Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable AP upright view of the chest was reviewed and compared to the prior studies . The right subclavian line is ends in the upper portion of the superior vena cava . Median sternotomy wires and additional sternal fixation devices are relatively unchanged . Low lung volumes and bibasilar atelectasis persist . Interval increase in the extent of blunting of the left costophrenic sulcus since ___ is caused by atelectaiss , pleural effusion or a combination of both . Mild cardiac enlargement and mediastinal widening are unchanged . There is no definite pneumothorax .
    OUTPUT:
    
1 . No definite pneumothorax . 2 . Low lung volumes , bibasilar atelectasis . 3 . Interval increase in the extent of blunting of the left costophrenic sulcus since ___ is caused by atelectaiss , pleural effusion or a combination of both . 4 . Mild cardiac enlargement and mediastinal widening are unchanged .