Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable supine chest film ___ at 04 :49 is submitted .
    OUTPUT:
    
Endotracheal tube and nasogastric tube are likely unchanged in position . Overall cardiac and mediastinal contours are stable . Lung volumes are slightly lower and there is increasing opacity at the right medial lung base and in the retrocardiac area . Although this may represent atelectasis , pneumonia should also be considered . There is likely a layering left effusion . No evidence of pulmonary edema . No large pneumothorax is seen , although the sensitivity to detect pneumothorax is diminished given supine technique .