Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable AP upright chest radiograph ___ at 21 :25 is submitted .
    OUTPUT:
    
The patient is status post median sternotomy with stable cardiac and mediastinal contours . The faint opacities in the right upper lobe have improved but there is increasing interstitial prominence as well as more focal patchy opacity at the left base . Given the acute fluctuations , findings favor mild interstitial edema rather than an infectious process . No large effusions . No pneumothorax .