Lung Ultrasound to Monitor Extremely Preterm Infants and Predict Bronchopulmonary Dysplasia. A Multicenter Longitudinal Cohort Study.

Rationale: Lung ultrasound is useful in critically ill patients with acute respiratory failure. Given its characteristics, it could also be useful in extremely preterm infants with evolving chronic respiratory failure, as we lack accurate imaging tools to monitor them. Objectives: To verify if lung ultrasound can monitor lung aeration and function and has good reliability to predict bronchopulmonary dysplasia in extremely preterm neonates. Methods: A multicenter, international, prospective, longitudinal, cohort, diagnostic accuracy study consecutively enrolling inborn neonates with gestational age 30+6 weeks or younger. Lung ultrasound was performed on the 1, 7, 14, and 28 days of life, and lung ultrasound scores were calculated and correlated with simultaneous blood gases and work of breathing score. Gestational age-adjusted lung ultrasound scores were created, verified in multivariate models, and subjected to receiver operator characteristics (ROC) analyses to predict bronchopulmonary dysplasia at 36 weeks postmenstrual age. Measurements and Main Results: Mean lung ultrasound scores are different between infants developing (n = 72) or not developing (n = 75) bronchopulmonary dysplasia (P < 0.001 at any time point). Lung ultrasound scores significantly correlate with oxygenation metrics and work of breathing at any time point (P always < 0.0001). Gestational age-adjusted lung ultrasound scores significantly predict bronchopulmonary dysplasia at 7 (area under ROC curve, 0.826-0.833; P < 0.0001) and 14 (area under ROC curve, 0.834-0.858; P < 0.0001) days of life. Bronchopulmonary dysplasia severity and gestational age-adjusted lung ultrasound scores are significantly correlated at 7 and 14 days (P always < 0.0001). Conclusions: Lung ultrasound scores allow monitoring of lung aeration and function in extremely preterm infants. Gestational age-adjusted scores significantly predict the occurrence of bronchopulmonary dysplasia, starting from the seventh day of life.