Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP view of the chest provided . As compared to prior study from 1 day ago , lung volumes are lower and there is increased bibasilar atelectasis . There is a small degree of volume overload . Post-operative related left upper mediastinal opacity is stable . There is no pneumothorax .
    OUTPUT:
    
Low lung volumes , otherwise stable exam .