Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP portable upright view of the chest . Tracheostomy tube projects over the superior mediastinum as on prior . Lung volumes are low which limits assessment . Allowing for this , the lungs are clear . No large effusion or pneumothorax is seen . The imaged osseous structures appear intact . Mild inferior subluxation of the right humeral head relative to the glenoid fossa may be positional .
    OUTPUT:
    
No acute findings .