tension pneumothorax n pneumothorax resulting from a wound in the chest wall which acts as a valve that permits air to enter the pleural cavity but prevents its escape
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pneumothorax in which the pressure within the pleural space is greater than atmospheric pressure; this may occur when air enters under positive pressure, such as when caused by positive pressure ventilation, or when the tissues around the opening into the pleural cavity act as valves, allowing air to enter but not to escape. The resultant positive pressure in the cavity displaces the mediastinum to the opposite side, with consequent interference with respiration. Called also pressure p.
Tension pneumothorax with total collapse of the right lung and shift of mediastinal structures to the left. Air is forced into the pleural space during expiration and cannot escape during inspiration.
Medical dictionary. 2011.