Weirdest Question: The Science to Debunk the Theory

In our last Newsletter, you heard from the War-Fighter on his real world experience wound packing on the field of battle, and why tampons are not effective.

In this Newsletter, Dr. Rick Hammesfahr is back with the science behind why tampons are ineffective, and what materials you can use to properly pack a wound. 

Tampons Are Not the Solution

To understand why a tampon is not the best answer for packing a GSW, it is necessary to understand ballistics, blood loss, and absorption.


When a bullet hits the body, it creates a damage channel that is slightly larger then the diameter of the bullet.  This is called the primary cavitation channel.  As the bullet goes through the body, it may hit blood vessels (arteries, veins, and capillaries), bones, and internal organs.

There is something called the secondary (or temporary) cavitation channel.  This is a temporary cavity that surrounds the bullet track (primary cavity) and results from the sudden energy transfer from the bullet to the surrounding tissues.  The secondary cavitation is variable in size.  The temporary cavity increases in size as the amount of energy transferred from the bullet to the tissue increases. It increases in size with shrapnel, fragmented bullets, and bone fragments. As the temporary cavity increases, the tissue affected becomes stretched, torn, crushed, and otherwise damaged.  In other words, the tissue of the temporary cavity is pulverized. This creates a large area of tissue that has lost structural strength resulting in a large cavity that becomes soft and mushy.  Needless to say, any blood vessels within the secondary cavity now begin to bleed and ooze.  When arteries are affected, the result is a high-pressure bleed with rapid blood loss, often hundreds of ccs of blood in minutes, if not seconds!

What is the best way to deal with a gunshot wound?

Remember, not only do you have to deal with the readily obvious bullet tract (primary cavity), but also the hidden secondary cavity that occurs in the body, deep to the entrance wound.

The best material to pack a wound is a hemostatic gauze such as Combat Gauze.   Combat Gauze is a 12-foot roll of gauze material that is manufactured with Kaolin.  Kaolin activates the process of blood clot formation (“clotting cascade”).  When packing a wound, it is necessary to find the major bleeding vessel at the base of the wound, apply direct pressure, and then firmly pack the Combat Gauze into all of the crevices of the wound while maintaining direct pressure on the packing material.  When done successfully, the packing completely fills the primary and secondary cavities. This effectively applies prolonged direct pressure on the bleeding vessels and tissue.  The hemostatic gauze activates the clotting process at the same time, thereby promoting the formation of the blood clots that are necessary to stop the bleeding.

While the best material for wound packing is hemostatic gauze, any type of material (shirt, towel, etc.) can be used as long as the basic principles of wound packing are followed – pack the cavity tightly, fill the cavity completely, hold pressure on the dressing for 3 minutes (if using Combat Gauze) or until the bleeding stops (if using non hemostatic gauze – clothes, towels, etc.). Obviously regular material or non-hemostatic gauze does not accelerate or activate the blood clotting process.  For that reason, prolonged direct pressure (until the bleeding stops) is necessary.

Combat Gauze is 12 feet x 3 inches in size.   While this may seem like a lot of material, when packed into a wound, it may not completely fill the primary and secondary cavities.  If this occurs, additional packing material must be packed into the wound.

Due to the amount of material required to thoroughly pack the primary and secondary cavity, smaller sizes of Combat Gauze (or any other hemostatic gauze) are ineffective.  There just is not enough material to pack the wound.  In addition, as the size of the hemostatic gauze decreases, the amount of hemostatic agent that promotes blood clotting also decreases.

In summary, wound packing works due to the direct pressure placed into the wound by the packing material, the volume of packing material, and ideally with the addition of a hemostatic agent that promotes blood clotting.

Blood loss

The average human body has 5,000-6,000 cc of blood in the body. Each heart contraction results in about 75 cc of blood being pumped.  With an average heart rate of 70 beats per minute, this means that each minute the heart pumps approximately 5,270 cc of blood throughout the body.  Obviously, any major blood vessel injury results in a lot of blood loss in a short period of time.  To put this into perspective, with a major blood vessel injury, such as a femoral artery, approximately 1,000 cc of blood may be lost in the first 30 seconds!!

Packing Material:

Let’s look at the different types of packing material.

