Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The patient has been extubated . Lung volumes are within normal limits except note mild left lower lobe atelectasis . Superimposed infection can not be excluded . No consolidation or pneumothorax seen . No frank pulmonary edema . Pulmonary vascular congestion has improved .
    OUTPUT:
    
Left lower lobe atelectasis , superimposed infection can not be excluded .