Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP portable upright view of the chest . Midline sternotomy wires and mediastinal clips are noted . Lung volumes are low markedly low limiting assessment . Allowing for low lung volumes , there is no convincing evidence for pneumonia or edema . Hilar congestion difficult to exclude . No large effusion or pneumothorax . Cardiomediastinal silhouette appears grossly within normal limits . Bony structures are intact .
    OUTPUT:
    
Limited exam without overt evidence for pneumonia or edema . If there is further concern , a repeat is recommended with more optimal inspiratory effort .