The body has two lungs. Each lung is enclosed in a separate airtight area within the chest. These areas are under negative pressure. If an object punctures the chest wall, air may be allowed to enter the chest. If air enters into one of the formerly airtight areas, the lung within that area begins to collapse. In order for both lungs to collapse, both sides of the chest would have to be punctured. Any degree of collapse, however, interferes with the casualty’s ability to breathe and reduces the amount of oxygen available for the body to use.
The figures above show a chest and lungs, during inhalation and exhalation, with a penetrating (open) chest wound in the casualty’s right chest. Air rushes into the chest cavity as the casualty inhales, and out as he exhales. Sometimes the hole acts like a one-way valve allowing more air in than out, causing a build up of air in the space between the chest wall and the lung, leading to a collapse of the lung.
Figure 6-2 below shows a penetrating (open) chest wound in the casualty’s left chest that has caused the left lung to collapse. The lung does not collapse immediately, but does so gradually as air enters and remains in the chest cavity.
6-2. SIGNS AND SYMPTOMS OF AN OPEN CHEST WOUND
An open chest wound can be caused by the chest wall being penetrated by a bullet, knife blade, shrapnel, or other object. If you are not sure if the wound has penetrated the chest wall completely, treat the wound as though it were an open chest wound. Some of the signs and symptoms of an open chest wound are given below.
a. Sucking or hissing sounds coming from chest wound. (When a casualty with an open chest wound breathes, air goes in and out of the wound. This air sometimes causes a “sucking” sound. Because of this distinct sound, an open chest wound is often called a “sucking chest wound.”)
b. Casualty coughing up blood (hemoptysis).
c. Frothy blood coming from the chest wound. (The air going in and out of an open chest wound causes bubbles in the blood coming from the wound.)
d. Shortness of breath or difficulty in breathing.
e. Chest not rising normally when the casualty inhales. (The casualty may have several fractured ribs and the lung may be deflated.)
f. Pain in the shoulder or chest area that increases with breathing.
g. Bluish tint of lips, inside of mouth, fingertips, and/or nail beds (cyanosis). (This color change is caused by the decreased amount of oxygen in the blood.)
h. Signs of shock such as a rapid and weak heartbeat.
6-3. CHECK FOR OPEN CHEST WOUNDS
Check for both entry and exit wounds. Open the casualty’s armor and uniform to look for any penetrating wounds. Look for a pool of blood under the casualty’s back. Use your hands to feel for wounds. If there is more than one open chest wound, treat the initial wound you find first.
6-4. EXPOSE THE WOUND
Expose the area around the open chest wound by removing, cutting, or tearing the clothing covering the wound. If clothing is stuck to the wound, do not try to remove the stuck clothing as this may cause additional pain and injury. Cut or tear around the stuck clothing. Do not try to clean the wound or remove objects from the wound.
6-5. SEAL THE OPEN CHEST WOUND
Since air can pass through most dressings and bandages, you must seal the open chest wound with plastic, cellophane, or other nonporous, airtight material to prevent air from entering the chest and collapsing the lung. The wrapper from an Emergency Bandage or a field first aid dressing can be used. The following steps assume that the wrapper from an Emergency Bandage is being used. However, the same general steps can be used with any airtight material.
NOTE: If you have a commercially available chest seal in your aid bag (see figure 6-3), you may use it instead of improvised sealing materials described in this lesson. Follow the instructions on the commercial chest seal.
NOTE: Put on your gloves.
The following video demonstrates applying a commercially-available chest seal:
Below are instructions for making a chest seal when a commercial chest seal like the one in the above video is not available:
a. Prepare the Plastic Wrapper. Use your scissors or other sharp instrument to cut open one end of the plastic wrapper of an Emergency Bandage. Remove the inner packet and put it aside. Continue to cut around the edges of the plastic wrapper until a flat surface is created. This plastic wrapper will be used to make the airtight seal. You can prepare these dressings prior to the mission. The Emergency Bandage remains sterile as long as the inner package remains sealed.
NOTE: If there is both an entry wound and an exit wound, the plastic wrapper may be cut to make two seals if the wounds are not too large. The edges of the sealing material should extend at least two inches beyond the edges of the wound.
b. Have the Casualty Exhale. Tell the casualty to exhale (breathe out) and hold his breath. This forces some of the air out of the chest wound. The more air that can be forced out of the chest before the wound is sealed, the better the casualty will be able to breathe after the wound is sealed.
NOTE: The casualty can resume normal breathing after the wound is sealed.
NOTE: If the casualty is unconscious or cannot hold his breath, place the plastic wrapper over the wound after his chest falls but before it rises.
c. Apply the Sealing Material Over Wound.
(1) Place the inside surface of the plastic wrapper (the side without printing) directly over the hole in the chest to seal the wound.
(2) Check the plastic wrapper to ensure that it extends at least two inches beyond the wound edges in all directions. If the wrapper does not have a two-inch margin, it may not form an airtight seal and may even be sucked into the wound. If the wrapper is not large enough or is torn, use foil, material from a poncho, cellophane, or other airtight material to form the seal.
d. Secure the Sealing Material.
(1) Tape down all four edges of the plastic wrapper to the casualty’s chest. The airtight seal will keep air from entering the casualty’s chest through the wound. Use the tape from your aid bag.
(2) Open an Emergency Bandage pack. Place the white side of the dressing over the wound (and sealing material), wrap the tails around the casualty’s chest, and secure the Emergency Bandage over the center of the dressing.
NOTE: This step may not be necessary if the occlusive material stays in place with the tape you have applied to it and it effectively seals the wound.
CAUTION: If an object is protruding from the chest wound, do not try to remove it. Place airtight material (such as Vaseline gauze) around the object to form as airtight a seal as possible. Stabilize the object by placing a bulky dressing made from the cleanest material available around the object. Apply improvised bandages to hold the sealing material and dressings in place. Do not wrap the bandages around the protruding object.
e. Seal Other Open Chest Wounds. If there is more than one open chest wound, apply an airtight seal over the other wound and tape all four sides of the airtight material.
6-6. POSITIONING A CASUALTY WITH A DRESSED OPEN CHEST WOUND
Place a conscious casualty in the sitting position or on his side (recovery position) with his injured side next to the ground (see figure 6-4). Pressure from contact with the ground acts like a splint to the injured side and helps to reduce the pain. Place an unconscious casualty in the recovery position on his injured side.
NOTE: The casualty may be able to breathe easier when sitting up than when lying on his side. If he wishes to sit up, have him to sit with his back leaning against a tree, wall, or other support. If he becomes tired, have him lie on his injured side in the recovery position.
NOTE: Evacuate the casualty with his injured side down.