Oxygenation Factors Associated with Retinopathy of Prematurity in Infants of Extremely Low Birth Weight

Controlled oxygen delivery to power tissue regeneration

Oxygen plays a crucial role in human embryogenesis, homeostasis, and tissue regeneration. Emerging engineered regenerative solutions call for novel oxygen delivery systems. To become a reality, these systems must consider physiological processes, oxygen release mechanisms and the target application. In this review, we explore the biological relevance of oxygen at both a cellular and tissue level, and the importance of its controlled delivery via engineered biomaterials and devices. Recent advances and upcoming trends in the field are also discussed with a focus on tissue-engineered constructs that could meet metabolic demands to facilitate regeneration.

Continuous oxygen saturation and risk of retinopathy of prematurity in a Japanese cohort

BACKGROUND/AIMS

We assessed the associations between retinopathy of prematurity (ROP) and continuous measurements of oxygen saturation (SpO2), and developed a risk prediction model for severe ROP using birth data and SpO2 data.

METHODS

This retrospective study included infants who were born before 30 weeks of gestation between August 2009 and January 2019 and who were screened for ROP at a single hospital in Japan. We extracted data on birth weight (BW), birth length, gestational age (GA) and minute-by-minute SpO2 during the first 20 days from the medical records. We defined four SpO2 variables using sequential measurements. Multivariate logistic regression was used to develop a model that combined birth data and SpO2 data to predict treatment-requiring ROP (TR-ROP). The model's performance was evaluated using the area under the receiver operating characteristic curve (AUC).

RESULTS

Among 350 infants, 83 (23.7%) required ROP treatment. The SpO2 variables in infants with TR-ROP differed significantly from those with non-TR-ROP. The average SpO2 and high SpO2 showed strong associations with GA (r=0.73 and r=0.70, respectively). The model incorporating birth data and the four SpO2 variables demonstrated good discriminative ability (AUC=0.83), but it did not outperform the model incorporating BW and GA (AUC=0.82).

CONCLUSION

Data obtained by continuous SpO2 monitoring demonstrated valuable associations with severe ROP, as well as with GA. Differences in the distribution of average SpO2 and high SpO2 between infants with TR-ROP and non-TR-ROP could be used to establish efficient cut-off values for risk determination.

Oxygenation Fluctuations Associated with Severe Retinopathy of Prematurity: Insights from a Multimodal Deep Learning Approach

Purpose

Retinopathy of prematurity (ROP) is one of the leading causes of blindness in children. Although the role of oxygen in the pathophysiology of ROP is well established, a precise understanding of the dynamic relationship between oxygen exposure ROP incidence and severity is lacking. The purpose of this study was to evaluate the correlation between time-dependent oxygen variables and the onset of ROP.

Design

Retrospective cohort study.

Participants

Two hundred thirty infants who were born at a single academic center and met the inclusion criteria were included. Infants are mainly born between January 2011 and October 2022.

Methods

Patient data were extracted from electronic health records (EHRs), with sufficient time-dependent oxygen data. Clinical outcomes for ROP were recorded as none/mild or moderate/severe (defined as type II or worse). Mixed-effects linear models were used to compare the 2 groups in terms of dynamic oxygen variables, such as daily average and the coefficient of variation (COV) fraction of inspired oxygen (FiO2). Support vector machine (SVM) and long-short-term memory (LSTM)-based multimodal models were trained with fivefold cross-validation to predict which infants would develop moderate/severe ROP. Gestational age (GA), birth weight, and time-dependent oxygen variables were used to develop predictive models.

Main Outcome Measures

Model cross-validation performance was evaluated by computing the mean area under the receiver operating characteristic (AUROC) curve, precision, recall, and F1 score.

Results

We found that both daily average and COV of FiO2 were associated with more severe ROP (adjusted P < 0.001). With fivefold cross-validation, the multimodal LSTM models had higher performance than the best static models (SVM using GA and 3 average FiO2 features) and SVM models trained on GA alone (mean AUROC = 0.89 ± 0.04 vs. 0.86 ± 0.05 vs. 0.83 ± 0.04).

