Reduced Lung Function at Preschool Age in Survivors of Very Low Birth Weight Preterm Infants

Hung-Yang Chang; Jui-Hsing Chang; Hsin Chi; Chyong-Hsin Hsu; Chia-Ying Lin; Wai-Tim Jim; Chun-Chih Peng

doi:10.3389/fped.2020.577673

Reduced Lung Function at Preschool Age in Survivors of Very Low Birth Weight Preterm Infants

Front Pediatr. 2020 Sep 22:8:577673. doi: 10.3389/fped.2020.577673. eCollection 2020.

Authors

Hung-Yang Chang^{1

2}, Jui-Hsing Chang^{1

2}, Hsin Chi^{1

2}, Chyong-Hsin Hsu¹, Chia-Ying Lin¹, Wai-Tim Jim¹, Chun-Chih Peng^{1

2}

Affiliations

¹ Department of Pediatrics, MacKay Children's Hospital, Taipei, Taiwan.
² Department of Medicine, MacKay Medical College, New Taipei City, Taiwan.

Abstract

Background: Survivors of preterm birth are at risk of long-term respiratory consequences. The objective of this prospective study was to assess pulmonary function at preschool age of former very low birth weight (VLBW) preterm children. Methods: Lung function of children born preterm and term controls aged 5-6 years were assessed by spirometry. The results were converted to z-scores. A questionnaire regarding respiratory symptoms was completed. Associations to gestational age (GA), birth weight (BW), bronchopulmonary dysplasia (BPD), and perinatal factors were assessed. Results: In total, 85 VLBW preterm children and 29 term controls were studied. Of the preterm children, the mean GA was 28.6 ± 2.6 weeks and the mean BW was 1,047 ± 273 gm. Preterm children had significantly lower z-scores of forced expiratory volume in 1 s (FEV₁), FEV₁/forced vital capacity (FVC) ratio, and forced expiratory flow rate between 25-75% of FVC (FEF_25-75), compared with term controls (-0.73 vs. 0.04, p = 0.002; -0.22 vs. 0.39, p = 0.003; -0.93 vs. 0.0, p < 0.001; respectively). Further segregation of the preterm group revealed significantly impaired FEV₁, FEF_25-75 in children at earlier gestation (≤ 28 weeks, n = 45), lighter at birth (≤ 1,000 g, n = 38), or with BPD (n = 55) compared with term controls (p < 0.05). There were significant negative relationships between the severity of BPD with FEV₁, FVC, and FEF_25-75 (p < 0.05). However, no correlation between lung function measurements and respiratory symptoms was found. Conclusions: VLBW preterm infants have reduced lung function at preschool age, especially among those with younger GA, lower BW, and BPD. Additional long-term follow-up of respiratory outcomes are needed for this vulnerable population.

Keywords: bronchopulmonary dysplasia; lung function; prematurity; spirometry; very low birth weight.