Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable semi-upright radiograph of the chest demonstrates low lung volumes resulting in bronchovascular crowding . Trace left - sided pleural effusion is a new over the interval . There has been interval clearing of retrocardiac opacity . Cardiomediastinal and hilar contours are unchanged . No pneumothorax .
    OUTPUT:
    
New trace left - sided pleural effusion .