Editing Pneumothorax (section)

===Tension pneumothorax===
Tension pneumothorax is generally considered to be present when a pneumothorax (primary spontaneous, secondary spontaneous, or traumatic) leads to significant impairment of [[Respiration (physiology)|respiration]] and/or [[perfusion|blood circulation]].<ref name="Leigh-Smith">{{cite journal | vauthors = Leigh-Smith S, Harris T | title = Tension pneumothorax--time for a re-think? | journal = Emergency Medicine Journal | volume = 22 | issue = 1 | pages = 8–16 | date = January 2005 | pmid = 15611534 | pmc = 1726546 | doi = 10.1136/emj.2003.010421 }}</ref> This causes a type of circulatory shock, called [[obstructive shock]]. Tension pneumothorax tends to occur in clinical situations such as ventilation, resuscitation, trauma, or in people with lung disease.<ref name=BTS /> It is a [[medical emergency]] and may require immediate treatment without further investigations (see [[#Treatment|Treatment section]]).<ref name=BTS/><ref name=Leigh-Smith/>

The most common findings in people with tension pneumothorax are chest pain and respiratory distress, often with an increased [[heart rate]] ([[tachycardia]]) and rapid breathing ([[tachypnea]]) in the initial stages. Other findings may include quieter breath sounds on one side of the chest, low [[Oxygenation (medical)|oxygen levels]] and [[blood pressure]], and displacement of the [[human trachea|trachea]] away from the affected side. Rarely, there may be [[cyanosis]], [[altered level of consciousness]], a hyperresonant percussion note on examination of the affected side with reduced expansion and decreased movement, pain in the [[epigastrium]] (upper abdomen), displacement of the [[apex beat]] (heart impulse), and resonant sound when tapping the [[sternum]].<ref name=Leigh-Smith/>

Tension pneumothorax may also occur in someone who is receiving mechanical ventilation, in which case it may be difficult to spot as the person is typically receiving [[sedation]]; it is often noted because of a sudden deterioration in condition.<ref name=Leigh-Smith/> Recent studies have shown that the development of tension features may not always be as rapid as previously thought. Deviation of the trachea to one side and the presence of raised [[jugular venous pressure]] (distended neck veins) are not reliable as clinical signs.<ref name=Leigh-Smith/>