Conclusions

The development of severe ROP might not only be influenced by oxygen exposure but also by its fluctuation, which provides direction for future study of pathophysiological factors associated with severe ROP development. Additionally, we demonstrated that multimodal neural networks can be a method to extract useful information from time-series data, which may be a valuable methodology for the investigation of other diseases using EHR data.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Extended CPAP or low-flow nasal cannula for intermittent hypoxaemia in preterm infants: a 24-hour randomised clinical trial

OBJECTIVE

Optimal timing of continuous positive airway pressure (CPAP) cessation in preterm infants remains undetermined. We hypothesised that CPAP extension compared with weaning to low-flow nasal cannula (NC) reduces intermittent hypoxaemia (IH) and respiratory instability in preterm infants meeting criteria to discontinue CPAP.

DESIGN

Single-centre randomised clinical trial.

SETTING

Level 4 neonatal intensive care unit.

PATIENTS

36 infants <34 weeks' gestation receiving CPAP≤5 cmH2O and fraction of inspired oxygen (FiO2) ≤0.30 and meeting respiratory stability criteria.

INTERVENTIONS

Extended CPAP was compared with weaning to low-flow NC (0.5 L/kg/min with a limit of 1.0 L/min) for 24 hours.

OUTCOMES

The primary outcome was IH (number of episodes with SpO2<85% lasting ≥10 s). Secondary outcomes included: coefficient of variability of SpO2, proportion of time in various SpO2 ranges, episodes (≥10 s) with SpO2<80%, median cerebral and renal oxygenation, median effective FiO2, median transcutaneous carbon dioxide and bradycardia (<100/min for≥10 s).

RESULTS

The median (IQR) episodes of IH per 24-hour period was 20 (6-48) in the CPAP group and 76 (18-101) in the NC group (p=0.03). Infants continued on CPAP had less bradycardia, time with SpO2 <91% and <85%, and lower FiO2 (all p<0.05). There were no statistically significant differences in IH<80%, median transcutaneous carbon dioxide or median cerebral or renal oxygenation.

CONCLUSION

In preterm infants meeting respiratory stability criteria for CPAP cessation, extended CPAP decreased IH, bradycardia and other hypoxaemia measures compared with weaning to low-flow NC during the 24-hour intervention.

TRIAL REGISTRATION NUMBER

NCT04792099.

Research hotspots and trends in retinopathy of prematurity from 2003 to 2022: a bibliometric analysis

Background

In order to understand the research hotspots and trends in the field of retinopathy of prematurity (ROP), our study analyzed the relevant publications from 2003 to 2022 by using bibliometric analysis.

Methods

The Citespace 6.2.R3 system was used to analyze the publications collected from the Web of Science Core Collection (WoSCC) database.

Results

In total, 4,957 publications were included in this study. From 2003 to 2022, the number of publications gradually increased and peaked in 2022. The United States was the country with the most publications, while Harvard University was the most productive institution. The top co-cited journal PEDIATRICS is published by the United States. Author analysis showed that Hellström A was the author with the most publications, while Good WV was the top co-cited author. The co-citation analysis of references showed seven major clusters: genetic polymorphism, neurodevelopmental outcome, threshold retinopathy, oxygen-induced retinopathy, low birth weight infant, prematurity diagnosis cluster and artificial intelligence (AI). For the citation burst analysis, there remained seven keywords in their burst phases until 2022, including ranibizumab, validation, trends, type 1 retinopathy, preterm, deep learning and artificial intelligence.

Conclusion

Intravitreal anti-vascular endothelial growth factor therapy and AI-assisted clinical decision-making were two major topics of ROP research, which may still be the research trends in the coming years.

Epidemiologic Evaluation of Retinopathy of Prematurity Severity in a Large Telemedicine Program in India Using Artificial Intelligence

PURPOSE

Epidemiological changes in retinopathy of prematurity (ROP) depend on neonatal care, neonatal mortality, and the ability to carefully titrate and monitor oxygen. We evaluate whether an artificial intelligence (AI) algorithm for assessing ROP severity in babies can be used to evaluate changes in disease epidemiology in babies from South India over a 5-year period.

DESIGN

Retrospective cohort study.

PARTICIPANTS

Babies (3093) screened for ROP at neonatal care units (NCUs) across the Aravind Eye Care System (AECS) in South India.

METHODS

Images and clinical data were collected as part of routine tele-ROP screening at the AECS in India over 2 time periods: August 2015 to October 2017 and March 2019 to December 2020. All babies in the original cohort were matched 1:3 by birthweight (BW) and gestational age (GA) with babies in the later cohort. We compared the proportion of eyes with moderate (type 2) or treatment-requiring (TR) ROP, and an AI-derived ROP vascular severity score (from retinal fundus images) at the initial tele-retinal screening exam for all babies in a district, VSS), in the 2 time periods.

