Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable AP upright chest radiograph ___ at 08 :02 is submitted .
    OUTPUT:
    
Retrocardiac opacity likely reflects atelectasis , although pneumonia can not be excluded . There is a layering right effusion and likely a smaller left effusion . The right internal jugular central line has its tip in the proximal right atrium . The endotracheal tube , nasogastric tube and bilateral chest tubes are unchanged in position . The patient is status post median sternotomy for CABG with stable postoperative cardiac and mediastinal contours . There is mild pulmonary edema . No pneumothorax .