Oxygen Monitoring Reduces the Risk for Retinopathy of Prematurity in a Mexican Population

Oxygen delivery and monitoring in neonatal intensive care units in Mexico in 2011 and in 2023: an observational longitudinal study

BACKGROUND

Retinopathy of prematurity (ROP) is a leading cause of avoidable blindness in children, particularly in Latin America, where hyperoxia is a significant risk factor. This study evaluated resource availability and use for administering and monitoring supplemental oxygen in Mexico.

METHODS

In 2011, an observational study in which 32 government neonatal intensive care units (NICUs) across Mexico were visited. Data collected included occupancy, staffing levels, and equipment to deliver and monitor supplemental oxygen. Preterm infants receiving oxygen were observed. In 2023, 13 NICUs were revisited, and similar data collected. Staffing levels were benchmarked against Argentinian and US recommendations.

RESULTS

In 2011, only 38% of NICUs had adequate medical and staffing levels to meet recommended cot-to-staff ratios for all shifts. Staffing ratios were worse during weekends and at night than during weekdays. Only 25.5% of cots had blenders, and 80.1% had saturation monitors. 153 infants were observed 87% of whom were being monitored. Upper and lower oxygen saturations were ≥ 96% in 53%, and ≤ 89% in 8%, respectively. Alarm settings were inadequate, as 38% and 32% of upper and lower alarms were switched off and 16% and 53% were incorrectly set, respectively. In the 13 NICUs with data from 2011  and 2023, cot-to-staff ratios deteriorated over time, and in 2023 no unit had recommended ratios for all shifts. Equipment provision did not change, with similar proportions of babies in oxygen being monitored (79% 2011; 75% 2023). Rates of hyperoxia decreased slightly from 54% in 2011 to 49% in 2023. More upper alarms were set (46% 2011; 75% 2023), but a higher proportion were incorrectly set (52% 2011; 68% 2023).

CONCLUSIONS

Between 2011 and 2023, cot-to-staff ratios worsened, and equipment for safe oxygen delivery and monitoring remained insufficient. Despite available monitoring equipment, oxygen saturations often exceeded recommended levels, and alarms were frequently not set or incorrectly configured. Urgent improvements are needed in healthcare workforce numbers and practices, along with ensuring adequate equipment for safe oxygen delivery.

Comparison of Weight-Gain-Based Prediction Models for Retinopathy of Prematurity in an Australian Population

Purpose

Four weight-gain-based algorithms are compared for the prediction of type 1 ROP in an Australian cohort: the weight, insulin-like growth factor, neonatal retinopathy of prematurity (WINROP) algorithm, the Children's Hospital of Philadelphia Retinopathy of Prematurity (CHOPROP), the Colorado Retinopathy of Prematurity (CO-ROP) algorithm, and the postnatal growth, retinopathy of prematurity (G-ROP) algorithm.

Methods

A four-year retrospective cohort analysis of infants screened for ROP in a tertiary neonatal intensive care unit in Brisbane, Australia. The main outcome measures were sensitivities, specificities, and positive and negative predictive values.

Results

531 infants were included (mean gestational age 28 + 3). 24 infants (4.5%) developed type 1 ROP. The sensitivities, specificities, and negative predictive values, respectively, for type 1 ROP (95% confidence intervals) were for WINROP 83.3% (61.1-93.3%), 52.3% (47.8-56.7%), and 98.4% (96.1-99.4%); for CHOPROP 100% (86.2-100%), 46.0% (41.7-50,3%), and 100% (98.4-100%); for CO-ROP 100% (86.2-100%), 32.0% (28.0%-36.1%), and 100% (98.3-100%); and for G-ROP 100% (86.2-100%), 28.2% (24.5-32.3%), and 100% (97.4-100%). Of the five infants with persistent nontype 1 ROP that underwent treatment, only CO-ROP was able to successfully identify all.

Conclusions

CHOPROP, CO-ROP, and G-ROP performed well in this Australian population. CHOPROP, CO-ROP, and G-ROP would reduce the number of infants requiring examinations by 43.9%, 30.5%, and 26.9%, respectively, compared to current ROP screening guidelines. Weight-gain-based algorithms would be a useful adjunct to the current ROP screening.

Incidence of retinopathy of prematurity treatment in extremely preterm infants in China

BACKGROUND

Retinopathy of prematurity (ROP) continues to be a major cause of visual impairment and blindness in premature infants and children.

OBJECTIVES

To investigate the incidence of severe ROP receiving treatment in extremely preterm (EP) infants in China over time. The risk factors for ROP treatment were also assessed.

