Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A tracheostomy tube and left subclavian catheter are unchanged in position compared to the prior study . Right internal jugular and right subclavian catheters had been removed . No pneumothorax seen . Increased opacity at the left lung base has decreased slightly in extent compared to the prior study and likely reflects a combination of pleural fluid and atelectasis .
    OUTPUT:
    
Interval improvement in the aeration of the bilateral lung bases , otherwise no significant interval change .