Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP upright portable view of the chest was obtained . In the interval since the prior study , there has been development of a very large left pneumothorax with collapse of the left lung . There may be slight tension component . The right lung is clear . No pleural effusion . The left cardiac border appears somewhat flattened , which may be due to tension .
    OUTPUT:
    
Interval development of large left pneumothorax . The above findings were discussed with Dr . ___ at 9 :___ p .m . via telephone on ___ .