An occlusive dressing is a specialized material EMTs and other pre-hospital providers use to create an airtight and watertight seal over certain wounds. These dressings are non-porous, meaning they do not permit the passage of air or fluids. Their primary purpose in emergency medicine is to manage specific traumatic injuries that threaten the patient’s internal environment. This intervention stabilizes the patient before transport to a higher level of care.
Defining Occlusive Dressings and Their Function
Occlusive dressings are typically made from materials like petroleum-impregnated gauze or commercial plastic seals that adhere securely to the skin. This non-porous characteristic sets them apart from conventional dressings, which are designed to be absorbent and allow air exchange. The fundamental function of an occlusive dressing is to completely block the passage of air and contaminants into or out of a wound, thereby maintaining the body’s internal pressure balance and preventing external contamination.
The choice of material often depends on availability and the specific protocol. Commercial chest seals are pre-packaged, adhesive, and sometimes include a built-in one-way valve, making them a vented option. When commercial seals are unavailable, an EMT may improvise an occlusive dressing using plastic wrappers or sterile packaging, securing it with tape to create a three-sided seal. This improvised three-sided technique functions as a flutter valve, allowing air to escape while preventing it from being drawn back in.
Primary Indication: Penetrating Chest Trauma
The most common and immediate indication for an occlusive dressing in the field is managing a penetrating wound to the chest, often called a “sucking chest wound” or open pneumothorax. A wound that penetrates the chest wall allows atmospheric air to be drawn into the pleural space. This influx of air disrupts the negative pressure required for the lung to fully expand, leading to a partial or complete lung collapse known as a pneumothorax.
Sealing this open wound is necessary to stop the continuous entry of air into the chest cavity during inhalation. The goal of the occlusive dressing is to restore the integrity of the chest wall, preventing the pneumothorax from worsening. When using a vented commercial chest seal, the one-way valve allows air already trapped in the pleural space to escape during exhalation, but the valve closes during inhalation to block outside air entry.
If an improvised three-sided seal is used, it should be secured firmly on three edges, leaving the fourth edge unsealed to act as a flutter valve. This unsealed side permits air and blood to exit the chest cavity, which helps to mitigate the risk of air pressure accumulating. The use of an occlusive dressing is considered a time-critical intervention for these injuries due to the high risk of rapid deterioration.
Application Procedure and Monitoring
Application Procedure
Once an open chest wound is identified, the EMT must ensure the wound area is clear of excessive blood or debris to allow for proper adhesion of the dressing. The ideal timing for applying the seal is as the patient fully exhales, which helps to push as much air as possible out of the chest cavity before the seal is applied. The dressing is then placed directly over the wound and secured tightly to the surrounding skin to create the necessary seal.
Monitoring and Complications
Continuous and vigilant patient monitoring after application is necessary. The provider must assess the patient’s respiratory status, including breath sounds and overall effort of breathing, for any signs of worsening distress. A dangerous complication is the development of a tension pneumothorax, where air continues to leak from an injured lung into the chest cavity, building pressure that compresses the heart and uninjured lung. If the patient’s condition rapidly deteriorates—evidenced by increasing difficulty breathing or absent breath sounds on the affected side—the seal must be immediately released or “burped.” This involves momentarily lifting one side of the dressing during the patient’s exhalation to allow the trapped air to escape, then immediately resealing it.
Secondary Applications
Occlusive dressings also have secondary applications. They are used to cover abdominal eviscerations, where internal organs protrude from the abdomen, but must be applied over a moist, sterile dressing to prevent the organs from drying out. They may also be used in some burn treatments to help retain warmth and moisture, but this is highly dependent on local protocol and the type of burn.
When Not to Use or When to Modify Treatment
Occlusive dressings should not be used in a way that creates a completely airtight seal on a patient who has a confirmed or suspected tension pneumothorax without an escape vent. Applying a non-vented seal to such a wound will trap air that is leaking from the injured lung, rapidly worsening the pressure build-up and leading to catastrophic cardiovascular collapse. The use of a vented chest seal or the three-sided technique is specifically designed to mitigate this life-threatening risk.
For simple soft tissue wounds that do not involve a body cavity, an occlusive dressing is not indicated. Standard, non-occlusive dressings are preferred for most cuts and scrapes because completely sealing these wounds can trap moisture and bacteria. This trapped environment can inadvertently increase the risk of infection by creating conditions favorable for bacterial growth. The decision to use an occlusive dressing is highly specific, reserved for injuries where sealing the wound is necessary to manage internal pressure dynamics or prevent organ desiccation.