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Tension pneumothorax occurs when there is a buildup of air under pressure in the plural space and the air cannot escape. As the air outside the lung continues to increase, the affected lung continues to collapse. In addition to causing further collapse of the affected lung, the increasing pressure of the trapped air pushes on the mediastinum (the mass of material separating the two plural sacs). This movement of the mediastinum may compress the uninjured lung, major blood vessels, and the heart. You will need to perform a needle chest decompression to relieve the pressure of the tension pneumothorax.


Signs and symptoms of tension pneumothorax include the following.

a. Anxiety, agitation, and apprehension.

b. Diminished or absent breath sounds.

c. Increasing difficulty in breathing (dyspnea) with cyanosis (bluish tint of lips, inside of mouth, fingertips, and/or nail beds).

d. Rapid, shallow breathing (tachypnea).

e. Distended neck veins.

f. Abnormally low blood pressure (hypotension) evidenced by a loss of radial pulse.

g. Cool, clammy skin.

h. Decreased level of consciousness (AVPU scale).

i. Visible deterioration.

j. Loss of consciousness.

k. Tracheal deviation (a shift of the windpipe to the right or left).

NOTE: Tracheal deviation is a late sign of tension pneumothorax and will probably not be observed.

IMPORTANT NOTE: The above signs and symptoms may be difficult to assess in a combat situation. You must be alert to the possibility of tension pneumothorax whenever a casualty has a penetrating chest wound. Therefore, the sole criterion for treating a tension pneumothorax with needle decompression is a penetrating chest wound with progressive respiratory distress.


CAUTION: A needle chest decompression is performed if the casualty has torso trauma and increasing trouble breathing.

a. Gather Materials. You will need the large bore needle and catheter unit (14 gauge, 3 1/4 inches long) from your aid bag. You will also need an isopropyl alcohol pad and a strip of tape from the spool in your aid bag. If you have gloves, put them on.

b. Locate the Insertion Site. The insertion site is located in the second intercostal space (the area between the second and third ribs, counting from the top) at the mid-clavicular line (an imaginary line per pendicular to the ribs approximately in line with the casualty’s nipple) on the same side of the chest as the injury . Figure 6-5 shows the location of the second intercostal space and mid-clavicular line on the casualty’s left side. Figure 6-6 demonstrates finding the second intercostal space and mid-clavicular line on a person’s right side (person is in a sitting position).

NOTE: A simple way to find the second intercostal space is to put two fingers together and slide them up the chest wall until they bump into the bottom of the clavicle. Place the needle catheter just below your fingers and you should be in the second intercostal space. Insert the needle just above the top border of the third rib.

A more accurate way to find the correct needle insertion point is illustrated below:

Step 1
Step 1: Draw an imaginary line down the center of the sternum, and a second imaginary line down from the armpit (mid-axillary line.)


Step 2
Step 2: Bisect the first two imaginary lines, dropping a third imaginary line down from the midpoint between the first two lines. This is the midclavicular line. You will insert the needle on this line. It should be approximately the nipple line. Make sure the needle insertion point is at or lateral to the nipple line. The numbers indicate the ribs not the intercostal spaces. The intercostal spaces are named from the rib above it. Therefore, the 2nd intercostal space is above the 3rd rib, or the space between the 2nd and 3rd ribs.
Step 3: Locate the clavicle at the mid-clavicular line and count straight down the mid clavicular line two rib spaces. This is the third intercostal space, the space between the 2nd rib and the 3rd rib. Insert the needle in the 3rd intercostal space, just above the top border of the third rib. The angle of insertion should be perpendicular to the chest wall. (Note that the first rib is not palpable below the clavicle because it lies underneath the clavicle. The first rib you will feel inferior to the clavicle will be the 2nd rib.) So from the clavicle moving downward, you will feel an indention which is the 2nd intercostal space, then the 2nd rib, and then another indention the third intercostal space, where you will insert the needle.

Injection site on the casualty's right side.Injection site B & CFigure 6-6. Locating the injection site on the casualty’s right side.

c. Cleanse the Site. Clean the insertion site with an isopropyl alcohol pad or iodine pad from the combat lifesaver aid bag.

d. Insert the Needle/Catheter. Firmly insert the needle into the skin slightly above the top of the third rib into the second intercostal space at a 90-degree angle (figures 6-5B and 6-6C). Continue inserting the needle (with its catheter covering) all the way to the hub. You will feel a “pop” as the needle enters the chest cavity. A hiss of escaping air under pressure should be heard.

CAUTION: Ensure the needle is not inserted medially to the patient’s nipple or directed towards the patient’s heart.

CAUTION: Proper positioning of the needle is essential to avoid damaging blood vessels and nerves that run along the bottom of each rib. This is why you insert the needle/catheter just above the third rib rather than at the bottom of the second rib.

e. Advance the Needle/Catheter. Continue advancing the needle/catheter all the way to the hub.

f. Withdraw the Needle. Withdraw the needle while holding the catheter in place. The catheter will remain as a means for air trapped in the chest to continue to escape to the atmosphere.

NOTE: When you withdraw the needle, place it in a location that is not dangerous to you or the casualty. When you complete the task, safely dispose of the needle (sharps shuttle).

NOTE: Figure 6-7 illustrates a casualty with a catheter and airtight dressing in place.

Casuality with catheter in place Fig 6-7

g. Secure the Catheter. Use the strip of tape to secure the catheter hub to the chest wall. Do not cover the opening of the catheter hub.

h. Monitor Casualty. By allowing trapped air to escape from the plural area, the casualty’s respirations should quickly improve. Applying airtight material over the wound and having a catheter release trapped air releases the pressure on the heart and the good lung. If possible, monitor the casualty until medical care arrives or until the casualty is evacuated to the nearest medical facility. Be prepared to take measures to treat for shock.

i. Transport Casualty. If you have performed a needle decompression on a casualty with a tension pneumothorax, the casualty should be transported with his injured side down. The casualty may be transported in a sitting-up position if the casualty is conscious and finds that position more comfortable.