Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable semi-upright radiograph of the chest demonstrates increased opacification of the bilateral bases , which may represent atelectasis , aspiration , or pneumonia in the appropriate clinical setting . Heart and mediastinal contours are unremarkable . The patient is status post tracheostomy , which ends 4 .5 cm from the carina .
    OUTPUT:
    
Increased opacification of the bilateral bases may represent atelectasis , aspiration , or pneumonia in the appropriate clinical setting .