Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Upright PA and lateral radiographs of the chest . Right pacer projects over the right lateral chest wall with lead in the right ventricle . Tracheostomy tube is in stable position terminating in the mid thoracic trachea . There has been waxing and waning opacity in the left base since about ___ . Compared to the next most recent study 10 days ago , the left base is better aerated with some residual opacity and blunting of the costophrenic sulcus . There is chronic streaky atelectasis at the right base . No new focal airspace consolidation is detected . The cardiomediastinal silhouette and hilar contours are stable . There is no pneumothorax .
    OUTPUT:
    
Improved aeration of the left lower lobe with some residual patchy opacity and blunting of the left costophrenic sulcus . No new focal airspace consolidation .