Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is complete opacification of the left hemithorax since the prior exam . The trachea appears slightly shifted to the right , suggesting that there is a large pleural effusion on the left side . Known left hilar mass with associated left upper lobe collapse also likely contributes to the white out within the left hemithorax . Patient is status post median sternotomy and CABG . The right lung appears clear . No pneumothorax . There are no acute osseous abnormalities .
    OUTPUT:
    
Interval opacification of the left hemithorax is likely due to a combination of a large pleural effusion and left upper lobe collapse due to obstructing left hilar mass .