A chest seal is an occlusive dressing designed to manage penetrating chest trauma, commonly referred to as a sucking chest wound. Its purpose is to create an airtight barrier over the wound, preventing atmospheric air from being drawn into the chest cavity. If air enters the space between the chest wall and the lung, it can lead to a pneumothorax, causing the lung to collapse partially or completely. Applying a chest seal is a time-sensitive intervention intended to stabilize the injury and prevent a more severe, life-threatening complication known as tension pneumothorax.
Recognizing Tension Pneumothorax
The need to “burp” a chest seal is indicated by tension pneumothorax, a condition where air accumulates under pressure inside the chest cavity, compressing the lung and shifting central vital structures. This pressure buildup severely impairs the heart’s ability to fill with blood and the uninjured lung’s ability to function. Recognizing the signs of this deterioration immediately after applying a chest seal is paramount.
The first sign is a rapid worsening of breathing difficulty, often accompanied by an increased respiratory rate (tachypnea) and severe shortness of breath. This respiratory distress is quickly followed by circulatory compromise due to pressure on the heart and major blood vessels. The heart rate will accelerate (tachycardia) as the body attempts to compensate for reduced blood return, manifesting as a rapid, weak pulse.
As tension increases, signs of obstructive shock appear, including a drop in blood pressure (hypotension) and decreased level of consciousness. A physical examination may reveal distended neck veins (jugular venous distention), though this sign can be unreliable if the person is also experiencing significant blood loss. A later sign is the deviation of the trachea away from the injured side, signaling a massive pressure buildup. Any of these signs after chest seal application requires immediate intervention to relieve the trapped air.
The Manual Burping Procedure
The manual burping procedure relieves dangerous pressure buildup when tension pneumothorax is suspected after chest seal application. This action involves temporarily breaking the airtight seal to allow pressurized air to escape from the chest cavity. The first step is positioning the person to maximize pressure relief, often meaning placing a conscious individual sitting up to aid breathing.
If the person is unconscious, they should be placed in the recovery position with the injured side facing downward, which may help drainage and slight decompression. Locate the applied chest seal and select an easily accessible corner or edge. Gently lift this corner of the occlusive dressing just enough to break the seal, allowing the trapped air to rush out.
A distinct rush of air or a hissing sound should be heard as the positive pressure inside the pleural space is released. Hold the corner open for a few seconds to ensure adequate decompression. Immediately after the sound of escaping air stops, the corner must be pressed back down firmly onto the skin to re-establish the airtight barrier, preventing air from being sucked back in.
Following the burp, the casualty’s condition must be immediately reassessed to confirm that the intervention was effective. Look for a decrease in the respiratory rate, an improvement in the quality of breathing, and a stabilization of the heart rate and blood pressure. If the signs of tension pneumothorax rapidly return, the burping procedure must be repeated as often as necessary until the person can receive definitive medical care.
Vented Versus Non-Vented Chest Seals
The necessity of manually burping a chest seal is directly related to the type of dressing used on the open wound. Chest seals are categorized into two primary types: non-vented (occlusive) and vented. Non-vented seals are simple, airtight barriers that completely seal the wound, preventing both the entry and exit of air.
If air continues to leak from the injured lung tissue into the chest cavity, a non-vented seal will trap the air, leading to tension pneumothorax and requiring manual burping. These seals are often simpler, less expensive, and can be improvised from materials like plastic and tape.
Vented chest seals are manufactured with a built-in one-way valve or multiple channels. This design allows air and fluid to escape from the chest cavity during exhalation while preventing outside air from entering during inhalation. The mechanical venting mechanism is intended to automatically relieve pressure, significantly reducing the likelihood that manual burping will be needed.
However, even a vented seal can fail if the valve becomes clogged with blood or debris, or if the person lies directly on the vent. Should signs of tension pneumothorax develop, the response remains the same: lift an edge of the seal to manually decompress the chest. This action ensures pressure is relieved immediately, regardless of equipment malfunction or obstruction.