Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Left chest tube is in unchanged position . Small left pneumothorax is unchanged . There is mild bibasilar atelectasis . Elevation of left hemidiaphragm is similar to prior . There is no pleural effusion . Cardiomediastinal silhouette is mildly enlarged . Again seen are multiple left rib fractures posteriorly .
    OUTPUT:
    
Small left pneumothorax is unchanged since 5 hr prior .