Neonatology Fellow University of Alabama School of Medicine Birmingham, Alabama, United States
Background: Oxidant injury and barotrauma/volutrauma are thought to increase the risk of BPD. The National Institute of Child Health and Human Development (NICHD) bronchopulmonary dysplasia (BPD) outcome estimator (2022) includes FiO2 but doesn’t include MAP as a predictor. It is possible that MAP may also be associated with the risk of BPD. Objective: To determine whether MAP during the first week after birth is associated with higher risk of BPD or death in addition to FiO2. Design/Methods: This retrospective study included extremely preterm infants 22w0d to 27w6d born at the University of Alabama at Birmingham from Dec 2019 and Dec 2021. We included data from infants who were intubated within 48 hours after birth and remained intubated for at least 4 days or died during the first week after birth. The median MAP and FiO2 were determined using hourly data available during the first week after birth. Missing data were not imputed. The primary outcome was Jensen’s grade 2-3 BPD or death by 36 weeks’ post menstrual age (PMA). We used logistic regression to adjust for gestational age, sex, birth weight, and antenatal corticosteroid exposure. Results: : Of 202 inborn extremely preterm infants, 100 infants were eligible for inclusion (54 had grade 2-3 BPD or died before 36 weeks’ PMA). The mean gestational age was 24w3d and the mean birth weight was 629g (Table 1). FiO2 was a higher among infants with grade 2-3 BPD or death (0.42 vs 0.33; p=0.02), and higher levels of FiO2 were associated with a higher risk of grade 2-3 BPD or death (odds ratio (OR) 3.43; 95% confidence intervals (CI) 1.05-11.17; p=0.04). There was no difference in MAP between groups (7.1±1.6 cmH2O vs 7.1±1.0 cmH2O; p=0.94) and there was no association between MAP and grade 2-3 BPD or death (OR 0.73; 95% CI 0.37-1.41; p=0.34). The ratio of MAP to FiO2 did not differ significantly between groups and was not associated with the risk of grade 2-3 BPD or death (Table 2).
Conclusion(s): Among extremely preterm infants on mechanical ventilation during the first week after birth, FiO2 was associated with the risk of grade 2-3 BPD or death. However, MAP was not associated with the risk of grade 2-3 BPD or death suggesting that MAP may not be an important predictor of pulmonary outcomes.
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