Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Patient is status post median sternotomy , aortic valve and tricuspid valve replacements . Cardiac silhouette size remains mildly enlarged . Mediastinal and hilar contours are unchanged . No pulmonary edema is present . Small left pleural effusion has decreased in size compared to the previous exam . Patchy airspace opacities in both lung bases , more so on the left may reflect areas of atelectasis however infection particularly in the left lower lobe can not be completely excluded . No pneumothorax is demonstrated . There are no acute osseous abnormalities .
    OUTPUT:
    
Patchy bibasilar airspace opacities , more pronounced on the left , may reflect areas of atelectasis , however , infection particularly in the left lower lobe can not be excluded . Decreased small left pleural effusion .