Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Compared to approximately 1 week prior , lung volumes are substantially reduced . Left greater than right bibasilar atelectasis is now present . No pleural abnormality . Low lung volumes exaggerate top - normal heart size . No pulmonary edema . There is new mediastinal widening with rightward tracheal deviation and silhouetting of the superior aortic arch .
    OUTPUT:
    
Findings raise the possibility of intraoperative vascular injury causing mediastinal hematoma . Depending on level of clinical suspicion , CTA could be considered for further evaluation .