Tension pneumothorax during positive pressure ventilation — FFICM MCQ

Correct answer: D — Immediate left-sided pleural decompression

The correct answer is D, immediate left-sided pleural decompression. The combination of sudden hypotension, severe hypoxaemia, abruptly rising peak airway pressure, unilateral hyperresonance with reduced air entry, contralateral tracheal deviation, and falling end-tidal CO2 in a ventilated trauma patient is the classic clinical picture of tension pneumothorax. Positive pressure ventilation drives air into the pleural space on every inspiration with no escape, rapidly converting a simple pneumothorax into a tension pneumothorax that obstructs venous return and collapses cardiac output. This is a clinical diagnosis and treatment must not be delayed for radiological confirmation; needle or finger thoracostomy decompression on the affected side is immediately life saving and takes priority over any other intervention. Why the other options are wrong: E. Request urgent CT pulmonary angiography: this delays life-saving treatment for a peri-arrest emergency and CTPA is inappropriate in an unstable ventilated patient who needs decompression, not further imaging. B. Increase PEEP to improve oxygenation: raising PEEP will worsen intrathoracic pressure and further impair venous return and cardiac output, accelerating cardiovascular collapse. A. Give a fluid bolus and observe: fluid will not correct the mechanical obstruction to venous return caused by tension physiology and merely observing wastes critical time before irreversible cardiac arrest. C. Perform diagnostic bronchoscopy: this addresses airway obstruction, not a pleural space problem, and does nothing to relieve tension pneumothorax; it also delays definitive treatment. Key point: Tension pneumothorax in a ventilated patient is a clinical diagnosis treated with immediate pleural decompression, never delayed for imaging.

Reference: NICE Guideline NG39, Major trauma: assessment and initial management (2016, updated), section on immediate life-threatening chest injuries, www.nice.org.uk/ng39