Tension pneumothorax
USMLE Step 2 CKDifficulty: easyLast updated:
A 30-year-old man is brought to the emergency department after a high-speed motorcycle collision. He is agitated and in respiratory distress. Blood pressure is 74/40 mm Hg, pulse 136/min, respirations 34/min, and oxygen saturation 84% on a nonrebreather mask. Breath sounds are absent over the left hemithorax, which is hyperresonant to percussion. The trachea is deviated to the right and the neck veins are distended.
Which of the following is the most appropriate next step?
Answer and explanation
Correct answer: C. Perform immediate needle decompression of the left chest
Hypotension, distended neck veins, absent breath sounds, hyperresonance, and tracheal deviation away from the affected side after chest trauma indicate a tension pneumothorax. This is a clinical diagnosis. The source advises that when hypotension occurs with decreased breath sounds and hyperresonance, tension pneumothorax should be presumed and treated immediately without waiting for chest radiograph confirmation. It lists immediate needle decompression as the treatment for tension pneumothorax. Decompression is followed by tube thoracostomy, which the source recommends for traumatic pneumothoraces. Delaying for imaging risks cardiovascular collapse. Pericardial tamponade also causes hypotension with distended neck veins, but it does not cause unilateral absent breath sounds, hyperresonance, or tracheal deviation.
Each option explained
- A. Obtain a portable chest x-rayIncorrect. Tension pneumothorax should be treated without waiting for radiographic confirmation.
- B. Obtain a CT scan of the chestIncorrect. Transporting an unstable patient to CT delays lifesaving decompression.
- C. Perform immediate needle decompression of the left chestCorrect. Immediate needle decompression is indicated for clinically diagnosed tension pneumothorax, followed by tube thoracostomy.
- D. Perform pericardiocentesisIncorrect. Tamponade does not explain unilateral absent breath sounds, hyperresonance, and tracheal deviation.
- E. Start a rapid infusion of 2 L of crystalloid and reassessIncorrect. Fluids will not relieve the obstructive shock; decompression is the definitive immediate measure.
Key point
Tension pneumothorax is a clinical diagnosis; perform immediate needle decompression without waiting for imaging.
From the source
“If the patient also has decreased breath sounds and hyperresonance to percussion, tension pneumothorax should be presumed and treated immediately without awaiting confirmation by chest radiograph.”