How does a Chest Seals Work and Why We Apply Them

Chest seals are designed to pre-medically assist (stabilize) a penetrating chest wound to prevent air from entering the wound from the outside. They are a ventilated chest seal that allows air to escape from the lungs through the wound but prevents air from entering the lungs in the opposite direction. Without such a dressing, in a casualty with a large open sucking chest wound, the air is sucked in through the outside of the lung rather than through the trachea, creating conditions for lung collapse – which in turn threatens hypoxia (oxygen deprivation).
When breathing in, the diaphragm descends and the chest expands – and if the hole in the chest wall is not closed, air can be sucked in through the wound instead of the normal airway.

How to Apply a Vented Chest Seal

  1. Take chest seal out of the sealed bag.
  2. Blot the wound and surrounding area with a gauze wipe (if supplied) to ensure good adhesion.
  3. Remove the protective film and stick the dressing centered on the wound so that the ventilation channels are properly directed.
  4. Make sure the dressing seals the wound tightly.

Now, when the casualty takes a deep breath, the diaphragm and rib cage expand and air cannot enter through this pathway. Instead, it flows through the trachea into the chest, filling the lungs, and the casualty can breathe naturally.

Monitoring After Chest Seal Application

You should continue to monitor the casualty even though he is ventilated, as there is a chance that he may develop a volumetric pneumothorax.
Check his vital signs and external manifestations. Symptoms may include:
Shortness of breath,
Drop in blood pressure,
Bulging jugular veins,
Dislocation of the trachea (in advanced stages).

If a tension pneumothorax begins to develop, where air expands beyond the lung into the pleural cavity and collapses the lung, several different actions can be taken:

  • If a tension pneumothorax is suspected – temporarily remove the dressing (decompression).
  • If the wound is large – insert a gloved finger to allow air to escape.
  • If this does not help – perform needle decompression (by trained personnel only!).

Reapplying the Chest Seal

Once the air is out, replace the chest seal to maintain the one-way valve function, ensuring that air only flows through the trachea, properly inflating the lungs. If air continues to leak, the ventilation channels in the seal will allow it to escape without causing further complications.

Examining for Additional Wounds
After treating a penetrating chest wound, the rest of the chest should also be inspected.
Inspect:
The opposite side of the chest
Axillae
Back

Important: Even if only the entry wound is visible – look for the exit wound. Both need to be occluded.

The Risk of Internal Hemorrhage

Another thing to be aware of: with a penetrating wound to the torso is internal bleeding. You just don't know the path the projectile took in the chest cavity. Evaluate breathing in conjunction with: consciousness, skin color, pulse, and signs of shock.

Prioritize Evacuation

So, any time there is a penetrating chest or abdominal wound, give first pre-medical care as described in this article and make sure evacuation is a priority.