Diaphragmatic Thickness and Excursion in Preterm Infants With Bronchopulmonary Dysplasia Compared With Term or Near Term Infants: A Prospective Observational Study

Abstract

Diaphragmatic atrophy associated with mechanical ventilation is reported in pediatric and adult patients, but a similar association has not been described in preterm infants with bronchopulmonary dysplasia (BPD). Does BPD impact the diaphragm thickness (DT) and diaphragm excursion (DE) in infants born before 32weeks' gestation compared with healthy late preterm or term infants? In this prospective observational case-control study, DT at end of expiration (DTexp), DT at end of inspiration (DTins), DT fraction (DTF), and DE (DE) were assessed using bedside ultrasound. Two groups were compared: infants with BPD (patients) and healthy, postmenstrual age-matched infants (control participants). To account for variations in body size between groups, diaphragmatic measurements were expressed as a ratio of body surface area (BSA). Statistical analyses were conducted using SAS software version 9.4 (SAS Institute, Inc.). We enrolled 111 infants, including 56 preterm infants with BPD (mean ± SD study age, 37.7 ± 1.7weeks) and 55 healthy control participants (mean ± SD study age, 38.1 ± 1.5weeks). DTexp and DTexp to BSA ratio were significantly lower in the BPD group compared with the healthy control group (mean ± SD, 1.3 ± 0.4mm vs1.5 ± 0.4mm [P= .01] and 7.1 ± 1.4mm/m2 vs7.8 ± 1.8mm/m2 [P= .03]). DTF and DE were significantly higher in the BPD group vsthe healthy control group (mean ± SD, 61.8 ± 26.0 vs43.3 ± 19.7 [P< .01] and 6.0 ± 1.7mm vs4.4 ± 1.6mm [P< .01], respectively). In infants with BPD, DTexp was significantly lower, whereas DTF and DE were significantly higher, compared with healthy, age-matched control participants. Future studies are required and should focus on describing the evolution of diaphragmatic dimensions in preterm infants with and without BPD. ClinicalTrials.gov; No.: NCT04941963; URL: www. gov.