Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP semi-upright portable chest radiograph obtained . As seen previously , there is a left IJ central venous catheter with its tip unchanged in the expected location of the superior vena cava . Lung volumes remain low with an elevated right hemidiaphragm again seen . There is improved aeration in the left lower lung with probable residual left basilar atelectasis . No large effusion is seen . Upper lungs are well aerated . Clips in the right upper quadrant noted .
    OUTPUT:
    
Left IJ central venous catheter in unchanged and appropriate position . Improved aeration at the left lung base . Stable elevated right hemidiaphragm .