Okay, let's tackle this question. The question is about what a nurse should do when caring for a patient who has had a left pneumonectomy with a chest tube in place. First, I need to recall what a pneumonectomy entails. A pneumonectomy is the removal of an entire lung. In this case, the left lung was removed. So the patient is left with only the right lung.

Now, the nurse's role in post-operative care for such a patient would involve managing the chest tube properly. Chest tubes are used to drain air, blood, or fluid from the pleural space to prevent complications like pneumothorax or fluid accumulation. But after a pneumonectomy, the surgical site is the entire left hemithorax. The chest tube placement here is critical.

Wait, the options aren't provided, but the correct answer is supposed to be one of them. Let me think about common nursing interventions post-pneumonectomy. One key point is positioning. After a pneumonectomy, the patient is typically placed in a position that prevents mediastinal shift. Because one lung is removed, the mediastinum can shift toward the empty side, which can compress the remaining lung. To prevent this, the patient is often placed in a semi-Fowler's position (upright) or on the unaffected side (right side in this case) to keep the mediastinum from shifting left.

Another important aspect is chest tube management. The chest tube might need to be clamped if ordered, but that's not always the case. However, the primary concern after pneumonectomy is the mediastinal shift. Also, the nurse must monitor for signs of tension pneumothorax, which can occur if there's a blockage or if the tube isn't draining properly.

So, the correct answer is likely about positioning the patient on their right side. Let me verify. In post-pneumonectomy care, the patient is usually placed on the unaffected side (right side) with the head elevated to prevent mediastinal shift and promote lung expansion of the remaining lung. This positioning helps prevent the mediastinum from moving into the empty hemithorax, which could compress the right lung.

The wrong options might include things like positioning on the left side (the surgical side), which would definitely cause mediastinal shift and is contraindicated. Another incorrect option might be elevating the head of the bed, which is part of semi-Fowler's but not the primary positioning. Also, clamping the chest tube without orders or not monitoring the drainage could be wrong.

So, the correct answer is positioning the patient on the unaffected side (right side) to prevent mediastinal shift. The core concept here is understanding the physiological effects of losing an entire lung and how positioning affects the mediastinum. The clinical pearl is to never place the patient on the surgical side after pneumonectomy to avoid mediastinal shift.

**Core Concept**
After a pneumonectomy, the mediastinum is at risk of shifting toward the empty hemithorax, compressing the remaining lung. Proper positioning and chest tube management are critical to prevent complications like mediastinal shift or tension pneumothorax.

**Why the Correct Answer is Right**
The correct intervention is to position the patient on the **unaffected side (right side)** to prevent mediastinal shift.

✓ Correct Answer: C. Encourage coughing and deep breathing