Lung Ultrasonography to Diagnose Bronchopulmonary Dysplasia of Premature Infants

Abstract

Background: Bronchopulmonary dysplasia (BPD) is a common severe respiratory problem in premature infants, and imaging information has important reference value for its diagnosis. Recently, lung ultrasonography (LUS) has been successfully used for the diagnosis and differential diagnosis of neonatal lung diseases (NLDs), but the study of the diagnosis of BPD is still rare. Objectives: The purpose of this study was to investigate the ultrasonographic characteristics of BPD and its value for the diagnosis and differential diagnosis of premature infants’ BPD. Methods: From January 2015 to December 2019, 25 premature infants diagnosed with early-stage BPD and 32 infants diagnosed with late-stage BPD according to their medical history, clinical manifestation, and chest X-ray were included in this study. The LUS examinations were performed on each infant. The LUS findings were recorded and compared with those of 40 premature infants without lung diseases. Results: The gestational age of 25 early-stage BPD infants was 26+1 – 31+6 weeks, and their birth weight was between 730 and 1,810 g. The gestational age of 32 late-stage BPD infants was 26 - 32 weeks, and their birth weight was 750 - 1,760 g. The gestational age of 40 control infants was 25+6 - 32+1 weeks, and their birth weight was 810 - 2,050 g. There was no difference in the proportion of primary lung diseases (including RDS, TTN, pneumonia, etc.) between the three groups. The proportions of infants receiving invasive and/or non-invasive respiratory support at admission in the three groups of early BPD, late BPD, and normal control were 20/25 (80.0%), 26/32 (81.2%), and 33/40 (77.5%), respectively, with no significant difference (P > 0.05). The mechanical ventilation duration over one week in three groups was 15/20 (75%), 21/26 (80.7%), and 24/33 (72.7%), respectively, with no significant difference (P > 0.05). Nonspecific pleural line abnormalities were seen in all early and late BPD patients (100%), alveolar-interstitial syndrome (AIS) in 16 cases (64%) of early BPD and 32 cases of late BPD infants (100%), pleural insect erosion-like change (PIE-like change) in two cases of early-stage BPD infants (8.0%) and 20 cases (62.5%) of late-stage BPD infants, and air vesicle signs (AVS) only in 17 cases of late-stage BPD infants. The sensitivity and specificity of PIE-like change for the diagnosis of late-stage BPD were 62.5% and 92.0%, respectively, and the sensitivity and specificity of AVS for the diagnosis of late-stage BPD were 53.1 and 100%, respectively. Conclusions: Lung ultrasonography is not specific for the diagnosis of early-stage BPD, but has a high reference value and specificity for the diagnosis of late-stage BPD when combined with obvious pulmonary fibrosis and pulmonary vesicle formation, which is mainly manifested by AIS, PIE-like change, and AVS.