REDUCTION IN THE RISK OF BRONCHOPULMONARY DYSPLASIA FROM 1980-1990 - RESULTS OF A MULTIVARIATE LOGISTIC-REGRESSION ANALYSIS

A retrospective analysis (1980-1990) of normally formed low birthweigh t (< 2500 g) infants surviving to at least 28 days following intermitt ent positive pressure ventilation (IPPV) for longer than 12 h was perf ormed. Bronchopulmonary dysplasia (BPD) was defined as oxygen dependen cy at 28 days with characteristic radiographic findings. Logistic regr ession analysis of risk factors, before and after the initiation of IP PV was performed on 412 infants. Decreasing birth weight (BW) and gest ational age (GA) were associated with an increased risk of BPD. When c ontrolled for these variables, predictive factors prior to IPPV were g ender, age at IPPV, respiratory diagnosis, and year of birth. Followin g IPPV, duration of peak inspiratory pressure > 25 cm H2O, duration of fraction of inspired oxygen (FiO2) > 0.60 (DO2), maximum peak inspira tory pressure (MPIP), maximum FiO2, patent ductus arteriosus, bacterae mia and either pneumothorax or pulmonary interstitial emphysema were a ssociated with an increased risk of BPD. Adjusting for BW and GA, ther e was a significant reduction in BPD risk from 1980-1990 (relative odd s of 0.88 for each year compared to the previous year). This trend cou ld be largely accounted for by decreases in MPIP and DO2 during the st udy period. Surfactant treatment was not independently associated with a significant change in the risk of BPD. Based on this analysis, we d eveloped a scoring system for predicting the risk of BPD in the neonat al period which we evaluated in a random sample of infants. This predi cted infants at risk of BPD with a sensitivity of 65% and a specificit y of 88%. Use of this score would allow prediction of BPD at a time wh en earlier preventive treatment could be started.