Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable semi supine chest radiograph ___ at 04 :55 is submitted .
    OUTPUT:
    
Tracheostomy tube is unchanged in position . Overall cardiac and mediastinal contours are stable with prominent calcification in the aorta consistent with atherosclerosis . Improving aeration at the left lung base . Streaky linear opacities in the left mid lung consistent with subsegmental atelectasis . Parenchymal distortion consistent with known underlying emphysema . No developing airspace opacities to suggest pneumonia . No pulmonary edema .