Risk factors of severe bronchopulmonary dysplasia in extremely low birth weight infants

Abstract

Objective To study the occurrence of bronchopulmonary dysplasia (BPD) in extremely low birth weight (ELBW) infants and to determine the risk factors of severe BPD. Method From January 2007 to January 2017, ELBW infants admitted to neonatal intensive care unit (NICU) in Hunan Children′s Hospital were retrospectively analyzed. They were assigned into severe and mild/moderate groups based on the severity of BPD. The general condition, maternal status, prenatal and delivery room treatment, transportation, clinical courses, therapy and outcome in NICU of the two groups were compared, and the risk factors of severe BPD were analyzed. Result A total of 367 cases were hospitalized during the 10 years. 281 ELBW infants with complete medical records survived longer than 28 days were enrolled in this study. Among them, 233 had BPD. Among BPD infants, 116 cases were in the severe BPD group, 47 cases (40.5%) died. 117 cases were in the mild/moderate BPD group and 1 case (0.9%) died. The difference between the two groups was statistically significant (P<0.05). Multivariate Logistic regression analysis showed that the risk factors of severe BPD were duration of mechanical ventilation≥7 days (OR=7.518, 95%CI 3.197~17.676), ventilator-associated pneumonia (OR=3.047, 95%CI 1.436~6.464), 1 min Apgar score≤7 (OR=2.341, 95%CI 1.142~4.796) and patent ductus arteriosus (OR=2.223, 95%CI 1.079~4.582). Conclusion The incidence and mortality of BPD, especially severe BPD, are high in ELBW infants. Avoiding asphyxia, shortening the time of mechanical ventilation, preventing infection and closing ductus arteriosus are important measures to reduce the severity of BPD. Key words: Infant, extremely low birth weight; Bronchopulmonary dysplasia; Risk factors