METHODS

This was a multicentre retrospective study and a subanalysis of baseline data from the "Outcomes of EP infants in China 2010-2019" study. This study was conducted in 68 tertiary neonatal care centres from 31 provinces of China. Infants with a gestational age of 23⁰ -27⁶  weeks and admitted to a neonatal unit within the first 72 h of life between 2010 and 2019 were enrolled. Incidence of ROP was analysed in infants who survived to 32 weeks postmenstrual age and screened for ROP. Multivariable modified Poisson regression models were used to identify risk factors for ROP treatment.

RESULTS

Among 7295 eligible infants, 4701 (64.5%) survived to 32 weeks postmenstrual age and met ROP screening criteria. Of the 3756 infants who screened and with ROP data, 2320 (61.8%) developed ROP of any stage. The overall incidence of ROP treatment was 12.6%, decreasing from 45.5% at 23 weeks to 8.3% at 27 weeks. During the 10-year period, the incidence of ROP treatment did not change, although the incidence of any ROP increased over time. Independent risk factors associated with ROP treatment included lower gestational age, small for gestational age, multiple birth, severe intraventricular haemorrhage, patent ductus arteriosus and supplemental oxygen duration.

CONCLUSIONS

The incidence of EP infants receiving ROP treatment showed no change during this 10-year period in China. Prevention of prematurity and foetal growth restriction, judicious use of oxygen and reducing comorbidities are promising factors that may reduce the incidence of ROP needing treatment in these high-risk infants.

Individual Risk Prediction for Sight-Threatening Retinopathy of Prematurity Using Birth Characteristics

Question

Can a prediction model be constructed for retinopathy of prematurity needing treatment by using only birth characteristics data and applying advanced statistical methods?

Findings

In this cohort study of 6947 infants born at gestational age 24 to 30 weeks, the prediction model incorporating only postnatal age, gestational age, sex, and birth weight provided a predictive ability for retinopathy of prematurity needing treatment that was comparable to current models requiring postnatal data (not always available). The risk for retinopathy of prematurity needing treatment increased up to 12 weeks’ postnatal age irrespective of the infants’ gestational age.

Meaning

This prediction model identifying infants with a high risk for developing sight-threatening disease at an early time may improve the conditions for optimal screening.

Importance

To prevent blindness, repeated infant eye examinations are performed to detect severe retinopathy of prematurity (ROP), yet only a small fraction of those screened need treatment. Early individual risk stratification would improve screening timing and efficiency and potentially reduce the risk of blindness.

Objectives

To create and validate an easy-to-use prediction model using only birth characteristics and to describe a continuous hazard function for ROP treatment.

Design, Setting, and Participants

In this retrospective cohort study, Swedish National Patient Registry data from infants screened for ROP (born between January 1, 2007, and August 7, 2018) were analyzed with Poisson regression for time-varying data (postnatal age, gestational age [GA], sex, birth weight, and important interactions) to develop an individualized predictive model for ROP treatment (called DIGIROP-Birth [Digital ROP]). The model was validated internally and externally (in US and European cohorts) and compared with 4 published prediction models.

Main Outcomes and Measures

The study outcome was ROP treatment. The measures were estimated momentary and cumulative risks, hazard ratios with 95% CIs, area under the receiver operating characteristic curve (hereinafter referred to as AUC), sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV).

Results

Among 7609 infants (54.6% boys; mean [SD] GA, 28.1 [2.1] weeks; mean [SD] birth weight, 1119 [353] g), 442 (5.8%) were treated for ROP, including 142 (40.1%) treated of 354 born at less than 24 gestational weeks. Irrespective of GA, the risk for receiving ROP treatment increased during postnatal weeks 8 through 12 and decreased thereafter. Validations of DIGIROP-Birth for 24 to 30 weeks’ GA showed high predictive ability for the model overall (AUC, 0.90 [95% CI, 0.89-0.92] for internal validation, 0.94 [95% CI, 0.90-0.98] for temporal validation, 0.87 [95% CI, 0.84-0.89] for US external validation, and 0.90 [95% CI, 0.85-0.95] for European external validation) by calendar periods and by race/ethnicity. The sensitivity, specificity, PPV, and NPV were numerically at least as high as those obtained from CHOP-ROP (Children’s Hospital of Philadelphia–ROP), OMA-ROP (Omaha-ROP), WINROP (weight, insulinlike growth factor 1, neonatal, ROP), and CO-ROP (Colorado-ROP), models requiring more complex postnatal data.

Conclusions and Relevance

This study validated an individualized prediction model for infants born at 24 to 30 weeks’ GA, enabling early risk prediction of ROP treatment based on birth characteristics data. Postnatal age rather than postmenstrual age was a better predictive variable for the temporal risk of ROP treatment. The model is an accessible online application that appears to be generalizable and to have at least as good test statistics as other models requiring longitudinal neonatal data not always readily available to ophthalmologists.