Clothing material (clothes, towels, etc.) allow for packing the wound, absorption of blood and the application of direct pressure.

There is a type of dressing called a 4 x 4 gauze sponge. Although it may absorb some blood, it is typically used for superficial wounds that have little bleeding.  (Figure 4, C)

A roll of Kerlix (rolled gauze) is typically 12 feet long and comes in a variety of different widths from 2 inches to 6 inches.  This does not have any type of hemostatic agent and is the standard roll of gauze that may be purchased in any drug store.

Figure 1: 12 foot roll of Kerlix gauze


Figure 2: 12 feet of Kerlix gauze unrolled

Compressed gauze is typically 2 inches x 12 feet and does not contain any hemostatic agents. This is a simply a vacuum-packed roll of gauze.

Combat Gauze is similar to a roll of Kerlex gauze, but it is manufactured with Kaolin, which is placed into the gauze during the manufacturing process.  Combat Gauze is available in different sizes – 4 feet x 3 inches and 12 feet x 3 inches.  There is also a QuikClot Bleeding Control dressing that is a 4 x 4 gauze sponge that is made with Kaolin.

Figure 3:  12 feet x 3 inches of Combat Gauze (Folded)

Xstat – This is an injector that looks like a large syringe.  It contains approximately 92 small sponges.  When they are exposed to fluid, each sponge, which is approximately 1-2 cm in size, expands to approximately 4 cm in size.  When packed into a tight wound cavity, they expand, filling the cavity and creating direct pressure. However, this device requires a narrow diameter wound tract to contain the sponges and create the pressure as they expand.  In addition, direct pressure still needs to be exerted on the wound until the bleeding stops.  This device is not an “inject and forget” method of stopping the bleeding.

Figure 4: Xstat injector with 92 small cellulose sponges



Tampons – The plastic sheath insertion device is typically about the width of an index finger (1/2 inch).  When taken apart, the size of the sponge in a tampon is less then ½ the size of a 4 x 4 gauze sponge. A normal size tampon absorbs about 5 cc of blood and cellular debris (lining of the uterus).  A tampon is not designed to exert direct pressure and stop the bleeding, but merely absorb the blood and fluid that occur during the menstrual cycle.

Figure 5

  1. Standard size tampon
  2. Tampon unrolled
  3. 4 x 4 standard gauze sponge

Notice that the 4 x 4 standard gauze pad is at least 3 times the size of the unrolled tampon.

Figure 6

  1. Standard 4 x 4 gauze sponge doubled over
  2. Side view of unrolled tampon

Notice that the height of the tampon is approximately the size of the doubled thickness 4 x 4 standard gauze dressing.

Wound tracts:

If a finger can be placed into the wound tract, wound packing can be performed.  It may be difficult, and it will be painful for the victim, but this can be a lifesaving technique.

Bleeding from injuries, whether it be from an artery (high pressure) or a vein (low pressure), involves the relatively high-volume loss of blood in a pressurized system.  Menstrual bleeding involves a low volume of non-pressurized fluid that is discharged over several days and includes old blood, uterine wall lining, cellular debris, etc.  The average blood loss is 30-40 cc over 5-7 days, not several hundred ccs in a few minutes (or seconds) as with an arterial bleed.

Packing a wound with a tampon is similar to packing a wound with ½ of a 4 x 4 gauze sponge. This is completely inadequate, fails to fill the cavity, fails to exert direct pressure, and rapidly becomes impregnated with blood.  It does not work.

Despite the urban myths, tampons by themselves are inadequate for wound packing purposes.  If someone says that they do work, the real issue is whether there was ever enough bleeding that wound packing was required.  Medical professionals are well aware that wounds may often look horrible and bloody, but they may not require anything more then a simple bandage!!

When dealing with wounds, the most important point is to identify life threatening massive bleeding and stop this as quickly as possible with a proven technique (tourniquets or effective wound packing), not a technique popularized by urban myth, internet stories, and unsupported by research!


Use wound packing methods and materials that have a proven track record and the scientific research to support their use.

Want to learn more, go to and sign-up for our First Aid for Gunshot Wounds online certification course, or take a live, in-person certification course. Go to to find a course in your area.

—Dr. Rick Hammesfahr, U.S. LawShield Medical Director

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