ICD-11

Pneumothorax is an abnormal collection of air or gas in the pleural space that separates the lung from the chest wall, and that may interfere with normal breathing.

A tension pneumothorax is present when the intrapleural pressure is greater than atmospheric throughout expiration and often during inspiration as well. The mechanism responsible for tension pneumothorax is the disruption of the visceral or parietal pleura in such a manner that a one-way valve develops. A tension pneumothorax can occur after any type of pneumothorax; it is independent of the etiology. It can sometimes occur after a spontaneous pneumothorax but is more common after a traumatic pneumothorax, with mechanical ventilation, or during cardiopulmonary resuscitation.