Types of hemostatic products

Hemostatics, or hemo-coagulants, antihemorrhagic, blood-twisting and blood-retaining agents are names of a fairly broad group of substances that promote hemostasis, that is, stop bleeding. In medicine, this is a large group that includes both systemic hemostatics acting on the whole body and local hemostatics – medical devices for rapid bleeding stop directly at the site of application.

In the field of tactical medicine, we usually refer to a second group: medical products that combine forms (bandages, granules, applicator, sponge) and active agents for a successful result – stopping bleeding (zeolite, smectin, chitosan, kaolin or more rarely occurring smectin, thrombin-fibrinogen of a salmon).

Hemostatics can work in three ways:

1. Absorption of water from the blood and concentration of blood components at the bleeding site: materials with this capability are called factor concentrators.

2. Activation of the blood clotting cascade: materials with this ability are called procoagulants.

3. Providing a physical barrier for blood flow by «gluing» of cellular components of the blood: materials with such ability are called mucoadhesives.

All active substances used to produce hemostatics have one result: upon contact with blood, a chain of biochemical reactions is triggered, leading to the rapid and powerful formation of a clot. Formation of the clot in close proximity to the damaged vessel closes the bleeding and stops blood loss.

Generation of hemostatics

For the first time, hemostatic agents and bandages were included in the TCCC protocol (the basic protocol for treating wounded in combat adopted by the US Army) as a recommended means of stopping bleeding in places not convenient for the application of a tourniquet in 2003. Since then they have not disappeared from the pages of the protocol, although specific names have changed along with the evolution of hemostatic agents. The term «generation of hemostatics» can often be found in articles about hemostatics.

Contrary to the periodically occurring assertions, the concept of generations is not related either to the active substance on the basis of which the hemostat is manufactured, or to the form factor, nor to the principle of action. It relates to the work of organizations in the US responsible for the approval and recommendation of medical devices for military use.

The criteria to be met by a perfect hemostatic were formulated in 2003, and later refined and supplemented:

1. Fast and effective bleeding control in a wide range of conditions and from various wounds within 2 minutes, even when used on an actively bleeding area.

2. The duration of a stable hemostasis for several hours when used on the battlefield.

3. Ready for use without prior preparation.

4. Easy to use even by non-professionals in harsh conditions.

5. Light weight, durability, shelf life of at least 2 years in storage under possible extreme environmental conditions.

6. Safe to use without risk of further tissue damage or transmission of infection; no toxic effects on either the victim or the caregiver.

7. Easy to manufacture and sterilization, low cost.

8. Ease of removal or no need to remove during further surgical work with the injured.

Despite the large choice of hemostatic agents on the market, it is believed that the emergence of a hemostatic that will meet all the above requirements is yet to come.

Zeolite-based hemostatic

Zeolites are inert volcanic aluminosilicate minerals, relatives of clay. Zeolites have physical and chemical stability, are non-toxic and can absorb a large amount of water. These qualities led to the production of the first hemostatic agents based on them.

Zeolite-based hemostatics are factor concentrators. The mechanism of their action is based on the fact that the zeolite quickly absorbs water and retains it. This results in a concentration of platelets and blood clotting factors at the point of contact between zeolite and blood. Moreover, zeolite slightly accelerates the blood clotting process by interacting with its ion-level components. Due to the fact that zeolite is biologically inert and sterile, the likelihood of allergic reactions or transmission of viral infection when used is minimal.

Hemostasis based on chitosan

Chitosan is a polymer derived from the ichthys of crustaceans. It is a complex carbohydrate that is biodegradable. The hemostatic property of сhitosan, its ability to stop bleeding, arises from direct electrostatic interaction between negatively charged cell membranes of erythrocytes, blood cells, and positively charged chitosan. Simply put, the blood particles and chitosan «glued» to each other, thus forming clot-clot, physically sealing the wound. Chitosan also has some antibacterial properties.

Despite years of experience with the use of hemostatic based chitosan by military and civilian doctors in different countries under various conditions, the issue of its safety is still considered ambiguous. First of all, this is due to the fact that there is certainly a wide practice on chitosan hemostats, which statistics give reason to affirm that chitosan is safe. But the clinical trials are much more modest. There are also questions about the clot-forming properties of chitosan if it enters the bloodstream – studies studying this aspect are few. Will chitosan-based products show safety in the long run when used, for example, on a ruptured carotid artery – a question that clinical studies do not answer. At the same time, statistics still speak in favor of chitosan.

Kaolin-based hemostatic

Kaolin is a clay consisting of mineral kaolinite. The physical and chemical properties of kaolin are such that when in contact with plasma it can lead to activation of the blood clotting process, at several levels. This makes kaolin an attractive material for the manufacture of local hemostatic.

The unique plus of kaolin hemostatic is that such hemostatics do not contain proteins of animal or human origin that can cause allergic reactions. Also, the results of studies have shown that kaolin bandages can remain in the wound long enough without causing adverse effects (in the studies, the 24-hour period was listed as safe, but also for longer periods of time the safety profile of Kaolin bandages was not bad). In addition, the bandage factor used for them facilitates simple removal of material from the wound during surgical treatment, although it is also important to remove all the substance from the wound (as opposed to chitosan, which breaks down safely in the body).

The main drawback of kaolin-based hemostatics is that kaolin is generally used as a hemostatic agent: kaolin-based hemostatics to stop bleeding should activate blood clotting. If the injured person has a problem with blood clotting (coagulopathy), then the effectiveness of Kaolin hemostatic can be greatly reduced. This is an important specificity of the application of Kaolin hemostatic, since coagulopathy accompanies up to 38% of injuries and often develops due to, for example, shock, hypothermia, severe burns and other factors, often in combat injury situations.

As a solution to the problem of wounds accompanied by coagulopathy, it is recommended to have in stacking not only hemostatic based on kaolin but also alternative options such as ceolite-based hemostatic to use them in case of kaolin ineffectiveness.

Hemostatic Forms Factors and their application

Granules or powder

The weight in grams is usually indicated on the packaging of such products, allowing us to understand the size of the wound.

Instruction:

1. Soak the area of the wound from blood
2. Blow into the wound all contents of the package
3. Cover the wound with a cloth/bandage or straight packing, press for at least 3 minutes
4. Apply a pressing bandage to the wound

Granules or powder are well suited for superficial wounds or large area wounds, but have obvious disadvantages in the case of wounds with a narrow channel. Getting the powder to the depth of the wound can be difficult.

Bandage

Is a non-woven cloth, soaked or covered with active substance. Can be in roll or Z-fold. The length of the bandage is usually written on the package, in most manufacturers it ranges from 1 to 4 meters.

Instruction:

1. Soak the area of the wound from blood
2. Clog the wound tightly
3. Cover the wound with the same bandage or cloth, press for at least 3 minutes
4. Apply a compression bandage to the occluded wound

The most universal of form-factors. Because the bandage is inserted into the wound in the process of tamponade by hands, it is suitable for most wounds, including narrow ones that can pass through the finger with the bandage. The main limitation in use – for the correct application it is desirable to own the technique of tamponade. Z-Wrap for tamponades is considered to be more convenient than a roll. Z-bandages are now part of the main recommendations of the TCCC protocol.

The TCCC protocol drafters make a clear choice in favor of Z-compound bandages. However, all the form factor variants are capable of saving lives when used correctly.