Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP portable supine view of the chest . Tracheostomy tube projects over the superior mediastinum . There is a layering small left pleural effusion . Right lung is clear . No overt signs of edema or pneumonia . Cardiomediastinal silhouette is normal . No supine evidence for pneumothorax . Bony structures appear intact .
    OUTPUT:
    
Small layering left pleural effusion .