Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A right PICC ends in the mid SVC , as before . A left pleural catheter ends at the left lung apex , not significantly changed . There is redemonstration of midline sternotomy wires and fixation devices . Lung volumes remain low . There is bilateral lower lung subsegmental atelectasis . Mild enlargement of the cardiac silhouette is not significantly changed . The mediastinal contours are unchanged . There is no definite pneumothorax . No pleural effusions are seen .
    OUTPUT:
    
1 . No definite pneumothorax . 2 . Persistent low lung volumes with unchanged subsegmental bibasilar atelectasis .