Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Endotracheal tube tip terminates approximately 6 .5 cm from the carina . The patient is status post median sternotomy and aortic valve replacement . Heart size is top normal . The aortic knob is calcified . There is mild pulmonary vascular engorgement . Bibasilar airspace opacities could reflect atelectasis but aspiration or infection is not excluded . No large pleural effusion or pneumothorax is demonstrated . No acute osseous abnormalities seen .
    OUTPUT:
    
1 . Endotracheal tube in standard position . 2 . Mild pulmonary vascular engorgement . Probable bibasilar atelectasis , though aspiration or infection is not excluded .