Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Moderate - to - large left pleural effusion may be minimally smaller , after insertion of a new left pleural drain proximal level of the carina effusion contact to the midpoint . No pneumothorax . Right lung clear . Left lung base severely atelectatic .
    OUTPUT:
    
Small decrease moderate left pleural effusion , pleural drain in place . No pneumothorax .