Fig. 2

Relationship between respiratory system compliance and ultrasound-assessed lung aeration. A and B represent adults (N = 40) and neonates (N = 56), respectively. Different symbols indicate the patient subgroups. Data from subgroups and all patients (ie: cases and control subjects together) are depicted in the main figures and in the inserts, respectively. Lung ultrasound score is a dimensionless number; compliance is indexed per predicted ideal body weight and birth weight in adults and neonates, respectively. Correlation lines are shown per each subgroup (main figures), while the hatched curves are drawn for the whole adult and newborn population (inserts) and represent the best fitting data curves generated with local smoother regression. ARDS acute respiratory distress syndrome, Crs compliance of the respiratory system, LUS lung ultrasound score, NARDS neonatal acute respiratory distress syndrome, NLD-A adults with no lung disease, NLD-neo neonates with no lung disease, RDS respiratory distress syndrome due to primary surfactant deficiency (i.e., hyaline membrane disease)