Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable AP upright chest film ___ at 05 :32 is submitted .
    OUTPUT:
    
There has been some interval improvement in the bilateral airspace process consistent with resolving but persistent moderate pulmonary edema . Lung volumes remain low . Overall cardiac and mediastinal contours are stable in this patient status post median sternotomy . No pneumothorax is seen .