Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Semi-upright portable AP view of the chest provided . The tip of the endotracheal tube is appropriately positioned approximately 3 .4 cm above the carina . The NG tube courses into the left upper abdomen . There is retrocardiac opacity most likely representing atelectasis . The lungs appear otherwise clear . Heart and mediastinal contours are stable with mild cardiomegaly redemonstrated . No bony abnormalities are seen .
    OUTPUT:
    
Appropriately positioned ET and NG tubes . Left lower lobe atelectasis . Mild cardiomegaly .