Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Supine portable view of the chest demonstrates low lung volumes , which accentuate bronchovascular markings . Endotracheal tube terminates 4 .3 cm above the carina . The nasogastric tube is positioned within the stomach . Mild elevation of the right hemidiaphragm . No pleural effusion or pneumothorax . Hilar and mediastinal silhouettes are unchanged . The heart size is top normal . Bibasilar opacities most likely represent atelectasis . No pulmonary edema is seen .
    OUTPUT:
    
1 . Appropriately positioned endotracheal and nasogastric tubes . 2 . Low lung volumes . Mild elevation of the right hemidiaphragm and bibasilar opacities , most likely atelectasis have been present for at least several months .