fig1

Figure 1. Images from a CT scan of the chest of the incident patient with dynamic evaluation of the airways at 3 months of age before closure of the ductus arteriosus. There was a minimum transverse area of 25.2 mm² (A) and a maximum transverse area of 33.2 mm²; (B) of the lower trachea with a positive end-expiratory pressure of 4 cm H₂O. There was a minimum transverse area of 30.3 mm²; (C) and a maximum transverse area of 47.3 mm²; (D) of the lower trachea with a positive end-expiratory pressure of 12 cm H₂O.