Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP portable upright radiograph demonstrates clear lungs . Cardiomediastinal and hilar contours are within normal limits . There is no pneumothorax or pleural effusion . No evidence of pulmonary edema . Imaged upper abdomen demonstrates no free air under the right hemidiaphragm .
    OUTPUT:
    
No acute intrathoracic abnormality .