Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The patient is status post median sternotomy and aortic valve replacement . Postoperative widening of cardiomediastinal contours is unchanged . Persistent bilateral lower lobe atelectasis and small - to - moderate pleural effusions . Small collections of gas in the retrosternal region are likely a normal postoperative finding given recent sternotomy procedure .
    OUTPUT:
    
Persistent bilateral lower lobe atelectasis and pleural effusions .