Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A single portable AP upright view of the chest was obtained . Heart is normal in size and cardiomediastinal contour is unremarkable . Lungs are symmetrically expanded and clear . Mild atelectasis at the right base noted . There is no pleural effusion or pneumothorax .
    OUTPUT:
    
No acute intrathoracic abnormality .