Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable AP upright chest film ___ at 17 33 is submitted .
    OUTPUT:
    
Lung volumes are low . There is some overlying motion limiting evaluation of the lung parenchyma . However , there is increasing patchy retrocardiac opacity , which in the setting of low lung volumes , may reflect atelectasis , although aspiration and pneumonia should also be considered . No evidence of pulmonary edema . Interposition of the colon under the right hemidiaphragm consistent with Chiladiti 's . No pneumothorax . Overall cardiac and mediastinal contours are likely stable given patient rotation on the current study .