Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A right - sided chest tube is unchanged in position . Subcutaneous air tracking along the right chest wall persists . There is no definite right pneumothorax . Profound atelectasis on the left is worse from the preoperative chest radiograph of ___ and results in volume loss of the left hemithorax . This finding probably relates to a decrease in ventilation , which is most commonly from mucous plugging or an inability to clear secretions . Mild pulmonary edema is improved . A small left pleural effusion is presumed . Heart is mildly enlarged but stable . An epidural catheter is present .
    OUTPUT:
    
Profound atelectasis on the left is worse from the preoperative chest radiograph of ___ . This finding is most commonly from mucous plugging or an inability to clear secretions .