Definition of Tension pneumothorax:

A tension pneumothorax is a complete collapse of the lung. It occurs when air enters, but does not leave, the space around the lung (pleural space).

See also: Pneumothorax

Causes, incidence, and risk factors:

Any condition that leads to pneumothorax can cause a tension pneumothorax. In uncomplicated pneumothorax, air can enter and leave the pleural space easily. In tension pneumothorax, however, air enters the pleural space with each breath and gets trapped there.

As the amount of trapped air increases, pressure builds up in the chest. The lung collapses on that side and can push the important structures in the center of the chest (such as the heart, major blood vessels, and airways) toward the other side of the chest. The shift can cause the other lung to become compressed, and can affect the flow of blood returning to the heart.

This situation can lead to low blood pressure, shock, and death.