A chest seal, also known as an occlusive dressing, is a specialized medical device designed to treat a penetrating injury to the chest wall. Its primary function is to seal the opening, preventing outside air from entering the chest cavity and disrupting the pressure dynamics required for lung function. This intervention is time-sensitive and can stabilize a patient with a life-threatening condition known as a sucking chest wound until professional medical care is available. Sealing the defect helps mitigate the risk of a collapsed lung, known as a pneumothorax.
Identifying the Need for a Chest Seal
A sucking chest wound occurs when penetrating trauma, such as from a gunshot or stabbing, creates an open pathway between the external atmosphere and the pleural space surrounding the lung. This injury immediately compromises the negative pressure system the body uses to draw air into the lungs during inhalation. Signs of this condition include difficulty breathing, rapid and shallow breaths, and visible trauma to the chest or upper abdomen. A characteristic sound is often heard, described as a hissing, bubbling, or sucking noise as air moves in and out of the wound. Recognizing these signs is the initial step, as an untreated open chest wound can quickly lead to respiratory failure and cause the lung on the injured side to partially or completely collapse.
Preparing the Wound and Seal
Before attempting any intervention, ensure the safety of the surrounding environment. Once the scene is secure, the injured person’s clothing must be quickly removed or cut away to fully expose the wound and the entire chest area. This exposure is important to ensure that all entry and potential exit wounds are located and addressed. The area of skin immediately surrounding the chest defect must then be cleaned and dried as thoroughly as possible. Commercial chest seals rely on a strong adhesive to create an airtight barrier, and this adhesion is significantly reduced by blood, sweat, or debris on the skin. A gauze pad or the seal’s included wipe should be used to clear the area.
Step-by-Step Application Techniques
The application process begins by removing the protective backing from the adhesive side of the chest seal. Place the seal directly over the wound, centering the defect beneath the device. The goal is to ensure the seal covers the wound with at least a two-inch border of adhesive material on all sides. This generous overlap helps to maximize the contact area and maintain a secure hold.
After placement, the entire surface of the seal must be pressed down firmly onto the chest wall for several seconds, working from the center outward toward the edges. This action removes any air bubbles and ensures a complete, airtight seal around the wound perimeter. It is important to check the patient’s back and sides for a potential exit wound, which would also need to be sealed using a second occlusive dressing. If a second injury is found, the same cleaning and application steps should be followed.
Modern trauma guidelines recommend the use of a vented chest seal, which incorporates a one-way valve mechanism. This valve allows air and fluid to escape the chest cavity during exhalation while preventing outside air from entering during inhalation. This design makes the application simpler, as the entire seal is placed directly over the wound without alteration. If a non-vented, fully occlusive seal is used, it must be applied completely and the patient monitored more intently, as the dressing has no mechanism to release trapped air.
Monitoring for Complications
Even after a chest seal is properly applied, the patient must be monitored continuously for a potentially fatal complication called tension pneumothorax. This condition occurs if air continues to leak from the injured lung into the pleural space, but the newly applied seal prevents that air from escaping. The trapped air builds pressure, which can collapse the lung and eventually push the heart and major blood vessels to the opposite side of the chest.
Signs of this pressure buildup include a noticeable worsening of breathing difficulty, a drop in blood pressure, and a rapid heart rate. Additional late-stage indicators can include distended neck veins and, in some cases, the trachea shifting away from the injured side. If these signs appear, immediate action is necessary to release the accumulating pressure.
For a vented seal, the one-way channels should be checked to ensure they are not blocked by clotted blood or debris, and gently wiped clean if necessary. If a non-vented seal was used, or if the patient’s condition does not improve after clearing a vented seal, the technique known as “burping” must be performed. This involves briefly lifting one edge of the seal to allow the trapped, pressurized air to escape, and then immediately re-adhering the seal firmly to the skin.