Final answer:
CXR findings of hydropneumothorax include the presence of a pleural line indicating the collapsed lung and a fluid level within the pleural cavity, which will appear as a denser shadow under the air pocket on the radiograph.
Step-by-step explanation:
The CXR (chest x-ray) findings of a hydropneumothorax typically include the presence of both air and fluid levels within the pleural cavity. This condition is characterized by a visceral pleural line, indicating the presence of air where the lung has separated from the chest wall, as well as a horizontal fluid level that moves with changes in patient positioning. Unlike simple pneumothorax or pleural effusion, a hydropneumothorax shows both the presence of free air ('pneumo') and fluid ('hydro') within the pleural space. On the radiograph, the air will be visualized as a dark area (due to its lower density), and the fluid will create a denser shadow above which the air will appear to float.