Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable AP upright view of the chest was reviewed and compared to the prior studies . An endotracheal tube ends 4 cm above the carina . A nasogastric tube ends in the mid portion of the stomach . Low lung volumes persist and exaggerate the mediastinal and cardiac contours that are unchanged . A retrocardiac opacity is unchanged and likely represents atelectasis or infection . There is a new small left pleural effusion . Right lower lobe atelectasis has minimally improved .
    OUTPUT:
    
1 . Endotracheal tube ends 4 cm above the carina . 2 . Persistent low of lung volumes and retrocardiac opacity are unchanged . 3 . New small left pleural effusion .