed a sensitivity of 48/93 (51.6%), which increased to 89/93 (95.7%) after modification with the addition of postnatal risk factors. In infants with a gestational age < 28 weeks or birth weight < 1000 g, the DIGIROP-Birth model exhibited sensitivities of 36/39 (92.3%) and 20/23 (87.0%), respectively.

Conclusions

Although the predictive performance was less satisfactory in China than in developed countries, modification of the DIGIROP-Birth model with postnatal risk factors shows promise in improving its efficacy for TR-ROP. The model may also be effective in infants with a younger gestational age or with an extremely low birth weight.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-021-01952-0.

Cholestasis after very preterm birth was associated with adverse neonatal outcomes but no significant long-term liver disease: A population-based study

AIM

To describe outcome linked to neonatal cholestasis in a defined cohort of very preterm infants.

METHODS

Population-based retrospective case-control study of preterm infants, gestational age <30 weeks, surviving for 28 days, in Stockholm County. Cholestasis was defined as conjugated bilirubin ≥30 μmol/L exceeding 20% of total level at least twice and graded as high if exceeding 100 μmol/L. Cholestatic cases were matched on gestational week with two non-cholestatic controls.

RESULTS

The incidence rate of cholestasis was 37/250 (14.8%), with increasing rates in lower gestational weeks. Perinatal factors associated with cholestasis were pre-eclampsia and being born small for gestational age. Cholestatic infants had three times more bronchopulmonary dysplasia and eight times more retinopathy of prematurity. The mortality was 13.5% in cholestatic infants versus 2.7% in controls (P = .040). All deceased cholestatic infants had high-grade cholestasis. No surviving infants developed chronic liver disease by 10 years of age.

CONCLUSION

Cholestasis was common in very preterm infants and linked to disease severity and adverse outcome. Cholestasis may be an independent risk factor for bronchopulmonary dysplasia and retinopathy of prematurity and more severe cholestasis associated with increased mortality. Cholestasis was not associated with chronic liver disease later in childhood.

Lung and Eye Disease Develop Concurrently in Supplemental Oxygen-Exposed Neonatal Mice

Bronchopulmonary dysplasia (BPD) and retinopathy of prematurity (ROP) are two debilitating disorders that develop in preterm infants exposed to supplemental oxygen to prevent respiratory failure. Both can lead to lifelong disabilities, such as chronic obstructive pulmonary disease and vision loss. Due to the lack of a standard experimental model of coincident disease, the underlying associations between BPD and ROP are not well characterized. To address this gap, we used the robust mouse model of oxygen-induced retinopathy exposing C57BL/6 mice to 75% oxygen from postnatal day 7 to 12. The cardinal features of ROP were replicated by this strategy, and the lungs of the same mice were simultaneously examined for evidence of BPD-like lung injury, investigating both the short- and long-term effects of early-life supplemental oxygen exposure. At postnatal days 12 and 18, mild lung disease was evident by histopathologic analysis together with the expected vasculopathy in the inner retina. At later time points, the lung lesion had progressed to severe airspace enlargement and alveolar simplification, with concurrent thinning in the outer layer of the retina. In addition, critical angiogenic oxidative stress and inflammatory factors reported to be dysregulated in ROP were similarly impaired in the lungs. These data shed new light on the interconnectedness of these two neonatal disorders, holding potential for the discovery of novel targets to treat BPD and ROP.

Cumulative evidence for association of sepsis and retinopathy of prematurity

BACKGROUND

Retinopathy of prematurity (ROP) is a retinal vasoproliferative disease affected by multiple factors such as infection and preterm birth. The role of sepsis in the development of ROP remains controversial. This systematic review and meta-analysis aimed to identify the impact of sepsis on ROP.

METHODS

The PubMed, Embase, and Cochrane Library databases were searched using terms related to sepsis and ROP. Cohort or case-control studies that reported the association of sepsis and ROP were eligible. The odds ratios (ORs) together with the 95% confidence interval (CI) were extracted from the studies or computed by authors if not provided.

RESULTS

Thirty-four studies were ultimately included in this meta-analysis. The pooled results showed that sepsis increased the risk for the development of any stage ROP (OR = 2.16; 95% CI: 1.65-2.82). Both early onset (OR = 2.50; 95% CI: 1.97-3.18) and late-onset (OR = 1.37; 95% CI: 1.22-1.55) sepsis were associated with severe ROP. Furthermore, both bacterial sepsis (OR = 1.74; 95% CI: 1.21-2.50) and fungal sepsis (OR = 2.96; 95% CI: 2.05-4.28) were also found to be associated with severe ROP.

CONCLUSION

Sepsis increased the risk of any stage ROP, especially for the severe ROP. Further high-quality clinical studies are needed to eliminate heterogeneity and publication bias to validate these findings.

Correlation between serum transforming growth factor β1, interleukin-6 and neonatal respiratory distress syndrome

Trend and correlation of transforming growth factor β1 (TGF-β1) and interleukin-6 (IL-6) in serum of children with neonatal respiratory distress syndrome (NRDS) were investigated. A total of 75 NRDS children born in the Xiangyang Central Hospital from July 2015 to August 2017 were analyzed retrospectively. A total of 45 NRDS premature infants who received pulmonary surfactant (PS) within 12 h after birth were treated as PS group, 30 who did not receive PS treatment as non-PS group, and 32 premature infants without NRDS in the same period were selected as control group. Serum levels of TGF-β1 and IL-6 were detected by enzyme linked immunosorbent assay (ELISA) at various time points after birth and their correlation was analyzed. The expression level of TGF-β1 in serum of children in PS group was significantly higher than that in control group on days 1 and 3 after birth (P<0.05). The expression level of TGF-β1 in non-PS group increased continuously with the increase of number of days and was significantly higher than that in control group on days 1, 3 and 7 after birth (P<0.05), and significantly higher than that in PS group on days 3 and 7 after birth (P<0.05). The analysis of the correlation between the severity of the disease and the expression levels of TGF-β1 and IL-6 showed that the expression levels were elevated with the increase of the disease severity. The expression levels of TGF-β1 and IL-6 were positively correlated with severity of the disease (r=0.7509, P<0.05; r=0.8056, P<0.05). The expression levels of TGF-β1 and IL-6 in PS and non-PS groups were positively correlated (r=0.9042, P<0.05; r=0.8905, P<0.05). The results showed that serum TGF-β1 and IL-6 were elevated in NRDS children, and there was a positive correlation between them.

Speed of Retinal Vascularization in Retinopathy of Prematurity: Risk and Protective Factors

Objective

The objective was to study the risk and protective factors involved in retinal vascular development of preterm infants with retinopathy of prematurity.

Methods

Between 2000 and 2017, 185 preterm infants were included in the protocol for retinopathy of prematurity. Risk factors associated with speed of retinal vascularization <0.5 disc diameter/week were studied in each of them.

Results

The statistically significant variables related to retinal vascular development <0.5 DD/w were intubation days, degree 3 of bronchopulmonary dysplasia, weight gain at 4-6 weeks, avascular temporal area, gestational age, number of transfusions, sepsis, number of risk factors, apnea at birth, presence of ductus arteriosus, and days of continuous positive airway pressure therapy. After the multivariate logistic regression analysis, only three variables were found to be significant: intubation days (p=0.005), degree 3 of bronchopulmonary dysplasia (p=0.022), and weight gain at 4–6 weeks (p=0.031).

Conclusion

In retinopathy of prematurity, degree 3 of bronchopulmonary dysplasia and intubation days cause delayed retinal vascular development, whereas greater postnatal weight gain favors an appropriate rate of retinal vascularization.