Incidence and Risk Factors Associated with Retinopathy of Prematurity in Peru

Purpose

The purpose of this research is to determine retinopathy of prematurity (ROP) prevalence and possible risk factors associated with ROP development in newborns admitted to a neonatal unit of a Peruvian National Reference Hospital.

Patients and Methods

This retrospective study included 216 preterm infants. The data were collected between January 2016 and December 2018. All infants were examined according to Peruvian guidelines for screening and treatment of ROP. The association of clinical risk factors and the development of ROP was analyzed and predictive factors were determined.

Results

The study subjects were 216 preterm infants of which 72 had some stage of ROP (32 stage 1; 23 stage 2 and 17 stage 3) and 144 preterm infants without ROP. The incidence of ROP in preterm infants less than 32 weeks was 60.9%, while for those weighing less than 1500 g it was 71.6%. The factors associated with ROP were gestational age below 32 weeks, birth weight below 1500 grams, neonatal sepsis, oxygen therapy, mechanical ventilation, hyaline membrane disease, bronchopulmonary dysplasia, persistence of ductus arteriosus and intraventricular hemorrhage. Exclusive breastfeeding was found to play a protective role against ROP. Binary logistic regression analysis found that only gestational age below 32 weeks (OR, 2.637; 95% CI, 1.04–6.69), weight below 1500 grams (OR, 4.377; 95% CI, 1.75–10.92), neonatal sepsis (OR, 6.517; 95% CI, 2.81–15.14), vaginal delivery (OR, 3.748; 95% CI: 1.54–9.14), and the presence of hyaline membrane disease (OR, 3.58; 95% CI, 1.47–8.74) are predictors of ROP.

Conclusion

The incidence of ROP among very low birth weight infants was 71.6%. Infants with weight below 1500 grams, neonatal sepsis, presence of hyaline membrane disease whose mother had vaginal delivery are at risk for the development of ROP. Thus, preventing premature births and encouraging exclusive breastfeeding are two main ways to prevent ROP.

Validation of WINROP (online prediction model) to identify severe retinopathy of prematurity (ROP) in an Australian preterm population: a retrospective study

INTRODUCTION

Retinopathy of prematurity (ROP) is the most common disease leading to blindness in extreme preterm infants. Current screening guidelines recommend frequent eye examinations. There is a dearth of trained ophthalmologists for these frequent screening procedures. The ANZNN neonatal network report (2013) found that only 6.4% of all screened infants had severe ROP and less than half received treatment. WINROP (online prediction model, Sweden) uses the postnatal weight gain (surrogate marker for low insulin-like growth factor IGF-1 and poor retinal vascular growth) to identify ROP requiring treatment and aims to reduce the number of examinations. Our objective was to validate the WINROP model in an Australian cohort of preterm infants.

METHODS

Birth weight, gestational age, and weekly weight measurements were retrieved retrospectively along with the final ROP outcomes and plotted on the online WINROP software.

RESULTS

The sensitivity, specificity, positive predictive value, and negative predictive value of WINROP were 85.7%, 59.0%, 6.98%, and 99.1% respectively for a cohort of 221 preterm infants (Median birth weight, 1040 g; Gestational age, 27.9 weeks). WINROP alarm was signaled in 42.6% of all infants. WINROP did not signal an alarm in one infant who needed treatment. This infant had intra ventricular hemorrhage grade 3-4 and temporary ventricular dilatation.

CONCLUSIONS

This is the first Australian study validating WINROP model. Our findings suggest that it lacked sensitivity to be used alone. However, adjusting the algorithm for the Australian population may improve the efficacy and reduce the number of examinations when used along with the current screening guidelines.

Association of Retinopathy of Prematurity With Low Levels of Arachidonic Acid: A Secondary Analysis of a Randomized Clinical Trial

Importance

Mice with oxygen-induced retinopathy fed matched diets except for ω-3 long-chain polyunsaturated fatty acids (LC-PUFAs) vs ω-6 LC-PUFAs demonstrate relative antiangiogenic and neuroprotective associations of ω-3 LC-PUFAs. However, supplementing preterm infants with LC-PUFAs has been inconsistent in reducing major preterm morbidities. However, few studies measured serum lipid levels after supplementation.

Objective

To examine the associated risk of retinopathy of prematurity (ROP) from the levels of circulating ω-3 and ω-6 LC-PUFAs.

Design, Setting, and Participants

This longitudinal clinical study was a further analysis of serum lipid levels from a randomized controlled trial cohort of 90 infants born at gestational age (GA) less than 28 weeks. From April 4, 2013, to September 22, 2015, cord blood samples, followed by venous blood samples, were obtained at birth and at 1, 7, 14, and 28 days after birth and then at postmenstrual age (PMA) 32, 36, and 40 weeks at the neonatal intensive care unit at Sahlgrenska University Hospital in Göteborg, Sweden.

