A 32-year-old man presents to the emergency department following a motor vehicle collision with severe left-sided chest trauma. On examination, he has tachycardia (HR 118/min), hypotension (BP 92/58 mmHg), absent breath sounds on the left, and severe respiratory distress. Bedside assessment suggests a large left-sided pneumothorax with haemodynamic compromise. Which investigation is the most appropriate next step?

Explanation

## Clinical Context This patient has a **tension pneumothorax** — a life-threatening emergency characterized by haemodynamic instability (hypotension, tachycardia), severe respiratory distress, and absent breath sounds. Tension pneumothorax is a **clinical diagnosis** and does NOT require imaging confirmation before intervention. ## Key Point: **Tension pneumothorax is a clinical diagnosis. Do NOT delay treatment for imaging.** Immediate needle decompression (14–16 G needle in the 2nd intercostal space, midclavicular line) followed by chest tube insertion is the standard of care. ## Why Imaging is Contraindicated Here - Portable chest X-ray (supine) takes time and delays life-saving intervention. - CT chest is absolutely contraindicated — the patient is haemodynamically unstable and requires immediate decompression. - Ultrasound, while useful for pneumothorax detection in stable patients, should not delay needle decompression in a haemodynamically compromised patient. ## High-Yield: In **ATLS protocol**, tension pneumothorax management follows the sequence: 1. **Clinical suspicion** (hypotension + respiratory distress + absent breath sounds) 2. **Immediate needle decompression** (do not wait for imaging) 3. **Chest tube insertion** (definitive management) 4. **Imaging** (CXR after stabilization, if needed) ## Clinical Pearl: The classic teaching is: "If you think it's a tension pneumothorax, treat it. If you wait for imaging, the patient may die." This is one of the few conditions in trauma where imaging confirmation is NOT required before intervention.