Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP upright portable chest radiograph obtained . Midline sternotomy wires are again noted . There are tiny bilateral pleural effusions , slightly increased from prior exam . There is no definite sign of pneumonia or overt CHF . The heart size is stable . Mediastinal contour is widened reflecting an unfolded thoracic aorta . No pneumothorax . Bony structures appear intact .
    OUTPUT:
    
Small bilateral pleural effusions , mildly increased from prior .