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Association between Intermittent Hypoxemia and Severe Bronchopulmonary Dysplasia in Preterm Infants
Erik A Jensen1, Robin K Whyte2, Barbara Schmidt1,3
1Division of Neonatology, Department of Pediatrics, Children's Hospital of Philadelphia and University of Pennsylvania, Philadelphia, Pennsylvania.
Insights
Prolonged intermittent hypoxemia in extremely preterm infants significantly increases the risk of severe bronchopulmonary dysplasia. Early hypoxemia, starting within the first week, is strongly associated with this condition.
Area of Science:
- Neonatal Medicine
- Pediatric Pulmonology
- Critical Care
Background:
- Bronchopulmonary dysplasia (BPD) is a major cause of long-term disability in extremely preterm infants.
- The exact causes of BPD are not fully understood, but intermittent hypoxemia may be a contributing factor.
- Understanding the relationship between hypoxemia and BPD is crucial for improving infant outcomes.
Purpose of the Study:
- To investigate the association between prolonged intermittent hypoxemia and the development of severe bronchopulmonary dysplasia in extremely preterm infants.
- To quantify the risk of severe BPD based on the frequency and duration of hypoxemic episodes.
Main Methods:
- A post hoc analysis of data from the Canadian Oxygen Trial involving extremely preterm infants surviving to 36 weeks postmenstrual age.
- Continuous pulse oximetry data (sampled every 10 seconds) were used to quantify oxygen saturations <80% for at least 1 minute and the proportion of time spent in hypoxemia from birth to 36 weeks.
- Severe BPD was defined according to the 2001 NIH Workshop Summary criteria.
Main Results:
- Out of 1,018 infants, 332 (32.6%) developed severe BPD.
- A dose-dependent relationship was observed: the adjusted relative risk of severe BPD increased progressively with higher deciles of hypoxemic episodes, reaching 20.40 in the highest decile compared to the lowest.
- Significant differences in hypoxemia rates between infants with and without severe BPD were evident within the first week of life.
Conclusions:
- Prolonged intermittent hypoxemia, particularly when starting in the first week after birth, is significantly associated with an increased risk of severe bronchopulmonary dysplasia in extremely preterm infants.
- These findings highlight the importance of monitoring and managing oxygenation in the early neonatal period for this vulnerable population.
- Further research may focus on interventions to mitigate the effects of early hypoxemia on lung development.
Abstract:
Rationale: Bronchopulmonary dysplasia increases the risk of disability in extremely preterm infants. Although the pathophysiology remains uncertain, prior exposure to intermittent hypoxemia may play a role in this relationship. Objectives: To determine the association between prolonged episodes of intermittent hypoxemia and severe bronchopulmonary dysplasia. Methods: A post hoc analysis of extremely preterm infants in the Canadian Oxygen Trial who survived to 36 weeks' postmenstrual age was performed. Oxygen saturations <80% for ⩾1 minute and the proportion of time per day with hypoxemia were quantified using continuous pulse oximetry data that had been sampled every 10 seconds from within 24 hours of birth until 36 weeks' postmenstrual age. The study outcome was severe bronchopulmonary dysplasia as defined in the 2001 NIH Workshop Summary. Measurements and Main Results: Of 1,018 infants, 332 (32.6%) developed severe bronchopulmonary dysplasia. The median number of hypoxemic episodes ranged from 0.8/day (interquartile range, 0.2-1.1) to 60.2/day (interquartile range, 51.4-70.3) among the least and most affected 10% of infants. Compared with the lowest decile of exposure to hypoxemic episodes, the adjusted relative risk of severe bronchopulmonary dysplasia increased progressively from 1.72 (95% confidence interval, 1.55-1.90) at the 2nd decile to 20.40 (95% confidence interval, 12.88-32.32) at the 10th decile. Similar risk gradients were observed for time in hypoxemia. Significant differences in the rates of hypoxemia between infants with and without severe bronchopulmonary dysplasia emerged within the first week after birth. Conclusions: Prolonged intermittent hypoxemia beginning in the first week after birth was associated with an increased risk of developing severe bronchopulmonary dysplasia among extremely preterm infants. Clinical trial registered with www.isrctn.com (ISRCTN62491227) and www.clinicaltrials.gov (NCT00637169).
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