Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Moderate bibasilar atelectasis is increased and lung volumes remain low . A right chest tube is in unchanged position . Heart size is top normal . No pneumothorax . Part of the right posterior 4th rib is removed . Small amount of bilateral apical fluid is noted . Mild mediastinal widening , predominantly paratracheal , is improved since ___ , an expected finding after tracheobronchoplasty .
    OUTPUT:
    
Increased moderate bibasilar atelectasis and improvement of mild postoperative mediastinal widening .