Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable AP upright chest radiograph ___ at 09 :38 is submitted .
    OUTPUT:
    
There is a small left effusion with retrocardiac consolidation favoring compressive atelectasis , although pneumonia can not be excluded . In addition , there is a faint patchy opacity at the right lung base favoring atelectasis . No pulmonary edema . Status post median sternotomy for CABG with stable postoperative cardiac and mediastinal contours . No pneumothorax .