Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Single AP upright portable view of the chest was obtained . There is mild left base atelectasis . No focal consolidation , pleural effusion , evidence of a pneumothorax is seen . The cardiac silhouette is mildly enlarged , likely in part exaggerated by AP technique . The aorta is tortuous . Hilar contours are stable . Multiple old left - sided rib fractures are again seen .
    OUTPUT:
    
Mild left base atelectasis . Otherwise , no acute cardiopulmonary process .