Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable AP upright chest radiograph is obtained . Lung volumes are low , though the imaged portion of the lungs appears clear . The heart size can not be assessed . No large effusion or definite signs of pneumothorax . Mediastinal contour appears unremarkable . Bony structures are intact .
    OUTPUT:
    
No definite signs of aspiration or pneumonia .