Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A tracheostomy tube is present terminating approximately 2 .8 cm above the carina in appropriate position . Compared to the prior radiograph there is slight increase opacity in the left lower lobe which may represent atelectasis . There is no pleural effusion or pneumothorax . The right lung appears clear . The cardiomediastinal silhouette is unchanged . Imaged upper abdomen is unremarkable .
    OUTPUT:
    
Mild increase in left lower lobe opacity which may represent atelectasis , although infection or aspiration can not be entirely excluded .