Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable upright chest radiograph ___ at 18 :45 is submitted .
    OUTPUT:
    
Interval appearance of pneumoperitoneum consistent with known recent surgery . Lung volumes are low with patchy bibasilar opacities likely reflecting atelectasis . There may be a small right effusion . No pulmonary edema or pneumothorax . Cardiac and mediastinal contours are likely unchanged given patient rotation and portable technique .