## **Core Concept**
The correct placement of a double-lumen tube (DLT) is crucial for lung surgery to ensure proper ventilation and isolation of the lungs. This involves understanding the anatomy of the airways and the design of the DLT. The DLT has two lumens, each leading to a separate bronchus, allowing for selective ventilation of each lung.

## **Why the Correct Answer is Right**
The correct answer, **C. Fiberoptic bronchoscopy**, is the gold standard for confirming the correct placement of a DLT. This method allows direct visualization of the bronchial tree, ensuring that each lumen of the DLT is correctly positioned in the respective mainstem bronchus. Fiberoptic bronchoscopy provides immediate feedback on the position of the tube, allowing for adjustments to be made before the start of surgery. It is highly accurate and considered the most reliable method for confirming DLT placement.

## **Why Each Wrong Option is Incorrect**
- **Option A: Clinical assessment** - While clinical assessment (e.g., observing for equal breath sounds and chest rise) can provide initial clues about tube placement, it is not reliable for confirming precise positioning of a DLT, especially in noisy operating rooms or in patients with abnormal lung function.
- **Option B: Chest X-ray** - A chest X-ray can provide information on the position of the DLT but is not practical for immediate confirmation during the procedure. It also does not provide direct visualization of the bronchial tree.
- **Option D: Capnography** - Capnography can confirm that the tube is in the airway and that there is gas exchange occurring but does not provide specific information about the position of the DLT in relation to the bronchi.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that fiberoptic bronchoscopy is not only useful for confirming the placement of a DLT but also for troubleshooting issues related to difficult ventilation or suspected malposition of the tube during surgery. It is a versatile tool that enhances the safety and efficacy of lung surgery.

## **Correct Answer: C. Fiberoptic bronchoscopy**