This article focuses on the life-threatening problem of trapped air between the chest wall and the lung, otherwise known as a tension pneumothorax. A tension pneumothrax is believed to cause about one third of combat deaths from penetrating injuries to the chest. These deaths can be reduced or prevented with immediate recognition and treatment. After a victim has suffered a penetrating injury to the chest, a progressive build-up of air can occur. This is usually secondary to an injury such as a gunshot wound or stab wound. The air escapes from the torn or lacerated lung and moves into the area between the chest wall and the lung called the pleural space. A major problem begins when the air cannot return to the lung and with each breath more and more air accumulates in the pleural space.
Essentially what has happened is the creation of a one-way-valve effect. Progressive build-up of air pressure in the pleural space pushes the heart and the major blood vessels exiting and entering the heart to the opposite side of the chest and obstructs venous blood returning to the heart. This leads to circulatory collapse and eventually death if not treated STAT.
If your victim has suffered a penetrating injury to the chest, immediately look for the signs of a tension pneumothorax.
• Deviation of the trachea away from the side of the injury (rare, last to present)
• Decreased breath sounds
• Distended neck veins
Unfortunately these classic signs are often absent and more commonly the victim has only a fast heart rate and is having trouble breathing. It is extremely difficult if not impossible to appreciate decreased breath and percussion sounds in a loud tactical or combat situation. A chest x-ray is diagnostic but you are out of luck on this one because all you have is your brain and a needle to save this victim’s life.
So what happens if the victim has penetrating injuries to both sides of the chest? The victim may have bilateral tension pneumothorax. The trachea will be found central, while percussion and breath sounds are equal on both sides. These victims are usually found in traumatic arrest. Emergency bilateral chest needle decompression should be done immediately by a trained medical provider.
A simple procedure called needle thoracentesis is used to diagnose and treat a tension pneumothorax. The management of tension pneumothorax is emergent chest decompression with needle thoracostomy. A 14-gauge Angiocath-type (catheter over needle) needle is preferred.