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

BACKGROUND: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). RESEARCH QUESTION:Does BPD impact the diaphragm thickness (DT) and diaphragm excursion (DE) in infants born before 32 weeks' gestation compared with healthy late preterm or term infants? STUDY DESIGN AND METHODS: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.). RESULTS:We enrolled 111 infants, including 56 preterm infants with BPD (mean ± SD study age, 37.7 ± 1.7 weeks) and 55 healthy control participants (mean ± SD study age, 38.1 ± 1.5 weeks). DTexp and DTexp to BSA ratio were significantly lower in the BPD group compared with the healthy control group (mean ± SD, 1.3 ± 0.4 mm vs 1.5 ± 0.4 mm [P = .01] and 7.1 ± 1.4 mm/m2 vs 7.8 ± 1.8 mm/m2 [P = .03]). DTF and DE were significantly higher in the BPD group vs the healthy control group (mean ± SD, 61.8 ± 26.0 vs 43.3 ± 19.7 [P < .01] and 6.0 ± 1.7 mm vs 4.4 ± 1.6 mm [P < .01], respectively). INTERPRETATION: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. TRIAL REGISTRY:ClinicalTrials.gov; No.: NCT04941963; URL: www. CLINICALTRIALS:gov.