Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The patient is status post recent median sternotomy and coronary bypass surgery and mitral valve replacement . Cardiomediastinal contours are within normal limits for postoperative status of the patient . Interval improvement in extent of bibasilar atelectasis . Bilateral small to moderate pleural effusions also appears slightly improved . No visible pneumothorax .
    OUTPUT:
    
Improving bibasilar atelectasis and bilateral pleural effusions .