NBRC Registered Respiratory Therapist (RRT) Exit Practice Exam

Air bronchograms show up when the airways remain air-filled while the surrounding alveoli are filled with fluid, pus, or have collapsed, creating dark, branching lines within an opaque area. This pattern appears most with conditions that cause alveolar consolidation or significant atelectasis, because the bronchi stay patent while the surrounding lung tissue becomes airless or full of inflammatory material. Pneumonia causes alveolar filling, atelectasis involves collapsed airspaces with open bronchi, and ARDS produces diffuse alveolar damage with consolidation—all of which reveal air-filled bronchi against the dense background. In contrast, simple pleural effusion or pneumothorax doesn’t typically produce this look, since the primary issue is fluid collection or air in the pleural space rather than widespread alveolar consolidation with visible airways.