Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP single view of the chest has been obtained with patient in sitting semi-upright position . Analysis is performed in direct comparison with the next preceding similar study of ___ . The tracheal cannula is in midline position , seen to terminate in the trachea . Termination point is similar as it was before . The on previous examination identified paratracheal air and subcutaneous air in the left lower neck region , indicative of pneumomediastinum at that time , can not be seen anymore . No pneumothoraces present . Heart size unchanged . The previously existing pulmonary congestive pattern and bilateral basal parenchymal infiltrates have regressed markedly . No new abnormalities are seen . A remaining diffuse haze on the left base is indicative for some pleural effusion layering posteriorly .
    OUTPUT:
    
Stable position of tracheostomy cannula , previously identified pneumomediastinum has disappeared . No pneumothorax .