Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is complete opacification of left lung with leftward mediastinal shift . Given the interval change in such a short time interval findings are likely consistent with mucous plugging causing obstruction . There is interval increase in aeration of the right lung however it is unclear if this is secondary to the shift of midline structures versus interval improvement of right lower lung collapse .
    OUTPUT:
    
Complete opacification of the left lung with leftward mediastinal shift , likely consistent with obstructive mucous plugging given short time course .