Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Support and monitoring equipment is unchanged in appearance when compared to the prior study . Lung volumes are unchanged with persistent left lower lobe atelectasis . There is moderate cardiomegaly with prominence of the bilateral hila but no overt pulmonary edema . Probable small left pleural effusion .
    OUTPUT:
    
Mild pulmonary vascular congestion without overt pulmonary edema . Background changes of COPD . Left lower lobe atelectasis , superimposed infection can not be excluded .