Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Persistent chronic collapse of the left lower lobe is accompanied by a left pleural effusion , increased since the prior study . Right lung is essentially clear . The patient is status post median sternotomy . No focal opacities concerning for an infectious process are present .
    OUTPUT:
    
Persistent and increased collapse of the left lower lobe accompanied by a pleural effusion . Bronchoscopy is probably indicated to assess persistent collapse .