Which statement supports the diagnosis of right middle lobe pneumonia in a mechanically ventilated patient?

• A. Infiltrate on chest radiograph in the right middle lobe.
• B. Infiltrate in the left lower lobe.
• C. There are no infiltrates on imaging.
• D. Breath sounds are normal in all lobes.

Answer: (A)

Localization of a new air-space opacity on the chest radiograph is the strongest sign of lobar pneumonia in a mechanically ventilated patient. If that opacity is specifically in the right middle lobe, it supports right middle lobe pneumonia. Other findings don’t fit because an infiltrate in a different lobe points to a different location, lack of infiltrates argues against pneumonia on imaging, and normal breath sounds can occur even with pneumonia in ventilated patients since auscultation is not reliably diagnostic in this setting.