Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Single semi-erect AP portable view of the chest was obtained . There has been significant interval decrease in left pleural effusion , which is now small with overlying atelectasis . There is no evidence of pneumothorax . The right lung is clear . Cardiac and mediastinal silhouettes are stable with the left aspect of the cardiac silhouette difficult to assess due to right basilar opacity . The patient is status post median sternotomy .
    OUTPUT:
    
Significant interval decrease in left pleural effusion , which is now small with overlying atelectasis . No pneumothorax .