Lung aeration and gas exchange in SGA or AGA infants with moderate-severe BPD: secondary analysis of the PATH-BPD study

Background: Small-for-gestational-age (SGA) infants have a higher prevalence and severity of bronchopulmonary dysplasia than appropriate-for-gestational-age (AGA) infants but the evolution of their respiratory pathophysiology characteristics is unknown RESEARCH QUESTION: Do SGA infants with moderate-severe bronchopulmonary dysplasia (msBPD) have different pathophysiological phenotypes (in terms of lung aeration and gas exchange) compared to AGA infants with msBPD? Study design and methods: Secondary analysis of the PATH-BPD multicenter cohort. Patients were classified as SGA if their birthweight was <10th percentile or <-2 Z-scores. Lung aeration was assessed with quantitative lung ultrasound. Gas exchange was considered using SpO2/FiO2, PtcO2/FiO2 and PtcCO2. msBPD was defined using NIH-2001, NICHD-2018 and Jensen definitions. Data were analyzed by linear mixed effect regression models RESULTS: Of 347 enrolled neonates, 62 and 32 infants were classified as SGA using the percentile and Z-score threshold, respectively. Regardless of the BPD definition and the growth classification, evolution of lung aeration (β varying between -0.32 and 0.23, p varying between 0.379 and 0.575), SpO2/FiO2 (β varying between 0.78 and 6.1 , p varying between 0.896 and 0.250), PtcO2/FiO2 (β varying between -0.64 and 2.2, p varying between 0.936 and 0.700) and PtcCO2 (β varying between -0.63 and 0.03, p varying between 0.295 and 0.968) was similar in SGA and AGA infants with msBPD INTERPRETATIONS: The evolution of lung aeration and gas exchange in SGA and AGA patients with msBPD is similar, regardless of the BPD definition and growth classification.