Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Endotracheal tube and nasogastric tube are in unchanged position . Left subclavian catheter again terminates in the left brachiocephalic vein . Lung volumes are low but improved from the previous examination without focal parenchymal opacity , pleural effusion or pneumothorax . Surgical drains project over the left upper quadrant .
    OUTPUT:
    
No acute intrathoracic process .