Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There has been interval placement of a right - sided chest tube . There is a persistent moderately large pleural effusion similar to slightly increased in size when compared to the prior study . There is a small amount of air within the pleural fluid . The right hilar mass is less clearly seen , partially obscured by a atelectasis related to the pleural fluid . The left lung appears grossly clear . The known pulmonary nodules are not clearly visualized . No pneumothorax seen .
    OUTPUT:
    
Persistent moderately large right pleural effusion status post chest tube placement .