Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Single AP upright view of the chest was reviewed . Heart size is normal . The mediastinal and hilar contours are stable . There is no pleural effusion , pneumothorax , or pneumoperitoneum . There are low lung volumes but no focal consolidation . Pulmonary vasculature is within normal limits .
    OUTPUT:
    
No free air or other acute process .