Main Outcomes and Measures

Serum phospholipid fatty acids were transmethylated and measured by gas chromatography-mass spectrometry. Mann-Whitney test, logistic regression Spearman rank correlation, and receiver operating characteristic curve analysis were used to compare differences between infants with no ROP and infants who developed ROP.

Results

Serum levels from 78 infants (43 male [55%]; mean [SD] GA, 25.5 [1.4] weeks) with a known ROP outcome were evaluated. Lower area under the curve (AUC) of arachidonic acid (AA) (20:4 ω-6) was seen in infants with a later diagnosis of ROP compared with infants with no ROP in the first month of life (mean, 34.05 [95% CI, 32.10-36.00] vs 37.15 [95% CI, 34.85-39.46]; P < .05). In addition, lower levels of AA at 32 weeks' PMA were seen in infants with later severe ROP compared with in those without ROP (mean, 7.06 [95% CI, 6.60-7.52] vs 8.74 [95% CI, 7.80-9.67]; P < .001). In logistic modeling, low postnatal serum levels of AA and GA at birth identified with a sensitivity greater than 90% of infants who developed ROP.

Conclusions and Relevance

Low postnatal levels of the ω-6 LC-PUFAs (AA) are strongly associated with ROP development. Evaluating postnatal AA fraction after birth in addition to GA may be useful for ROP prediction.

Trial Registration

clinicaltrials.gov Identifier: NCT02760472.

Impact of Early Postnatal Weight Gain on Retinopathy of Prematurity in Very Preterm Infants in Southwestern Ontario

PURPOSE

To examine the relationship between post-natal growth and development of retinopathy of prematurity (ROP) among preterm infants in southwestern Ontario.

METHODS

The medical records of 431 preterm infants, born between January 1, 2008, and June 1, 2015, with a gestational age (GA) of less than 31 weeks or birth weight (BW) of less than 1,250 g were reviewed. Information collected included pregnancy and birth history, neonatal characteristics, ROP status, comorbidities, and postnatal weight measurements at specified intervals. Infants diagnosed as having ROP and no ROP were compared.

RESULTS

Low weight velocity from day 7 to day 28 (P < .001), high weight velocity from birth to first day of full enteral feeding (FEF) (P < .001), long duration from birth to FEF (P < .001), and long duration from FEF to discharge/transfer (P < .001) were associated with ROP. After controlling for GA and BW, the durations, birth to FEF, and FEF to discharge/transfer remained significant (P < .05). In a multivariable logistic regression analysis adjusting for GA, bronchopulmonary dysplasia, and surgical ligation for patent ductus arteriosus, the only independent risk factor of ROP was duration from FEF to discharge/transfer (P < .05).

CONCLUSIONS

Low weight velocity from day 7 to day 28 may be a useful predictor for the development of ROP but is dependent on GA and BW. A delay to reach FEF, which is associated with comorbidities of ROP, appears to be a risk factor for ROP that is independent of GA and BW. [J Pediatr Ophthalmol Strabismus. 2019;56(3):168-172.].

Vascular changes on fluorescein angiography of premature infants with low risk of retinopathy of prematurity after high oxygen exposure

Purpose

To describe a wide array of peripheral vascular changes using fluorescein angiography in preterm neonates, without high risk characteristics for developing retinopathy of prematurity, that were exposed to high oxygen concentration.

Methods

Retrospective, two center, case series. Newborns at two different hospitals with ≥1500 g or gestational age of ≥32 weeks, fluorescein angiography performed, and with high oxygen exposure without adequate control were included.

Results

294 infants diagnosed with ROP were analyzed. Only 28 eyes from 14 patients with peripheral vascular abnormalities in older and heavier babies were included. Two distinct type of peripheral vascular changes were observed: group 1 or non-proliferative: areas of capillary non-perfusion along with widespread arteriovenous shunting between adjacent primary vessels, tortuosity of primary vessels, abnormal budding of tertiary vessels and capillaries, abnormal capillary tufts and absence of foveal avascular zone; group 2 or proliferative: all of the characteristics of group 1 plus leakage of dye from the boundary between perfused and non-perfused retina and/or optic disc.

Conclusion

Peripheral vascular abnormalities different from retinopathy of prematurity are observed in older than 32 weeks of gestational age, and heavier than 1500 g babies. This makes the authors classify these patients as having a disease caused solely by oxygen dysregulation at the neonatal intensive care unit similarly to the oxygen induced retinopathy in experimental studies.