Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart size is normal . Mediastinal and hilar contours are unchanged . Median sternotomy hardware is unchanged . Lungs are clear . Pulmonary vascularity is normal . Minimal blunting of the left costophrenic angle posteriorly on the lateral view is suggestive of a trace pleural effusion . No pneumothorax is identified . No acute osseous abnormalities seen .
    OUTPUT:
    
Small left pleural effusion .