What You Should Know About a Collapsed Lung

Lungs don't collapse as much as get squished by high pressure.. BSIP/UIG / Getty Images

Pneumothorax means air in the chest and refers to the accumulation of air around the lung, which exerts pressure on the lung and causes it to collapse. Pneumothorax is a relatively common condition in patients with serious blunt chest trauma. It is more prevalent in patients with chronic lung disease.

Simple Pneumothorax

The basic example of pneumothorax occurs when air escapes the lung and becomes trapped between the lining of the chest wall (parietal pleura) and the sac surrounding the lungs (visceral pleura).

In healthy patients, these two pleura slide against one another when we breathe.

A simple pneumothorax occurs when air gets between the two layers of pleura and force them apart. A giant bubble of air takes over the chest wall and pushes the lung out of the way.

Tension Pneumothorax

As the pneumothorax grows, the pressure of the air in the chest can lead to the patient feeling short of breath and eventually might lead to obstructive shock from pressure on the heart and large blood vessels.

Tension pneumothorax is more likely to occur when there is an open wound in the chest allowing air to come in (see sucking chest wound below). Left untreated, a tension pneumothorax is a life threatening condition.

Spontaneous Pneumothorax

Occasionally, patients can experience a spontaneous pneumothorax, which is just like it sounds: a patient is walking along, minding her own business, and pop, the lung springs a leak.

Spontaneous pneumothoraces are usually simple, but can develop into tension if left untreated.

Signs and Symptoms

The signs and symptoms of pneumothorax are fairly consistent:

  • Shortness of breath
  • Diminished lung sounds on the affected side (air movement is restricted so sound is less obvious when the patient takes a breath)

    In patients that develop a tension pneumothorax, lung sounds can be even more diminished, possibly absent, and the patient's blood pressure begins to drop due to obstructive shock. Some textbooks suggest that structures in the middle of the chest (trachea, esophagus) can be pushed away from a severe, tension pneumothorax. In fact, this is a very rare occurrence and does not have to be present in order for the patient to be experiencing a tension pneumothorax.


    Any chest injury followed by shortness of breath should be seen by a doctor. For severe shortness of breath after an injury, call 911.

    A simple pneumothorax might very well become self-limiting if left untreated; meaning that it will only get so bad, then stop getting worse. Unfortunately, you wouldn't know that unless you simply ignored the pneumothorax and waited.

    Tension pneumothorax is a life-threatening condition that must be treated immediately. Call 911 if you suspect a tension pneumothorax or if you know there is a chest injury and suspect that it is developing into a pneumothorax.

    Paramedics will treat a tension pneumothorax by inserting a large bore needle (at least a 14 gauge IV needle with a catheter) into the space just above the third rib into the side of the chest where the lung sounds are most diminished. The needle will allow excess pressure from the tension pneumothorax to escape, decompressing the thoracic cavity and relieving the patient's shortness of breath and obstructive shock. The procedure is a needle thoracentesis.

    Sucking Chest Wound

    In cases when there is an open wound in the wall of the chest allowing air to enter the thoracic cavity other than through the proper airways, it is called a sucking chest wound. Gunshot wounds can often develop into sucking chest wounds.

    Sucking chest wounds are treated by covering them with an airtight bandage known as an occlusive dressing. They can easily lead to a pneumothorax, especially if treated with an occlusive dressing. If a patient with a sucking chest wound is treated with an occlusive dressing and becomes severely short of breath after the dressing is placed: remove it. Opening up a sucking chest wound after a tension pneumothorax develops will allow the chest cavity to decompress.


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    Lai-Fook, SJ. Mechanics of the pleural space: fundamental concepts. Lung. 1987;165(5):249-67. Review.

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