Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP upright and lateral views of the chest were provided . Midline sternotomy wires are noted . The lungs appear clear . Valve replacement is noted . No effusion or pneumothorax is seen . Bony structures are intact . Free air below the right hemidiaphragm .
    OUTPUT:
    
No acute intrathoracic process .