Neonatal bronchopulmonary dysplasia predicts abnormal pulmonary HRCT scans in long-term survivors of extreme preterm birth

Background: There is an increasing understanding that extreme preterm birth carries a risk of long-term pulmonary sequelae. A study was undertaken to investigate if, and in what way, neonatal factors were associated with subsequent abnormalities on pulmonary high-resolution CT (HRCT) scanning and if pulmonary function was related to these abnormalities. Methods: HRCT scanning and pulmonary function tests were performed less than 2 weeks apart in 74/86 eligible subjects (86%) born at a gestational age of <= 28 weeks or with a birth weight of <= 1000 g within a defined area in Western Norway in 1982-5 (n=42) or 1991-2 (n=32). Mean age at examination was 18 and 10 years, respectively. HRCT scans were interpreted by a paediatric radiologist blinded to the clinical data using a structured system allowing scores from 0 to 50. Results: Lung parenchymal abnormalities were found in 64 subjects (86%), the median (interquartile range) score being 3.0 (1.75-5.0) points. Prolonged neonatal requirement for oxygen treatment predicted poor outcome, and an increase of 100 days increased the average HRCT score by 3.8 points (p < 0.001). There was also a positive association of the severity of pulmonary function abnormalities with the extent of HRCT abnormalities, exemplified by the relation between forced expiratory volume in 1 s and total HRCT score (beta=-0.090; p < 0.001). Conclusions: In area-based cohorts of long-term survivors of extremely preterm birth, prolonged neonatal requirements for oxygen treatment predicted subsequent structural abnormalities on HRCT scans and in pulmonary function, and these two outcome measures were interrelated.