Lung function development after preterm birth in relation to severity of Bronchopulmonary dysplasia

Abstract

BackgroundBronchopulmonary dysplasia (BPD) is a strong risk factor for respiratory morbidity in children born preterm. Our aims were to evaluate lung function in adolescents born preterm with and without a history of BPD, and to assess lung function change over time from school age.MethodsFifty-one individuals born in Stockholm, Sweden between gestational ages 24 to 31 weeks (23 neonatally diagnosed with respiratory distress syndrome (RDS) but not BPD, and 28 graded as mild (n = 17), moderate (n = 7) or severe (n = 4) BPD) were examined in adolescence (13–17 years of age) using spirometry, impulse oscillometry (IOS), plethysmography, and ergospirometry. Comparison with lung function data from school age (6–8 years of age) was also performed.ResultsAdolescents with a history of BPD had lower forced expiratory volume in 1 s (FEV1) compared to those without BPD (−0.61 vs.-0.02 z-scores, P < 0.05), with lower FEV1 values significantly associated with BPD severity (P for trend 0.002). Subjects with severe BPD had higher frequency dependence of resistance, R5–20, (P < 0.001 vs. non-BPD subjects) which is an IOS indicator of peripheral airway involvement. Between school age and adolescence, FEV1/FVC z-scores decreased in all groups and particularly in the severe BPD group (from −1.68 z-scores at 6–8 years to −2.74 z-scores at 13–17 years, p < 0.05 compared to the non-BPD group).ConclusionsOur results of spirometry and IOS measures in the BPD groups compared to the non-BPD group suggest airway obstruction including involvement of peripheral airways. The longitudinal result of a decrease in FEV1/FVC in the group with severe BPD might implicate a route towards chronic airway obstruction in adulthood.

Neonatal respiratory status predicts longitudinal respiratory health outcomes in preterm infants

“…Prior studies in extremely preterm children aged 3 to 7 years are limited. At school age (6–8 years of age), Um‐Bergström et al reported that FEV 1 and FVC z‐scores for severe BPD group was −2.6 and −2.2, respectively, and were similar to our findings for preschool‐aged children with severe BPD history. In addition, longitudinal comparison of spirometry between 7 and 14 years of age, Um‐Bergström et al reported significant increases of FVC with a very limited improvement of FEV 1 in adolescents with BPD history and lower FEV 1 values in adolescents significantly associated with BPD severity ( P for trend = 0.002).…”

“…At school age (6–8 years of age), Um‐Bergström et al reported that FEV 1 and FVC z‐scores for severe BPD group was −2.6 and −2.2, respectively, and were similar to our findings for preschool‐aged children with severe BPD history. In addition, longitudinal comparison of spirometry between 7 and 14 years of age, Um‐Bergström et al reported significant increases of FVC with a very limited improvement of FEV 1 in adolescents with BPD history and lower FEV 1 values in adolescents significantly associated with BPD severity ( P for trend = 0.002). On the other hand, our findings were in contrary to those reported by Verheggen et al who found that the median FEV 1 and FVC z‐scores preterm children with BPD at 4 to 8 years of age were −0.59 and −0.26, respectively, and only FEV 1 z‐score was significantly lower than that of term control (0.49).…”

Lung Function in a Cohort of Italian Children Born Preterm

“…Same results were obtained in a similar cohort of 49 Finnish children studied at the age of 5-10 years 29 . Findings in adolescents born preterm between 24 and 31 weeks of gestation con rmed that those with a diagnosis of BPD had higher R5-R20 compared to peers without BPD 26 . In all the three studies FEV 1 was lower and often impaired in subjects with BPD.…”

“…We speculate that the nding of lower FEF 25 − 75 in our cohort may re ect the impairment of small airways demonstrated with the increased values of the IOS indices. Previous studies showed concordant information between the oscillometric method and spirometry 26,28,29 but IOS is considered to be more sensitive in evaluating peripheral airways 13 . However, while we found a signi cant lower FEV 1 in subjects with BPD compared to those without BPD (-0.93 z-score), we did not nd a signi cant difference with IOS.…”

“…Over the years, longitudinal studies demonstrated signi cant reduction of FEV 1 in cohorts of children born extremely preterm, especially in those with BPD 5,7,8,18,19 , and also in children born late preterm 20 . Anomalies in airway elastic properties and resistance have been assessed in preterm children by different techniques such as the interrupter resistance Rint 21,22 , the forced oscillation technique (FOT) 7,[23][24][25][26] and IOS 20,26−30 .…”