Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable AP upright chest film ___ at 03 :51 is submitted .
    OUTPUT:
    
Status post median sternotomy with stable cardiac and mediastinal contours . Lungs appear slightly hyperinflated . No pleural effusions pneumothorax or pulmonary edema . Subtle streaky opacity at the left base does not appear to be appreciably changed since the earlier exam but could reflect an area of atelectasis , although early pneumonia can not be entirely excluded . Clinical correlation is advised and followup imaging may be helpful .