Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Rotated positioning . Compared to the prior film , the tracheostomy is no longer visualized . The cardiomediastinal silhouette is probably unchanged . There is upper zone redistribution , without overt CHF . Slight crowding of the vessels at both bases , similar to the prior film , may reflect atelectasis . No definite infiltrate is identified . No consolidation or gross effusion .
    OUTPUT:
    
As above . .