Which of the following is a key characteristic of a tension pneumothorax?

A key characteristic of a tension pneumothorax is increased intrathoracic pressure. In this condition, air enters the pleural space and cannot escape, leading to a progressive buildup of pressure within the thoracic cavity. This elevated pressure compresses the lung on the affected side, resulting in severe respiratory distress and impaired gas exchange. It can also push the mediastinum towards the opposite side, which can compromise cardiovascular function.

The increased intrathoracic pressure is critical because it can lead to significant physiological changes, such as reduced venous return to the heart, resulting in cardiovascular instability and hypoxemia due to impaired lung function. This situation requires immediate intervention, such as needle decompression, to relieve the pressure and restore normal respiratory and circulatory mechanics.