## **Core Concept**
Postoperative lung collapse, also known as atelectasis, is a common complication following surgery, particularly after thoracic or abdominal operations. It occurs due to reduced lung volume and impaired gas exchange, often resulting from shallow breathing, decreased cough reflex, and immobility. The management involves measures to improve lung expansion and secretion clearance.

## **Why the Correct Answer is Right**
The treatment of choice for postoperative lung collapse primarily involves physiotherapeutic measures and supportive care to improve lung expansion and facilitate the clearance of secretions. This includes **chest physiotherapy**, which encompasses techniques such as percussion, vibration, and suctioning to help mobilize secretions. Additionally, encouraging **deep breathing exercises** and **coughing** helps in expanding the lungs and clearing the airways. Among the given options, the one that aligns best with these principles would likely involve these therapeutic interventions.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Without the specific details of option A, it's challenging to provide a direct explanation. However, if option A suggests pharmacological treatment as the first line, it might be incorrect because initial management typically focuses on non-invasive physiotherapeutic measures.
- **Option B:** Similarly, if option B proposes a more invasive procedure as the first line of treatment, it could be considered incorrect because such interventions are usually reserved for cases that do not respond to initial management.
- **Option C:** If option C suggests a treatment that does not directly address the need for lung expansion and secretion clearance, it would be incorrect.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that early mobilization and respiratory physiotherapy are crucial in preventing and managing postoperative atelectasis. Patients should be encouraged to perform deep breathing exercises and cough regularly to prevent lung collapse.

## **Correct Answer: D.**