MAIN OUTCOME MEASURES

Differences in the proportions of type 2 or worse and TR-ROP cases, and VSS between time periods.

RESULTS

Among BW and GA matched babies, the proportion [95% confidence interval {CI}] of babies with type 2 or worse and TR-ROP decreased from 60.9% [53.8%-67.7%] to 17.1% [14.0%-20.5%] (P < 0.001) and 16.8% [11.9%-22.7%] to 5.1% [3.4%-7.3%] (P < 0.001), over the 2 time periods. Similarly, the median [interquartile range] VSS in the population decreased from 2.9 [1.2] to 2.4 [1.8] (P < 0.001).

CONCLUSIONS

In South India, over a 5-year period, the proportion of babies developing moderate to severe ROP has dropped significantly for babies at similar demographic risk, strongly suggesting improvements in primary prevention of ROP. These results suggest that AI-based assessment of ROP severity may be a useful epidemiologic tool to evaluate temporal changes in ROP epidemiology.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Modifiable Risk Factors and Preventative Strategies for Severe Retinopathy of Prematurity

Severe ROP is characterized by the development of retinal fibrovascular proliferation that may progress to retinal detachment. The purpose of this report is to review five of the most common and well-studied perinatal and neonatal modifiable risk factors for the development of severe ROP. Hyperoxemia, hypoxia, and associated prolonged respiratory support are linked to the development of severe ROP. While there is a well-established association between clinical maternal chorioamnionitis and severe ROP, there is greater variability between histologic chorioamnionitis and severe ROP. Neonatal sepsis, including both bacterial and fungal subtypes, are independent predictors of severe ROP in preterm infants. Although there is limited evidence related to platelet transfusions, the risk of severe ROP increases with the number and volume of red blood cell transfusions. Poor postnatal weight gain within the first six weeks of life is also strongly tied to the development of severe ROP. We also discuss preventative strategies that may reduce the risk of severe ROP. Limited evidence-based studies exist regarding the protective effects of caffeine, human milk, and vitamins A and E.

Early prediction of severe retinopathy of prematurity requiring laser treatment using physiological data

BACKGROUND

Early risk stratification for developing retinopathy of prematurity (ROP) is essential for tailoring screening strategies and preventing abnormal retinal development. This study aims to examine the ability of physiological data during the first postnatal month to distinguish preterm infants with and without ROP requiring laser treatment.

METHODS

In this cohort study, preterm infants with a gestational age <32 weeks and/or birth weight <1500 g, who were screened for ROP were included. Differences in the physiological data between the laser and non-laser group were identified, and tree-based classification models were trained and independently tested to predict ROP requiring laser treatment.

RESULTS

In total, 208 preterm infants were included in the analysis of whom 30 infants (14%) required laser treatment. Significant differences were identified in the level of hypoxia and hyperoxia, oxygen requirement, and skewness of heart rate. The best model had a balanced accuracy of 0.81 (0.72-0.87), a sensitivity of 0.73 (0.64-0.81), and a specificity of 0.88 (0.80-0.93) and included the SpO₂/FiO₂ ratio and baseline demographics (including gestational age and birth weight).

CONCLUSIONS

Routinely monitored physiological data from preterm infants in the first postnatal month are already predictive of later development of ROP requiring laser treatment, although validation is required in larger cohorts.

IMPACT

Routinely monitored physiological data from the first postnatal month are predictive of later development of ROP requiring laser treatment, although model performance was not significantly better than baseline characteristics (gestational age, birth weight, sex, multiple birth, prenatal glucocorticosteroids, route of delivery, and Apgar scores) alone. A balanced accuracy of 0.81 (0.72-0.87), a sensitivity of 0.73 (0.64-0.81), and a specificity of 0.88 (0.80-0.93) was achieved with a model including the SpO₂/FiO₂ ratio and baseline characteristics. Physiological data have potential to play a significant role for future ROP prediction and provide opportunities for early interventions to protect infants from abnormal retinal development.

Oxygenation in the NICU: there is more to it than meets the eye

Dormishian and colleagues in their study address an issue that care teams in the NICU encounter on a daily basis, regarding motion artifacts during oxygenation monitoring. In our commentary, we discuss the available tools that allow continuous noninvasive monitoring of oxygenation in the NICU, and modalities that increase the time premature infants spend in the desired SpO₂ range and impact their clinical outcomes.