Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Compared to the prior radiograph , increased severe leftward mediastinal shift and now complete left lung opacification is due to worsening left lung collapse . Right lower lung opacification , probably pneumonia , is stable . No large right pleural effusion or pneumothorax is identified . There is likely a small left pleural effusion . Multiple rib fractures , bilateral clavicle fractures and a left scapular fracture are again identified .
    OUTPUT:
    
Severe leftward mediastinal shift and the sudden left lung opacification is due to worsening left lung collapse .