Variability in Practice and Implementation of Oxygen Target Saturation Policies in United States' Neonatal Intensive Care Units.

OBJECTIVE: This study aimed to describe target oxygen saturation (SpO2) ranges used for premature infants in United States' neonatal intensive care units (NICUs) and to describe if these target SpO2 ranges have changed in recent years. STUDY DESIGN: A 29-question survey focused on target SpO2 practices and policies was distributed via the NICU medical directors listservs for the American Academy of Pediatrics Section of Neonatal-Perinatal Medicine and Pediatrix Medical Group between August and October of 2021. Results were collected via Research Electronic Data Capture (REDCap). RESULTS: We received responses representing 170 unique, levels 2, 3, and 4 NICUs from 36 states. Most NICUs (130, 78%) have recently changed their SpO2 targets in response to target SpO2 clinical trials. Over time, the most commonly reported target SpO2 range has shifted from 88-92% to 90-95. Of NICUs that changed limits, the most common lower SpO2 limits increased from 88 to 90% and the upper SpO2 limits changed from 92 to 95%. The interquartile range for lower SpO2 limit shifted from 85-88% to 88-90% and the IQR for upper SpO2 limit decreased from 92-95 to 94-95%. Most NICUs had designated conditions that would allow for deviations from standard target SpO2 ranges. These most commonly include pulmonary hypertension (152, 95%), severe bronchopulmonary dysplasia (81, 51%), and retinopathy of prematurity (51, 32%). CONCLUSION: Oxygen saturation limits have changed over time with an overall increase in targeted SpO2. However, there remains considerable interunit variation in SpO2 policies. There is a need to achieve consensus to optimize clinical outcomes. KEY POINTS: · What are the SpO2 ranges in United States' NICUs?. · There is a shift in SpO2 ranges for preterm infants in NICUs across United States.. · Variability still persists in SpO2 ranges for preterm infants in United States' NICUs..

Direct-to-participant recruitment of mothers and infants: A strategic approach during challenging pandemic times.

Under traditional circumstances, most clinical trials rely on in-person operations to identify, recruit, and enroll study participants and to complete study-related visits. During unusual circumstances, such as the COVID-19 pandemic, the typical clinical trial model is challenged and forced to explore alternative approaches to implementing study recruitment, participant enrollment, and data collection strategies. One such alternative is a direct-to-participant approach which leverages electronic resources and relevant technological devices (e.g., smart phones) available to researchers and patients. This approach functions under the assumption that a participant has access to a device that connects to the internet such as a smart phone, tablet, or computer. Researchers are then able to transition a typical paper-based, in-person model to an electronic-based, siteless, remote study. This article describes the challenges clinicians and researchers faced when implementing a direct-to-participant study approach during the COVID-19 pandemic. The lessons learned during this study of infant populations could help increase efficiency of future trials, specifically, by lessening the burden on participants and clinicians as well as streamlining the process for enrollment and data collection. While direct-to-adult participant recruitment is not a novel approach, our findings suggest that studies attempting to recruit the infant population may benefit from such a direct-to-participant approach.

Nasal ventilation alters mesenchymal cell turnover and improves alveolarization in preterm lambs.

RATIONALE: Bronchopulmonary dysplasia (BPD) is a frequent cause of morbidity in preterm infants that is characterized by prolonged need for ventilatory support in an intensive care environment. BPD is characterized histopathologically by persistently thick, cellular distal airspace walls. In normally developing lungs, by comparison, remodeling of the immature parenchymal architecture is characterized by thinning of the future alveolar walls, a process predicated on cell loss through apoptosis. OBJECTIVES: We hypothesized that minimizing lung injury, using high-frequency nasal ventilation to provide positive distending pressure with minimal assisted tidal volume displacement, would increase apoptosis and decrease proliferation among mesenchymal cells in the distal airspace walls compared with a conventional mode of support (intermittent mandatory ventilation). METHODS: Accordingly, we compared two groups of preterm lambs: one group managed by high-frequency nasal ventilation and a second group managed by intermittent mandatory ventilation. Each group was maintained for 3 days. MEASUREMENTS AND MAIN RESULTS: Oxygenation and ventilation targets were sustained with lower airway pressures and less supplemental oxygen in the high-frequency nasal ventilation group, in which alveolarization progressed. Thinning of the distal airspace walls was accompanied by more apoptosis, and less proliferation, among mesenchymal cells of the high-frequency nasal ventilation group, based on morphometric, protein abundance, and mRNA expression indices of apoptosis and proliferation. CONCLUSIONS: Our study shows that high-frequency nasal ventilation preserves the balance between mesenchymal cell apoptosis and proliferation in the distal airspace walls, such that alveolarization progresses.

The Effect of Continuous Positive Airway Pressure in a Mouse Model of Hyperoxic Neonatal Lung Injury.

BACKGROUND: Continuous positive airway pressure (CPAP) and supplemental oxygen have become the mainstay of neonatal respiratory support in preterm infants. Although oxygen therapy is associated with respiratory morbidities including bronchopulmonary dysplasia (BPD), the long-term effects of CPAP on lung function are largely unknown. We used a hyperoxia-induced mouse model of BPD to explore the effects of daily CPAP in the first week of life on later respiratory system mechanics. OBJECTIVE: We wanted to test the hypothesis that daily CPAP in a newborn-mouse model of BPD improves longer-term respiratory mechanics. METHODS: Mouse pups from C57BL/6 pregnant dams were exposed to room air (RA) or hyperoxia (50% O2, 24 h/day) for the first postnatal week with or without exposure to daily CPAP (6 cm H2O, 3 h/day). Respiratory system resistance (Rrs) and compliance (Crs) were measured following a subsequent 2-week period of RA recovery. Additional measurements included radial alveolar and macrophage counts. RESULTS: Mice exposed to hyperoxia had significantly elevated Rrs, decreased Crs, reduced alveolarization and increased macrophage counts at 3 weeks when compared to RA-treated mice. Daily CPAP treatment significantly improved Rrs, Crs and alveolarization and decreased lung macrophage infiltration in the hyperoxia-exposed pups. CONCLUSIONS: We have demonstrated that daily CPAP had a longer-term benefit on baseline respiratory system mechanics in a neonatal mouse model of BPD. We speculate that this beneficial effect of CPAP was the consequence of a decrease in the inflammatory response and resultant alveolar injury associated with hyperoxic lung injury in newborns.

Mechanisms of injury to the preterm lung and airway: implications for long-term pulmonary outcome.

Despite changes in the epidemiology of bronchopulmonary dysplasia (BPD), longer-term morbidity, particularly in the form of airway dysfunction, remains a substantial problem in former preterm infants. The stage for this respiratory morbidity may begin as early as the transition from fetal to neonatal life. Newer therapeutic approaches for BPD should be directed toward minimizing this longer-term respiratory morbidity. Neonatal animal models focused primarily on hyperoxic exposure may provide important insights into the pathogenesis of longer-term airway hyperreactivity in this population.