Tension Pneumothorax

A tension pneumothorax happens when a lung is punctured and air accumulates in the pleural space causing pressure on the uninjured lung. If left untreated the patient may go into shock and eventually, into full respiratory collapse.

A collapsed lung, or closed pneumothorax typically results from a traumatic impact to the chest wall. This impact, as seen above, will cause the alveoli to puncture and air to enter the pleural space. The pressure exerted by the air in the pleural space will cause the lung to collapse, leaving the patient in serious respiratory distress.

Puncture of the lung and later collapse may be caused by rib fractures, they may be spontaneous or they may be due to damage to the lung tissue itself caused by something called the ‘paper bag effect’. Very often, seconds before a traumatic event such as a car accident, patients will instinctively take a deep breath and hold it in. At the point of collision, the chest will hit the steering wheel; this will subsequently increase pressure in the thoracic cavity. As the patient is holding their breath and their glottis is closed, air will sometimes exit at the point of impact, into the pleural space, causing a closed pneumothorax.

Though, they do not typically cause a tension pneumothorax other types of lung punctures may arise from the different causes mentioned above. The pneumothorax may be open providing an opening for air to enter but to escape as well. Simple pneumothoraces may also occur, meaning that they did not develop into tension pneumothoaces. Even though the lung is collapsed to some extent, it is not bad enough to say that the patient cannot still fairly compensate for their injury. Constituting a less dire emergency.

The extent of injury will depend on a few factors such as the percentage of lung tissue that has collapsed, how effective or ineffective unassisted ventilations seem to be. Hypoxia will also be a factor in determining the severity of the patient’s condition. The patient will complain of chest pain and dyspnea. They will be tachypneic in order to compensate for their injuries. Breath sounds will be diminished or non-existent on one side. Chest rise and expansion will also be altered. When compared to the healthy lung, the injured lung will not expand as much causing paradoxical chest wall motions.

Air may accumulate in the pleural space during inspiration; if it becomes trapped it will increase pressure inside the chest cavity, which may result in a tension pneumothorax. This shift in pressure will produce many changes in the patient’s presentation that should be constantly monitored for and immediately treated. The patient will appear cyanosed due to poor perfusion and hypoxia. They will become increasingly dyspneic, tachycardic and may appear increasingly anxious as well. A mediastinal shift will also occur as the organs of the thoracic cavity are all pushed towards the opposite side of the occurring tension pneumothorax. Later, this may produce tracheal deviation as a result of the mediastinal structures being displaced. Subcutaneous emphysema may also be noticed midline in the sub-clavicular region of the injured side. Distended neck veins may also be noticeable if the patient is not hypovolemic. Signs of shock and unexplained hypotension may be the result of compression to the vena cava decreasing cardiac output. The presence of air in the pleural cavity may also be determined using hyperresonance at specific pressure points.

As soon as these symptoms are noticed, steps should be immediately taken in order to prevent increasing hypoventilation and hypoxia.

In the field treatments for a simple closed pneumothorax includes high-concentration oxygen and careful monitoring. Tension pneumothoraxes on the other hand, merit more surgical procedures as they are life-threatening. A needle thoracic decompression will be performed in order to relieve the building pressure. A large bore catheter-over-needle (10 or 14 gauge), about 8 cm or more in length will be inserted into the patient’s chest, into the second intercostal space following the midclavicular line. Moreover, the needle may also be placed in the involved side, laterally in the fourth and fifth intercostal spaces respectfully. Careful consideration is put into the exact placement of the needle. In order to avoid any underlying nerve or blood vessel, it should be placed just above the rib and not directly under it. Air will exit the injury, confirming a tension pneumothorax and producing an audible rush as pressure inside equalizes with the outside atmosphere. The needle should be withdrawn and the catheter should be secured in place. At any point during an intervention of this sort, when a patient starts breathing under 12 breaths/min or above 28 breaths/min a bag valve mask may be indicated in order to assist their ventilations.

Prompt recognition and rapid execution of treatments are necessary steps in order to prevent a traumatic cardiac arrest in a patient suffering from a tension pneumothorax. Should traumatic cardiac arrest happen, cardiopulmonary resuscitation (CPR) should be immediately started and intubation but pulseless electrical activity (PEA) will be the likely heart rhythm on the monitor making patient survival unlikely.

Chest Trauma Pneumothorax - Tension. (2004, February). Retrieved September 01, 2017, from http://www.trauma.org/archive/thoracic/CHESTtension.html

Sanders, M. J. (2015). Mosbys paramedic textbook (4th ed.). St-Louis, MI: Jones & Bartlett Learning.