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Merck Manual

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Open Pneumothorax

(Sucking Chest Wound)


Thomas G. Weiser

, MD, MPH, Stanford University School of Medicine

Last full review/revision Jun 2020| Content last modified Jun 2020
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An open pneumothorax occurs when air accumulates between the chest wall and the lung as the result of an open chest wound or other physical defect. The larger the opening, the greater the degree of lung collapse and difficulty of breathing.

  • Symptoms include chest pain, shortness of breath, rapid breathing, and a racing heart, sometimes followed by shock.

  • Doctors can diagnose open pneumothorax based on the person's symptoms and examination results.

  • Doctors immediately cover the wound with a three-way dressing and then insert a tube into the chest space to remove air.

When people with an unsealed opening in the chest wall inhale, the negative pressure generated by the inhalation sucks air into the space between the lung and chest wall (pleural space) from two different sources at once, the trachea (windpipe) and the opening in the chest wall. There is little airflow through small chest wall defects (or wounds), so there are few adverse effects. However, when the opening in the chest wall is about two thirds the diameter of the trachea or larger, more air passes into the pleural space through the chest wall opening than through the trachea. Larger openings can lead to complete collapse of the lung. 


The chest wound (or opening) is painful and causes breathing difficulties. The air entering the wound typically makes a characteristic sucking sound. As the pressure inside the chest increases, blood pressure can drop, sometimes dangerously low (shock), people feel weak and dizzy, and the veins of the neck may bulge.


  • A doctor's evaluation

Doctors diagnose open pneumothorax based on the person's history, symptoms, and an examination of the entire surface of the chest wall.


  • Wound dressing followed by placement of a chest tube (thoracostomy)

Doctors immediately cover the wound with a rectangular sterile dressing that is securely taped on only three sides. The dressing prevents air from entering the chest wall during inhalation but allows air to exit the lung on exhalation. Then a chest (thoracostomy) tube is inserted to continue to drain the air and allow the lung to reinflate. The wound may require later surgical repair.

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