Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable AP upright chest radiograph was obtained . Large left pneumothorax is identified with rightward deviation of the mediastinum concerning for tension physiology . No acute rib fractures are identified although subtle fracture could be missed , with old right rib fractures and small right pleural effusion or pleural scarring noted . Cardiomediastinal contours aside from slight rightward shift are unremarkable .
    OUTPUT:
    
Large left tension pneumothorax . Findings discussed with Dr . ___ by Dr . ___ at ___ on ___ by phone , 2 minutes after discovery .