Chest seals are used in emergency settings to treat penetrating injuries to the torso. These adhesive bandages are known as occlusive dressings because they are designed to create an airtight barrier over the wound. Their primary purpose is to stabilize a patient who has suffered a “sucking chest wound” until they can receive definitive medical care. The ability of a chest seal to manage air pressure within the chest cavity makes it a life-saving tool in pre-hospital and field trauma care.
Understanding Penetrating Chest Trauma
A penetrating chest injury disrupts the closed system of the chest, leading to a condition called an open pneumothorax. Normally, the space between the lung and the chest wall maintains a negative pressure that keeps the lung expanded. A breach in the chest wall allows atmospheric air to rush into this space, which rapidly equalizes the pressure.
This influx of air causes the lung on the injured side to collapse, a result known as a pneumothorax. Because the opening allows air to be drawn in with every breath, the injury is often referred to as a “sucking chest wound.” If the external opening is roughly two-thirds the diameter of the windpipe or larger, more air enters the chest through the wound than through the airway, leading to rapid lung deflation and difficulty breathing. This severe imbalance in pressure compromises the patient’s ability to oxygenate their blood and can quickly become life-threatening.
How Chest Seals Function to Save Lives
The application of a chest seal works by restoring the integrity of the chest wall’s closed system. The seal’s adhesive material creates an airtight barrier over the wound, preventing any further air from entering the pleural space. By stopping external air entry, the seal allows the natural negative pressure gradient necessary for lung expansion to be re-established. This allows the unaffected lung to continue functioning and stabilizes the patient’s breathing until advanced medical help arrives.
A significant complication that chest seals must address is the risk of a tension pneumothorax, where air trapped inside the chest cavity cannot escape. The trapped air builds pressure, which can push the heart and major blood vessels to the opposite side of the chest, a phenomenon called mediastinal shift. This shift compresses the unaffected lung and kinks blood vessels, severely reducing the heart’s ability to pump blood and causing a rapid drop in blood pressure. Specialized vented chest seals mitigate this risk by incorporating a one-way valve or multiple channels. This valve allows air that may be leaking from the injured lung to escape from the chest cavity but snaps shut to prevent outside air from being sucked back in.
Varieties of Chest Seals and Proper Placement
Chest seals are categorized into two types: non-vented and vented seals. Non-vented seals are simple occlusive dressings that create a complete barrier over the wound. While they successfully block air from entering, they require careful monitoring, and a corner may need to be temporarily lifted to release any accumulating internal pressure, a process sometimes called “burping” the seal.
Vented seals are the preferred option in most emergency protocols because their integrated one-way mechanism automatically manages internal pressure, reducing the chance of a tension pneumothorax. The application process for both types begins with identifying and exposing the wound, which includes removing clothing and wiping away any blood or debris to ensure the adhesive can stick firmly to the skin. The seal is then centered directly over the injury, and firmly pressed down, paying attention to the edges to create a complete, airtight seal. If a penetrating injury has both an entry and an exit wound, a separate chest seal must be applied to each opening. After placement, the patient must be continually monitored for any signs of worsening breathing, which could indicate a developing tension pneumothorax or a failing seal.