Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is a large right - sided pleural effusion , mildly increased . The patient is status post coronary artery bypass graft surgery and aortic valve replacement . Parenchymal opacity in the right lung could be explained as associated atelectasis . There is no clear evidence for parenchymal edema . The left lung remains clear , without left - sided pleural effusion , aside from streaky opacities suggesting mild fluid in the major fissure .
    OUTPUT:
    
Increasing large right - sided pleural effusion . If the etiology is uncertain , then chest CT , preferably with intravenous contrast if feasible , is suggested when clinically appropriate to evaluate for the potential cause .