Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable semi-erect chest film ___ at 04 : 12 is submitted .
    OUTPUT:
    
There is improved aeration at the bases with resolving atelectasis . Lung volumes remain low . No pulmonary edema . Possible small left effusion . Overall cardiac and mediastinal contours are stable . Nasogastric tube is seen with its tip projecting over the stomach . The right internal jugular venous catheter is unchanged in position with its tip at the cavoatrial junction . No pneumothorax .