Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The endotracheal nasogastric tubes are in unchanged position . A new left internal jugular line ends in the upper superior vena cava . The lung volumes are low . A large retrocardiac opacity is again identified . Focal opacity at the right lung base may represent atelectasis , aspiration or pneumonia . There is a left shoulder prosthesis . There is no pleural effusion or pneumothorax .
    OUTPUT:
    
Extremely low lung volumes . Bilateral lower lobe opacities could represent atelectasis , aspiration or infection . Appropriately positioned lines and tubes .