Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There has been previous median sternotomy and cardiovascular surgery . Stable post-operative appearance of cardiomediastinal contours . Improved lung volumes compared to the previous study with improving aeration at the lung bases . Residual partial atelectasis of left lower lobe , and persistent small bilateral pleural effusions , left greater than right . No visible pneumothorax .
    OUTPUT:
    
Left lower lobe atelectasis and small pleural effusions , left greater than right .