Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP and lateral upright chest radiographs demonstrate hyperexpanded lungs and flattening of the diaphragms suggestive of COPD . No focal consolidation is identified within the lungs to suggest infectious process . Cardiomediastinal silhouette and hilar contours are within normal limits . Retrocardiac density may represent a moderate to large hiatal hernia , not appreciated on the prior examination . No evidence of pulmonary edema , pleural effusion or pneumothorax .
    OUTPUT:
    
COPD . Retrocardiac density may represent a moderate to large hiatal hernia , not appreciated on the prior examination .